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jcmarchi · 3 months

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Professor Emeritus Peter Schiller, a pioneer researcher of the visual system, dies at 92

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Professor Emeritus Peter Schiller, a pioneer researcher of the visual system, dies at 92

Peter Schiller, professor emeritus in the Department of Brain and Cognitive Sciences and a member of the MIT faculty since 1964, died on Dec. 23, 2023. He was 92.

Born in Berlin to Hungarian parents in 1931, Schiller and his family returned to Budapest in 1934, where they endured World War II; in 1947 he moved to the United States with his father and stepmother. Schiller attended college at Duke University, where he was on the soccer and tennis teams and received his bachelor’s degree in 1955. He then went on to earn his PhD with Morton Weiner at Clark University, where he studied cortical involvement in visual masking. In 1962, he came to what was then the Department of Psychology at MIT for postdoctoral research. Schiller was appointed an assistant professor in 1964 and full professor in 1971. He was appointed to the Dorothy Poitras Chair for Medical Physiology in 1986 and retired in 2013.

“Peter Schiller was a towering figure in the field of visual neurophysiology,” says Mriganka Sur, the Newton Professor of Neuroscience. “He was one of the pioneers of experimental studies in nonhuman primates, and his laboratory, together with those of Emilio Bizzi and Ann Graybiel, established MIT as a leading center of research in brain mechanisms of visual and motor function.”

Recalls John Maunsell, the Albert D. Lasker Distinguished Service Professor of Neurobiology at the University of Chicago, who did postdoctoral research with Schiller, “Peter was the boldest experimentalist I’ve ever known. Once he engaged with a question, he was unintimidated by how exacting, intricate, or extensive the required experiments might be. Over the years he produced an impressive range of results that others viewed as beyond reach.”

Schiller’s former PhD student Michael Stryker, the W.F. Ganong Professor of Physiology at the University of California at San Francisco, writes, “Schiller was merciless in his criticism of weakly supported conclusions, whether by students or by major figures in the field. He demanded good data, real measurements, no matter how hard they were to make.”

Schiller’s research spanned multiple areas. As a graduate student, he designed an apparatus, the five-field tachitoscope, that rigorously controlled the timing and sequence of images shown to each eye in order to study visual masking and the generation of optical illusions. With it, Schiller demonstrated that several well-known optical illusions are generated in the cortex of the brain rather than by processes in the peripheral visual system.

Seeking postdoctoral research, he turned to his father’s friend, Hans-Lukas Teuber, who had just accepted an offer to be founding head of the Department of Psychology at MIT. Schiller learned how to make single-unit electrophysiological recordings from the brains of awake animals, which added a new dimension to his studies of the circuitry and mechanisms of cortical processing in the visual system. Among other findings, he saw that brightness masking in the visual system was caused by interactions among retinal neurons, in contrast to the cortical mechanism of illusions.

In 1964, Schiller was appointed assistant professor. Soon after, he embarked on productive collaborations with Emilio Bizzi, who had just arrived in the Department of Psychology. Schiller and Bizzi, who is now an Institute Professor Emeritus, shared an interest in the neural control of movement; they set to work on the oculomotor system and how it guides saccades, the rapid eye movements that center objects of interest in the visual field. They quantified the firing patterns of motor neurons that generate saccadic eye movements; paired with studies of the superior colliculus, the brain center that guides saccades in primates, and the frontal eye fields of the cortex, they outlined a fundamental scheme for the control of saccades, in which one system identifies targets in the visual scene and another generates eye movements to direct the gaze toward the target.

Continuing his dissection of visual circuitry, Schiller and his colleagues traced the connections that two different types of retinal cells, known as parasol cells and midget cells, send from the retina to the lateral geniculate nucleus of the thalamus. They discovered that each cell type connects to a different area, and that this physical segregation reflects a functional difference: Midget cells process color and fine texture while parasol cells carry motion and depth information. He then turned to the ON and OFF channels of the visual system — channels originating in different types of retinal neurons: some which respond to the onset of light, others that respond to the offset of light, and others that respond to both on and off. Building on earlier work by others, and inspired by recent discoveries of ways to pharmacologically isolate ON and OFF systems, Schiller and several of his students extended the previous studies to primates and developed an explanation for the evolutionary benefit of what seems at first like a paradoxical system: that the ON/OFF system allows animals to perceive both increments and decrements in contrast and brightness more rapidly, a beneficial attribute if those shifts, for instance, represent the approach of a predator.

At the same time, the Schiller lab delved further into the role of various parts of the cortex in visual processing, especially the areas known as V4 and MT, later steps in visual processing pathways. Through single-neuron recordings and by making lesions in specific areas of the brain in the animals they studied, they revealed that area V4 has a major role in the selection of visual targets that are smaller or have lower contrast compared to other stimuli in a scene, an ability that, for example, helps an animal unmask a camouflaged predator or prey. Strikingly, he showed that many variations in images that are important for perception have a delayed influence on the responses of neurons in the primary visual cortex, indicating that they are produced by feedback from higher stages of visual processing.

Schiller’s many significant contributions to vision science were recognized with his election to the National Academy of Sciences and the American Academy of Arts and Sciences in 2007, and, in his home country, he was made an honorary member of the Magyar Tudományos Akadémia, the Hungarian Academy of Sciences, in 2008.

Schiller’s legacy is also evident in his students and trainees. Schiller counted more than 50 students and postdocs who passed through his lab in its 50 years. Four of his trainees have since been elected to the National Academy of Sciences: graduate students Larry Squire and Stryker, and postdocs Maunsell and Nikos Logothetis.

His mentorship also extended to faculty colleagues, recalls Picower professor of neuroscience Earl Miller: “He generously took me under his wing when I began at MIT, offering invaluable advice that steered me in the right direction. I will forever be grateful to him. His mentorship style was not coddling. It was direct and frank, just like Peter always was. I remember early in my nascent career when I was rattled by finding myself in a scientific disagreement with a senior investigator. Peter calmed me down, in his way. He said, ‘Don’t worry, controversy is great for a career.’ But he quickly added, ‘As long as you are right; otherwise, well …’

Schiller’s creative streak did not just influence his scientific thinking; he was an accomplished guitar and piano player, and he loved building complex and abstract sculptures, many of them constructed from angular pieces of colored glass. He is survived by his three children, David, Kyle, and Sarah, and five grandchildren. His wife, Ann Howell, died in 1999.

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stemgirlchic · 2 months

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why neuroscience is cool

space & the brain are like the two final frontiers

we know just enough to know we know nothing

there are radically new theories all. the. time. and even just in my research assistant work i've been able to meet with, talk to, and work with the people making them

it's such a philosophical science

potential to do a lot of good in fighting neurological diseases

things like BCI (brain computer interface) and OI (organoid intelligence) are soooooo new and anyone's game - motivation to study hard and be successful so i can take back my field from elon musk

machine learning is going to rapidly increase neuroscience progress i promise you. we get so caught up in AI stealing jobs but yes please steal my job of manually analyzing fMRI scans please i would much prefer to work on the science PLUS computational simulations will soon >>> animal testing to make all drug testing safer and more ethical !! we love ethical AI <3

collab with...everyone under the sun - psychologists, philosophers, ethicists, physicists, molecular biologists, chemists, drug development, machine learning, traditional computing, business, history, education, literally try to name a field we don't work with

it's the brain eeeeee

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compneuropapers · 3 months

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Interesting Reviews for Week 4, 2024

Cognition from the Body-Brain Partnership: Exaptation of Memory. Buzsáki, G., & Tingley, D. (2023). Annual Review of Neuroscience, 46(1), 191–210.

Prefrontal Cortical Control of Anxiety: Recent Advances. Mack, N. R., Deng, S., Yang, S.-S., Shu, Y., & Gao, W.-J. (2023). The Neuroscientist, 29(4), 488–505.

Neural Circuits for Emotion. Malezieux, M., Klein, A. S., & Gogolla, N. (2023). Annual Review of Neuroscience, 46(1), 211–231.

Recent Insights on Glutamatergic Dysfunction in Alzheimer’s Disease and Therapeutic Implications. Pinky, P. D., Pfitzer, J. C., Senfeld, J., Hong, H., Bhattacharya, S., Suppiramaniam, V., … Reed, M. N. (2023). The Neuroscientist, 29(4), 461–471.

#neuroscience #science #research #brain science #scientific publications #cognitive science #reviews #neurobiology #cognition #psychophysics #computational neuroscience

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thebardostate · 4 months

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Is the Brain a Driver or a Steering Wheel?

This three part series summarizes what science knows, or thinks it knows, about consciousness. In Part 1 What Does Quantum Physics Imply About Consciousness? we looked at why several giants in quantum physics - Schrodinger, Heisenberg, Von Neumann and others - believed consciousness is fundamental to reality. In Part 2 Where Does Consciousness Come From? we learned the "dirty little secret" of neuroscience: it still hasn't got a clue how electrical activity in the brain results in consciousness.

In this concluding part of the series we will look at how a person can have a vivid conscious experience even when their brain is highly dysfunctional. These medically documented oddities challenge the materialist view that the brain produces consciousness.

Before proceeding, let's be clear what what is meant by "consciousness". For brevity, we'll keep things simple. One way of looking at consciousness is from the perspective of an outside observer (e.g., "conscious organisms use their senses to notice differences in their environment and act on their goals.") This outside-looking-in view is called behavioral consciousness (aka psychological consciousness). The other way of looking at it is the familiar first-person perspective of what it feels like to exist; this inside-looking-out view is called phenomenal consciousness (Barušs, 2023). This series is only discussing phenomenal consciousness.

Ready? Let’s go!

Source: Caltech Brain Imaging Center

A Hole in the Head

Epilepsy is a terrible disease in which electrical storms in the brain trigger seizures. For some people these seizures are so prolonged and frequent that drastic action is needed to save their lives. One such procedure is called a hemispherectomy, the removal or disconnection of half the brain. Above is an MRI image of a child who has undergone the procedure.

You might think that such radical surgery would profoundly alter the memory, personality, and cognitive abilities of the patient.

You would be wrong. One child who underwent the procedure at age 5 went on to attend college and graduate school, demonstrating above average intelligence and language abilities despite removal of the left hemisphere (the zone of the brain typically identified with language.) A study of 58 children from 1968 to 1996 found no significant long-term effects on memory, personality or humor, and minimal changes in cognitive function after hemispherectomy.

You might think that, at best, only a child could successfully undergo this procedure. Surely such surgery would kill an adult?

You would be wrong again. Consider the case of Ahad Israfil, an adult who suffered an accidental gunshot to the head and successfully underwent the procedure to remove his right cerebral hemisphere. Amazingly, after the five hour operation he tried to speak and went on to regain a large measure of functionality (although he did require use of a wheelchair afterwards.)

Another radical epilepsy procedure, a corpus collosotomy, leaves the hemispheres intact but severs the connections between them. For decades it was believed that these split-brain patients developed divided consciousness, but more recent research disputes this notion. Researchers found that, despite physically blocking all neuronal communication between the two hemispheres, the brain somehow still maintains a single unified consciousness. How it manages this feat remains a complete mystery. Recent research on how psychedelic drugs affect the brain hints that the brain might have methods other than biochemical agents for internal communication, although as yet we haven't an inkling as to what those might be.

So what's the smallest scrape of brain you need to live? Consider the case of a 44-year-old white collar worker, married with two children and with an IQ of 75. Two weeks after noticing some mild weakness in one leg the man went to see his doctor. The doc ordered a routine MRI scan of the man's cranium, and this is what it showed.

Source: The Lancet

What you are seeing here is a giant empty cavity where most of the patient's brain should be. Fully three quarters of his brain volume is missing, most likely due to a bout of hydrocephalus he experienced when he was six months old.

Last Words

Many unusual phenomena have been observed as life draws to an end. We're going to look at two deathbed anomalies that have neurological implications.

The first is terminal lucidity, sometimes called paradoxical lucidity. First studied in 2009, terminal lucidity refers to the spontaneous return of lucid communication in patients who were no longer thought to be medically capable of normal verbal communication due to irreversible neurological deterioration (e.g., Alzheimers, meningitis, Parkinson's, strokes.) Here are three examples:

A 78-year-old woman, left severely disabled and unable to speak by a stroke, spoke coherently for the first time in two years by asking her daughter and caregiver to take her home. She died later that evening.

A 92-year-old woman with advanced Alzheimer’s disease hadn’t recognized her family for years, but the day before her death, she had a pleasantly bright conversation with them, recalling everyone’s name. She was even aware of her own age and where she’d been living all this time.

A young man suffering from AIDS-related dementia and blinded by the disease who regained both his lucidity and apparently his eyesight as well to say farewell to his boyfriend and caregiver the day before his death.

Terminal lucidity has been reported for centuries. A historical review found 83 case reports spanning the past 250 years. It was much more commonly reported in the 19th Century (as a sign that death was near, not as a phenomenon in its own right) before the materialist bias in the medical profession caused a chilling effect during the 20th Century. Only during the past 15 years has any systematic effort been made to study this medical anomaly. As a data point on its possible prevalence a survey of 45 Canadian palliative caregivers found that 33% of them had witnessed at least one case of terminal lucidity within the past year. Other surveys found have that the rate of prevalence is higher if measured over a longer time window than one year, suggesting that, while uncommon, terminal lucidity isn't particularly rare.

Terminal lucidity is difficult to study, in part because of ethical challenges in obtaining consent from neurocompromised individuals, and in part because its recent identification as a research topic presents delineation problems. However, the promise of identifying new neurological pathways in the brains of Alzheimer's and Parkinson's patients has gotten a lot of attention. In 2018 the US National Institute on Aging (NIA) announced two funding opportunites to advance this nascent science.

Due to the newness of this topic there will continue be challenges with the data for some time to come. However, its impact on eyewitnesses is indisputably profound.

Near Death Experiences

The second deathbed anomaly we will take a look at are Near-Death Experiences (NDEs.) These are extraordinary and deeply personal psychological experiences that typically (but not always) occur during life-threatening emergencies such as cardiac arrest, falls, automobile accidents, or other traumatic events; they are also occasionally reported during general anesthesia. Much of the research in this area has focused on cardiac arrest cases because these patients are unconscious and have little to no EEG brain wave activity, making it difficult to account for how the brain could sustain the electrical activity needed to perceive and remember the NDE. This makes NDEs an important edge case for consciousness science.

NDEs are surprisingly common. A 2011 study published by the New York Academy of Sciences estimated that over 9 million people in the United States have experienced an NDE. Multiple studies have found that around 17% of cardiac arrest survivors report an NDE.

There is a remarkable consistency across NDE cases, with experiencers typically reporting one or more of the following:

The sensation of floating above their bodies watching resuscitation efforts, sometimes able to recall details of medical procedures and ER/hallway conversations they should not have been aware of;

Heightened sensations, occasionally including the ability of blind and deaf people to see and hear;

Extremely rapid mental processing;

The perception of passing through something like a tunnel;

A hyper-vivid life review, described by many experiencers as "more real than real";

Transcendent visions of an afterlife;

Encounters with deceased loved ones, sometimes including people the experiencer didn’t know were dead; and

Encounters with spiritual entities, sometimes in contradiction to their personal belief systems.

Of particular interest is a type of NDE called a veridical NDE. These are NDEs in which the experiencer describes events that occurred during the period when they had minimal or no brain activity and should not have been perceived or remembered if the brain were the source of phenomenal consciousness. These represent about 48% of all NDE accounts (Greyson 2010). Here are a few first-hand NDE reports.

A 62-year-old aircraft mechanic during a cardiac arrest (from Sabom 1982, pp. 35, 37)

A 23-year-old crash-rescue firefighter in the USAF caught by a powerful explosion from a crashed B-52 (from Greyson 2021, pg. 27-29)

An 18-year-old boy describes what it was like to nearly drown (from the IANDS website)

There are thousands more first person NDE accounts published by the International Association for Near-Death Studies and at the NDE Research Foundation. The reason so many NDE accounts exist is because the experience is so profound that survivors often feel compelled to write as a coping method. Multiple studies have found that NDEs are more often than not life-changing events.

A full discussion of NDEs is beyond the scope of this post. For a good general introduction, I highly recommend After: What Near-Death Experiences Reveal about Life and Beyond by Bruce Greyson, MD (2021).

The Materialist Response

Materialists have offered up a number of psychological and physiological models for NDEs, but none of them fits all the data. These include:

People's overactive imaginations. Sabom (1982) was a skeptical cardiologist who set out to prove this hypothesis by asking cardiac arrest survivors who did not experience NDEs to imagine how the resuscitation process worked, then comparing those accounts with the veridical NDE accounts. He found that the veridical NDE accounts were highly accurate (0% errors), whereas 87% of the imagined resuscitation procedures contained at least one major error. Sabom became convinced that NDEs are real. His findings were replicated by Holden and Joesten (1990) and Sartori (2008) who reviewed veridical NDE accounts in hospital settings (n = 93) and found them to be 92% completely accurate, 6% partially accurate, and 1% completely inaccurate.

NDEs are just hallucinations or seizures. The problem here is that hallucinations and seizures are phenomena with well-defined clinical features that do not match those of NDEs. Hallucinations are not accurate descriptions of verifiable events, but veridical NDEs are.

NDEs are the result of electrical activity in the dying brain. The EEGs of experiencers in cardiac arrest show that no well-defined electrical activity was occurring that could have supported the formation or retention of memories during the NDE. These people were unconscious and should not have remembered anything.

NDEs are the product of dream-like or REM activity. Problem: many NDEs occur under general anesthesia, which suppresses dreams and REM activity. So this explanation cannot be correct.

NDEs result from decreased oxygen levels in the brain. Two problems here: 1) The medical effects of oxygen deprivation are well known, and they do not match the clinical presentation of NDEs. 2) The oxygen levels of people in NDEs (e.g., during general anesthesia) has been shown to be the same or greater than people who didn’t experience NDEs.

NDEs are the side effects of medications or chemicals produced in the brain (e.g. ketamine or DMT). The problem here is that people who are given medications in hospital settings tend to report fewer NDEs, not more; and drugs like ketamine have known effects that are not observed in NDEs. The leading advocate for the ketamine model conceded after years of research that ketamine does not produce NDEs (Corraza and Schifano, 2010).

Summing Up

In coming to the end of this series, let's sum up what we discussed.

Consciousness might be wired into the physical universe at fundamental level, as an integral part of quantum mechanics. Certainly several leading figures in physics thought so - Schrodinger, Heisenberg, Von Neumann, and more recently Nobel Laureate Roger Penrose and Henry Stapp.

Materialist propaganda notwithstanding, neuroscience is no closer to identifying Neural Correlates of Consciousness (NCCs) than it was when it started. The source of consciousness remains one of the greatest mysteries in science.

Meanwhile, medical evidence continues to pile up that there is something deeply amiss with the materialist belief that consciousness is produced by the brain. In a sense, the challenge that NDEs and Terminal Lucidity pose to consciousness science is analogous to the challenge that Dark Matter poses to physics, in that they suggest that the mind-brain identity model of classic materialist psychology may need to be rethought to adequately explain these phenomena.

Ever since the Greeks, science has sought to explain nature entirely in physical terms, without invoking theism. It has been spectacularly successful - particularly in the physical sciences - but at the cost of excluding consciousness along with the gods (Nagel, 2012). What I have tried to do in this series is to show that a very credible argument can be made that materialism has the arrow of causality backwards: the brain is not the driver of consciousness, it's the steering wheel.

I don't think we are yet ready to say what consciousness is. Much more research is needed. I'm not making the case for panpsychism, for instance - but I do think consciousness researchers need to throw off the assumption drag of materialism before they're going to make any real progress.

It will be up to you, the scientists of tomorrow, to make those discoveries. That's why I'm posting this to Tumblr rather than an academic journal; young people need to hear what's being discovered, and the opportunities that these discoveries represent for up and coming scientists.

Never has Planck's Principle been more apt: science advances one funeral at a time.

Good luck.

For Further Reading

Barušs, Imants & Mossbridge, Julia (2017). Transcendent Mind: Rethinking the Science of Consciousness. American Psychological Association, Washington DC.

Barušs, Imants (2023). Death as an Altered State of Consciousness: A Scientific Approach. American Psychological Association, Washington DC.

Batthyány, Alexander (2023). Threshold: Terminal Lucidity and the Border of Life and Death. St. Martin's Essentials, New York.

Becker, Carl B. (1993). Paranormal Experience and Survival of Death. State University of New York Press, Albany NY.

Greyson, Bruce (2021). After: A Doctor Explores What Near-Death Experiences Reveal about Life and Beyond. St. Martin's Essentials, New York.

Kelly, Edward F.; Kelly, Emily Williams; Crabtree, Adam; Gauld, Alan; Grosso, Michael; & Greyson, Bruce (2007). Irreducible Mind: Toward a Psychology for the 21st Century. Rowman & Littlefield, New York.

Moody, Raymond (1975). Life After Life. Bantam/Mockingbird, Covington GA.

Moreira-Almeida, Alexander; de Abreu Costa, Marianna; & Coelho, Humberto S. (2022). Science of Life After Death. Springer Briefs in Psychology, Cham Switzerland.

Penfield, Wilder (1975). Mystery of the Mind: A Critical Study of Consciousness and the Human Brain. Princeton Legacy Library, Princeton NJ.

Sabom, Michael (1982). Recollections of Death: A Medical Investigation. Harper and Row Publishers, New York.

van Lommel, Pim (2010). Consciousness Beyond Life: The Science of the Near-Death Experience. HarperCollins, New York.

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volgacankaya · 6 months

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“Forgetting: The Benefits of Not Remembering” with Dr. Scott Small

People aspire to have a better memory and to retain information effectively. However, there are instances when memory fails them. Not too long ago, both individuals and memory scientists believed that forgetfulness served no discernible purpose. Yet, recent research across diverse fields such as medicine, psychology, computer science, and neuroscience has revealed a different perspective.

It turns out that forgetting is not a flaw of the mind; rather, it serves a vital role. In fact, it contributes positively to people's lives by fostering creativity and benefiting their overall well-being. Forgetting clears the clutter from the mind, enabling better decision-making.

Forgetting appears to be an independent cognitive function, distinct from the processes governing memory retention.

As Schacter explains, the act of remembering and retrieving memories is a practical process, albeit not without its flaws. The memory system possesses inherent imperfections that people encounter daily. In his book, 'The Seven Sins of Memory,' Schacter identifies seven common memory failures: transience, absentmindedness, blocking, misattribution, suggestibility, bias, and persistence. He argues that these 'sins' should not be viewed as flaws in the memory system; instead, they are intrinsic features of memory.

Schacter further asserts that memory serves the needs of the present, and that current knowledge, beliefs, and emotions influence the recollection of the past. This function is orchestrated by the Default Brain Network, an intriguing system responsible for both remembering the past and imagining the future. It's a remarkable case of a single network managing two distinct processes.

The ability to forget plays a pivotal role in helping people prioritize, think more effectively, make decisions, and enhance their creativity. In the delicate balance between remembering and forgetting, mental flexibility emerges, allowing individuals to extract abstract concepts from their stored knowledge, ultimately enabling them to see the bigger picture.

Forgetting, far from being a hindrance, is a natural and beneficial aspect of human cognition.

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informationatlas · 4 months

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So long, and thanks for all the fish

Dolphins are known for their high level of intelligence among non-human animals. While brain size is one factor often considered in discussions of intelligence, it's important to note that intelligence is a complex trait influenced by various factors.

Dolphins, particularly species like bottlenose dolphins, have large and highly developed brains relative to their body size. The encephalization quotient (EQ), which measures brain size relative to body size, is often used to compare the intelligence of different species. Dolphins have relatively high EQs, indicating that their brains are larger than expected for an animal of their size.

Dolphins are renowned for their intricate communication skills, employing a diverse range of vocalizations, body language, and distinctive whistles. Their communication is not only used for basic interaction but also for conveying complex information within their social groups. The ability to convey and understand various messages suggests a high level of cognitive sophistication.

Research has confirmed that dolphins engage in cooperative problem-solving. They often work together to achieve common goals, such as hunting for prey or navigating challenging environments. Dolphins have been observed using coordinated tactics to corral fish into tight groups, making it easier for them to capture their prey. This collaborative approach to problem-solving reflects a high level of social intelligence and effective communication within dolphin pods.

Dolphins are known for their ability to teach and learn from one another. This includes the transmission of behaviors and skills within the group, a phenomenon known as cultural transmission. Dolphins can pass on knowledge about hunting techniques, communication signals, and other behaviors to younger or less experienced members of the pod. This cultural exchange contributes to the transmission and preservation of complex behaviors across generations.

Another indicator of advanced cognitive abilities is self-awareness, and dolphins have demonstrated this trait. Through the mirror test, where animals recognize themselves in a mirror, dolphins have displayed a level of self-awareness. This suggests a cognitive capacity for introspection and an understanding of one's own identity, a characteristic shared by a select group of intelligent species.

While not as extensively studied as in some other intelligent species, there is evidence that dolphins engage in tool use. For instance, some dolphins use sponges to protect their snouts while foraging on the ocean floor. This behavior reflects a certain level of cognitive flexibility and innovation, as dolphins adapt objects from their environment for specific purposes, showcasing a capacity for tool use.

Photo credits:

https://www.instagram.com/p/C1FmXM-v-W3/

©Elena Larina/Shutterstock.com

https://discoverycove.com/orlando/blog/how-do-dolphins-communicate

https://www.flickr.com/photos/fascinationwildlife/22394533689

#bottlenose dolphins #dolphin #dolphins #the hitchhiker's guide to the galaxy #science #animals #animal behavior #animal intelligence #brain #intelligence #non-human animals #cognitive abilities

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geometrymatters · 1 year

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Infants may recognize regular sound sequences during their first year of life. As we grow older, we gain the capacity to recognize increasingly complicated patterns in streams of words and musical sounds. Traditionally, cognitive scientists thought that the brain used a complex algorithm to discover connections between dissimilar concepts, resulting in a higher-level comprehension.

Christopher Lynn, Ari Kahn, and Danielle Bassett of the University of Pennsylvania are developing an altogether new model, showing that our capacity to identify patterns may be influenced in part by the brain’s drive to encode things in the simplest way possible.

The brain does more than just process incoming information, said Lynn, a physics graduate student. “It constantly tries to predict what’s coming next. If, for instance, you’re attending a lecture on a subject you know something about, you already have some grasp of the higher-order structure. That helps you connect ideas together and anticipate what you’ll hear next.”

#geometry #geometrymatters #geometriccognition #cognitivegeometry #cognition #information #knowledge #perception #study #research #science #pattern #brain #academic

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quotesfrommyreading · 11 months

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Some of the most compelling evidence of neurological damage after mild COVID-19 comes from U.K. researchers who investigated brain changes in people before and after they got the disease.

The 785 participants, between 51 and 81 years old, who had already been scanned before the start of the pandemic, were scanned on average three years apart as part of the U.K. Biobank project. Tests or medical records showed that 401 of these volunteers had become infected with SARS-CoV-2. Most had mild infections; only 15 of the 401 were hospitalized.

The results showed that four and half months after a mild COVID infection, patients had lost, on average, between 0.2 and 2 percent of brain volume and had thinner gray matter than healthy people. By comparison, older adults lose between 0.2 and 0.3 percent of their gray matter each year in the hippocampus, a region linked to memory.

In the region of the brain linked to smell, the COVID-19 patients had 0.7 percent more tissue damage compared to healthy people.

The infected participants’ performance on cognitive tests also declined more rapidly than before illness. They took 8 and 12 percent longer on the two tests that measured attention, visual screening ability, and processing speed. The patients were not significantly slower on memory recall, reaction time, or reasoning tests.

“We could in turn relate this greater mental ability decline to their greater loss of gray matter in a specific part of the brain,” says Gwenaëlle Douaud, a neuroscientist at the University of Oxford who led the U.K. study.

Overall, studies consistently show that COVID-19 patients score significantly lower in tests of attention, memory, and executive function compared to healthy people. Jacques Hugon, a neurologist at University of Paris Lariboisiere Hospital, says it isn’t clear if the brain will mend itself or whether patients will ever recover, even with cognitive rehabilitation.

“We don't know exactly what's going on in the brain,” says Hugon. Perhaps the damage COVID-19 causes in the brain will evolve into various neurodegenerative disorders. “We don't know that for sure at the moment, but it is a risk, and we need to follow [the patients] very carefully for the years to come.”

— Even mild COVID-19 can cause your brain to shrink

#sanjay mishra #even mild covid-19 can cause your brain to shrink #medicine #science #neuroscience #virology #viruses #covid 19 #pandemic #brain #cognitive rehabilitation therapy #gwenaëlle douaud #jacques hugon

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tmorganart · 1 year

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“One prediction – made by the futurist Kurzweil, the physicist Stephen Hawking and the neuroscientist Randal Koene, among others – is that, because human consciousness is supposedly like computer software, it will soon be possible to download human minds to a computer, in the circuits of which we will become immensely powerful intellectually and, quite possibly, immortal. This concept drove the plot of the dystopian movie Transcendence (2014) starring Johnny Depp as the Kurzweil-like scientist whose mind was downloaded to the internet – with disastrous results for humanity.

Fortunately, because the IP metaphor is not even slightly valid, we will never have to worry about a human mind going amok in cyberspace; alas, we will also never achieve immortality through downloading. This is not only because of the absence of consciousness software in the brain; there is a deeper problem here – let’s call it the uniqueness problem – which is both inspirational and depressing.

Because neither ‘memory banks’ nor ‘representations’ of stimuli exist in the brain, and because all that is required for us to function in the world is for the brain to change in an orderly way as a result of our experiences, there is no reason to believe that any two of us are changed the same way by the same experience. If you and I attend the same concert, the changes that occur in my brain when I listen to Beethoven’s 5th will almost certainly be completely different from the changes that occur in your brain. Those changes, whatever they are, are built on the unique neural structure that already exists, each structure having developed over a lifetime of unique experiences.”

#neuroscience #neurology #science #brain #memory #article #cognitive #thought #cognition #biology

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betta-every-day · 2 years

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06.13.2022

Had a Meet & Greet with the biology and neuroscience fellowship students. It was a nice time, but we did need to take a bunch of photos for the website (I am personally not a fan of closeups). There is also a Meet & Greet tomorrow for the brain & cognitive sciences fellowship students that I need to attend as well. Might try to get away with wearing the same outfit again...

#personal #updates #fellowship 2022 #academia #light academia #research #neuroscience #psychology #studyblr #study #brain and cognitive sciences #bcsc #psyc #neuro

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jcmarchi · 3 days

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Mapping the brain pathways of visual memorability

New Post has been published on https://thedigitalinsider.com/mapping-the-brain-pathways-of-visual-memorability/

Mapping the brain pathways of visual memorability

For nearly a decade, a team of MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) researchers have been seeking to uncover why certain images persist in a people’s minds, while many others fade. To do this, they set out to map the spatio-temporal brain dynamics involved in recognizing a visual image. And now for the first time, scientists harnessed the combined strengths of magnetoencephalography (MEG), which captures the timing of brain activity, and functional magnetic resonance imaging (fMRI), which identifies active brain regions, to precisely determine when and where the brain processes a memorable image.

Their open-access study, published this month in PLOS Biology, used 78 pairs of images matched for the same concept but differing in their memorability scores — one was highly memorable and the other was easy to forget. These images were shown to 15 subjects, with scenes of skateboarding, animals in various environments, everyday objects like cups and chairs, natural landscapes like forests and beaches, urban scenes of streets and buildings, and faces displaying different expressions. What they found was that a more distributed network of brain regions than previously thought are actively involved in the encoding and retention processes that underpin memorability.

“People tend to remember some images better than others, even when they are conceptually similar, like different scenes of a person skateboarding,” says Benjamin Lahner, an MIT PhD student in electrical engineering and computer science, CSAIL affiliate, and first author of the study. “We’ve identified a brain signature of visual memorability that emerges around 300 milliseconds after seeing an image, involving areas across the ventral occipital cortex and temporal cortex, which processes information like color perception and object recognition. This signature indicates that highly memorable images prompt stronger and more sustained brain responses, especially in regions like the early visual cortex, which we previously underestimated in memory processing.”

While highly memorable images maintain a higher and more sustained response for about half a second, the response to less memorable images quickly diminishes. This insight, Lahner elaborated, could redefine our understanding of how memories form and persist. The team envisions this research holding potential for future clinical applications, particularly in early diagnosis and treatment of memory-related disorders.

The MEG/fMRI fusion method, developed in the lab of CSAIL Senior Research Scientist Aude Oliva, adeptly captures the brain’s spatial and temporal dynamics, overcoming the traditional constraints of either spatial or temporal specificity. The fusion method had a little help from its machine-learning friend, to better examine and compare the brain’s activity when looking at various images. They created a “representational matrix,” which is like a detailed chart, showing how similar neural responses are in various brain regions. This chart helped them identify the patterns of where and when the brain processes what we see.

Picking the conceptually similar image pairs with high and low memorability scores was the crucial ingredient to unlocking these insights into memorability. Lahner explained the process of aggregating behavioral data to assign memorability scores to images, where they curated a diverse set of high- and low-memorability images with balanced representation across different visual categories.

Despite strides made, the team notes a few limitations. While this work can identify brain regions showing significant memorability effects, it cannot elucidate the regions’ function in how it is contributing to better encoding/retrieval from memory.

“Understanding the neural underpinnings of memorability opens up exciting avenues for clinical advancements, particularly in diagnosing and treating memory-related disorders early on,” says Oliva. “The specific brain signatures we’ve identified for memorability could lead to early biomarkers for Alzheimer��s disease and other dementias. This research paves the way for novel intervention strategies that are finely tuned to the individual’s neural profile, potentially transforming the therapeutic landscape for memory impairments and significantly improving patient outcomes.”

“These findings are exciting because they give us insight into what is happening in the brain between seeing something and saving it into memory,” says Wilma Bainbridge, assistant professor of psychology at the University of Chicago, who was not involved in the study. “The researchers here are picking up on a cortical signal that reflects what’s important to remember, and what can be forgotten early on.”

Lahner and Oliva, who is also the director of strategic industry engagement at the MIT Schwarzman College of Computing, MIT director of the MIT-IBM Watson AI Lab, and CSAIL principal investigator, join Western University Assistant Professor Yalda Mohsenzadeh and York University researcher Caitlin Mullin on the paper. The team acknowledges a shared instrument grant from the National Institutes of Health, and their work was funded by the Vannevar Bush Faculty Fellowship via an Office of Naval Research grant, a National Science Foundation award, Multidisciplinary University Research Initiative award via an Army Research Office grant, and the EECS MathWorks Fellowship. Their paper is published in PLOS Biology.

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academicelephant · 3 months

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H.M (the guy who underwent a surgery to get his medial temporal lobes removed in order to alleviate his severe epilepsy but ended up losing his ability to remember things that happened after the surgery) was able to count passing cars of certain color and when not distracted, could continue doing this with no problems. The reason is that his short-term memory was intact and as long as he kept the task active in his mind, he could remember it. However, when his attention got directed somewhere else, he forgot he ever counted any cars because the memory of doing so never got to his long-term memory. I think this is very interesting because it goes to show that short-term memory isn't necessarily short and in theory "[the information in] it can -- be maintained indefinitely"

Source: Postle, B.R. Essentials of Cognitive Neuroscience, 2015. p. 363

#psychology #cognitive neuroscience #science #h.m.#patient h.m.#brain #memory #short term memory

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compneuropapers · 9 months

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Interesting Papers for Week 30, 2023

Adult-born neurons inhibit developmentally-born neurons during spatial learning. Ash, A. M., Regele-Blasco, E., Seib, D. R., Chahley, E., Skelton, P. D., Luikart, B. W., & Snyder, J. S. (2023). Neurobiology of Learning and Memory, 198, 107710.

Behavioral origin of sound-evoked activity in mouse visual cortex. Bimbard, C., Sit, T. P. H., Lebedeva, A., Reddy, C. B., Harris, K. D., & Carandini, M. (2023). Nature Neuroscience, 26(2), 251–258.

Exploration patterns shape cognitive map learning. Brunec, I. K., Nantais, M. M., Sutton, J. E., Epstein, R. A., & Newcombe, N. S. (2023). Cognition, 233, 105360.

Distinct contributions of ventral CA1/amygdala co-activation to the induction and maintenance of synaptic plasticity. Chong, Y. S., Wong, L.-W., Gaunt, J., Lee, Y. J., Goh, C. S., Morris, R. G. M., … Sajikumar, S. (2023). Cerebral Cortex, 33(3), 676–690.

An intrinsic oscillator underlies visual navigation in ants. Clement, L., Schwarz, S., & Wystrach, A. (2023). Current Biology, 33(3), 411-422.e5.

Not so optimal: The evolution of mutual information in potassium voltage-gated channels. Duran-Urriago, A., & Marzen, S. (2023). PLOS ONE, 18(2), e0264424.

Successor-like representation guides the prediction of future events in human visual cortex and hippocampus. Ekman, M., Kusch, S., & de Lange, F. P. (2023). eLife, 12, e78904.

Residual dynamics resolves recurrent contributions to neural computation. Galgali, A. R., Sahani, M., & Mante, V. (2023). Nature Neuroscience, 26(2), 326–338.

Dorsal attention network activity during perceptual organization is distinct in schizophrenia and predictive of cognitive disorganization. Keane, B. P., Krekelberg, B., Mill, R. D., Silverstein, S. M., Thompson, J. L., Serody, M. R., … Cole, M. W. (2023). European Journal of Neuroscience, 57(3), 458–478.

A striatal circuit balances learned fear in the presence and absence of sensory cues. Kintscher, M., Kochubey, O., & Schneggenburger, R. (2023). eLife, 12, e75703.

Hippocampal engram networks for fear memory recruit new synapses and modify pre-existing synapses in vivo. Lee, C., Lee, B. H., Jung, H., Lee, C., Sung, Y., Kim, H., … Kaang, B.-K. (2023). Current Biology, 33(3), 507-516.e3.

Neocortical synaptic engrams for remote contextual memories. Lee, J.-H., Kim, W. Bin, Park, E. H., & Cho, J.-H. (2023). Nature Neuroscience, 26(2), 259–273.

The effect of temporal expectation on the correlations of frontal neural activity with alpha oscillation and sensory-motor latency. Lee, J. (2023). Scientific Reports, 13, 2012.

Describing movement learning using metric learning. Loriette, A., Liu, W., Bevilacqua, F., & Caramiaux, B. (2023). PLOS ONE, 18(2), e0272509.

The geometry of cortical representations of touch in rodents. Nogueira, R., Rodgers, C. C., Bruno, R. M., & Fusi, S. (2023). Nature Neuroscience, 26(2), 239–250.

Contextual and pure time coding for self and other in the hippocampus. Omer, D. B., Las, L., & Ulanovsky, N. (2023). Nature Neuroscience, 26(2), 285–294.

Reshaping the full body illusion through visuo-electro-tactile sensations. Preatoni, G., Dell’Eva, F., Valle, G., Pedrocchi, A., & Raspopovic, S. (2023). PLOS ONE, 18(2), e0280628.

Experiencing sweet taste is associated with an increase in prosocial behavior. Schaefer, M., Kühnel, A., Schweitzer, F., Rumpel, F., & Gärtner, M. (2023). Scientific Reports, 13, 1954.

Cortical encoding of rhythmic kinematic structures in biological motion. Shen, L., Lu, X., Yuan, X., Hu, R., Wang, Y., & Jiang, Y. (2023). NeuroImage, 268, 119893.

Mindful self-focus–an interaction affecting Theory of Mind? Wundrack, R., & Specht, J. (2023). PLOS ONE, 18(2), e0279544.

#science #Neuroscience #computational neuroscience #Brain science #research #cognition #neurons #cognitive science #neural networks #neural computation #neurobiology #psychophysics #scientific publications

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thebardostate · 10 months

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Where Does Consciousness Come From?

(This is Part 2 of a three part series on consciousness. Part 1 is here. Part 3 is here.

A 25 year bet was settled last week when two rival scientific explanations for consciousness - Global Workspace Theory (GWT) and Integrated Information Theory (IIT) - both failed to discover any neuronal correlates of consciousness (NCC) in the human brain. Neuroscientist Cristof Koch and philosopher David Chalmers agreed that neuroscience can't yet explain how our brains produce consciousness.

I say "yet" because it is an article of faith among the disciples of Richard Dawkins and Daniel Dennett that consciousness (if it exists at all) will eventually be shown to be a mere illusion or "epiphenomenon" generated by biochemical activity in our brains. They argue that the mind is only what the brain does, so consciousness ceases when the brain dies. They dismiss as pseudoscientific "woo" fantasy any notion that consciousness might survive the physical death of the brain.

(source: @myjetpack)

Materialist neo-Darwinism appears to enjoy broad support across the physical and biological sciences, in medicine, and from science popularizers like Neil DeGrasse Tyson and Carl Sagan. It can fairly be called the orthodox scientific view.

And yet, we see from the results of the wager that the origins of consciousness remain an open question. It is considered one of the greatest unsolved problems in science. Thus far, scientific orthodoxy has gotten us exactly...nowhere.

What is it Like to be a Bat?

Enter Thomas Nagel, a marquee name in the philosophy of mind and cognitive science. In 1974 Nagel published the widely influential essay "What is it Like to be a Bat?" in which he argued that there's a lot more to being a bat than just hanging around upside down in the dark. Bats perceive their world thru echo location. Nothing in human experience prepares us for what that must be like: bats don't "see" their homes because they're in pitch darkness, nor do they "feel" their way along in the dark because they're flying thru the air. We can speculate, but we humans don't have a clue what it feels like to be a bat. And yet, science knows a great deal about bat brains.

In his 2012 book Mind and Cosmos Nagel argues that the materialist neo-Darwinist conception of reality is almost certainly false, with far-reaching implications for evolution and quantum physics. He is incredulous at the just-so story that Dawkins, Dennett, et. al. are expecting us to swallow:

It is prima facie highly implausible that life as we know it is the result of a sequence of physical accidents together with the mechanism of natural selection. We are expected to abandon this naive response, not in favor of a fully worked out physical/chemical explanation but in favor of an alternative that is really a schema for explanation, supported by some examples. What is lacking, to my knowledge, is a credible argument that the story has a nonnegligible probability of being true.

However, Nagel is no sock puppet for religion, as some of his materialist critics have insinuated. In fact, he is an atheist:

I do not find theism any more credible than materialism as a comprehensive world view. My interest is in the territory between them. I believe that these two radically opposed conceptions cannot exhaust the possibilities.

Back to the Drawing Board

So if consciousness doesn't come from the brain, then where does it come from?

In Nagel's estimation it's high time science started looking for alternative explanations instead of continuing to double down on materialist neo-Darwinism, which by now has had ample time to put up or shut up (Karl Popper called these breezy we'll-solve-it-someday assurances "promissory materialism".) Nagel critiques the three basic approaches that materialists have pursued thus far:

Treat consciousness as a black box, and infer what might lurk inside the box by carefully observing its behavior from the outside. This is the behaviorist approach, whose sterility was so evident by the late 1960s that it sparked the cognitive revolution in psychology.

Systematically trace all mental events to physical counterparts "somewhere" in the brain. This is the approach that GWT and IIT take, using medical techniques like functional MRI to observe the brain as we carry out various activities. One of the problems with this approach is brain plasticity, the ability of the brain to rewire itself (e.g., after a stroke); plasticity makes it difficult to pin down exactly where in the brain mental events occur (to say nothing about how the brain pulls off the plasticity trick in the first place.) Another problem is that mental activities can interact and overlap, such as when we drive a car and talk on the phone at the same time. Sometimes we can multitask, and sometimes we can't. Where do those complex interactions play out in the brain? What about things produced by the brain itself but not experienced by the senses like imagination, the placebo effect and hallucinations? And finally, there is a world of difference between images from fMRI and the actual, subjective, first-person experiences we have when performing those tasks. They're just not the same. I'll have much more to say about this approach to consciousness research in Part 3 of this series.

Deny that there is any such thing as consciousness - this is eliminative materialism aka illusionism, whose most prominent proponent is Dennett. But if we buy into this, why should we stop at questioning our own consciousness? Why don't we just deny that anything exists at all, and go full-on nihilist atheist? Philosopher Galen Strawson called illusionism "the silliest claim ever made" while philosopher John Searle called it an "intellectual pathology." (Plus which, when you get down into the weeds of eliminative materialism, you find that it's just reheated behaviorism anyway.)

Nagel believes these materialist accounts are all incomplete because each in its own way fails to explain the familiar first-person experience of being alive and conscious. But even setting that aside, he points out a further problem for the neo-Darwinists.

Why Did Consciousness Evolve?

In its own way, materialist Neo-Darwinism is a "theory of everything" in so far as biology goes. As such, it must be able to explain why consciousness evolved in the first place.

It's quite plausible that natural selection could have produced organisms that adapt and reproduce without being conscious. We can imagine robot-like zombies that carry out a series of evolved instructions and reproduce without ever having experiencing first-person subjective consciousness, like little automatons. And yet, we are conscious. Why? What evolutionary purpose could first-person awareness have served?

A standard materialist explanation is that consciousness emerged as a byproduct of evolution (a "spandrel" as Steven Jay Gould called it) rather like junk DNA. If we are not satisfied with the just-so story that the mental comes as a free bonus to the physical, then we will have to look for our answers elsewhere.

Opening the Window on Consciousness

We landed in this situation because science has sought to explain nature entirely in physical terms, without invoking theism. It has been spectacularly successful - particularly in the physical sciences - but the cost has been excluding consciousness along with the gods. Eventually this exclusion was bound to be challenged. We cannot have a complete picture of the world without understanding our own consciousness that makes that picture possible. If consciousness isn't generated by the brain, the implications for evolution and quantum physics will be far-reaching. (Nagel, 2012)

In the concluding part of this series we'll take a fresh look at the medical evidence for certain so-called 'paranormal' phenomena. These have been systematically excluded from mainstream scientific consideration because, if they proved true, they would undercut materialist explanations of consciousness. What do medical anomalies like Near-Death Experiences and Terminal Lucidity imply about the nature of consciousness?

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