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13

The key point is that the brain is not a uniform structure. The outer layer, known as grey matter, is a relatively uniform and flat structure. Underneath the grey matter is white matter. An overly-simple characterization of these two areas is that grey matter performs computations, and white matter lets different areas of grey matter talk to each other. ...


8

I think Keegan provides a great set of references, but I just wanted to expand on his answer in a little bit more detail. Penrose and Hameroff's ideas are mentioned a lot on the internet and although they are often debunked, you can never do it enough. I want to discuss (1) what microtubules are and (2) are there quantum effects in them? And, more ...


8

One thing worth pointing out as a very terse hint of an answer: we all know that activation of the sympathetic nervous system is often referred to as the "fight-or-flight response," but parasympathetic nervous system (PNS) activation is less commonly known as the "rest-and-digest" response...though this does appear on Wikipedia's PNS page. Eating (or maybe ...


7

Like many topics in neuroscience, this is a controversial subject. While dopamine is very popular among the public as a mechanism for pleasure, recent research challenges that view and has started to tease apart pleasure from motivation, finding a distinction in dopamine. John Salamone's opinion: Low levels of dopamine make people and other animals ...


7

There are (at least) two ways epigenetic traits are inherited. The important background in both cases is gene expression: there is a misconception that genes are for this or that, where the reality is that most traits come from an overlap of several genes expressing themselves in different ratios. As a simple example, consider two varieties of bird of the ...


7

As you have already hinted at, the issue is controversial. I could leave it at that and say "no, there is no consensus", and it would be a true answer, but it wouldn't be satisfying, wouldn't it? Instead, I'll briefly define the topic, give a few examples, and then a few recent criticisms. My answer will be weighted somewhat towards "cognition" instead of ...


6

Research exists on craniopagus twins, maybe most notably Tatiana and Krista, who seem to share sensory input somewhat. I doubt that connective mechanisms such as this abnormal case would suffice to permit "compound cognition" in ways that would enhance cognitive ability similarly to your point about hominid evolution. Your relatively simple proposal for a ...


6

From Stevens & Galanter (1957) Although an extensive investigation of the subjective scale of brightness is still in progress in this laboratory, enough has been learned to show that, for patches of white light viewed in a dark room, subjective brightness is a power function of luminance. Moreover, the exponent is of the order of one-third ...


6

There are two kinds of neuron-to-neuron connections in the brain. The most well known is the chemical synapse, which is unidirectional. Despite this, two neurons can each synapse on each other with a chemical synapse, and both types of connection are observable in brain networks (unidirectional and bidirectional) The second kind of connection is a ...


6

Personality studies are typically investigated via the "big five" traits. Some attempts to legitimize the personality traits through biology have been pursued [1]. Following are some excerpts from a particular study that proposed a hypothesis and searched for confirmation in 116 subjects. Of course, this means we should be wary of confirmation bias when ...


6

There are anatomical features that make lobe demarcations fairly non-arbitrary. From Wikipedia: by Sebastian023 There are some borders here that may be more arbitrary than others: The border between the occipital and parietal lobe between the preoccipital notch and parieto-occipital sulcus The border between the parietal and temporal lobes between the ...


6

Have you ever seen IBM's Watson? Watson is composed of a cluster of ninety IBM Power 750 servers, each of which uses a 3.5 GHz POWER7 eight core processor, with four threads per core. In total, the system has 2,880 POWER7 processor cores and has 16 terabytes of RAM. It must be kept in a (very) large refrigerated room. Watson is a question answering (QA) ...


6

Interesting question! I performed a fairly extensive search in Google Scholar and Scopus using various keyword searches, including, but not limited to "color blindness and plasticity", "color blind and brain", "dichromates brain", and "monochromates brain". Strikingly, I found nothing. The reason is aptly explained by Solomon & Rosa, 2014 and I quote ...


6

Typically 'presynaptic' and 'postsynaptic' are used to indicate two neurons that are connected, as you indicate correctly in your second example. Information flow in the nervous system basically goes one way. If one neuron fires (presynaptic cell) it can chemically activate another cell on which it synapses, as shown in the figure. As an illustrative ...


5

This is a continuation of Penrose's Quantum Mind. It's not taken seriously by the majority of the neuroscience or quantum community. Here are some references to get you started: Tegmark, M. (2000). Importance of quantum decoherence in brain processes. Physical Review E, 61(4), 4194. Seife, C. (2000). Cold numbers unmake the quantum mind. Science, ...


5

researched with "sensory cortex latency" on google: according nowak et al, latency in macaque v1 is ~75 ms, although there are cells with latency as short as 30 ms. according to camalier at al, latency in macaque A1 is more like 15-25 ms. Also, see shriki et al for a computational perspective on latency coding in V1. There is research into the latency ...


5

Wen & Chklovskii (2005) looked at exactly this question through a simulation study. They assumed that the segregation of white and gray matter was the the result of evolutionary pressure to maximize some aspect of connectivity. They tested the idea that simultaneously maximizing interconnectivity (neurons should be able to connect to all other neurons ...


5

This is partially an aspect of the binding problem. Sensory information arrives in parallel as a variety of heterogeneous hints, (shapes, colors, motions, smells and sounds) encoded in partly modular systems. Typically many objects are present at once. The result is an urgent case of what has been labelled the binding problem. We must collect the hints, ...


5

The short answer is we don't know for sure. Look up "alexia" and "agraphia"; pinpointing the regions of the brain that, if damaged, interfere with reading might give some indication of the cortical regions involved. Visual cortex (back of the brain) is obviously necessary for the general population, but it's clearly possible for blind people to learn to ...


5

First of all, the human brain is distinctively larger than that of any other primate, mainly due to the great expansion of the cerebral cortex. The underlying structures have remained relatively stable (Toro et al., 2008). As the cortex overlies the rest of the brain, a solution had to be found, because the whole brain did not have to inflate to increase ...


5

I'm not sure the math checks out in the question (the CPU cycles per second seems awfully high), but I think there are some useful principles to keep in mind regardless of the details of the math. So let's assume that we do have a computer that can perform more operations per second than the combined sum of all action potentials in the brain per second. Is ...


4

Michelle Heijblom's (2009) master thesis on Visualising tinnitus with fMRI and EEG mentions the following: Different studies report that tinnitus is characterised by an increase in slow-wave activity (0.5- 4Hz: delta activity) and a decrease in alpha activity (8-12 Hz) at temporal regions. Recently it has been suggested that this loss of alpha ...


4

Firstly, you wouldn't be directly controlling neurotransmitter. From the human perspective, you'd be controlling higher-level events (and they aren't necessarily describable on more than a phenomenological level). Of course, this would also lead to some changes in neurotransmitter release, but in a complex way: that's all handled at a lower level by the ...


4

In adult mouse cortex, synaptic spines can last anywhere from days to months. I'm not sure that any such work has been done on human Broca's area, but keep in mind that many synapses are experience dependent. One study found that fear conditioning and fear extinction lead, respectively, to synapse formation and elimination. So the lifetime of a synapse ...


4

Sure, to some extent mind reading implies brain reading. For instance, if you were reading someone's mind by their behavior or their heart rate, it would be through their brain's effect on those organs. We largely do this through inference. Without a heart monitor or perspiration monitor, we have whole sections of brain dedicated to recognizing human ...


4

If you look at the paper Strong and Weak Emergence by David J. Chalmers he states his belief that consciousness is the only example we have of strong emergence. However, he also states that it is quite possible that there is no such thing as strong emergence, and therefore, our perception of the mind as an example of strong emergence stems from our current ...


4

It may interest you to know that depression and anxiety relate to emotional stability (essentially the opposite of neuroticism), a personality trait which tends to decrease over the lifespan, especially in young adulthood (Roberts & Mroczek, 2008). Here's a figure depicting this trend (bottom left): This article points out that most of the personality ...



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