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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

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 following figure 1. As an ...


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 ...


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

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 ...


7

Short answer Yes, there is a difference between hearing and understanding sound. Background Acoustic information is processed in different neural centers along the auditory pathway. The auditory system runs from the peripheral end organ in the inner ear (the cochlea) to the cortex. Along the way various processing steps are carried out. For ...


6

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 ...


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

From my undergraduate biology degree, I am only familiar with the second use of the terms which you describe. That is, the terms pre-synaptic and post-synaptic describe a spatial relationship to the synapse, which has directionality, as you know. If the terms are used to describe whole cells, as Chris Stronks covers, and as people often do when describing a ...


6

Visual acuity is highest in the foveal region, namely around 1/60 of a degree, or 1 minute of arc (1 MAR). At about 30 degrees of eccentricity, visual acuity is reduced to anywhere between 1.5 and 10 MAR when determined by a shape recognition task, as shown in Fig. 1 taken from Lie, 1980: A later study (Anderson et al., 1991) shows the following picture: ...


6

They are ordered based on when they were discovered/named (as pointed about by Ana's comment). Alpha and beta waves were among the first signals observed in EEG data. From Wikipedia: Alpha waves were discovered by German neurologist Hans Berger, most famous for his invention of the EEG. Alpha waves were among the first waves documented by Berger, along ...


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

I think the major reason is inertia, in the sense that many labs use Matlab, so many Matlab toolboxes are available, so many labs train people in the use of Matlab... However, as a trained software engineer turned Neuroscientist who has been programming in various languages for close to 30 years, there are several reasons why I actually enjoy using Matlab. ...


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

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

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 ...


5

It is well documented that people are able to selectively attend to different speakers. The ability to tune-in to a particular speaker and filter out others was dubbed the cocktail party effect, since it is the kind of skill that is required in when trying to have a conversation with another person in a crowded party. A common way of studying this ...


4

Complexity. That is, the fundamental laws governing the behavior isn't terribly difficult to comprehend or model. However, putting it all together and hoping it reproduces the correct behavior is a great challenge. Once you develop a model that has the appropriate underlying mechanisms in it's components, you still have to put them all together and ...


4

Generally, EEG potentials are primarily averaged over trials, not electrodes. Averaging over electrodes is often done in addition to trial averaging, but this by itself does not make the potentials visible on a single-trial basis since the "noise" overshadowing the potentials is largely shared by all adjacent electrodes. The Bereitschaftspotential is also ...


4

I completely agree with most the factors you've identified, but before I suggest some additional points, I'd like to correct one of yours: file formats that can only be read in MATLAB Unless you're talking about some obscure format that I'm unaware of (entirely possible!), MATLAB files are readable by non-MATLAB tools. In particular, scipy.io provides ...


4

It is highly variable, depending on the strength and placement of the synapse (which in turn depends on synapse activity and how often the two neurons fire together, among other things). The wikipedia page here is a pretty good place to start, or if you want more detail on how that pulls together in an actual system, this paper is a good place to start.


4

Building off of Nick Stauner's answer, the lobes are named after the cranial bones that cover them. You can see the overlap by looking at the bones of the skull (image from Wikipedia). I'm speculating now, but my guess would be that an anatomist simply picked sulci (the "valleys" in the folds of the cortical surface) that were close to the bone boundaries ...


4

I will just show the statistics of last attempt to mimic the brain process. Last year Japan launched there fastest supercomputer: K computer OR SPARC64 VIIIfx 2.0GHz Features: Manufacturer: Fujitsu Cores: 705,024 Linpack Performance (Rmax) 10,510 TFlop/s Theoretical Peak (Rpeak) 11,280.4 TFlop/s Power: 12,659.89 kW Memory: 1,410,048 GB ...


4

You've received a few great comments from our neuroscience-savvy users that indicate ways in which this question can be construed as particularly challenging or maybe even unanswerable. However, I think there's a much more basic and limited understanding of your question that takes into account your self-professed unfamiliarity with neuropharmacology and ...


4

Point by point: The Melon headband has three electrodes. Our primary electrode is on the forehead region known as FP1, where Melon can monitor brainwave activity from the prefrontal cortex. The problem with this is that electricity doesn't work like that. Current always flows between two points, and our electrodes measure the potential between two ...


4

I think you should reverse your approach. Rather than trying to find every prerequisite, start reading sections of PNS and as you encounter something you don't understand, look up the background information. It's an exhaustive work (and well worth reading!) but you're going to find different sections require different levels of background. For example, ...


4

The question that you are referring to is worded in a way that I think is leading to the confusion. The question in the title is "Can the mind affect the brain?" but in the question body the final question posed is "Does [a thought producing a tear] not contradict the (physical) law of cause and effect?". The answer is yes to the title question: the mind ...



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