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7

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 ...


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

Donald Hebb originally formulated what would later come to be known as spike-time dependent plasticity by famously stating "neurons that fire together wire together". In actuality, the firing has to be sequential (not simultaneous) and causal: if a neuron A fires and causes B to consequently fire, the synaptic strength between them increases. This is how the ...


7

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

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. ...


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

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

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) ...


5

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 ...


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 first question is, what is normal human sexual behavior. The answer to this changes over time. For example, a hundred years ago masturbation was thought to cause physical degeneration and be a sin, today it is perceived as healthy, even recommended. Research shows that adolescent girls who masturbate have more and stronger orgasms as adults. So, if anal ...


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

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, ...


4

Ahh yes, The Secret. I'd recommend starting with Wikipedia for a critical view of the "law of attraction" and the book as a whole. The former page has some particularly good excerpts to offer (emphasis added; hyperlinks not preserved, though I'd appreciate help editing them back in): Skeptical Inquirer magazine criticized the lack of falsifiability and ...


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

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

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 ...


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

There is no difference between "computational neuroscience" and "theoretical neuroscience" in practice. The two are almost always used interchangeably. Neuroinformatics, like bioinformatics, is more about managing data and designing analysis software (that's always somehow integrated with data storage and management). Generally, it is informational ...


4

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 ...


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

My answer to this question would be pretty straightforward. From a neurobiological standpoint, sex causes the release of various pair-bonding influencing hormones oxytocin, vasopressin and dopamine. These "feel good" hormones promote bonding and basically encourage the couple to stay together. The more the pair have sex, the more these hormones get ...


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.



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