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8

To quote the University of Sidney site: People often think that other people are staring at them even when they aren't research led by the University of Sydney has found. When in doubt, the human brain is more likely to tell its owner that they're under the gaze of another person, researchers from the University of Sydney and The Vision Centre ...


8

It's less a problem of speed and more of raw photon count. Assuming a brightly lit day, the bullet will move so fast that it doesn't reflect enough photons to register against the background. High speed images of bullets usually involve a very bright flash (and other controlled settings) for the camera to pick it up. (Also, a very short flash helps the ...


7

You are correct in that the neurons themselves do not sense pain. However, the brain contains layers of coverings, blood vessels, the scalp and some muscles. All of these other structures have pain receptors. The coverings of the brain are called meninges and consist of the dura, arachnoid and pia. The dura in particular has a lot of pain receptors and may ...


7

Briefly the "Stoned Ape theory" posits that psychoactive Psilocybin mushrooms in the diet of pre-Homo sapiens primates catalyzed the change Homo sapiens. It suggests that the mushrooms conveyed selective benefits to consumers of the mushrooms, dissolving the 'egos' of our ancestors and allowing them to form communities. It may also be sexual stimulant, ...


7

The temporal lobe is in the temporal region of the head, near the temples of the skull, hence the name. It's name does not relate to it's biological function, it is mainly involved in processing language, visual memories, and emotions. The medulla oblongata is one region of the brain that deals with a lot of the "tempo" type functions (tempo as in keeping ...


6

The current working theory (note this is still an open question, but there are many leads being followed): Sensory systems receive a combination of signals from an event, which are initially bound to the hippocampus (this is called episodic memory). Then, typically during sleep, the memories are consolidated. A simplified view is that consolidation ...


6

The idea that memories could be stored as RNA or proteins is an old one. It got a lot of attention decades ago when James McConnell did a number of experiments where he conditioned planarian flatworms to respond to certain stimuli, ground them up, fed them to worms that hadn't gone through the conditioning. He claimed to have observed that the worms fed ...


6

Refute? No. Shigeta summarized the work pretty well, and though I have my own opinions on McKenna's theory the fact is that Darwin and McKenna are not opposed. The "Stoned Ape theory" is a specific idea for how human intelligence might have appeared from earlier hominids. Darwin (and Wallace) proposed a broad theory that has borne out for the process of ...


5

As the father of two sons with diagnoses of ASD, I think that it is best to think in terms of an extended spectrum which encompasses 'normal' people. We are all somewhere on this spectrum, but there is a threshold zone around where we cross from "normal" to "diagnosable as ASD". Now, if the distribution of spectral position for males is displaced towards the ...


4

Not so empty, actually. The human brain has a mass of ~1.5kg, and volume ~1200cc (a little bigger for men, a little smaller for women). So is heavier than water by a good margin. While it has Cerebrospinal fluid, that only occupies the subarachnoid space (the space below the skull and above the cortex, contained between two layers: pia matter and arachnoid ...


4

It seems there's way too many variables here. Crushing can occur in a number of ways, leading to different primary damage in different regions first and different people have a different level of system failure thresholds. Technically, there are no pain sensors on the brain, so you wouldn't feel any pain in the classical sense. However, it's hard to ...


4

V1-V5 are different (sub) regions of the visual cortex itself. via http://www.tecsyn.com The layers L1-L5 (some regions have a layer 6) refer to the different cellular strata in the depth dimension of the cortical mass. This stratification occurs to some extent or another in various areas. Different sections of the cortex, e.g., the primary motor ...


4

There is no widely-accepted neurological structure that mediates 'consciousness.' Even if some structures have been shown to be necessary for consciousness, they have not been shown to be sufficient. This is true with anesthetic mechanisms as well -- their ability to paralyze and block pain signals is fairly well-understood, but the mechanism of ...


4

Yes, they do. A blog post on the National Geographic website describes the results of a study about how blind people dream.(1) The participants who were born blind did not report any visual impressions. Among those who previously had sight, the number of visual impressions reported decreased with the time since loss of sight. Just as there are many ways ...


3

"Is it possible" has a carefully conditional "yes". Do we have the expertise or technology to do it now? No. One of the biggest difficulties is that nerve tissues (the connections between brain and rest of body) will take time to heal... time during which the brain cannot sufficiently give commands to the rest of the body to keep autonomic functions ...


3

You are probably referring to the suprachiasmatic nucleus. Note that, although this is the central clock, there are also so-called "peripheral clocks", for instance in the liver, pituitary and other organs that can finely tune rhythms in the organism. You may also want to have a look at the Wikipedia page for circadian clock and references therein.


3

This is a common phenomena which most of us come across. Seeing flashes of light, stars and other shapes in the eyes occur when the body goes through stressful activities. For example while you are climbing the blood flow will be more to other prominent parts like hands and lower waist so brain and eyes will get less supply of blood as well as nutrients. ...


3

One of the many advantage of an all-or-none system is that resources can be conserved for timing events that require synchronized collaboration between many cells (like locomotion). Binary behavior may also partially be a side effect of speed and efficient long-distance information transfer (which is one of the great advantages of neurons as cells in the ...


3

Auditory information is routed to cerebral hemispheres via the brainstem and midbrain. Structures in the midbrain receive information from both ears and combine it (including differencing it for spatial location) before sending the combined information on to both cerebral hemispheres. Usually only the left hemisphere interprets the sound for language ...


3

Indeed, C. elegans nematodes (which are the ones you are talking about) do not show cognitive responses. AFAIK, Drosophila melanogaster is also able to learn and display some quite complex behaviors, but no cognitive functions. I believe the "simplest" organism known to display what could be called "cognitive" functions is the honeybee (see for example this ...


2

Sleep is not homogenous - there are different phases of sleep - REM, NREM-1 to NREM-4. And these different stages may play different roles in 'rejuvenating' the body (as you put it). When you first fall asleep, you go into NREM-1 phase, which is the lightest sleep, and progresses into NREM-4, and for the first half of your sleep cycle, this cycles so you go ...


2

Well nerve crossing or misinterpretation of nerve signal by the brain does not happen all the time. In case it happens frequently then I guess it would be Multiple Sclerosis or might be Fibromyalgia syndrome. In multiple sclerosis, the Myelin sheath surrounding neuron when gets damaged causes certain problem with nerve signal transmission to the brain. But ...


2

Males are more likely to develop ASD, but affected females tend to be more severely impaired. Why this occurs is an area of active research. However, to address your question, there is a study suggesting that mutations on the X-chromosome account for about 1% of ASD and intellectual disability cases. This clearly doesn't explain everything, but it's a ...


2

This question is difficult to answer and in the end, we'll just have to accept that we don't really know (at least for now). My own understanding is that what we call our consciousness is an emergent phenomenon, arising from the extraordinarily complex network of billions of neurons interacting with each other within the brain. Perhaps the rest of the cells ...


2

Remembering that neurons don't generate sinusoids, just spikes (mostly).... It depends on exactly how you want to define "depend on". For instance, a downstream neuron receiving inputs from two neurons will be more likely to fire as it spatially/temporally sums the inputs from the two neurons. Regardless of their specific rates, if their interaction is ...


2

Fragile X syndrome is a genetic disorder which is highly related to autism and is considered to be the most common single gene association with autism. Establishing what actually happens in autistic people is difficult because it is hard to quantify someone as being autistic or not - it is common for some people to show some signs of autistic type behaviour ...


2

I would guess hearing plays a part, as a powerful human sense that works in 360 degrees. Just as a hypothesis, I'd imagine that small sounds help you sense people behind you, and that this, plus chance, plus the very human capacity to see meaning in random events, gives the impression that there's a way to sense that someone not just behind you but ...


2

Have you ever tried to read a complicated book after several hours of hard work that required a high concentration? Imagine that you have forced a particular area of your brain. After a hard work, the areas of the brain that we used to finish a work seem don't respond to any stimulation and make us feeling tired and as we can't understand what we are doing ...


2

I've found the answer. The entire brain and spinal cord is bounded by the arachnoid mater, thus both channels would lead into the subarachnoid space, which also circulates the fluid into the spinal cord region. The CSF exits through the arachnoid granulations, which are like valves, found on the dorsal midline, into the superior sagital sinus, where it ...



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