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46

The brain is indeed stacked with blood vessels, as shown in a 3D model in Fig. 1. Fig. 1. 3D-printed model of blood vaculature. Source: Biobots. The blood supply on the surface of a live brain is readily seen during a craniotomy (Fig. 2.) Fig. 2. Surface of the brain. Source: The Sterile Eye. When freshly prepared, the interior of the brain appears ...


16

The idea that we only use 10% of our brain capacity is a myth. There is a great article at wired.com that discusses the myth and it's history. There is really no reason to evolve an entire brain of which only 10% is used. One great point that they make is that minor brain damage can cause devastating effects, not what you would expect if you had 90% ...


12

Is there a significant difference in calorie burn? No. The brain, while only making up 2% of our body weight, accounts for ~20% of our energy use at rest. That's because the brain, being critical for survival, is a very high-maintenance organ. At rest, the membrane potentials of all neurons - firing or at "rest" - need to be controlled/maintained. Of ...


12

First of all, I would like to point out that making analogy between digital computers and the brain is often very misleading. That being said, my answer is, some scientists believe so, some don't. Several things to consider: Some neural systems are not spiking. C. elegans for example has a nervous system that is entirely analogue. Human nervous system ...


10

Short answer The exact mechanism behind tinnitus (ringing in the ear) is unknown. Background Of the two theories you pose here, to the best of my knowledge the second one is the most widely accepted. It is a generally accepted phenomenon that whenever neural systems are being deprived of input, they start seeking new input, or even generate it ...


8

There's a very big difference between doing the calculations needed to simulate the human brain (or any animal brain FTM - we can do a fairly decent job on C. elegans.), and doing computations. While a basic leaky integrate & fire model is fairly simple, to ACCURATELY simulate a single neuron in real time takes a pretty fast computer. See e.g. these ...


6

The "wiring" of the brain is more important than the actual size. If only size would matter that basically humans would be rather unintelligent beings ( many many animals have larger head and brain than us). Intelligence is more related to the complexity of the brain (number and size of different brain components) and the number of connections between ...


6

I did a quick search and found some research in this area. Sleep inertia is the technical term for feeling groggy for a while after waking up. In a review article by Patricia Tassi, Alain Muzet (Sleep inertia. Sleep Medicine Reviews. Volume 4, Issue 4, August 2000, Pages 341–353), they define sleep inertia as Sleep inertia is a transitional state of ...


6

If firing rate is from 1 Hz to 200 Hz, 100 trillion to 20 quadrillion synaptic firings. Neuronal (say, measured from soma) firings will add up to 86 billion to 17.2 trillion action potentials per second. It important to remember, that synaptic firings "sum up" in soma or interfere between each other, so the are more of those. Read more: ...


6

The psychologic and behavioral components of sickness represent a highly organized strategy of the organism to fight infection. Sickness is generally accompanied by fatigue, numbness, coldness, muscle and joint aches, and reduced appetite. These symptoms are not simply an effect caused by the pathogen. Instead, it now believed to be an active defense ...


6

The brain does not "shut down" during sleep. While not everything about sleeping is understood, we do know that certain areas in the brain remain active during sleep. There is a good overview on sleep on the website of the National Institute of Neurological Disorders and Stroke. Until the 1950s, most people thought of sleep as a passive, dormant part of ...


5

The brain activity is electric and chemical. The male adult human brain contains about 86 billion neurons (Azevedo et al). There is about 100 trillion connections between them. Solving a puzzle like that is not easy.. what sort of breakthroughs would be necessary to intercept these signals and interpret them as exact thoughts? What you are referring to ...


5

While action potentials are usually binary, you should note that synaptic communication between neurons is generally not binary. Most synapses work by neurotransmittors, and this is a chemically mediated graded response that, for example, act on voltage-gated ion channels. So even though action potentials are often binary, communication between neurons are ...


5

Human body is a glucose driven machine which intake carbohydrates and converts to glucose. Energy is yielded from the glucose and glucose is stored as glycogen. When the carbohydrate intake is somehow reduced then body will shift its mechanism and uses the fatty acids to produce energy. Liver synthesis ketones from fatty acids in our diet or from body fat. ...


5

Feelings of pleasure and reward are transient in nature. Similarly, the dopamine release in the reward centers (the limbic structures) is transient, namely in the order of seconds (Rebec et al., 1997). One way to chronically elevate dopamine levels is by administering certain drugs. A notable/notorious example is methamphetamine, which elevates mood and ...


5

Socialization is a cognitive and executive brain based function that requires higher level thinking mechanisms usually dependent on the prefrontal coretex. A lot of social cues we obtain from our environment when we are young can shape our brains during its developmental growth (infancy-post puberty) and cause our brains to develop social habits and access ...


5

EEG has been recorded beginning in the late 20s, by people who were fairly clueless about electricity. While the strength of the EEG is indeed weak, it is readily observable with even such comparatively primitive technology. The first thing you should take note of is that EEG measures the aggregate field. It does not see single neurons. It sees the ...


4

T-cell migration to the brain is very limited and occurs at a very low level in healthy conditions, however during diseases the number of T cells passing through the blood-brain barrier is elevate due to increased expression of traffic signals and adhesive molecules. I've found two good articles on how T-cells migrate through blood-brain barrier: J Neural ...


4

Levo-Dopa is used as a first-line treatment of Parkinson's disease. Unlike dopamine, L-Dopa is able to cross the blood-brain barrier. There it is converted into dopamine. To prevent premature breakdown in the gastro-intestinal and circulatory system after oral intake, carbidopa can be co-administered. Also MAO-B inhibitors and COMT inhibitors can be applied ...


4

There is definite truth in the notion that we do not use the full capacity of our cortex. It is generally accepted that there is a reserve present in the brain that can act as a backup for cerebral damage. Brain reserve can be defined in terms of the amount of damage that can be sustained before reaching a threshold for clinical expression (Stern, 2002). A ...


4

Short answer Small electrical EEG signals need to be amplified and noise-reduced to be detectable. Noise reduction techniques include mathematical averaging and signal processing techniques like filtering. Background Neuronal activity is electrical and generates potential differences around each neuron. Potential changes generate electrical fields. These ...


3

Your question is basically a matter of defining brain plasticity or more broader, neuroplasticity. According to a well-cited paper in Brain (Cramer et al., 2011) neuroplasticity is defined as: [...] the ability of the nervous system to respond to intrinsic or extrinsic stimuli by reorganizing its structure, function and connections. Hence, the term can ...


3

Mordake was a conjoined twin fused at the head (Fig. 1). Twins conjoined at the heads are rare, occurring only once in every 2.5 million live births. Moreover, in Mordake's case it was a parasitic twin head with an undeveloped body that was fused with his own head. This condition is referred to as craniopagus parasiticus, or épicome / epicomus. Craniopagus ...


3

There is a model of an adult, male, real human brain here: http://brainder.org/download/brain-for-blender/ It can be imported into Blender or any other 3D application that can read Wavefront OBJ or Stanford PLY formats.


3

I think that the type of fMRI you are referring to is blood-oxygenation-level-dependent fMRI or BOLD fMRI. The principle behind MRI in general is the detection of proton signals from water molecules. The proton signal is generated by magnetizing the protons in tissue, which causes their spin to change. A subsequent powerful radio wave disrupts this spin ...


3

The mind is an abstraction which arises from physical and chemical processes within the brain. For a crude analogy, think of the brain as an incredibly complex, self-modifying, multithreaded program. The mind would then be the abstraction arising from the behavior of the program as it runs. Consciousness would be the abstraction arising from the behavior ...


3

Answering the question what is needed for a human brain to evolve starting from a cephalopod brain is hard. However, I can expand on what is thought to have been the driving forces behind the evolution of the humanoid brain (Hawks, 2013): The species of the famous Lucy fossil, Australopithecus afarensis (~3-4 mln yrs ago), had skulls with internal volumes ...


3

Short answer External stimuli can drive autonomic responses. Background The autonomic nervous system is a visceral sensory and motor system. The viscera are the internal organs. Virtually all visceral reflexes are mediated by local circuits in the brain stem or spinal cord (Fig. 1). It is one of two major subdivisions of the nervous system; the other being ...


3

The phenomenon in question is probably related to people with uncorrected/undercorrected myopia. This "ancient" phenomenon is called stenopeic slit effect (a case of pinhole effect): when the person squints the visual acuity becomes better because of smaller blur circles: the "slit" between the eyelids is the key point improving blurring. One can check if ...


3

The blood-brain barrier isn't a bag that surrounds the brain that you could puncture and then inject dopamine. It is a thin layer of cells around every blood vessel and capillary in the brain that mediate transfer of substances between the blood and the brain cells. As such, it is incredibly complex and branched (as complex and branched as the myriad blood ...



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