Hot answers tagged

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% ...


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

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 ...


5

Many EEG responses are swamped in random brain activity, artifacts and background noise. A single movement typically doesn't evoke measurable activity, because its amplitude is so small with respect to background noise. I think the potentials you are looking for are event-related potentials or ERPs (Fig. 1). During ERP recording, basically a regular EEG is ...


5

There can be many reasons to why BBB-like barrier is not present in all the capillaries of the body. Let's talk about them one at a time. Source Blood-brain barrier has its own side effects. Some major side effects are cerebral edema (accumulation of excess water in the extracellular space of the brain, which can result when hypoxia causes the ...


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 ...


4

According to this article appearing on the website of the American Association of Neurological Surgeons, gunshot injuries to the head are fatal in 90 per cent of cases. Many victims die before reaching the ER, and the 50 per cent who survive the initial trauma die in the ER.


4

You talk about memory loss. The hippocampus is involved in the formation and storage of memories and indeed one of the few places in the brain where new neurons are formed. The formation of new neurons here is indeed linked to the formation of memories (Coras et al., 2010). Hippocampal neurons do not lack centrioles (Dotti & Banker, 1991; Poppov & ...


3

There is no strong evidence for MSG having any kind of neurotoxic/neuromodulatory effect. However, A 2010 article says that, in a double blind trial, it was found that the people who consumed MSG containing soda, reported headache in significantly more numbers compared to the placebo subjects [1]. The concentration of MSG used in this study was 75-150 ...


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

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 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 ...


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

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 ├ępicome / epicomus. Craniopagus ...


3

Short answer Visual perception and visual imagery draw on much of the same neural machinery. Background I have interpreted your question as: What are the common neural circuitries between visual sensation and the imagination of sensation? In neuroimaging, mental imagery of visual images is a big deal. For example, there is a large body of literature on ...


3

This is a great quesion! There is lot of work still being done on this. Unfortunately I don't think I know enough about CS or computer engineering to make analogies, so I'll give a quick crash course and some examples instead and hope you find it helpful. Long story short though is that we are just now making really exciting headway into how memory might ...


3

I do not know the details of the innovation, but it's based on MEG. MEG is a complementary technique similar to EEG, sesitive to magnetic fields instead of electrical fields (hence the 'M' in place of the 'E'). It is used to read population brain activity in real time, and is less useful as a tool to assess structural changes. MEG is currently mainly used ...


2

There's really no answer to your question, unless you can define "smart." The brains of humans and cetaceans are very different, as are their environments. Our hands give us the ability to manipulate objects, a trait believed to have made enormous contributions to human intelligence. Octopuses - perhaps the most intelligent invertebrates - can similarly ...


2

Short answer The layers in the cortex are histologically and functionally defined. Both 3- and 6-layered cortices are found in the human brain. Hence, the different cortical layers are not models, but classifications based on empirical observations. Background The different cortical layers have been defined by histological staining and microscopy. The ...


2

Short answer The thalamus is the most important neural station for the filtering of peripheral information to the cerebral cortex. Background Sleep is a prime example of where much, if not all, of the peripheral input ascending to the brain is filtered out. The thalamus situated in the brain stem is the major gateway for the flow of information toward the ...


2

A neuron cannot know the importance of a signal in any applied sense, that is, it can't know the difference between one triggered by a feather or one by a hammer... on an individual basis. A single neuron can however accumulate information in a number of ways, either by requiring multiple incoming triggers (filtering out localised signals, i.e. from a ...


2

Short answer Glutamate cannot enter the brain due to the blood-brain-barrier. Background You are totally right that glutamate represents the principal excitatory neurotransmitter in the brain (Meldrum, 2000). However, glutamate is a regular amino acid and will be metabolized quickly. More importantly, the blood-brain barrier is extremely effective in ...


2

I found two references that talk about the circle of Willis in different kind of mammals so i think it's right to say that this particular anastomotic system of arteries is not exclusive to humans. Here are the two references: http://www.neuroanatomy.org/2008/054_065.pdf http://www.ncbi.nlm.nih.gov/pubmed/14651482


2

Short answer Neurons were (and still are) often identified based on their histological features (e.g., by Cajal). In turn, the structural hallmarks of neurons are often related to their specific functions. Background The question is broad and difficult to answer without restricting to some example types of neurons. As you say, about 10,000 types of neurons ...



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