18 votes
Accepted

Do the foldings in the brain vary person to person?

The major structure is consistent but there is a lot of variation in the details, including the presence and absence of certain gyri: Kennedy, D. N., Lange, N., Makris, N., Bates, J., Meyer, J., &...
Bryan Krause's user avatar
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16 votes
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How does methamphetamine (meth) damage neurons?

Nice question! I will directly begin with the process through which methamphetamine causes damage to neurons, putting in as much details as are known, and adding appropriate citations wherever ...
another 'Homo sapien''s user avatar
14 votes

What is the cause that angina pectoris is felt in your left arm?

It has mainly to do with the embryonic origin of organs, with the heart being a typically left sided organ, it develops sharing some nerves with the left thorax and left arm. There is however high ...
Giuseppe Biondi-Zoccai's user avatar
12 votes
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Does the recent concern over several papers about Aβ*56 call into question the association of Alzheimers Disease with any amyloyd beta oligomer forms?

Does the recent concern over several papers about Aβ*56 call into question the association of Alzheimers Disease with any amyloyd beta oligomer forms? From my understanding, no. alzforum.org has ...
Franck Dernoncourt's user avatar
8 votes
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Why Is Gray Matter Gray?

The terms gray and white matter relate to their color in gross specimens (i.e., not microscopic specimens) that have been formalin fixed. Nissl granules describe a microscopic structure, the rough ...
De Novo's user avatar
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7 votes
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What causes the range of severity of neurological deficits in Down's syndrome?

The symptoms of Down syndrome occur due to overexpression of genes present on the duplicated chromosome. If possessing an extra chromosome meant an equivalent change in gene expression, one would ...
Bryan Krause's user avatar
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7 votes

What is synaptic bias?

Often artificial neurons are created with conventions that zero is "rest" and 1 is "threshold". The unit starts at 0, and when it reaches 1 it will send an input to all of its targets and be reset ...
Bryan Krause's user avatar
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7 votes
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Are there any known rules that neurons always follow while transmitting/receiving signals?

Short Answer: "Always" is always a dangerous term in biology. Longer Answer: What does a neuron do if it does not get stimulated/receives no signal for a long time. Will it die ... or try to find ...
Bryan Krause's user avatar
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6 votes
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What is two photon calcium imaging?

what does the "two photon" means? Ordinary confocal microscopy uses single photon of laser light to excite the molecule of fluorescent dye. In two photon microscopy you use two photons, with lower ...
mpribis's user avatar
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6 votes
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If action potential is "all or nothing" then how are finely tuned signals sent from one neuron to another?

how is one type of neurotransmitter secreted rather than another Most neurons release a single major neurotransmitter. JM97 commented a link about cells releasing more than one, but that is talking ...
Bryan Krause's user avatar
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6 votes

Neuron connectivity- how are they connected physically

Neurons are suspended, as you say, in an extracellular matrix. Brain tissues are a little bit more specific. Here I quote a few summaries from literature to answer and give your a perspective on your ...
S Pr's user avatar
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5 votes
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Why can't dopamine cross the blood brain barrier but l-dopa can?

Both L-Dopa and Dopamine are polar molecules and thus hydrophilic. They are solvable in water but not in lipids, so they are not able to cross the Blood-brain barrier on their own. The difference is ...
macco's user avatar
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5 votes
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Why do polyneuropathies affect the extremities first?

Polyneuropathy is actually not a very specific term, so the reasons will no doubt vary depending on which specific class you are talking about. That said, here are two reasons that longer neurons are ...
Bryan Krause's user avatar
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5 votes

What is the cause that angina pectoris is felt in your left arm?

Our pain-sensing neurons work in useful ways only when they inform about skin areas or muscles. When nettles sting your left hand, you want to retract your left hand right away. This is in part an ...
nvja's user avatar
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5 votes
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If the Brain can store as much information as a billion hard disks why cant i memorize a single word document of random letters?

The brain is trained to remember patterns and predictable associations. Randomness is the absence of patterns, so it's the exact opposite of what the human brain is for. A human can remember random ...
bandybabboon's user avatar
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5 votes

Appropriate cell lines to study depression

tl;dr there is no 'depression' cell line. Cell lines would be suited for studying pharmacology, cellular or molecular mechanisms, none of which are depression. Depression also has no good correlates ...
S Pr's user avatar
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5 votes
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Does communication with new parts of body requires internal changes in brain?

I think you'd benefit from reading about the concept of "critical periods" - basically, at different times during development, the brain is learning specific tasks, associating sensory ...
Bryan Krause's user avatar
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5 votes

Do the foldings in the brain vary person to person?

Tl;DR: The folding pattern seems consistent among human species but they are not exact match when compared person to person. Long Answer: The folding is not random like a crumpled piece of paper. ...
Nilay Ghosh's user avatar
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4 votes
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What is the specific role of the cerebellum when it comes to 'coordinating movement'?

The principal function of the cerebellum, which was detected years ago, is to calibrate detailed movements rather than initiating movements or deciding which movements to execute (Ghez et al, 1985). ...
another 'Homo sapien''s user avatar
4 votes

difference between neurotransmitters and hormones

At heart, the distinction between neurotransmitters and hormones is how they are transmitted - not necessarily a difference in the chemicals themselves. Neurotransmitters are sent over synapses, ...
Jam's user avatar
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4 votes
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What parts of the visual system could be responsible for a fixed, monocular scotoma?

Yes. You're right. A scotoma only affecting one eye (i.e., one that is not perceived when one eye is closed) is diagnostic of a lesion upstream from the optic chiasm. See Brust's Practice of Neural ...
De Novo's user avatar
  • 8,791
4 votes

Neuron connectivity- how are they connected physically

It's true, neurons in the brain are really sparse within an extracellular matrix. But I would like to say that there exist several type of synapsis. The first one, to which you referred is the ...
Ad87F's user avatar
  • 41
4 votes
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How do anticholinesterase pesticides kill nematodes?

Cholinesterase inhibitors and plant-pathogenic nematodes While it is true that cholinesterase inhibition does not affect gas exchange in nematodes, it does produce other effects by paralysing motor ...
Adhish's user avatar
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3 votes

Why don't neurons die during a stent procedure in the brain?

I am assuming you are asking because of occlusion during balloon angioplasty. If not, please clarify. Ischemic stroke occurs when a blood vessel to the brain is occuluded by a clot or some other ...
Bryan Krause's user avatar
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3 votes

Names for effects of sleep deprivation on the brain & body

During extreme sleep deprivation you can briefly fall asleep, this is known as a microsleep. The disorientation that you experienced can be referred to as Hypogogia. Hypogogia covers a range of ...
Michael_A's user avatar
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3 votes

What causes the range of severity of neurological deficits in Down's syndrome?

The extra genetic material present in DS results in overexpression of a portion of the 310 genes located on chromosome 21. This over expression has been estimated at around 50%. Some research has ...
Arnb's user avatar
  • 511
3 votes
Accepted

Why can nervous inflammation radiate symmetrically in the limbs?

Padua et al. (1998) did find that 87% of followed patients developed bilateral CTS (i.e., carpal tunnel syndrome in both hands). Most patients that develop unilateral symptoms, eventually have the ...
theforestecologist's user avatar
3 votes
Accepted

What is a starter cell?

Nice question - this terminology isn't referring to a special type of cell or anything, but to a peculiarity of the technique they are using. They are labeling a subset of cells with rabies virus; ...
Bryan Krause's user avatar
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3 votes

Does the effect of light on melatonin release adapts to light level over long periods of time?

This paper, for example, shows that indeed, melatonin is suppressed more in the light after a week of dim light exposure compared to after a week of bright light exposure. However, the authors note ...
Bryan Krause's user avatar
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