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., &...
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16
votes
Accepted
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 ...
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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 ...
- 1,915
8
votes
Accepted
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 ...
- 8,811
7
votes
Accepted
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 ...
- 46.5k
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 ...
- 46.5k
7
votes
Accepted
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 ...
- 46.5k
6
votes
Accepted
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 ...
- 46.5k
6
votes
Accepted
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 ...
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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 ...
- 6,272
5
votes
Accepted
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 ...
- 262
5
votes
Accepted
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 ...
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5
votes
Accepted
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 ...
- 10.5k
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 ...
- 6,272
5
votes
Accepted
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 ...
- 46.5k
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. ...
- 1,333
4
votes
Accepted
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). ...
- 14.1k
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, ...
- 1,506
4
votes
Accepted
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 ...
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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 ...
- 41
4
votes
Accepted
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 ...
- 1,307
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 ...
- 1,305
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 ...
- 46.5k
3
votes
Accepted
Confusion about the construction of the rat's mental map
You have a couple small misunderstandings that I think are making it hard to understand the figure. There is no map of the hippocampus pictured here!
1) Note: this is a schematic figure. These aren't ...
- 46.5k
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 ...
- 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 ...
- 30.3k
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; ...
- 46.5k
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 ...
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3
votes
What is the specific role of the cerebellum when it comes to 'coordinating movement'?
When attempting to execute a movement, a signal is not only sent from the motor cortex through the spinal chord and to the muscles, but also one is sent from the same motor cortex to the cerebellum, ...
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