8
votes
Accepted
Can you get sad by sniffing onions, just like you can get happy by forcing yourself to smile?
I assume you're referring to the experiment by Strack, Martin, and Stepper (1988) in which people rated a cartoon as funnier when they had to hold their face in a smile shape by gripping a pencil in ...
- 361
7
votes
What is the computational role of the cortical column?
Cortical columns are groups of neurons in the brain that are oriented perpendicularly to the cortical surface. Cells within a column respond to the same stimulus property (Fig. 1). For example, ...
- 20.8k
7
votes
Accepted
What are the temporal limits of the auditory system?
As far as I know, auditory clicks are the shortest possible auditory stimuli. The shortest auditory click I was able to find in the literature, and which was used in a psychophysical context (i.e., ...
- 20.8k
7
votes
Accepted
How do hair cells recognize frequencies?
Short answer
Population activity in auditory neurons allows rate coding of soundwaves with frequencies that exceed the firing rate limit. Place coding is, however, believed to be the most important ...
- 20.8k
6
votes
Does the split brain disprove a materialistic mind?
The question title reads:
Does the split brain disprove a materialistic mind?
The simple answer being no, nothing disproves that - the brain harbors the mind (e.g., Lilienfeld & Arkowitz, 2008).
...
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6
votes
What are the temporal limits of the auditory system?
In terms of the shortest stimuli, the auditory system can process acoustic impulses, but defining the duration of an impulse is problematic. As the duration of the impulse gets shorter, the bandwidth ...
- 2,633
6
votes
Accepted
What degree of control do we have on eye movements?
Short answer
We have a lot of control over our eye movements, including saccades. We can suppress saccades and make an anti-saccade instead. So can monkeys, our close cousins. Children have a lot more ...
- 20.8k
5
votes
Accepted
What happens in my retina if I press on my eyeballs?
Short answer
Pressure phosphenes are believed to be induced by sensory neurons in the retina downstream from the photoreceptors due to stretch-mediated activation.
Background
You are referring to ...
- 20.8k
5
votes
Is it true that stimulants make neurons fire more often, and depressants make them fire less often?
Short answer
Generally spoken, yes.
Background
Excitatory neurotransmitters lower the firing threshold, inhibitory neurotransmitters raise the firing threshold (Fig. 1).
For example, glutamate is ...
- 20.8k
5
votes
Do neurons fire at a faster rate during dreaming?
In REM sleep, the EEG is remarkably similar to that of the awake state (Purves et al., 2001). Although the EEG represents the synchronized activity of many neurons in the cortex, it does give us a ...
- 20.8k
5
votes
Accepted
How does the brain project pain on to a particular part of the body?
Short answer
Peripheral sensory information is projected unidirectionally to the brain. A sensory strip of the brain contains a topographical representation of the surface of the body that facilitates ...
- 20.8k
5
votes
Do direct cortical pathways exist in the visual system, or do they all go via the thalamus?
Short answer
Intracortical projections can be routed directly to other cortical areas (cortico-cortical projections), or via the thalamus (cortico-thalamo-cortical projections).
Background
...
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5
votes
Why our brain can't fool itself to constantly produce dopamine?
Short answer
Continuous activation of the reward system leads to habituation and hence a downregulation of the pleasure feelings. Further, a continuous euphoric state is a potentially harmful state, ...
- 20.8k
5
votes
Accepted
Does NMDA-receptor activation depend on neighboring AMPA-receptor activity?
Yes, there most certainly is "local membrane potential". There are two major levels of compartmentalization in dendritic processing. For one, most excitatory synapses occur onto "spines", which have ...
- 1,875
5
votes
Accepted
Are there animals with only excitatory neurons?
Not in any well-studied animal; for example, C. elegans certainly has both excitatory and inhibitory neurons. Even in animals with very simple and poorly understood nervous systems (for example, ...
- 7,780
5
votes
Is there any justification for viewing neurons as self-interested agents?
The answer to "is there any justification" is pretty much always "yes", but that can be a quite uninteresting "yes" if those justifications are poor. People justify bad ...
- 7,780
5
votes
Accepted
How can someone enjoy something without dopamine?
It is oversimplifying things that a single compound mediates complex human behavior. To nuance things a bit, there are more neurotransmitters and modulators that mediate feelings of pleasure, as you ...
- 20.8k
5
votes
Why are there receptors inside neural cells?
Why are they inside if the role of receptors is communication between cells?
'Receptors' are ubiquitous in biology and not just for communication between cells: they carry signals within cells, too.
...
- 7,780
4
votes
Accepted
Do we perceive contrast colour patterns easily because of adaptation?
Short answer
Contrast is hardwired in the visual system and can be explained by retinal and brain connectivities without the need for adaptive processes. My answer pertains to adaptation at the ...
- 20.8k
4
votes
Are there bidirectional neurons?
Chemical synapses can be bidirectional, especially in invertebrates:
https://www.ncbi.nlm.nih.gov/pubmed/2984356
https://elifesciences.org/articles/16962
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4
votes
Accepted
Can two neurons in the brain be connected more than once?
I guess the answer depends on what you mean with "connected more than once".
Initially, being connected is a strictly binary relation: either two neurons are connected or not. (The question may be: ...
4
votes
Are there parts of the brain which don't change over a lifetime?
First off, 'neuroplasticity'is a broad term. Although structural changes are the most visible form of neuroplasticity, for example neurogenesis and axon outgrowth, generally subcellular changes are ...
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4
votes
Does the brain's architecture change while growing up?
Short answer
The brain is a highly dynamic organ that changes constantly through life. During adulthood, there is a general decline in the number of cells. Memory formation is generally thought to be ...
- 20.8k
4
votes
Accepted
Can an axon connect to dendrites of multiple other neurons?
Sure, look at the connectome of C. elegans for example: URB (circled in red) has synaptic connections to IL1, RIC and also to CEP (which also synapses back to URB, showing that cycles in the ...
4
votes
Accepted
What is the difference between principal neurons and pyramidal cells?
Short answer
In the cortex, pyramidal cells and projection neurons can be used interchangeably, as both terms refer to the same cells.
Background
One way to classify neurons is based on their ...
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4
votes
Can the brain be enhanced by adding more neurons?
I'll try to tackle this question from a developmental vantage point.
You hit the nail on the head by saying
...the brain is just neural connections...
Indeed, the power of the brain is based on ...
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4
votes
Myelin and Myelin Sheath
As Wikipedia points out:
Myelin is a lipid-rich (fatty) substance formed in the central nervous system (CNS) by glial cells called oligodendrocytes, and in the peripheral nervous system (PNS) by ...
- 12.3k
4
votes
Accepted
What happens to your body when overcoming side effects of SSRIs?
Well, I think that's a good question!
The resolution of side effects following the initiation of selective serotonin reuptake inhibitors (SSRIs) can be attributed to the capacity of the human body to ...
- 336
3
votes
How to differentiate attentiveness, arousal and memory via gamma oscillations
You'd need to "shut down arousal" to give a causal dissociation of arousal and memory reactivation, right?
E.g.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174240/
Then you'd need to define what ...
- 316
3
votes
What explains the characteristics of the receptive fields of simple cells in V1?
The retinal ganglion cells (RGCs) and the neurons in the upstream lateral geniculate nucleus (LGN) both have relatively simple receptive fields that are organized in in a center-surround fashion (Fig. ...
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