Questions tagged [neurophysiology]

The study of the physiology of the nervous system, with emphasis on transcellular communication, and cellular and molecular processes involved in neural communication.

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11
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2answers
265 views

How is tone volume encoded?

I am wondering whether increasing the volume would result in (a) a neuron that was already firing to now increase its spike rate, (b) a different group of neurons to add their activity to the ...
11
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1answer
7k views

How many dendrite connections vs axon terminals does a multipolar cerebral neuron have?

I find countless places stating that neurons have tens of thousands of "connections" or "synapses" and one axon. Do neurons have tens of thousands of dendrite connections, and a few axon terminals; ...
10
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1answer
933 views

Does adult neurogenesis occur only in the olfactory bulb and the hippocampus?

The scholarpedia article on this subject says: Adult neurogenesis is the process of generating new neurons which integrate into existing circuits after fetal and early postnatal development has ...
10
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1answer
82 views

How to differentiate attentiveness, arousal and memory via gamma oscillations

I am planning an experiment using mice with in vivo extracellular recordings (and maybe also optogenetic stimulation). In these kinds of experiments, the mouse is getting a reward after executing a (...
9
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2answers
437 views

Why can we not see around our point of focus of our eyes?

Why do we have to strictly focus on something to really see what it looks like? Is everything else around blurred, or is our brain trained only to see in the center of the image projected on the ...
9
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2answers
40k views

What is the difference between pre-synaptic versus post-synaptic?

As a non-specialist, I am unclear as to the exact meaning of the terms pre-synaptic and post-synaptic. Specifically, do they refer to the same neuron, either transmitting or receiving, before and ...
9
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2answers
1k views

How does masking work?

Masking occurs when the delay between the target and the mask is less than a threshhold (say 50 milliseconds). If sensory data passes from lower to higher visual cortices/processing regions as in a ...
9
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1answer
4k views

How does the inner ear encode sound intensity?

Different areas of the inner ear (the cochlea) are sensitive to different acoustic frequencies. Hence, the cochlea basically performs a fast Fourier transform on the audio signal. This spectral ...
8
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1answer
162 views

What is the meaning of "little efferent input" to retina?

Gollisch & Meister (2010) state that "the retina receives little efferent input from the brain" (p. 157). Could anyone describe what exactly this "little efferent input" (where it originates, ...
8
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1answer
817 views

Frissons on demand

Have you ever listened to music and it gives you "chills?" This response is called a "frisson," a french word meaning "to shiver." When I want to access certain emotional and inspirationally charged ...
8
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1answer
1k views

What explains the characteristics of the receptive fields of simple cells in V1?

Here is a YouTube video of a Hubel & Wiesel experiment from 1965 in the visual cortex. The video shows the experimenters outlining the receptive field of a simple cell in the first part of the ...
8
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2answers
522 views

What is the result of an excess of dopamine?

I'm pretty familiar with the results of having not enough dopamine, though the reasons are not so clear to me. To get a better insight on the topic I'd like to know something about having too much ...
7
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1answer
3k views

What are presynaptic puncta?

What are presynaptic puncta? And what makes them different from presynaptic terminals? I encountered the term puncta in the following article: Molofsky AV, Kelley KW, Tsai HH, Redmond SA, Chang SM, ...
7
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1answer
483 views

Does the split brain disprove a materialistic mind?

According to materialism, the conscious mind is the product of the brain. Thus, if the brain is split in half such that the two hemispheres cannot communicate with each other, then there are three ...
7
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1answer
222 views

What regulates the strength of motor signals?

I've seen cognitive and robot models where the input signals from the sensors are directly used as the signal for outgoing motor control. This doesn't make much sense, because obviously we're able ...
7
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1answer
159 views

How does it come about that specific areas of the brain are associated with specific functions?

During the development of the human brain, specific areas come to perform specific functions. How (and when) does this differentiation come about? Presumably, some areas of the brain naturally take ...
7
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1answer
71 views

Is it possible to imitate two way communication between a brain and a limb?

Human muscles are controlled by action potentials that travel along the nerves. Below is an image of a train of action potentials that are decoded by the brain into a sensation or interpreted by a ...
6
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2answers
2k views

How would synapses behave if resting potential was zero?

Assuming that the resting potential is zero and the other mechanisms were exactly the same, how would it affect the generation of spikes in terms of excitatory and inhibitory postsynaptic potentials(...
6
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2answers
566 views

How do neurons decide how to alter their output signals?

In computer science, neural networks are trained using backpropagation and other methods. Backpropagation heavily relies on mathematical formulas to describe how the weights should be changed ...
6
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1answer
530 views

Physiology behind EEG measurements

Many questions were asked about general procedures of Electroencephalography (EEG), which were phrased in a rather specific context. Not only were these questions hard to find, they might also be ...
6
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2answers
2k views

Are there bidirectional neurons?

Neurons are mostly unidirectional, i.e. electrical impulses enter from one end and leave through the other. Are there bidirectional neurons as well, i.e., neurons that have a receiving end and a ...
6
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1answer
61 views

Does NMDA-receptor activation depend on neighboring AMPA-receptor activity?

This question is coming out of a couple points of confusion after I learned about about NMDA receptors' role in LTP. I got the impression that after AMPA receptors were activated enough, which ...
6
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1answer
695 views

Why our brain can't fool itself to constantly produce dopamine?

There are experiments [1] showing that our brain tries to maximize amount of dopamine. At the same time it is the brain who controls the dopamine level, because the reward system is located in the ...
6
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2answers
88 views

Spike-timing-dependent plasticity versus Homeostatic plasticity

How can spike-timing-dependent plasticity and homeostatic plasticity both be right? If spike-timing-dependent plasticity consistently tries to strengthen connections, but homeostatic plasticity ...
6
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1answer
121 views

Is inhibitory brain circuitry involved in cross-modal sensory perception?

In many research articles, a vague description of a inhibitory circuitry in the brain is mentioned. This is presented as an inhibitory mechanism that prevents input from one sensory modality to excite ...
6
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1answer
273 views

Does STDP make the Hebbian learning rule redundant?

On Scholarpedia they introduce STDP (spike timing dependent plasticity) as a temporally asymmetric form of Hebbian learning, making it sound as if the original Hebbian rule still has relevance in ...
6
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1answer
74 views

Are there synapses on other neuron terminals in human brain like in Aplysia

I am referring to Eric Kandel and his experiment on Aplysia where he shows that synapses between a pair of neurons can be modulated by means of a third neuron that synapses onto the terminals of the ...
6
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2answers
78 views

How does neuron stimulation work?

Neurons are excited via an external electrode by passing current through it. A neuron at rest is at -70 mV, it needs additional charge amounting to around 15 mV to initiate an action potential. But ...
5
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2answers
138 views

What are the temporal limits of the auditory system?

I would like to know what the time scale is of the human ear. I mean, what is the shortest duration of a sound that a human ear can notice and what is the longest duration of a sound that a human ear ...
5
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2answers
370 views

Can LSD connect sensory regions in the brain?

How is it possible that after using LSD you can hear sounds and see colors? I have my own experience with this phenomenon. When I´m lying totally relaxed in bed and suddenly a door is closed loudly, I ...
5
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1answer
124 views

Can neuron change from excitatory to inhibitory (and vice versa) over time?

According to this answer a neuron can release only specific type of neurotransmitters at the time, however, could it change over time? For example a neuron that now releases only inhibitory ...
5
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2answers
170 views

What's the relation between firing of dopaminergic neurons and dopamine dispersion in terms of neurophysiological processes?

Question: How does the firing of dopaminergic neurons affect the dispersal of dopamine? Evidence of my limited familiarity with dopaminergic neurons and motivation for asking the question: Most of ...
5
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1answer
778 views

What are 'gap junctions' (electrical synapses) for?

I was reading this and I found the following sentences: Apart from chemical synapses neurons can also be coupled by electrical synapses, so-called gap junctions. Specialized membrane proteins make ...
5
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2answers
401 views

Can two neurons in the brain be connected more than once?

Can two given neurons in the human brain can be directly connected more than once, either mutually or in the same or direction? Also, can the same neuron have transitive connections to itself (in ...
5
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1answer
104 views

Are there parts of the brain which don't change over a lifetime?

We know that during our lifetime the brain develops new neural connections. In addition, there is pruning of neural connections. These phenomena together are called neuroplasticity. Is there any ...
5
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1answer
247 views

How are tactile pleasure and pain differentiated in the somatosensory cortex?

A recent question here asked about (mostly) how pain and pleasure are differentiated in pathways involving reward/aversion cues. But there was some confusion as to what the question really wanted to ...
5
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1answer
3k views

What is the definition of a receptive field?

I have read the wikipedia article on receptive fields (RFs). There, a receptive field is defined as: The receptive field of an individual sensory neuron is the particular region of the sensory ...
5
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1answer
41 views

What introductory textbook is available about the corticostriatal brain circuitry?

I want to understand the basal ganglia better. In particular, I want to understand the role of the corticostriatal brain circuitry for non-motor functions, including emotion and cognition. I have ...
5
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1answer
113 views

When does reward occur? When dopamine is released or when it is binded?

I know this is a silly question, but I'm curious as to what is the exact phase when we experience of the thrill of doing an exciting activity. I believe this briefly describes the whole process. So, ...
5
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0answers
144 views

What are the necessary preconditions for the emergence of a conscience?

I am aware of 2 brain anomalies that seem to be associated with the non-emergence of a conscience. One is associated with psychopathy. The other is associated with narcissism. psychopathy: My ...
5
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0answers
30 views

Do neurons involved in reflex movements process information or they just transmit a signal?

According to Reflex A reflex, or reflex action, is an involuntary and nearly instantaneous movement in response to a stimulus. A reflex is made possible by neural pathways called reflex arcs which ...
4
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2answers
150 views

Can you get sad by sniffing onions, just like you can get happy by forcing yourself to smile?

I've read about a study where they found that people who were forced to keep a smile-like face were reportedly happier than those who were forced to stay in a frown-like a face. Similarly, could ...
4
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4answers
276 views

"Nested Neurons": Are they biologically plausible?

Is there any evidence for neurons existing within other neurons in humans or other organisms? From what little I've learned about physical neuroscience while learning to build neural nets, I don't see ...
4
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2answers
496 views

Do neurons fire at a faster rate during dreaming?

When I dream it seems that the (subjective) time is slower than the objectively passed time as seen on my clock radio. Is this because neurones fire collectively at a faster rate, so you can "put an ...
4
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1answer
68 views

What degree of control do we have on eye movements?

When something "new" and "interesting" enters our visual field it can usually happen that our eyes move toward the new target. How "intentional" and "controllable&...
4
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2answers
180 views

Do we perceive contrast colour patterns easily because of adaptation?

I can understand that colours are just manipulation of our brain to light rays of different wavelength and energy. We perceive patterns better at higher contrast. Do we perceive patterns better at ...
4
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1answer
662 views

How does the brain project pain on to a particular part of the body?

How does our brain translate periheral sensations due to injuries into pain perceptions? As an in silico analogy - if a stimulus is applied to a sensor it can be transmitted to a microprocessor. The ...
4
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1answer
169 views

Is there knowledge of the receptive field patterns of cortical columns in associative brain regions?

The retinotopic, area-based connectivity patterns of the columnar receptive fields in the visual cortex are well-established. Do any mappings of the columnar receptive field connectivity patterns ...
4
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1answer
314 views

Are neural adaptation and drug tolerance to psychoactive drugs related?

Neural adaptation is "...a change over time in the responsiveness of the sensory system to a constant stimulus". The example given is placing your hand on the surface of a table. Eventually, you no ...
4
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1answer
132 views

Integrated Information Theory - If correct could humans create artificial consciousness?

First off please keep in mind I am self-learning and am learning about this for fun, I have no end goal. I'm trying to make predictions about what I am learning implies or means, so I can ask better ...