13 votes

Is a neuron's information processing more complex than a perceptron?

Even if you fully accept the analogy, a cortical pyramidal neuron's function is best described as that of a multi-layer perceptron, with each dendrite or part of it independently integrating ...
  • 239
11 votes

Is a neuron's information processing more complex than a perceptron?

Just a couple examples: Spatial integration This is the basis of @vkehayas's answer. More generally, despite integration at the soma being fairly linear up to a point, dendrites are highly non-linear ...
  • 6,377
7 votes

Is there a theoretical maximum for IQ?

There are a few ways that you could answer this question. First, IQ is defined with a mean of 100 and a standard deviation of 15. But this is a normative score and relative to a given target ...
6 votes
Accepted

How does the chemical structure of a drug determine potency?

In fact, the two binding affinities of fentanyl and morphine to the mu opiate receptors are considered to be fairly similar. The reason the former is the more potent one has more to due with its ...
  • 19.9k
5 votes

Is a neuron's information processing more complex than a perceptron?

I don't know enough about neural networks to properly define the difference between a perceptron and a neuron, I don't know how much machine learning definitions can be expanded or generalized to more ...
  • 51
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 ...
  • 19.9k
4 votes

Are memories stored as patterns of chemicals/emotions?

Understanding how memories are stored and retrieved in the brain is actually a pretty popular topic in neuronal dynamics. The mathematical theory of dynamical systems comes in handy here. A population ...
4 votes

How does acute tryptophan depletion work?

don't the neurons already have plenty of serotonin stored in the axon vesicles from which the neurotransmission happens Sure, but neurotransmission is happening all the time. It's not uncommon for a ...
  • 6,377
4 votes
Accepted

What does it mean if a neuron is "expressing" something?

Gene Expression "Expressing" refers to gene expression - in biology we say a cell is "expressing" a gene when the products of that gene are present. "Sst-expressing cell" ...
  • 6,377
3 votes
Accepted

Does only the time-series data of fMRI matter or does spatial distribution of the signal values also matter?

Usually, but not always, fMRI timeseries are used to compute functional connectivity by calculating Pearson correlations among voxels or ROIs. The equation for the Pearson correlation can be written ...
  • 6,377
3 votes
Accepted

What are the differences between bipolar channels and monopolar channels for EEG?

In general, closely situated electrodes work well to eliminate environmental noise, at least when a differential amplifier is used. Environmental noise is a major problem in case of scalp-recorded ...
  • 19.9k
3 votes
Accepted

Default Mode Network and: hyper-connectivity, hypo-connectivity, interconnectivity and intraconnectivity

The default mode network (DMN) is a collection of brain structures identified in human functional neuroimaging. Specifically, a type of neuroimaging called BOLD indirectly measures local metabolism in ...
  • 6,377
3 votes
Accepted

"Reverse Tolerance" Hypothetical

Drug tolerance (desensitization) is complicated, featuring many possible mechanisms. There certainly is reverse tolerance (sensitization) as described as well: The two notions are not incompatible, ...
  • 18.3k
3 votes

Does the brain send signals continuously to muscles during movement?

An answer from the bottom up would be as follows. A group of muscle fibers is innervated by a single motor neuron: this is called a motor unit, as it activates together, since a unique axon carries ...
3 votes

How to evaluate the convergence of a staircase?

A staircase is an adaptive procedure. To test whether its outcome is correct you can do the math (e.g., Levitt (1971); Zwislocki & Relkin (2001)) by calculating what a 2-up, 1-down method ...
  • 19.9k
3 votes

Is a neuron's information processing more complex than a perceptron?

Yes, a neuron's information processing is more complex than a perceptron's information processing. Here I describe one way it's more complex; I am not claiming this is the only way it is more complex. ...
3 votes

Why are there substances that give positive psychological effects but become unhealthy addictions?

The answer is simple; the brain with its reward centers did not evolve with purified plant-based stimulants (nicotine, cocaine) or synthetic variants ((meth)amphetamine and other designer drugs) ...
  • 19.9k
3 votes

Does the human eye have a muscle that if paralyzed would make us only see things that are in motion?

Short answer Eye musculature takes care of the movements of the eye, including microsaccades that prevent retinal fading (adaptation). If microsaccades are inhibited by inactivating the eye muscles, ...
  • 19.9k
2 votes
Accepted

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

Short answer Reflex arcs can perform basic processing operations like inversion, summation and integration. Background Reflexes include a wide variety of responses and in fact an all-inclusive ...
  • 19.9k
2 votes

"Reverse Tolerance" Hypothetical

While theoretically possible it seems impractical since adenosine has a half life of 0.6 - 10second. Adenosine is rapidly cleared from plasma by the cellular elements of the blood and by vascular ...
  • 215
2 votes

How do "ideas" or "concepts" appear in the brain?

First of all, let's look at human perception. Humans have several sensory modalities: sight, hearing, touch, etc... Note that there are many more than I just enumerated, and certainly not merely the ...
2 votes

where is the second electrode in case of electrostimulation

Current flows from a high potential to a low potential, so if you inject a great deal of current via an electrode it will still flow into the body. However, even in the case of unipolar setups for ...
2 votes

How do the outer hair cells amplify the traveling wave?

Short answer Outer hair cells physically contract at a rate corresponding to the characteristic resonant frequency at which they are situated on the basilar membrane, thereby mechanically amplifying ...
  • 19.9k
2 votes
Accepted

What does "all-or-nothing" means in spiking neural network?

For an artificial network, yes, it typically means there is a binary output; this is a standard neuron model. For a biological network, it's a bit more complicated, because although any moment in time ...
  • 6,377
2 votes
Accepted

BOLD->functional connectivity->spectral graph theory (e.g. Atasoy 2016) vs BOLD->Fourier Analysis

Interestingly enough, I myself have been reading papers like these for some weeks. Although I think your question does not have a correct answer (since it is a little bit open) I can try to give my ...
  • 54
2 votes

How to calculate Fano Factor for spike train data?

Frequently, Fano Factor is calculated across time points: it is a measure of the variability in the spiking of a particular neuron. For example, interneurons will frequently have lower Fano Factor ...
  • 1,855
2 votes
Accepted

Is thermoception part of the sense of touch in the 5 human senses or is it a 6th separate sense?

Short answer Heat receptors are often grouped under the 'skin receptors', and hence are bundled along with touch (pressure, vibration, stretch), cold and pain receptors. However, ciliopathy is a ...
  • 19.9k
2 votes
Accepted

Deflection of the basilar membrane

The wide, slack composition of the basilar membrane (BM) in the apex and the narrow, stiff characteristics at the base are among the factors that underlie the tuning of the BM. Slack, wide structures ...
  • 19.9k
2 votes
Accepted

What causes this motion illusion?

Peripheral drift illusions, as their name suggests, create the illusion of motion in the periphery of the visual field. Similar images that generate illusory motion in the center of the visual field ...
  • 18.3k
2 votes

Is a neuron's information processing more complex than a perceptron?

Biological neurons operate with response latency, refraction, and inhibition. It is my understanding that perceptrons do not employ these characteristics. Response latency In biological neurons, there ...
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