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This will be a long post. FYI. To my knowledge, there is no evidence for back propagation in the brain. If you're interested specifically in that topic, Geoffrey Hinton (Dept. of CS @ UofT) has written about it. I'll try to focus on the biology. Some basic neurophysiology first. Neurons have a slightly negative electrical resting potential (...


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Yes – electricity does pass through synapses if the link between the neurons in question is constituted by an electrical synapse. There are two different types of synapses, chemical synapses and electrical synapses. At a chemical synapse, an arriving pre-synaptic action potential indeed causes the release of neurotransmitters which carry the signal across ...


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As far as I know, it is not possible for a neuron to change which type of neurotransmitter it releases. However, it is the case that the neurotransmitter GABA changes from excitatory to inhibitory over the course of development. This is occurs because GABA activates Cl- (chloride) channels. The chloride concentration gradient across the cell membrane ...


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There is no such thing as "zero" activity in regards to brain circuits. Even when you record neurons from a brain slice in vitro, you have spontaneous network activity. There is a few studies that suggest that brain circuits are chaotic, where infinitesimal difference in the initial state will lead to exponentially diverging patterns of activity: Banerjee,...


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Short answer Hair cells in the cochlea can code sound intensity via the amount of neurotransmitter they release. Higher sound levels result in more neurotransmitter release and in turn to higher firing rates in the spiral ganglion cells of the auditory nerve. Background Sound waves are picked up by the mechanoreceptors in the inner ear: the hair cells. ...


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No, inner speech does not follow the same neural pathway as speech coming in from outside. Rather, inner speech uses the same neural mechanism as outer speech - that is, speech going out. The neural mechanisms of inner speech can be studied using recently developed technologies such as fMRI imaging of subjects instructed to or prevented from engaging in ...


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Generally spoken, synesthesia is unidirectional. For example, grapheme–color synesthesia (i.e., letter–color and digit–color synesthesia) is the most prevalent type of synesthesia. The presentation of a grapheme leads to an additional synesthetic color percept. Although grapheme–color synesthetes are strongly influenced by the synesthetic color perception ...


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The corpus callosum is a massive horizontal white matter tract (commissure) that connects the two hemispheres and it is considered the most important route of communication between the hemispheres. However, there are five additional commissures that cross the midline, namely: Anterior commissure, connecting the two olfactory bulbs and the temporal ...


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Psychophysiology is totally outside of my wheelhouse, but here it goes… Those feelings in your chest, face, arms, etc. aren't an illusion. Indeed, it's long been argued that physiological arousal (in your body) is a core component of emotional experience (e.g., James, 1884; Russell, 1980)--alongside feelings of pleasure and displeasure. Moreover, that ...


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You are right that active adult neurogenesis is generally considered to be restricted to the dentate gyrus of the hippocampus, and the subventricular zone of the lateral ventricles. The latter generates neurons that subsequently migrate through the rostral migratory stream to the olfactory bulb to become interneurons (Ming & Song, 2011). Although the ...


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20 Watts. Watson mentioned this in 2011: "The human brain only requires 20 watts of power to operate ... Watson? About 20,000 watts." An interview with John Kelly (an IBM senior vice president and director of IBM Research) also puts the brain at "about 20 watts" (but puts the machine at 85 kW; the inconsistency doesn't matter for this question). Popular ...


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I found that dF/F0 stands for the relative difference in fluorescence at a certain wavelength.


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The textbook convention is that neurons release only one type of chemical from their synaptic terminals. This is known as Dale's Principle (https://en.wikipedia.org/wiki/Dale%27s_principle), and would exclude the possibility that neurons can release both inhibitory and excitatory neurotransmitters. Examples have been found of neurons which co-release two ...


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Answer Yes, theoretically. Now According to my ongoing informal research, there are two sides of brain preservation innovation: 1) the preservation and mapping (building) the connectome; and 2) the reinstantiation of memories and/or creating consciousness from a connectome. From http://www.brainpreservation.org/overview/: [N]euroscience is now ...


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The superior colliculus can be regarded as the center of saccadic eye movement. It contains a topographically organized representation of the visual space in its upper layers, and saccade-related activity in its deeper layers (Van Gisbergen et al., 1987). Ablation of the superior colliculus unilaterally eliminates saccades contralateral to the lesion, and ...


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Gap junctions can couple cells directly electrically. Cell types electrically coupled via gap junctions include neurons, the pancreatic islets of Langerhans (Andreu et al, 1997) and cardiac cells (Fig. 1.). In contrast to chemical synapses, information transfer via electrical "synapses" (gap junctions) is nearly instantaneous. In chemical information flow, ...


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There is a good article on Wikipedia on the Neuroscience of Free Will, with far too much content to adequately summarize here. Since your question is focused on long-term prediction of behaviour, I'll just mention about that. Using newer fMRI technology, Soon et al (2008) used a learning algorithm to predict "free will" decisions from brain activity about ...


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Short answer Neurons can increase or decrease the amplitude of their response. A neuron's response strength can be regulated by adjustment of the cell-surface expression of excitatory receptors. Background First off, this question is very broad. To narrow it down I will focus on learning processes in the hippocampus involving long-term potentiation (LTP). ...


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It is generally accepted that all activity having to do with conscious experience is mediated by spiking in the cortex. Sub-threshold activity, such as excitatory postsynaptic potentials (EPSPs) are not carried forward in the nervous system and will 'fade' before having an effect. It all revolves around action potentials. Quoting from Kandel et al. (2000): ...


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Short answer Muscles are controlled by motor neurons in the spinal cord. The number of motor neurons that fire, as well as their individual firing rates govern the control of muscle force. Background Muscles consist of contractile elements: the muscle fibers. These muscle fibers are under direct control of the motor neurons in the spinal cord (Purves et al.,...


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I agree with much of AliceD's well-cited answer, but here are a few extras. What part of the brain is actively controlling saccadic movement? It is not clear how you would choose just one area of the brain, given that a whole network of cortical and sub-cortical areas are involved, and what you mean by "actively controlling". The superior ...


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Here's the only one that's easy to find in google scholar, but there might be more: Page, F., Coleman, G., & Conduit, R. (2006). The effect of transdermal nicotine patches on sleep and dreams. Physiology & Behavior, 88(4), 425-432.


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My question is: are these all the rules? No. Some things you left out: Plasticity (change) Very-short-term synaptic "plasticity" (changes in synaptic strength); at least a few different forms of this (post-tetanic potentiation, short term synaptic depression, synaptic facilitation). Very-short-term intrinsic "plasticity" (changes in spiking behavior): ...


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Does electricity pass through synapse? No because ... ... when a neuron fires the action potential generated in a cell body reaches only the presynaptic part of the synapse, then triggers the transmitter to pass through the gap, and that transmitter causes the membrane in the postsynaptic part to open ion channels, pumps, etc ..., which ...


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The phenomenon you are referring to is called synesthesia, which can be defined as (Sinke et al., 2012): Synesthesia (Greek: syn = together; aesthesis = perception) is [...] a crossing of sensory perceptions, where stimulation within one sensory modality/stream leads to an internally generated perceptual experience of another sensory modality/stream. ...


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Although this paper is not grounded in neurobiology "Up speeds you down. Awe-evoking monumental buildings trigger behavioral and perceived freezing" by Joey et al. should be a good starting point for further research into the domain of environmental psychology with a focus on human-made environments. In the paper, subjects are shown to have slower reaction ...


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The corpus callosum is the largest of the commissural neural pathways, linking the cerebral cortex of the left and right hemisphere. The sectioning of this tract is called a corpus callosotomy, which disconnects the two sides of the neocortex. A callosotomy is used in cases of intractable epilepsy, i.e., epilepsy that cannot be treated sufficiently with ...


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The phrase "fire together, wire together" comes from an explanation of Hebbian Learning and refers to the adaptation of synapses as a response to the firing of already connected neurons. This is one of several Synaptic Plasticity mechanisms. Two others that exist are Long Term Potentiation (strengthening and creation) and Long Term Depression (weakening and ...


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If there is literature that you are building off of or comparing your approach to, I would look in their papers to see what values they used and use the same. This is the standard approach, as it yields easily comparable experimental results. If you are just looking for some ballpark numbers for less formal research, these guys used 1 mΩ, these guys did the ...


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As in the ideal gas law, the universal gas constant allows for calculation of amount of energy associated with a certain group of molecules (see https://en.wikipedia.org/wiki/Gas_constant). As the Nernst equation compares the "osmotic pressure" to "electrical pressure", the universal gas constant is needed to convert amount of an ion on the two sides of a ...



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