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As far as I know, adaptation of peripheral receptors, including pain receptors, is transient (Giniatullin & Nistri, 2013) Instead, my educated guess is that the increase in subjective pain threshold plays an important role. Pain thresholds differ between the sexes (Chesterton et al., 2003), and depend on disease and physical status (Kosak et al., ...


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Short answer Both carbamazepine and lamotrigine are listed as Na+ channel blockers. Carbamezipine's action is mainly associated with inhibition of postsynaptic neural activity, while lamotrigine is thought to inhibit glutamate release. Given that glutamate is the principal excitatory neurotransmitter in the brain, and if you insist of using a one-liner I ...


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Yes, they both seem to affect glutamate function, by acting on Na(+) channels and thereby inhibiting glutamate release. Note that this is not my field of research though. Waldmeier et al. 1995. Similar potency of carbamazepine, oxcarbazepine, and lamotrigine in inhibiting the release of glutamate and other neurotransmitters. Neurology Abstract We ...


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There are spontaneously firing neurons known as intrinsically oscillatory neurons, or simply pacemaker neurons. Under the right conditions these can fire action potentials in a rhythmic pattern without neuronal input. Examples are the thalamocortical relay neurons in the thalamus and inferior olive neurons. The basic mechanism is that a low-threshold Ca2+ ...


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Short answer A single pacemaker neuron can generate oscillatory behavior. Background Given our exchange in the comments, I will focus on single neurons with intrinsic oscillatory behavior. For example, thalamocortical relay neurons and inferior olive neurons have intrinsic oscillatory properties, mainly through the interaction of a ...


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Answering the question what is needed for a human brain to evolve starting from a cephalopod brain is hard. However, I can expand on what is thought to have been the driving forces behind the evolution of the humanoid brain (Hawks, 2013): The species of the famous Lucy fossil, Australopithecus afarensis (~3-4 mln yrs ago), had skulls with internal volumes ...


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Although the exact site of action potential generation is debated, as well as the underlying physiological mechanism (Colbert & Johnsten, 1996), it is generally agreed upon that the initiation site is beyond the soma and namely at the axon hillock, or even further in the initial segment of the axon. The reason for the distal axonal initiation site of ...


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Short answer The causes of death after heroin, cocain or cannabis overdose are mainly due to cardiac and respiratory arrest, and not to neurotoxic effects. Background The cause of death after a lethal overdose of your mentioned drugs, and heroin for reference, are the following : Cocaine (lethal dose: 30 mg - 5 g via mucus membrane (EMCDDA)): ...


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Short answer Image blur on the retina is the most important monocular cue for lens accommodation. Background Focussing of an image on the retina is mediated by the lens. Re-shaping of the lens to focus the image on the retina is called accommodation. In general , the main cues for focussing are retinal disparity and blur, and to a lesser extent proximal ...


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Short answer Sleep negatively impacts attention, in turn leading to decreased control of balance in challenging situations. Background Schlesinger et al. (1998) argue that under normal conditions, postural control appears to be automatic, and to require little or no attention in young, healthy adults during quiet standing with full sensory input. However, ...


2

≈Yes, it's easy to conceptualize at a simple ganglionic circuit. A really good example is (I believe from Kandel's lab)demonstrated by Aplysia's gill withdrawal reflex. Repeated stimulation causes reduced EPSPs in motor neurons that innervate muscles that cause the withdrawal reflex. However when you apply a electric shock to the tail, the snail will ...


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I think that the type of fMRI you are referring to is blood-oxygenation-level-dependent fMRI or BOLD fMRI. The principle behind MRI in general is the detection of proton signals from water molecules. The proton signal is generated by magnetizing the protons in tissue, which causes their spin to change. A subsequent powerful radio wave disrupts this spin ...


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Remember that the action potential gets more positive in the first place, so increasing positivity is achievable. Net Na+ movement into the cell makes the potential more positive. This occurs as the Na+ gate (right on the image below) are open. The key message is that the membrane can move charge to cause an increase in either positive and negative ...


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Circulation of cerebrospinal fluid (CSF) through the ventricular system is driven by motile cilia on ependymal cells of the brain. Hagenlocher C1, Walentek P, M Ller C, Thumberger T, Feistel K.Ciliogenesis and cerebrospinal fluid flow in the developing Xenopus brain are regulated by foxj1.Cilia. 2013 Sep 24;2(1):12. doi: 10.1186/2046-2530-2-12.


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As far as I can see this paper is being a little misleading, by saying "VPA mimics Nogo-66 receptor deletion". The action of VPA doesn't seem to be related to this receptor. It seems that blocking this receptor and applying VPA both increase plasticity, but it is like taking a car or taking a train -- entirely different modes of transport that achieve the ...


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This is the figure OP talks about: Negative Conductance Caused by Entry of Sodium and Cesium Ions into the Potassium Channels of Squid Axons, Francisco Bezanill, Clay M. Armstrong (1972). Short answer is that in non-linear mode of ion channel operation other ions start passing through it (channel loses specificity). Cumulative effect (because of ...



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