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9

First, I must clarify that a nerve is not the same as a neuron. A nerve is a collection of axons (with each axon a part of an individual neuron) in the peripheral nervous system. Thus, when you mention “single long axon such as the sciatic nerve”, this is technically an incorrect phrase as the sciatic nerve is a collection of many long axons. If one of these ...


7

The problem is that box jellyfish doesn't specify one jellyfish but a group of different jellyfish. Some of these are highly venomenous - I pick here Chironex fleckeri, as this is often called "the most venemous jellyfish in the world". Chironex fleckeri has long tentacles which are covered with millions of explosive cells called Cnidocytes which inject a ...


7

The short answer is: Yes. Fatal familial insomnia is a genetically passed down disease that at some random point in a carriers life will suddenly stop them from sleeping, ever, they die within 7 to 18 months I know you did not ask about the disease, but it shows (even without illegal war tests) that it will kill you eventually, even in humans. I believe ...


4

Interesting question! You ask 3 questions if I am correct: What is tDCS; What are the adverse effects of tDCS (at 0.1 - 2 mA); What are the health benefits (enhanced focus); I will answer your questions one by one: (1) What is tDCS: tDCS devices are TransCranial Direct Current Stimulation (tDCS) devices. They send direct current through (trans) the ...


4

The pixels of the visual system are represented by the photoreceptors. Their shape is the following (adapted from "The Brain from Top to Bottom, MgGill University"): There are about a 180 photoreceptors packed on 288 microns on the retina (see "What's the smallest size a human eye can see?") so about 1 pixel per 2 microns. The rods and cones are packed ...


3

If you by pixels are referring to the photoreceptors (rods & cones), their density differs over the retina, and we can only see sharp images at high resolution in a small region of our eye (fovea). So the resolution varies over the retina. The image we actually see is also a continiously interpreted and updated, and the brain is very creative in this ...


2

This is a classic Brown-Sequard syndrome well- studied in the field of neurology. To answer your question, you would need to know what tracts are being severed and what sensations each tract is responsible for. A clean R hemi-section of the spinal cord at the level of T6 would affect the 1) R lateral corticospinal tract, 2) R spinothalamic tract, and 3) R ...


2

The quick and dirty answer is: fMRI doesn't perform well in the temporal domain, but excels in the spatial domain among non-invasive imaging methods. If you need an answer as to where the action is, use fMRI. If you need answers to temporal questions, I recommend using electrophysiology such as EEG, which excels in the temporal domain, or MEG for a ...


1

The answer is, in part, it depends. Let's think of the PI3K/AKT pathway. Akt actively phosphorylates BAD which abrogates the Bax/Bak apoptosis pathway. RTK's at the plasma membrane activate this pathway when bound with survival factors. In the absence of survival factors, Akt would become dephosphorylated and you'd have a net movement toward apoptosis. In a ...


1

It is impossible to objectively answer this question, as there is no defined method to objectively tell if the animal is dizzy. All that is known is the existence of vestibular system. Vestibular system helps to define ones orientation with respect to gravity. The response of a reptile to such a stimuli would most probably be freezing as opposed to a ...



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