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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 ...


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 ...


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 ...


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 ...


0

One event that comes to mind is the use of radiation on cancer patients. Radiation is an external event that can trigger apoptosis in humans 1. When cancer patients receive radiation, the treatment is localized. The brain isn't telling the cells to die it is the radiation effects on the cell. Ionizing radiation can also induce apoptosis via the ...


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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 ...


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 ...


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 ...


0

Nice question! The first question, namely what is the advantage of color opponency 'against' RGB, is technically incorrect. The opponent system (Red/Green; Blue/Yellow and brightness channels) is physiologically situated in the neuronal retinal layer and higher visual structures such as the lateral geniculate nucleus and receives input from the RGB system ...


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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