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34

For simplicity's sake, let's really reduce this to something like photography. A camera's aperture can stay open indefinitely, allowing the plate (or whatever is receiving and recording light) to "collect and save the effect of photons" over time, if you want to phrase it that way. That allows a camera to make images that our eyes never can, for example, of ...


14

The simple answer is, that eye is not constructed such way. The eye have much more "pixels" than "links" to the brain and sends in "preprocessed" image. Moreover the the eye is constantly moving and scanning the "area of vision" and the body and head are supposedly also moving (willingly or not - nobody can freeze totally) so longer accumulation of data ...


11

The differences at the photoreceptor level have been addressed by others. The mechanical restrictions of the visual system were shortly hinted at by @gilhad et al., but deserve more attention in my opinion. First off, in darkness we cannot focus on an object and our eyes will move. And even when we focus on a specific point there is always movement of the ...


11

There's probably a theoretical capacity to do so. The brain is amazingly good at signal processing, and could probably pull off such a summation. However, there is a limit. You have to hold very very still for it to work. Go take one of the time lapse pictures, like anongoodnurse's answer posted. The shutter is open for quite some time (her picture ...


4

The center-surround structure is created by the horizontal connectivity of the horizontal cells (Periman et al., 2012) that receive input from multiple photoreceptors (Fig. 1). Fig. 1. Retinal patch showing the connectivity between a horizontal cell and photoreceptors. Source: Harvey Mudd College The horizontal cell passes on the congregate output to the ...


3

The vector used in this study is based on the herpes simplex virus genome (HSV). Wildtype HSV mainly infects sensory neurons. After infection, it resides in a latent state in the nervous systems of the host for a lifetime. The viral genome persists in the cell, without integrating into the host genome (Marconi et al., 2000). The article cited is devoid of ...


2

Blood pressure is sensed in blood vessels by baroreceptors. Baroreceptors are stretch-sensitive nerve fibers located primarily in the aortic arch and carotid sinuses. The baroreceptors send aFferent fibers via the glossopharyngeal nerve to the nucleus tractus solitarii in the dorsal medulla in the brainstem. From there, efferent cardiovascular neurons send ...


2

Pretty much all answers which focus on movement of the eye causing blur (something a digital camera does not have to deal with) are wrong. The brain has absolutely no problem processing images in low-light at speed. The answer is all to do with the fact that the eye is not a camera. Much of the old-school theories which where based on the fact that the eye ...


2

I would argue the all-or-none principle is a rule of thumb. It is generally true if voltage hits a certain threshold then there will be a action potential with the same amplitude regardless the strength of the stimuli. But as you point out with the logic gate example, the threshold is notoriously hard to define mathematically. Furthermore Action Potentials ...


2

Since you tagged this with neuroscience, I'm going to assume the two forms you see are these: The top one is what you might call the "no assumptions form". Temperature is left as a variable, T, and will have to be plugged in, and one will also have to plug in the gas constant (R), Faraday's constant (F), and the valence (z) of the ion (X) in question when ...


2

What I believe you are referring to, is the phenomenon by which the camera adjusts light exposure by adjusting aperture. We can also do this, but it happens very fast. Go from a dark room to a brighter room and you will be blinded, but that effect soon subsides, and vice-versa. The pupil opens up in a dark room and production of visual purple or Rhodopsin ...


1

The term noise can mean a number of different (more or les related) things is used in a number of different fields such as signal processing, psychology and statistics. Outside of its context, it is impossible to say for certitude what you professors were referring to. The quotations below come from wikipedia > Communication noise, wikipedia > Statistical ...


1

The major hurdle for novel treatments to make it into humans is the assessment of its merits and added value over existing, proven treatments. And more importantly, the safety for humans has to be validated to a sufficient extent. The notorious from bench to bedside (Goldblatt & Lee, 2010) bottle neck. To answer your questions: Technically, going from ...


1

It seems like you suffer from a misconception. "The left eye sees more of the left side of an object..." is not how distance perception works. Otherwise we wouldn't be able to estimate the distance from flat objects, such as traffic signs and shooting targets. The actual mechanism is parallax estimation, or Binocular disparity. In a nutshell, the closer an ...


1

Unfortunately, there is no way to know how many sodium channels are active (or even present) in one person's brain due to the extremely high variability of channel and neuron density in a population and the lack of methodology around quantifying total number of healthy active synapses (1). Diseases like epilepsy can occur due various points of the sodium ...



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