In the visual thalamus, neurons are in contact with both eyes but respond to only one:
We have two eyes, but perceive the tree in front of us only once. Our brain therefore has the complicated task of combining the information of both eyes in a meaningful way. To do so, visual stimuli first travel from the retina via so-called ganglion cells to the visual thalamus. There, the information does end up in clearly defined areas -- depending on the type and eye-of-origin of retinal ganglion cells transporting the visual stimuli. Signals from the right and left eye are thus clearly separated in the visual thalamus and independently transmitted to the visual cortex. Only in this brain region, the incoming information is combined -- at least according to a long-standing theory.
However, recent anatomical studies describe that a surprising number of neurons in the mouse visual thalamus has contact to both eyes. Does the separation of 'left eye' and 'right eye' information channels not hold true in mice? Scientists from Tobias Bonhoeffer's department wanted to shed more light on this newly raised question. They further developed an optogenetic method, so that they could activate ganglion cells of both eyes successively with light of different colors and measure the corresponding electrical responses in a thalamic cell.
Journal Reference:
Joel Bauer, Simon Weiler, Martin H.P. Fernholz, David Laubender, Volker Scheuss, Mark Hübener, Tobias Bonhoeffer, Tobias Rose. Limited functional convergence of eye-specific inputs in the retinogeniculate pathway of the mouse. Neuron, 2021; DOI: 10.1016/j.neuron.2021.05.036
(Score: 2, Funny) by Anonymous Coward on Sunday June 20 2021, @12:03AM
Can you see both sides of the argument at once?
(Score: 1, Interesting) by Anonymous Coward on Sunday June 20 2021, @04:26AM
A better summary [www.mpg.de] [www.mpg.de] is also available from the research institute MPG.
I would like to read the original paper but I cannot because it is unfortunately behind the Great Paywall and other options are not working at the moment. The conclusions of this research as described in the summary do not seem to be justified by the experimental method and results. The results in the summary are enough to show only "limited functional connection" and "ocular dominance" in the LGN spiking responses, but some kind of binocular functional connection could still occur under other stimuli, conditions, and protocols which the experiment did not investigate. It is difficult to prove a negative.
(Score: 3, Informative) by dltaylor on Sunday June 20 2021, @09:18AM
Off-hand this looks like another case of extrapolation from too little data. Rodents do predate, but are also significant prey, so their eyes are rather more lateral than primates. The function of "seeing" in rodents may have little to do with the same function in primates. Can they fMRI some primates?
FWIW, many humans are cross-dominant, including me. I function almost exclusively right-handed, but my brain relies more on data from the left eye. Simple test: focus on an object apparently narrower than that a finger at arm's length and cover the object with a finger; most people will see a double image of finger, but one of them will more strongly obscure the distant object; alternately close each eye and discover which eye is dominant for you.
(Score: 2) by acid andy on Sunday June 20 2021, @09:05PM
I wrote on this subject [soylentnews.org] before but I'm not sure many people saw it:
If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?