Vision is the most vital senses of human behaviour. Eyes which plays an integral part communicates with the brain through a specific signalling pathway. But recently, it was found that retinal neurons take a different path. Eyes solely send excitatory signals (signals which enable neurons to fire more). However, Researchers of Northwest University discovered some subset of retinal neurons, which sends inhibitory signals(enables neurons to fire less) to the brain. These neurons assist subconscious behaviours, for instance, pupil constriction to intense bright lights and synchronization of circadian rhythms to light or dark cycles.
” These inhibitory signals prevent our circadian clock from resetting to dim light and prevent pupil constriction in low light, both of which are adaptive for proper vision and daily function”
said Tiffany Schmidt. (Research Scientist)
Schmidt and her team used “mouse model” to block the retinal neurons and their studies revealed that dim light was more effective at shifting the mice’s circadian rhythms. They concluded the presence of an inhibitory signal from the eye that hindered realignment of circadian rhythms when exposed to different light environments. This mechanism restricts pupils from contracting under very low light, allowing the intake of more light and thereby making it easier to see in low light conditions. Further studies could benefit a better understanding of retinal neuron’s behaviour in different light environments.
References :
https://news.northwestern.edu
https://www.sciencedaily.com
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