Introducing the brain: serotonin controls visual information (Introduction)

by David Turell , Tuesday, April 04, 2023, 17:25 (597 days ago) @ David Turell
edited by David Turell, Tuesday, April 04, 2023, 17:34

Information sent to the thalamus:

https://medicalxpress.com/news/2023-04-serotonin-gates-visual-eyes-thalamus.html

"Humans are known to perceive the environment around them differently based on the situation they are in and their own feelings and sensations. Internal states, such as fear, arousal or hunger can thus affect the ways in which sensory information is processed and registered by the brain.

"Researchers at Beth Israel...have recently carried out a study investigating the possible effects of serotonin, a neurotransmitter known to regulate sleep, mood, sexual desire, and other inner states, in the processing of visual information. Their findings, published in Neuron, suggest that serotonergic neurons in the brainstem (i.e., the central trunk of the mammalian brain) gate the transfer of visual information from the eyes to the thalamus, an egg-shaped area of the brain.

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"Chen, her collaborator Mark Andermann, and their colleagues specifically explored the effects of serotonin on the early processing of visual information and its transfer from the eyes to the thalamus. To do this, they used a technique known as two-photon calcium imaging to track the activity of individual retinal axons in the brains of awake mice as they viewed visual images on a computer monitor.

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"The experiments carried out by this team of researchers yielded very interesting results. Notably, they showed that serotonin can suppress calcium signals in retinal axons and the release of glutamate in the thalamus. This ultimately reduces the transmission of visual signals from the eye to the thalamus.

"When they analyzed their results more in detail, Andermann, Chen, and their colleagues found that some classes of retinal axons tended to be more suppressed by serotonin, with classes that responded to broad changes in light levels being more affected than those responding to fine visual details.

"The researchers also compared the selective modulation observed in their experiments to that naturally occurring when animals or humans are highly aroused. They found that periods of high arousals that were not accompanied by an increase in the release of serotonin tended to suppress the retinal axons transmitting information about fine details, rather than changes in light levels.

"Overall, the results of this study confirm that different internal states can impact the processing of separate types of visual information. In the future, this insight could inform new studies exploring the impact of neuromodulatory systems on downstream brain areas and on perception in animal models and humans, potentially leading to interesting new discoveries."

Comment: This demonstrates that the brain is not just neuron connections but has influences by neuroactive proteins like serotonin, adrenalin, glutamine, etc.