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Researchers at University College London recently discovered a brain mechanism that allows mice to overturn their intuition based on past experience
.
The study, published in the journal Neuron, discovered a new brain circuit in the ventrolateral geniculate body (vLGN) of the mouse thalamus
.
Neuroscientists have found that when activity in this brain area is inhibited, animals are more likely to seek safety and stay away from perceived dangers, while the activation of vLGN neurons completely eliminates the escape response to threats
.
Faced with sensory stimuli, animals may act or turn a blind eye, depending on the environment or past experience
.
For example, loud noises and strong lights may cause fear reactions
.
Previous studies have shown that many brain regions are involved in processing threat stimuli and regulating fear responses, but how these responses are controlled and the specific mechanism remains unclear
.
This control is essential because its damage can cause anxiety disorders, such as phobias or post-traumatic stress disorder (PTSD)
.
Professor Sonja Hofer of the Sainsbury Wellcome Centre of University College London led a team to conduct a new study
.
They adopted a mature experimental model in which the mice responded to the expanding black shadow above their heads and fled to the refuge
.
Researchers have found that vLGN can control escape behavior based on the animal's knowledge gained through previous experience and the assessment of risks in the current environment
.
When the mice did not anticipate the threat and felt safe, the inhibitory neurons in vLGN were highly active, which in turn could suppress the threat response
.
"We believe that vLGN may be used as an inhibitory gate, setting the threshold of sensitivity to potential threat stimuli based on the animal's past experience," said Alex Fratzl, a doctoral student in Hofer's laboratory and the first author of this paper.
Say
.
The next problem the researchers focused on was to determine which areas of the brain that vLGN interacts with in order to achieve suppression of the defense response
.
They have identified one such brain area, which is the superior midbrain colliculus
.
Sonja Hofer said: "We found that vLGN specifically inhibits the superior colliculus neurons that respond to visual threats, thereby specifically blocking related regulatory pathways in the brain
.
Visual threats refer to things that animals see that may pose a danger.
Like a predator that keeps approaching
Although humans do not have to worry about predators, in some cases they will also have an instinctive fear response
.
###
Alex Fratzl, Alice M.
Koltchev, Nicole Vissers, Yu Lin Tan, Andre Marques-Smith, A.
Vanessa Stempel, Tiago Branco, Sonja B.
Hofer.
Flexible inhibitory control of visually evoked defensive behavior by the ventral lateral geniculate nucleus.
Neuron, 2021; DOI: 10.
1016/j.
neuron.
2021.
09.
003