Researchers at Baylor College of Medicine working with animal models report in the journal Neuron that during social isolation, astrocytes become hyperactive, which in
turn suppresses brain circuit function and memory formation.
Importantly, inhibiting astrocyte hyperactivity reversed the cognitive
deficits associated with social deprivation.
“One
thing we have learned during the COVID pandemic is that social
isolation can influence cognitive functions, as previous studies
suggested,” said co-first author, Yi-Ting Cheng, graduate student in Dr.
Benjamin Deneen’s lab at Baylor. “This motivated co-first author Dr.
Junsung Woo and me to further investigate the effects of social
isolation in the brain, specifically in astrocytes.”
Astrocytes
play diverse roles in the brain such as supporting the functions of
neurons, participating in synapse formation and function, releasing
neurotransmitters and making the blood-brain barrier.
“Under
normal group housing conditions, astrocytes facilitate and promote
circuit function and memory,” said Deneen, professor and Dr. Russell J.
and Marian K. Blattner Chair of neurosurgery and director of the Center
for Cancer Neuroscience at Baylor. He also is the corresponding author
of the work.
“However,
we found that during social deprivation, astrocytes in the brain region
known as the hippocampus actually suppress circuit function and memory
formation. The broad conclusion is that astrocyte function is tuned to
social experiences.”
Looking
for a deeper understanding of the mechanism by which astrocytes of
socially-isolated mice cause learning and memory deficits, the
researchers studied calcium ions (Ca2+), which previous studies had shown play a central role in astrocyte-mediated learning and memory behaviors.
“We evaluated the effect of social deprivation on astrocyte Ca2+ activity and discovered that social isolation greatly increased it, specifically the activity involving Ca2+ channel TRPA1. This in turn was followed by the release of the
inhibitory neurotransmitter GABA that put a break on neural circuits
involved in memory and learning,” Cheng said.
“Importantly,
both pharmacological and genetic inhibition of TRPA1 reversed the
physiological and cognitive deficits associated with social
deprivation.”
“Although
social isolation also affects other brain cells, we are very excited
about the discovery that specifically manipulating astrocytes is enough
to restore learning and memory deficits triggered by social isolation in
animal models,” Deneen said.
“Our
findings show a new role for astrocytes in brain physiology,” Cheng
said. “What astrocytes do is affected by changes in the environment and
will reflect in the animal’s behavior. In this case, we learned that
social interaction is good for astrocytes and therefore, for the brain.”
About this social isolation and memory research news
Author: Graciela Gutierrez
Source: Baylor College of Medicine
Contact: Graciela Gutierrez – Baylor College of Medicine
Image: The image is in the public domain
Original Research: Closed access.
“Social deprivation induces astrocytic TRPA1-GABA suppression of hippocampal circuits” by Yi-Ting Cheng et al. Neuron