Astrocyte and L-lactate in the anterior cingulate cortex modulate schema memory and neuronal mitochondrial biogenesis.
Level 5 - mechanism / opinion, no new human data
Preclinical animal mechanism study without human data
PubMed 37960975 · doi:10.7554/eLife.85751
What was done
Researchers activated the astrocytic Gi signaling pathway chemogenetically in the anterior cingulate cortex (ACC) of rats. They evaluated performance on flavor-place paired associates (PA) learning, schema formation, and PA memory retrieval, both with and without bilateral exogenous L-lactate administration into the ACC. They also examined the relationship between astrocytic Gi activation, ACC L-lactate levels, neuronal mitochondrial biogenesis, and the involvement of monocarboxylate transporter 2 (MCT2) and NMDA receptors.
What was found
Astrocytic Gi activation in the ACC impaired flavor-place PA learning, schema formation, PA memory retrieval, and subsequent new PA learning. These deficits were mediated by reduced ACC L-lactate and were rescued by bilateral exogenous L-lactate administration. Furthermore, Gi activation reduced neuronal mitochondrial biogenesis via decreased L-lactate, an effect found to require MCT2 and NMDA receptor activity. The abstract reported these directional effects without providing specific numerical values, test statistics, or sample sizes.
Why it matters
The study outlines a specific pathway linking astrocytic Gi signaling and L-lactate release to cortical schema memory and neuronal mitochondrial biogenesis. It identifies a non-metabolic signaling role for L-lactate acting through MCT2 and NMDA receptors in complex learning.
Limits
The findings are derived entirely from rodent experiments; relevance to human cognitive processes and clinical memory disorders is unverified. The abstract does not report animal sample sizes, effect sizes, or quantitative physiological measurements, and testing was limited to a specific flavor-place associative paradigm.
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