Hippocampal Glutamatergic Hyperactivation Mediates High-Loading Intensity of Exercise-Induced Cognitive Deficits Via HPC-mPFC Circuit Dysfunction.

AIMS: Excessive exercise impairs cognition and elevates late-life cognitive risk. However, the underlying mechanisms remain unclear. This study investigates the neural mechanisms through which high-intensity endurance exercise induces cognitive deficits.

METHODS

Mice underwent high-loading intensity exercise (HLIE) with a 7-day treadmill procedure (25 m/min, 90 min/day). A battery of behavioral tests was conducted to assess cognitive performance, including the Morris Water Maze, Novel Object Recognition, and Y Maze. fMRI and c-Fos activity mapping were employed to identify key brain regions affected by HLIE. Single-nucleus RNA sequencing (snRNA-seq) was conducted to analyze transcriptional changes associated with disrupted neural activity. We used chemogenetic inhibition to identify the role of hippocampal glutamatergic neurons in HLIE-induced cognitive deficits.

RESULTS

HLIE caused significant spatial and working memory deficits. The hippocampus (HPC) was the primary brain region affected, exhibiting reduced functional connectivity with the medial prefrontal cortex (mPFC) and disrupted transcriptional profiles linked to neural activity. Further, hippocampal glutamatergic neurons were particularly activated by HLIE, and chemogenetic inhibition prevented cognitive function following HLIE exposure.

CONCLUSION

HLIE impairs cognition via hippocampal glutamatergic neuronal hyperactivation and downstream HPC-mPFC circuit dysfunction. Our findings identify neuronal calcium dysregulation as a targetable mechanism for preserving cognition in high-intensity exercise paradigms.