Neuronal timescales are functionally dynamic and shaped by cortical microarchitecture.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Computational Neuroscience

Background:

• Complex cognitive functions rely on maintaining information over diverse timescales.
• Theoretical models predict a hierarchy of neuronal timescales in the cortex.
• Empirical electrophysiological evidence for this hierarchy across the human cortex is limited.

Purpose of the Study:

• To investigate the hierarchy of neuronal timescales across the human cortex using invasive electrophysiological recordings.
• To correlate neuronal timescales with gene expression patterns and cognitive functions.
• To examine the dynamic nature of neuronal timescales in relation to working memory and aging.

Main Methods:

• Inferred neuronal timescales from invasive intracranial recordings in humans.
• Analyzed cortex-wide transcriptomic data to assess gene expression.
• Correlated timescales with gene expression of excitation/inhibition and ion transporters.
• Examined prefrontal cortex activity during working memory tasks.
• Assessed the impact of aging on neuronal timescales.

Main Results:

• Neuronal timescales exhibit a hierarchical organization, increasing along the sensorimotor-to-association axis of the human cortex.
• Timescales align with the expression of genes related to neuronal excitation, inhibition, and ion transport.
• Prefrontal cortex timescales expand during working memory maintenance, predicting performance.
• Neuronal timescales compress across the cortex with aging.

Conclusions:

• Neuronal timescales are organized according to cytoarchitectonic gradients in the human cortex.
• Neuronal timescales are linked to molecular and genetic factors.
• Neuronal timescales are functionally dynamic and play a critical role in cognition, from short-term working memory to long-term processes and are affected by aging.