Cunningham, P. J. | Search bioRxiv

bioRxiv2026

Measuring excitation/inhibition balance through field potentials

Several electroencephalography-based metrics have been proposed to index excitation/inhibition balance (E/I). We used single-unit and local field potential recordings from rat medial prefrontal and orbitofrontal cortex and mouse visual cortex and hippocampus to evaluate four candidate metrics against empirically-measured E/I. While 1/f slope and gamma oscillations showed region and context dependencies, broadband (6-80 Hz) and high gamma (80-150 Hz) power consistently correlated with E/I, supporting their use as proxy measures. If at least 30 minutes' data from medial prefrontal cortex were used per animal, broadband power could rank the animals by their E/I ratio, suggesting it could be used as an individual differences measure.

neuroscience↗

bioRxiv2024

A triple dissociation across the medial, ventral, and lateral orbitofrontal cortex in rats making sequential foraging decisions

Far medial and lateral aspects of the orbitofrontal cortex (OFC) serve distinct roles in value-based decision-making, though it remains unclear how more nearby lateral and ventral aspects differ in their information-processing characteristics. The present study leveraged high-density neural recording in the lateral orbital (LO) and ventral orbital (VO) subregions using a neuroeconomic task in rats to clarify how functional heterogeneity between LO and VO participates in sequential cost-benefit foraging. LO and VO contained opposing representations of an encountered rewards subjective benefit and its associated opportunity costs, respectively. The relative balance of these representations tracked decisions to approach or leave a reward during each stage of an encounter. Opposing representations of subjective benefit in LO and opportunity costs in VO were realized by distinct clusters of cells within each subregion across stages of a reward encounter (i.e., task state). In addition, overall activity in each subregion scaled with changes in the subjective value of rewards induced by external, economic conditions (reward scarcity) and internal, motivational factors (hunger). Collectively, these results suggest that lateral and ventral OFC encode opposing representations to guide sequential foraging decisions, but using a shared coding scheme which multiplexes information about subjective value (via overall activity) and world states (via distinct ensembles).

neuroscience↗