Nonmonotonic spatial structure of interneuronal correlations in prefrontal microcircuits

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Single neuron discharges typically show decreasing correlations with distance in sensory cortices.
• This decay reflects reduced lateral connection probability and excitation.
• However, nonmonotonic correlation structures are theoretically possible in association cortices.

Purpose of the Study:

• To investigate the spatial structure of functional connectivity in the macaque prefrontal cortex.
• To determine if nonmonotonic correlation structures exist in this brain region.
• To explore the influence of behavioral states (wakefulness vs. anesthesia) and stimuli on this structure.

Main Methods:

• Recorded correlated fluctuations of single neuron discharges in the macaque prefrontal cortex.
• Analyzed functional connectivity kernels as a function of lateral distance.
• Compared correlation structures during wakefulness and anesthesia.
• Examined the role of correlated variability between functionally similar neurons during visual stimulation.

Main Results:

• A spatially nonmonotonic correlation structure with significant long-range positive correlations was identified in the inferior convexity of the prefrontal cortex.
• This structure was more pronounced during wakefulness compared to anesthesia.
• The pattern was largely explained by correlated variability between similar neurons during visual stimulation.

Conclusions:

• The spatial decay of lateral functional connectivity is not a universal principle across all neocortical microcircuits.
• A nonmonotonic correlation structure in the prefrontal cortex may be a key feature for integrative cognitive functions.
• This finding challenges traditional models of cortical connectivity and highlights the unique organization of prefrontal circuits.