Long-range population dynamics of anatomically defined neocortical networks

Area of Science:

• Neuroscience
• Systems Neuroscience
• Sensory Processing

Background:

• Neocortical coordination is vital for mammalian brain function.
• Simultaneous functional measurements across cortical areas are needed to understand this coordination.
• Targeting anatomically projecting neuronal subpopulations is crucial to distinguish direct cortico-cortical interactions.

Purpose of the Study:

• To investigate simultaneous activity across mouse primary (S1) and secondary (S2) somatosensory whisker cortex.
• To identify and analyze feedforward and feedback neurons involved in inter-areal communication.
• To determine the role of direct S1-S2 interactions during texture discrimination behavior.

Main Methods:

• Combined anatomical tracers with a novel multi-area two-photon microscope.
• Performed simultaneous calcium imaging in S1 and S2 whisker cortex during behavior.
• Identified feedforward and feedback neurons based on anatomical projections.

Main Results:

• S1-S2 activity coordination increased during motor behaviors like whisking and licking.
• This coordination was not limited to identified feedforward and feedback neurons.
• Mutually projecting neurons showed increased inter-areal coordination when motor behavior was paired with whisker-texture touches, indicating sensory dependence.

Conclusions:

• Demonstrated specific functional coordination of anatomically identified projection neurons across sensory cortices.
• Direct S1-S2 interactions are sensory-dependent, particularly during active touch.
• Findings provide insights into the neural mechanisms of sensory integration and sensorimotor control.