Multimodal cortical sensory pathways revealed by sequential transcranial electrical stimulation in mice

Area of Science:

• Neuroscience
• Sensory processing
• Cortical circuitry

Background:

• Understanding polysynaptic cortical pathways is crucial for deciphering brain function.
• Multimodal sensory integration allows for a cohesive perception of the environment.

Purpose of the Study:

• To investigate polysynaptic cortical pathways linking primary sensory areas to multimodal association areas in mice.
• To identify the role of specific brain regions, particularly area 2, in sensory integration.

Main Methods:

• Utilized transcranial flavoprotein imaging.
• Applied sequential transcranial electrical stimulation (TES) to map neural activity.
• Investigated pathways from primary visual (V1), somatosensory (S1), and auditory (A1) cortices.

Main Results:

• Mapped reciprocal connections between V1 and V2, and V2 to area 2.
• Identified pathways from S1 to S2 and then to area 2.
• Revealed auditory pathways from A1 to area 22 and anterior auditory field to area 2.
• Demonstrated area 2's connections with parietal association cortex (PtA) and retrosplenial cortex (RSA).
• Visualized a pathway from RSA through anterior cingulate cortex (aCC) to frontal areas.

Conclusions:

• Area 2 receives input from primary visual, somatosensory, and auditory cortices.
• Area 2 projects to parietal association cortex, potentially integrating multimodal sensory information.
• These findings suggest a significant role for area 2 in multimodal sensory integration in mice.