Visceral-related area in the rat insular cortex

Area of Science:

• Neuroscience
• Autonomic Nervous System Research

Background:

• The insular cortex plays a crucial role in integrating visceral sensory information.
• Autonomic dysfunction is linked to neurological and psychosomatic disorders, with the insular cortex interacting with bulbar autonomic nuclei.

Purpose of the Study:

• To identify specific sites within the rat insular cortex responsible for gastrointestinal, respiratory, and cardiovascular autonomic responses.
• To elucidate the viscerotopic organization of autonomic control within the insular cortex.

Main Methods:

• Microinjections of horseradish peroxidase (HRP) into the bulbar dorsal vagal complex.
• Microstimulation of discrete sites within the rat insular cortex.
• Analysis of retrograde-labeled neurons in the insular cortex.

Main Results:

• A specific neuronal group in the middle insular cortex projects to the gastric region of the dorsal vagal complex.
• Microstimulation elicited gastric motor responses and altered respiratory airflow, with distinct patterns for middle and caudal insular cortex sites.
• Cardiovascular changes (blood pressure) accompanied respiratory responses.

Conclusions:

• Autonomic representation in the rat insular cortex is organized in a viscerotopic manner.
• The middle insular cortex controls gastrointestinal functions and inhibitory respiratory responses.
• Caudal insular cortex regions are involved in excitatory respiratory control and cardiovascular regulation.