Neuronal architecture of the mouse insular cortex underlying its diverse functions

Area of Science:

• Neuroscience
• Cellular Biology
• Systems Neuroscience

Background:

• The insular cortex integrates sensory information for homeostasis, emotion, and consciousness.
• Cellular and circuit mechanisms of the insula are less understood than primary cortices.

Purpose of the Study:

• To comprehensively characterize insular pyramidal neurons' morphology, electrical properties, and inputs.
• To establish a quantitative anatomical and functional framework for the insular cortex.

Main Methods:

• Quantified dendritic morphology, electrical properties, and local inputs of 1,093 insular pyramidal neurons.
• Mapped neurons onto a quantitative anatomical model of the insula.
• Utilized improved algorithms to define neuronal types.

Main Results:

• Defined 21 morphological, 12 electrical, and 9 input neuronal types, with several unique to the insula.
• Found morphological properties predict neuronal inputs, electrical characteristics, and projection targets.
• Identified differential distribution of neuronal types between anterior and posterior insula, and long-range intra-insular connections.

Conclusions:

• Established a detailed classification of insular pyramidal neurons, providing a structural basis for functional specialization.
• Revealed novel neuronal types and connectivity patterns within the insula, including long-range inputs.
• Provided a quantitative foundation for future research on the insular cortex's role in complex cognitive functions.