Dissection of insular cortex layer 5 reveals two sublayers with opposing modulatory roles in appetitive drinking behavior

Makoto Takemoto; Shigeki Kato; Kazuto Kobayashi; Wen-Jie Song

doi:10.1016/j.isci.2023.106985

Dissection of insular cortex layer 5 reveals two sublayers with opposing modulatory roles in appetitive drinking behavior

iScience. 2023 May 26;26(6):106985. doi: 10.1016/j.isci.2023.106985. eCollection 2023 Jun 16.

Authors

Makoto Takemoto¹, Shigeki Kato², Kazuto Kobayashi², Wen-Jie Song^{1

3}

Affiliations

¹ Department of Sensory and Cognitive Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
² Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan.
³ Center for Metabolic Regulation of Healthy Aging, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan.

Abstract

The insular cortex (insula) is known to play a modulatory role in feeding and drinking. Previous studies have revealed anterior-posterior differences of subcortical projections and roles for the insula, yet the anatomical and functional heterogeneity among the cortical layers remains poorly understood. Here, we show that layer 5 of the mouse dysgranular insula has two distinct neuronal subpopulations along the entire anterior-posterior axis: The L5a population, expressing NECAB1, projects bilaterally to the lateral and capsular divisions of the central amygdala, and the L5b population, expressing CTIP2, projects ipsilaterally to the parasubthalamic nucleus and the medial division of the central amygdala. Optogenetically activating L5a and L5b neuronal populations in thirsty male mice led to suppressed and facilitated water spout licking, respectively, without avoidance against or preference for the spout paired with the opto-stimulation. Our results suggest sublayer-specific bidirectional modulatory roles of insula layer 5 in the motivational aspect of appetitive behavior.

Keywords: Behavioral neuroscience; Neuroscience.