Encoding social preference by interhemispheric neurons in the Insula

Abstract

The Insula is a multisensory relay that participates in socio-emotional processing through multiple projections to sensory, cognitive, emotional, and motivational regions. Interestingly, the Insula interhemispheric projection to the contralateral Insula is a strong but understudied projection. Using cutting-edge neuroanatomy, ex vivo and in vivo electrophysiology associated with specific circuit manipulation, we unraveled the nature and role of Insula interhemispheric communication in social and anxiety processing in mice. In this study, we 1) characterized the anatomical and molecular profile of the interhemispheric neurons of the Insula, 2) highlighted that stimulation of this neuronal subpopulation triggers excitation in the Insula interhemispheric circuit 3) uncovered their engagement in social processing. In conclusion, this study demonstrates that interhemispheric neurons of the Insula constitute a unique class of Insula neurons and proposes new meaningful insights into the neuronal mechanisms underlying social behavior.

Social affective behaviors among female rats involve the basolateral amygdala and insular cortex

“…For BLA injections, data were included if the lowest point of cannula damage was found in the BLA. It is important to note that some rats only had unilateral injections but were included if cannula placement was correct in order to minimize the amount of animals used [ 62 ]. Social interaction and preference behaviors were analyzed using a repeated measures Analysis of Variance (ANOVA).…”

The neurophysiological basis of stress and anxiety - comparing neuronal diversity in the bed nucleus of the stria terminalis (BNST) across species

“…Even though the BNST is larger (in proportion to brain size) and more developed in humans, rs/fMRI data seems to support a high level of conservation of inputs across species with humans exhibiting some new and stronger connections with some cortical regions ( Avery et al, 2014 ). An interesting connection seen in both rodent and human BNST is with the insular cortex ( Dong et al, 2001a ; Avery et al, 2014 ; Flook et al, 2020 ; Sun et al, 2023 ) which is thought to regulate BNST activity in relation to affective behavior ( Luchsinger et al, 2021 ; Glangetas, 2022 ). Interesting is this regard is the presence of so-called Von Economo or spindle cells which are found in high numbers in insular cortex and other anterior limbic areas in humans but not in many other primates or species, potentially providing a unique input and regulation of BNST in humans only ( Seeley et al, 2012 ; Table 1 ).…”