Science Topics – 176

Unraveling the brain’s inhibitory pathways: From vision to action

Takahiro Osada (Seiki Konishi)

n everyday life, we constantly adjust our behavior by suppressing inappropriate actions and selecting appropriate ones in response to changing situations. This ability, known as response inhibition, involves multiple brain regions, primarily within the frontal lobe, but its detailed information processing pathways have remained elusive. In this study, we investigated the human neural circuits underlying response inhibition using functional magnetic resonance imaging (fMRI) and non-invasive brain stimulation techniques, including transcranial ultrasound stimulation (TUS) and transcranial magnetic stimulation (TMS). We measured brain activity during a "stop-signal task" with fMRI and examined anatomical connectivity between brain regions using diffusion MRI. Our findings revealed a four-step information processing pathway: from the primary visual cortex (V1) to the anterior insular cortex (daINS), then to the inferior frontal cortex (IFC), and finally to the basal ganglia (BG) and primary motor cortex (M1). Furthermore, by combining TUS and TMS, we examined causal interactions between these regions and found that the daINS exerts an influence on the ventral posterior IFC (vpIFC), which in turn unidirectionally influences the anterior IFC (aIFC). These results suggest that response inhibition is mediated through a structured neural circuit: V1→daINS→vpIFC/aIFC→BG/M1. Notably, the daINS serves as a critical bridge between sensory integration and action control, while the vpIFC and aIFC play distinct functional roles, collectively enabling efficient response inhibition.

Multiple insular-prefrontal pathways underlie perception to execution during response inhibition in humans.
Osada T, Nakajima K, Shirokoshi T, Ogawa A, Oka S, Kamagata K, Aoki S, Oshima Y, Tanaka S, Konishi S.
Nature Communications 15(1): 10380, 2024.
https://www.nature.com/articles/s41467-024-54564-9
DOI: 10.1038/s41467-024-54564-9

＜Figure Legends＞
(A) Stop-signal task used to investigate response inhibition. The task consists of Go trials, where participants press a button as quickly as possible in response to a left or right arrow, and Stop trials, where the arrow changes to an up-pointing arrow shortly after appearing, signaling participants to withhold their response.
(B) Information processing pathway underlying response inhibition identified in this study. From visual recognition to action cancellation, we identified a neural pathway spanning the primary visual cortex (V1), dorsal anterior insular cortex (daINS), inferior frontal cortex (ventral posterior IFC [vpIFC] and anterior IFC [aIFC]), basal ganglia (BG), and primary motor cortex (M1).

Department of Neurophysiology, Juntendo University School of Medicine, Tokyo, Japan