The insulo-opercular cortex encodes food-specific content under controlled and naturalistic conditions

Abstract

The insulo-opercular network functions critically not only in encoding taste, but also in guiding behavior based on anticipated food availability. However, there remains no direct measurement of insulo-opercular activity when humans anticipate taste. Here, we collect direct, intracranial recordings during a food task that elicits anticipatory and consummatory taste responses, and during ad libitum consumption of meals. While cue-specific high-frequency broadband (70–170 Hz) activity predominant in the left posterior insula is selective for taste-neutral cues, sparse cue-specific regions in the anterior insula are selective for palatable cues. Latency analysis reveals this insular activity is preceded by non-discriminatory activity in the frontal operculum. During ad libitum meal consumption, time-locked high-frequency broadband activity at the time of food intake discriminates food types and is associated with cue-specific activity during the task. These findings reveal spatiotemporally-specific activity in the human insulo-opercular cortex that underlies anticipatory evaluation of food across both controlled and naturalistic settings.

Increased functional connectivity following ingestion of dried bonito soup

“…The insular - opercular cortex is associated with spatiotemporal information regarding food intake. During meal consumption, time-locked high-frequency broadband activity at the time of food intake depends on the food types and is associated with cue-specific activity ( 32 ). The consumption of palatable foods results in greater activation of the frontal cortex and operculum/insula than the consumption of unpalatable foods ( 33 ).…”

An orexigenic subnetwork within the human hippocampus

“…Moreover, reports on hippocampal connectivity underlying dysregulated eating and obesity are lacking, and conspicuously absent are studies examining hypothalamic inputs in humans. Individuals undergoing brain mapping with intracranial electrophysiology provide a unique opportunity to overcome these limitations in the interrogation of specific regions of interest during controlled assays such as a food-incentive paradigm 12 .…”

“…We measured local field potential activity (Fig. 1b ) using intracranial electrodes ( n = 54; 34 dlHPC contacts, 20 non-dlHPC contacts) implanted into the human hippocampus while the participants ( n = 9) performed a sweet-fat incentive task paradigm 12 (Supplementary Fig. 1a ).…”

A common neural code for representing imagined and inferred tastes

“…Multiple imaging modalities, including studies employing fMRI [3][4][5][6][7]13], EEG [19], MEG [20], intracranial EEG [21], and cortical electrode stimulation [22] indicate that the dorsal midinsula is the location of 'primary' gustatory cortex. However, the responsiveness of the dorsal mid-insula, not just to taste, but to inferred and explicitly imagined taste, as well as its responsiveness to other sensory modalities, mentioned above, suggest that this region is not simply a primary cortical sensory region for taste, but rather a multimodal association region.…”