Responses In Insular Cortex Research Articles

The neural correlates of integrated aesthetics between moral and facial beauty

Facial beauty and moral beauty have been suggested to be two significant forms of social aesthetics. However, it remains unknown the extent to which there are neural underpinnings of the integration of these two forms of beauty. In the present study, participants were asked to make general aesthetic judgments of facial portraits and moral descriptions while collecting fMRI data. The facial portrait and moral description were randomly paired. Neurally, the appreciation of facial beauty and moral beauty recruited a common network involving the middle occipital gyrus (MOG) and medial orbitofrontal cortex (mOFC). The activities of the mOFC varied across aesthetic conditions, while the MOG was specifically activated in the most beautiful condition. In addition, there was a bilateral insular cortex response to ugliness specifically in the congruent aesthetic conditions, while SMA was selectively responsive to the most ugly condition. Activity associated with aesthetic conflict between facial and moral aesthetic information was limited to the medial prefrontal cortex (mPFC), with enhanced response to the incongruent condition compared to the congruent condition. These findings provide novel neural evidence for the integrated aesthetics of social beauty and suggest that integrated aesthetics is a more complex cognitive process than aesthetics restricted to a single modality.

P.2.042 - Cocaine-induced disruptions of information flow from the basolateral amygdala to the insula

Understanding persistent dysregulations induced by chronic drug use on neuronal networks is crucial in order to develop appropriate therapeutic approach for addiction. The basolateral amygdala (BLA), involved in emotional processing, as well as the insular cortex (IC), involved in interoception, have been proposed to play a central role in cue-induced reinstatement of cocaine seeking behavior. In addition, functional imaging studies in abstinent users have shown an increased synchronization of the IC and the amygdala, which suggests dysfunction of this circuitry that could increase vulnerability to cues associated to drug use [1]. Our hypothesis is that chronic drug use induces long-lasting disruption of information processing within the amygdala-IC circuit. In particular, exposure to drug cues during abstinence, would activate this pathway and reactivate the representations of the drug’s interoceptive effects leading to intense craving and increasing the risk of relapse. The aim of the present study was to examine cocaine-induced persistent changes in i) spontaneous activity of the BLA and the IC and ii) synaptic plasticity in the BLA-IC pathway. To test this hypothesis, we first allowed rats to self-administer cocaine for 10 days (6 h/day; FR1 schedule; 0.15 mg/injection). Control “yoked” received an injection of saline, each time the paired “master” rat self-administered an injection of cocaine. After a 30-day abstinence period, we performed in vivo single-unit extracellular recordings in anesthetized rats to measure spontaneous activity of the BLA and the IC. We then studied BLA-evoked IC local field potentials (eLFPs) after theta burst electrical stimulation (six trains of 100 pulses at 100 Hz, 20s between trains), that is known to induce an LTP of IC response in control animals, and low frequency electrical stimulation (5 Hz, 200 sec), that is known to induce a depotentiation of IC response, to the BLA. Two-way ANOVAs have been performed for behavioral and synaptic plasticity data and a Mann-Whitney test has been used for spontaneous activity analysis. We found that self-administration of cocaine produces a significant increase in the bursting activity (saline: 23.8% of spikes in bursts, n=35; cocaine: 41.01% spikes in bursts, n = 43; p

Homeostatic circuits selectively gate food cue responses in insular cortex.

Physiological needs bias perception and attention to relevant sensory cues. This process is 'hijacked' by drug addiction, causing cue-induced cravings and relapse. Similarly, its dysregulation contributes to failed diets, obesity, and eating disorders. Neuroimaging studies in humans have implicated insular cortex in these phenomena. However, it remains unclear how 'cognitive' cortical representations of motivationally relevant cues are biased by subcortical circuits that drive specific motivational states. Here we develop a microprism-based cellular imaging approach to monitor visual cue responses in the insular cortex of behaving mice across hunger states. Insular cortex neurons demonstrate food-cue-biased responses that are abolished during satiety. Unexpectedly, while multiple satiety-related visceral signals converge in insular cortex, chemogenetic activation of hypothalamic 'hunger neurons' (expressing agouti-related peptide (AgRP)) bypasses these signals to restore hunger-like response patterns in insular cortex. Circuit mapping and pathway-specific manipulations uncover a pathway from AgRP neurons to insular cortex via the paraventricular thalamus and basolateral amygdala. These results reveal a neural basis for state-specific biased processing of motivationally relevant cues.

The activity in the anterior insulae is modulated by perceptual decision-making difficulty

Previous neuroimaging studies provide evidence for the involvement of the anterior insulae (INSs) in perceptual decision-making processes. However, how the insular cortex is involved in integration of degraded sensory information to create a conscious percept of environment and to drive our behaviors still remains a mystery. In this study, using functional magnetic resonance imaging (fMRI) and four different perceptual categorization tasks in visual and audio-visual domains, we measured blood oxygen level dependent (BOLD) signals and examined the roles of INSs in easy and difficult perceptual decision-making. We created a varying degree of degraded stimuli by manipulating the task-specific stimuli in these four experiments to examine the effects of task difficulty on insular cortex response. We hypothesized that significantly higher BOLD response would be associated with the ambiguity of the sensory information and decision-making difficulty. In all of our experimental tasks, we found the INS activity consistently increased with task difficulty and participants’ behavioral performance changed with the ambiguity of the presented sensory information. These findings support the hypothesis that the anterior insulae are involved in sensory-guided, goal-directed behaviors and their activities can predict perceptual load and task difficulty.

Mode changes in activity of single neurons in anterior insular cortex across trials during multi-trial reward schedules

We previously showed that spike count response distributions in anterior cingulate neurons can be fitted by a mixture of a few Poisson distributions in our reward schedule task. Here we report that the neuronal responses in insular cortex, an area connected to anterior cingulate cortex, can also be nicely fitted. The ratio of Poisson distributions changed with schedule progress, suggesting that neuronal responses in these areas fall into discrete firing modes. More insular neurons show mode changes across the schedules. The selection of firing modes might be related to cognitive processes, but seems independent across the two areas.