Cunillera, T. | bioRxiv Science

bioRxiv2021

Fasting reduces inhibitory and attentional control of food-related cues

The metabolic and cognitive systems interact to create the motivational drive that occasionally leads to disrupted consummatory eating behaviors. In this study, we investigated whether stimulus-specific alterations of the inhibitory function are present following a period of food deprivation. Twenty-six participants with normal weight performed the Stop Signal Task (SST) and the Go/No-go (GNG) task to measure response inhibition to food images containing high or low caloric content after following -or not- a 12-hour fasting period. Response inhibition performance in the SST did not exhibit significant differences when considering neither fasting, stimulus type nor food caloric content. We instead found a higher percentage of commission errors in the No-go trials of the GNG task in the fasting session, and specially with high-caloric food items. In contrast, the accuracy in the Go trials was similar between conditions. A mixed logistic regression model confirmed the remarkable impact of fasting on the performance of response inhibition. Overall, our findings support an interpretation of the motivational drive to eat strongly associated with aspects of the inhibitory function underlying high attentional control, rather than to a proper response inhibition per se.

neuroscience↗

bioRxiv2021

Early changes in corticomotor excitability underlie proactive inhibitory control of error correction

Converging evidence indicates that response inhibition may arise from the interaction of effortful proactive and reflexive reactive mechanisms. However, the distinction between the neural basis sustaining proactive and reactive inhibitory processes is still unclear. To identify reliable neural markers of proactive inhibition, we examined the behavioral and electrophysiological correlates elicited by manipulating the degree of inhibitory control in a task that involved the detection and amendment of errors. Restraining or encouraging the correction of errors did not affect the time course of the behavioral and neural correlates associated to reactive inhibition. We rather found that a bilateral and sustained decrease of corticomotor excitability was required for an effective proactive inhibitory control, whereas selective strategies were associated with defective response suppression. Our results provide behavioral and electrophysiological conclusive evidence of a comprehensive proactive inhibitory mechanism, with a distinctive underlying neural basis, governing the commission and amendment of errors. Together, these findings hint at a decisive role for changes in corticomotor excitability in determining whether an action will be successfully suppressed. SIGNIFICANCE STATEMENTResponse inhibition is a fundamental brain function that must be flexible enough to incorporate volitional goal-directed demands, along with rapid, automatic and well consolidated behaviors. Previous studies reflect a lack of consensus regarding the neural correlates subserving these two -proactive and reactive- distinct modes of inhibitory control. We combined electrophysiological recordings with behavioral measures within a paradigm of detection and correction of errors under two degrees of inhibitory control to identify genuine neural markers of proactive inhibitory control. We found evidence supporting a sustained and global -not selective- reduction of corticomotor excitability subserving successful proactive inhibition of motor responses. Our findings favor a distinctive mechanism of comprehensive inhibitory control to amend errors under a high degree of response competition.

neuroscience↗