RESUMO
BACKGROUND: Obesity is a growing global issue that is linked to cognitive and psychological deficits. OBJECTIVE: This preliminary study investigated the efficacy of training to improve inhibitory control (IC), a process linked to overeating, on consumption and cognitive control factors. METHODS: This study utilized a multisession mobile phone-based intervention to train IC in an overweight and obese population using a randomized waitlist-control design. A combination of self-assessment questionnaires and psychophysiological measures was used to assess the efficacy of the intervention in terms of improved general IC and modified food consumption after training. Attitudes toward food were also assessed to determine their mediating role in food choices. A total of 58 participants (47 female) completed 2 assessment sessions 3 weeks apart, with 2 weeks of intervention training for the training group during this time. The groups did not differ in baseline demographics including age, body mass index, and inhibitory control. RESULTS: Inhibitory control ability improved across the training sessions, with increases in P3 amplitude implying increased cognitive control over responses. Inhibitory control training was associated with increased healthy and reduced unhealthy food consumption in a taste test and in the week following training, as measured by the Healthy Eating Quiz and the food consumption test. Cognitive restraint was enhanced after training for the training but not the waitlist condition in the Three-Factor Eating Questionnaire, implying that attempts to avoid unhealthy foods in the future will be easier for the training group participants. CONCLUSIONS: Inhibitory control training delivered via a purpose-designed mobile phone app is easy to complete, is convenient, and can increase cognitive restraint and reduce unhealthy food consumption. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12616000263493; http://www.ANZCTR.org.au/ACTRN12616000263493.aspx (Archived by WebCite at http://www.webcitation.org/6ioHjGING).
RESUMO
Facilitation and inhibition are asymmetric aspects of attention that differentially affect response times (RTs), accuracy and neuroelectric activity in many experimental tasks. Both vary as a function of stimulus context, with stimulus repetitions, for example, often resulting in facilitation in terms of speed, accuracy or reduced neural activity. Although inhibition has been extensively studied in the Go/NoGo task, facilitation has been overlooked. Twenty healthy adults performed an adapted Go/NoGo task which manipulated levels of facilitation and inhibition. Event-related potential (ERP) and behavioural measures were averaged according to preceding stimulus sequences. Established Go/NoGo effects for N2 and P3 components were replicated. Behavioural and ERP measures, however, showed strong sequence effects. Correlates of facilitation included reduced P1 and N1 latencies, and topographic effects in P1, to Go stimulus repetitions. Manipulations of inhibitory load through increasing Go before NoGo stimuli resulted in incremental increases in N1, P2 and N2 latencies. Several additional ERP and RT measures showed quadratic effects, with indications of facilitation or inhibition which reversed towards the end of longer stimulus trains. The results suggest that both facilitatory and inhibitory processes underlie performance in the Go/NoGo task. As Go stimuli are typically more frequently repeated than NoGo stimuli, the two processes may be confounded when sequence effects are not considered. Additionally, analysing stimuli by context indicates that the timing of the Go-P3 latency is closely related to responses, and the prolongation of N1, P2 and N2 with increasing difficulty of inhibition supports a possible relation of these components to inhibition.
