RESUMO
Behavioral evidence of impaired response inhibition (RI) and hyperactive error monitoring (EM) in obsessive-compulsive disorder (OCD) is inconsistent. Recent neuroimaging work suggests that EM plays a role in RI impairments in OCD, but this has rarely been investigated using behavioral measures. The aims of this study were to (1) compare RI and EM performance between adults with OCD and non-psychiatric controls (NPC) while investigating possible moderators, and (2) assess whether excessive EM influences RI in OCD. We compared RI and EM performance on the Stop-Signal Task (SST) between 92 adults with OCD and 65 NPC from two Brazilian sites. We used linear regression to investigate which variables (group, age, medication use, clinical symptomatology) influenced performance, as well as to examine possible associations between RI and EM. OCD and NPC did not differ in RI and EM. However, age moderated RI performance in OCD with a medium effect size, reflecting differential effects of age on RI between groups: age was positively associated with RI in OCD but not NPC. Further, OCD severity predicted EM with a medium to large effect size, suggesting that more symptomatic patients showed greater monitoring of their mistakes. Finally, group moderated the relationship between RI and EM with a small effect size. Our findings suggest that demographic factors may influence RI, whereas clinical factors may influence EM. Further, we found preliminary behavioral evidence to indicate that impaired RI and excessive EM are related in OCD.
Assuntos
Transtorno Obsessivo-Compulsivo , Adulto , Brasil , Humanos , Inibição Psicológica , Modelos Lineares , NeuroimagemRESUMO
BACKGROUND: Inhibitory control, a key modulatory component of cognition guiding strategy and behaviour, can be affected by diverse contingencies. We explore here the effect of expectation of reward over behavioural adjustment in a Stop Signal Task modulated by reward. We hypothesize that cognitive control is modulated by different expectation of the reward. METHODS: Participants were allocated to two groups differing in their degree of knowledge in what to expect from rewards. Expected Specific Reward participants (N = 21) were informed of the different monetary feedbacks they would receive after each successful inhibition. Unexpected Reward participants (N = 24) were only told that they would receive monetary reward after correct inhibitory trials, but not the amounts or differences. RESULTS: Our results confirmed previous observations demonstrating a "kick-start effect" where a high reward feedback at the beginning of the task increases response inhibition. The Expected Specific Reward condition seems also to improve inhibitory control -as measured by the stop signal reaction time (SSRT)-, compared to the Unexpected Reward group. CONCLUSIONS: Knowledge of reward magnitudes seems to play a role in cognitive control irrespective of feedback magnitude. The manipulation of reward expectation appears to trigger different strategies for cognitive control, inducing a bottom-up effect of external cues, or a top-down effect given by the anticipation of incoming rewards. This is an early exploration to unearth possible higher order modulators - expectation and motivation- of cognitive control. This approach aims to gain insight into diverse psychopathological conditions related to impulsivity and altered reward systems such as Attention Deficit Hyperactive Disorder (ADHD), personality disorders, substance abuse, pathological gambling and cognitive aspects of Parkinson Disease.
Assuntos
Função Executiva , Motivação , Recompensa , Adulto , Cognição , Sinais (Psicologia) , Feminino , Humanos , Inibição Psicológica , Masculino , Tempo de Reação , Adulto JovemRESUMO
Stroop-like and stop-signal tasks are commonly used to evaluate "inhibition", a multifaceted concept fundamental to better understanding of executive functions. Both tasks demand inhibitory processes for their execution; the first requires inhibition of an irrelevant attribute, while the second involves the inhibition of a prepotent motor response. Impulsivity and decision-making represent two other factors that could be associated to executive control and to inhibitory dyscontrol. In this study we developed a behavioral protocol combining the Stroop-matching (a variation of the classic Stroop task) and the stop-signal tasks to investigate possible interactions between the inhibitory mechanisms involved in both tasks. Moreover, we searched for associations between behavioral performance of healthy participants, and self-reported impulsivity and decision-making processes assessed by the BIS-11 scale and IGT, respectively. Our results showed that the primary-task reaction time in the Stroop-matching task influenced the ability to inhibit motor responses in the stop-signal task. Moreover, impulsiveness scores (but not decision-making) were associated to behavioral performance. Importantly, motor and attentional impulsiveness correlated differently to performance depending on the existence of stop-signal trials in the task. Our protocol revealed promising findings concerning the interaction between different inhibitory processes and their association with impulsivity levels.