RESUMEN
Studies that used conflict paradigms such as the Eriksen Flanker task show that many individuals with Parkinson's disease (PD) have pronounced difficulty resolving the conflict that arises from the simultaneous activation of mutually exclusive responses. This finding fits well with contemporary views that postulate a key role for the basal ganglia in action selection. The present experiment aims to specify the cognitive processes that underlie action selection deficits among PD patients in the context of variations in speed-accuracy strategy. PD patients (n=28) and healthy controls (n=17) performed an arrow version of the flanker task under task instructions that either emphasized speed or accuracy of responses. Reaction time (RT) and accuracy rates decreased with speed compared to accuracy instructions, although to a lesser extent for the PD group. Differences in flanker interference effects among PD and healthy controls depended on speed-accuracy strategy. Compared to the healthy controls, PD patients showed larger flanker interference effects under speed stress. RT distribution analyses suggested that PD patients have greater difficulty suppressing incorrect response activation when pressing for speed. These initial findings point to an important interaction between strategic and computational aspects of interference control in accounting for cognitive impairments of PD. The results are also compatible with recent brain imaging studies that demonstrate basal ganglia activity to co-vary with speed-accuracy adjustments.
Asunto(s)
Atención/fisiología , Trastornos del Conocimiento/etiología , Conflicto Psicológico , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/psicología , Tiempo de Reacción/fisiología , Anciano , Análisis de Varianza , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Reconocimiento Visual de Modelos , Enmascaramiento Perceptual , Estimulación Luminosa/métodosRESUMEN
Basal ganglia structures comprise a portion of the neural circuitry that is hypothesized to coordinate the selection and suppression of competing responses. Parkinson's disease (PD) may produce a dysfunction in these structures that alters this capacity, making it difficult for patients with PD to suppress interference arising from the automatic activation of salient or overlearned responses. Empirical observations thus far have confirmed this assumption in some studies, but not in others, due presumably to considerable inter-individual variability among PD patients. In an attempt to help resolve this controversy, we measured the performance of 50 PD patients and 25 healthy controls on an arrow version of the Eriksen flanker task in which participants were required to select a response based on the direction of a target arrow that was flanked by arrows pointing in the same (congruent) or opposite (incongruent) direction. Consistent with previous findings, reaction time (RT) increased with incongruent flankers compared to congruent or neutral flankers, and this cost of incongruence was greater among PD patients. Two novel findings are reported. First, distributional analyses, guided by dual-process models of conflict effects and the activation-suppression hypothesis, revealed that PD patients are less efficient at suppressing the activation of conflicting responses, even when matched to healthy controls on RT in a neutral condition. Second, this reduced efficiency was apparent in half of the PD patients, whereas the remaining patients were as efficient as healthy controls. These findings suggest that although poor suppression of conflicting responses is an important feature of PD, it is not evident in all medicated patients.
Asunto(s)
Atención/fisiología , Inhibición Psicológica , Enfermedad de Parkinson/fisiopatología , Enmascaramiento Perceptual/fisiología , Desempeño Psicomotor/fisiología , Anciano , Análisis de Varianza , Conducta de Elección/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Estimulación Luminosa/métodos , Tiempo de Reacción/fisiologíaRESUMEN
In osteopathic graduate medical education programs, the Director of Medical Education (DME) plays the key leadership role. This article outlines critical characteristics and skills that the DME should possess to successfully perform in this role. Central to this success is a passionate commitment to osteopathic medical education and a commitment to justice and fairness.