No abstract

Attention-deficit hyperactivity disorder (ADHD) has been considered a mental illness in which the frontal lobe is dysfunctional. The orbitofrontal cortex (OFC) controls emotional and motivational behaviors which are impaired in ADHD. Patients with OFC damage have shown impaired performance in reversal and extinction tasks in a simple go/no-go paradigm. We assigned ADHD subjects the two tasks to examine a hypothesized dysfunction of OFC. ADHD subjects indeed showed a performance deficit in the tasks, supporting OFC dysfunction in ADHD. Furthermore, a discriminat analysis using the task performance variables correctly classified 89.7% of the participants among ADHD patients and normal controls.

This research assessed the effect of an observer upon error-related negativity (ERN) in 20 children (ages 7-11): 9 worked alone and 11 worked under the observation of a friend of theirs (alone/audience groups). Erroneous motor responses were recorded to Go and No-Go visual stimuli (triangles in different orientations) at three brain sites (Fz, Cz, and Pz). Results for children were consistent with past adult studies in showing a significantly larger ERN only to erroneous responses in both the alone and the audience groups. Children in the audience group produced larger ERNs than those in the alone group. Furthermore, older children (ages 9-11) produced larger ERNs than younger children (ages 7-8) in both groups. These findings were discussed in the context of an action monitoring system that regulates responses, detects errors, and entrains affective responses associated with correct and incorrect responses.

The avian song system consists of two main parts: the descending motor pathway and the anterior forebrain (AF) pathway. The former directly controls the motor act of singing, but the role of the AF pathway in real-time song production is not understood; lesioning a nucleus in the AF pathway in adult zebra finches did not cause any notable effects. Here we show that in a related species of songbirds, the Bengalese finch, a partial lesion located in Area X, a nucleus of the avian basal ganglia that is part of the AF pathway, causes a transient but substantial song motor deficit. This is the first demonstration that the AF pathway is involved in real-time song production in adulthood.