Overt and covert attention in infants revealed using steady-state visually evoked potentials.

Although looking-time methods have long been used to measure infant attention and investigate aspects of cognitive development, steady-state visually evoked potential (SSVEP) measures may be more sensitive or practical in some contexts. Here, we demonstrate habituation of infants' SSVEP amplitudes to a flickering checkerboard stimulus, and recovery of attention upon presentation of a novel checkerboard stimulus. This modulation of SSVEP amplitude was more robust than the modulation of looking time.

Attentional effects of hand proximity occur later in older adults: Evidence from event-related potentials.

Research with young adults has shown hand proximity biases attention both early (by the time stimuli are categorized as relevant for action) and later, selectively for goal-relevant-stimuli. We examined age-related changes in this multisensory integration of vision and proprioception by comparing behavior and event-related potentials (ERPs) between younger and older adults. In a visual detection task, the hand was placed near or kept far from target and nontarget stimuli matched for frequency and visual features.

Attention's grasp: early and late hand proximity effects on visual evoked potentials.

Behavioral studies suggest that visual attention is biased toward stimuli in the region of space near the palm of the hand, but it is unclear whether this effect is universal or selective for goal/task-related stimuli. We examined event-related potentials (ERPs) using a visual detection task in which the hand was placed near or kept far from target and non-target stimuli that were matched for frequency and visual features to avoid confounding factors. Focusing on attention-sensitive ERP components, we found that P3 (350-450 ms) amplitudes were increased for Hand Near conditions for targets only, demonstrating a selective effect consistent with the P3's cross-modal and task-relevance influences.

Reduced behavioral and neural activation in stimulant users to different error rates during decision making.

Background: Behavioral processes and neural systems dysfunctions that put individuals at risk for drug use in general, and stimulant use in particular, are poorly understood. Here, the hypothesis is examined that stimulant-using subjects adjust their decision making less as a function of errors as evidenced by attenuated behavioral and neural substrate activation patterns.

Methods: Twelve young adults who had used stimulants were compared with 12 education-matched, stimulant-naive comparison subjects.

Anterior cingulate cortex and benefit of predictive cueing on response inhibition in stimulant dependent individuals.

Background: Methamphetamine dependence (MD) is associated with impaired response inhibition and with structural abnormalities and functional hypoactivity in the anterior cingulate cortex (ACC). The need to inhibit behavior is often forewarned by cues that do not call for immediate inhibition. We sought to determine whether such cues would engage the ACC and improve inhibition in MD individuals.

Impaired time perception and motor timing in stimulant-dependent subjects.

Stimulant-dependent individuals (SDI) have abnormal brain metabolism and structural changes involving dopaminergic target areas important for the processing of time. These individuals are also more impulsive and impaired in working memory and attention. The current study tested whether SDI show altered temporal processing in relation to impulsivity or impaired prefrontal cortex functioning.

Time and decision making: differential contribution of the posterior insular cortex and the striatum during a delay discounting task.

Delay discounting refers to the fact that an immediate reward is valued more than the same reward if it occurs some time in the future. To examine the neural substrates underlying this process, we studied 13 healthy volunteers who repeatedly had to decide between an immediate and parametrically varied delayed hypothetical reward using a delay discounting task during event-related functional magnetic resonance imaging. Subject's preference judgments resulted in different discounting slopes for shorter (<1 year) and for longer (> or =1 year) delays.

Young adult stimulant users' increased striatal activation during uncertainty is related to impulsivity.

Background: Young adults who use stimulants (e.g., cocaine, amphetamines) are at particular risk of transitioning to dependence.

Individuals with schizophrenia present hypo- and hyperactivation during implicit cueing in an inhibitory task.

Background: The primary purpose of this investigation was to assess the neural correlates of implicit cueing during an inhibitory task in schizophrenia when performance accuracy was matched with healthy comparison subjects.

Methods: We compared 17 individuals with chronic schizophrenia (SZ; medicated, 13.9 average years of illness) and 17 healthy comparison subjects (HC) matched for hit and false alarm rates, age, and education on a visual Go/Nogo task during functional magnetic resonance imaging.

Superior temporal gyrus and insula provide response and outcome-dependent information during assessment and action selection in a decision-making situation.

Decision-making is a complex process that comprises the assessment of a situation, the selection of an action, and the evaluation of an outcome. Distinct neural systems may contribute differentially during various stages within a decision-making situation. This study investigated whether neural activation during assessment or action selection is critically dependent on previous outcomes or actions.

Increased risk-taking decision-making but not altered response to punishment in stimulant-using young adults.

Stimulant-using and stimulant-naive young adults performed the "risky gains" decision-making task [Paulus, M.P., Rogalsky, C.