Previous research has highlighted brain regions associated with socioemotional processes in persuasive message encoding, whereas cognitive models of persuasion suggest that executive brain areas may also be important. The current study aimed to identify lateral prefrontal brain areas associated with persuasive message viewing and understand how activity in these executive regions might interact with activity in the amygdala and medial pFC. Seventy adolescents were scanned using fMRI while they watched 10 strongly convincing antidrug public service announcements (PSAs), 10 weakly convincing antidrug PSAs, and 10 advertisements (ads) unrelated to drugs. Antidrug PSAs compared with nondrug ads more strongly elicited arousal-related activity in the amygdala and medial pFC. Within antidrug PSAs, those that were prerated as strongly persuasive versus weakly persuasive showed significant differences in arousal-related activity in executive processing areas of the lateral pFC. In support of the notion that persuasiveness involves both affective and executive processes, functional connectivity analyses showed greater coactivation between the lateral pFC and amygdala during PSAs known to be strongly (vs. weakly) convincing. These findings demonstrate that persuasive messages elicit activation in brain regions responsible for both emotional arousal and executive control and represent a crucial step toward a better understanding of the neural processes responsible for persuasion and subsequent behavior change.

Healthy participants ( n = 79), ages 9–23, completed a delay discounting task assessing the extent to which the value of a monetary reward declines as the delay to its receipt increases. Diffusion tensor imaging (DTI) was used to evaluate how individual differences in delay discounting relate to variation in fractional anisotropy (FA) and mean diffusivity (MD) within whole-brain white matter using voxel-based regressions. Given that rapid prefrontal lobe development is occurring during this age range and that functional imaging studies have implicated the prefrontal cortex in discounting behavior, we hypothesized that differences in FA and MD would be associated with alterations in the discounting rate. The analyses revealed a number of clusters where less impulsive performance on the delay discounting task was associated with higher FA and lower MD. The clusters were located primarily in bilateral frontal and temporal lobes and were localized within white matter tracts, including portions of the inferior and superior longitudinal fasciculi, anterior thalamic radiation, uncinate fasciculus, inferior fronto-occipital fasciculus, corticospinal tract, and splenium of the corpus callosum. FA increased and MD decreased with age in the majority of these regions. Some, but not all, of the discounting/DTI associations remained significant after controlling for age. Findings are discussed in terms of both developmental and age-independent effects of white matter organization on discounting behavior.

It appears that functionally segregated visual pathways exist in the primate brain for the processing of visuospatial versus nonspatial information. Functional segregation has been demonstrated for the early associative processing of sensory information but may also exist at higher levels of cognitive analysis. Namely, connections between the dorsal visual system and dorsolateral prefrontal cortex (PFC) appear to mediate spatial working memory, which is modulated by dopamine receptor fields in the principal sulcal region of the PFC. It is speculated that nonspatial working memory may be modulated within connections between ventral visual processing regions and the inferior convexity of the PFC. Whether dopamine facilitates nonspatial memory through connections between the ventral visual system and ventral PFC has not been examined. In this study, normal humans completed spatial and nonspatial working memory tasks under pharmacological challenges with a dopamine receptor agonist (bromocriptine) and antagonist (haloperidol) in a double-blind placebcxontrolled repeated measures design. Findings indicated facilitation of spatial delayed working memory functions by bromocriptine and impairment of spatial working memory functions by haloperidol. Neither drug was effective in manipulating nonspatial memory performance. Control tasks were included to measure drug effects on basic sensorimotor and attentional processes. Findings suggest that separate processing mechanisms for remembering “What” versus “Where” an object is may exist at structural, but also neurochemical, levels in the human brain.

Recent studies on the neurobiology of cognition have focused on the ability of the prefrontal cortex (PFC) to support processes of working memory, i.e, mnemonic processes by which information relevant for a correct response is temporarily maintained to be reevaluated or updated on a trial-by-trial basis. Of most recent interest is the role played by dopamine (DA) in spatial working memory processes of the principal sulcal region of the PFC. Although D 1 DA receptors appear to modulate these mnemonic processes in monkeys, several lines of research suggest that D 2 DA receptors could also be relevant to cognitive functions. Therefore, we assessed the effects of a specific D 2 receptor agonist (bromocriptine) and placebo on visuospatial delayed response performance in human subjects. During delay periods of 0 or 8 sec, subjects were required to remember the spatial location of rapidly presented visual cues displayed in peripheral vision within a 360° circumference. The extent to which D 2 receptor activation by bromocriptine facilitated working memory in the 8–sec delay condition relative to placebo performance was assessed. As a means of providing validation of bromocriptine's D 2 receptor effect, maximum inhibition of prolactin (PRL) secretion, which is inhibited specifically by activation of D 2 receptor sites, was determined. Additionally, tasks having no working memory component were administered to rule out nonspecific effects of bromocriptine on sensory, arousal, attentional, and motor factors. Results demonstrated a significant facilitatory effect of bromocriptine on spatial delayed response performance (i.e., 8–sec delay performance). Results could not be explained by nonspecific effects of bromocriptine. Thus, findings of this study suggest that spatial working memory is facilitated by D 2 receptor activation. The role that DA may play in human cognitive processes is discussed within the larger theoretical framework of DA's general role in the facilitation of goal-directed behavior. In the case of cognition, DA may facilitate processes that serve to guide motivated behavior through complex environments.