Prefrontal brain activity predicts temporally extended decision-making behavior

Although functional neuroimaging studies of human decision-making processes are increasingly common, most of the research in this area has relied on passive tasks that generate little individual variability. Relatively little attention has been paid to the ability of brain activity to predict overt behavior. Using functional magnetic resonance imaging (fMRI), we investigated the neural mechanisms underlying behavior during a dynamic decision task that required subjects to select smaller, short-term monetary payoffs in order to receive larger, long-term gains. The number of trials over which the longterm gains accrued was manipulated experimentally (2 versus 12). Event-related neural activity in right lateral prefrontal cortex, a region associated with high-level cognitive processing, selectively predicted choice behavior in both conditions, whereas insular cortex responded to fluctuations in amount of reward but did not predict choice behavior. These results demonstrate the utility of a functional neuroimaging approach in behavioral psychology, showing that (a) highly circumscribed brain regions are capable of predicting complex choice behavior, and (b) fMRI has the ability to dissociate the contributions of different neural mechanisms to particular behavioral tasks.     

A facilitative role for corticosterone in the acquisition of a spatial task under moderate stress

Emotionally charged experiences alter memory storage via the activation of hormonal systems. Previously, we have shown that compared with rats trained for a massed spatial learning task in the water maze in warm water (25°C), animals that were trained in cold water (19°C) performed better and showed higher levels of the stress hormone corticosterone. Here, we examined whether manipulating the levels of corticosterone can determine the strength of spatial information acquisition and retention. Rats were injected with metyrapone (25, 50, and 75 mg/kg, i.p.) or with corticosterone (10 and 25 mg/kg, i.p.) and trained in a massed spatial task in either cold (19°C) or warm (25°C) water. We found that whereas animals injected with vehicle performed well in the spatial task in cold water (moderate stress), rats injected with the intermediate metyrapone dose showed impairment in performance. Moreover, whereas animals injected with vehicle on average did not perform well in warm water (mild stress), rats injected with the lower corticosterone dose showed improvement in performance in warm water. These two mirror experiments of corticosterone blockade and enhancement strongly suggest that corticosterone is instrumental in the acquisition and retention of the spatial learning task.     

Association and dissociation between detection and discrimination of objects of expertise: Evidence from visual search

Expertise in face recognition is characterized by high proficiency in distinguishing between individual faces. However, faces also enjoy an advantage at the early stage of basic-level detection, as demonstrated by efficient visual search for faces among nonface objects. In the present study, we asked (1) whether the face advantage in detection is a unique signature of face expertise, or whether it generalizes to other objects of expertise, and (2) whether expertise in face detection is intrinsically linked to expertise in face individuation. We compared how groups with varying degrees of object and face expertise (typical adults, developmental prosopagnosics [DP], and car experts) search for objects within and outside their domains of expertise (faces, cars, airplanes, and butterflies) among a variable set of object distractors. Across all three groups, search efficiency (indexed by reaction time slopes) was higher for faces and airplanes than for cars and butterflies. Notably, the search slope for car targets was considerably shallower in the car experts than in nonexperts. Although the mean face slope was slightly steeper among the DPs than in the other two groups, most of the DPs’ search slopes were well within the normative range. This pattern of results suggests that expertise in object detection is indeed associated with expertise at the subordinate level, that it is not specific to faces, and that the two types of expertise are distinct facilities. We discuss the potential role of experience in bridging between low-level discriminative features and high-level naturalistic categories.     

Linking Family Functioning and Self-Discrepancies among Children with Functional Somatic Symptoms

Functional somatic symptoms (FSS), defined as physical symptoms of unknown pathology, are common among children and adolescents and are often associated with high levels of functional impairment. Self-discrepancy theory (SDT) suggests that discrepancies between one’s ideal, ought, or undesired self-states and one’s actual self-representation may lead to emotional distress. Among families with dysfunctional patterns, such emotional distress may result in FSS. The current study examined the relationship between familial patterns and children’s levels of self-discrepancies, among children with and without FSS. Twenty-three children diagnosed with FSS and 23 children with orthopedic problems (non-FSS) and their mothers participated in the study. Mothers and children completed the Child Somatization Inventory and the Integrated Self-Discrepancies Index. Mothers also completed the general scale of the Family Assessment Device. Higher levels of symptom intensity were found in the FSS group than in the non-FSS group. Dysfunctional familial patterns were significantly higher in the FSS group, and higher levels of discrepancies were reported in the FSS group, compared with the non-FSS group. No significant relationship was found in the FSS group between level of self-state discrepancies and level of family functioning. Higher levels of dysfunctional patterns are observed among families of children with FSS. Furthermore, children with FSS and their mothers hold relatively high levels of self-state discrepancies. However, these elevated discrepancies are not significantly related to familial dysfunctional patterns. Viewing self-state discrepancies together with family maladaptive patterns might help address both inter- and intrapersonal conflicts within the family and reduce children’s symptoms.