Using fMRI to investigate

Using fMRI, we investigated the functional organization of prefrontal cortex (PFC) as participants briefly thought of a single just-experienced item (i.e., refreshed an active representation). The results of six studies, and a meta-analysis including previous studies, identified regions in left dorsolateral, anterior, and ventrolateral PFC associated in varying degrees with refreshing different types of information (visual and auditory words, drawings, patterns, people, places, or locations). In addition, activity increased in anterior cingulate with selection demands and in orbitofrontal cortex when a nonselected item was emotionally salient, consistent with a role for these areas in cognitive control (e.g., overcoming “mental rubbernecking”). We also found evidence that presenting emotional information disrupted an anterior component of the refresh circuit. We suggest that refreshing accounts for some neural activity observed in more complex tasks, such as working memory, long-term memory, and problem solving, and that its disruption (e.g., from aging or emotion) could have a broad impact.     

Performance of chronotypes on memory tests during the morning and the evening shifts

Memory consists of several phases or processes that can be influenced by many factors, including the individual's circadian rhythm and the time of day at which tests are performed. The present objective was to evaluate the performance on memory tests of different chronotypes during the morning and the evening shifts. Subjects (21 men and 26 women, between the ages of 20 and 35 yr.) were evaluated for memory and metamemory differences in the morning and in the afternoon, using a battery of neuropsychological tests composed of the Word List with Emotional Content, Visual Memory, Scale-Semantic Memory, Digit Span, Word-Pairs Associated, Verbal Fluency Test, and Metamemory questionnaire. In the evening shift, there was a statistical difference among chronotypes on the Word List with Neutral Content and on the Verbal Fluency Test. In the morning, there were no statistically significant differences; however, the morning-type subjects had higher scores on the metamemory tests (p<.01), while the evening-type subjects had higher scores in the afternoon (p<.01). In spite of their perception, on Word-Pairs Associated and Word List with Emotional Content, the subjects, independently of their chronotype, showed better performance by the evening than by the morning shift. These results highlight the importance of controlling the shift of day and chronotype in studies with the objective of exploration of human performance.     

Separable neural components in the processing of black and white faces

In a study of the neural components of automatic and controlled social evaluation, White participants viewed Black and White faces during event-related functional magnetic resonance imaging. When the faces were presented for 30 ms, activation in the amygdala-a brain region associated with emotion-was greater for Black than for White faces. When the faces were presented for 525 ms, this difference was significantly reduced, and regions of frontal cortex associated with control and regulation showed greater activation for Black than White faces. Furthermore, greater race bias on an indirect behavioral measure was correlated with greater difference in amygdala activation between Black and White faces, and frontal activity predicted a reduction in Black-White differences in amygdala activity from the 30-ms to the 525-ms condition. These results provide evidence for neural distinctions between automatic and more controlled processing of social groups, and suggest that controlled processes may modulate automatic evaluation.     

Synaptic plasticity and translation initiation

It is widely accepted that protein synthesis, including local protein synthesis at synapses, is required for several forms of synaptic plasticity. Local protein synthesis enables synapses to control synaptic strength independent of the cell body via rapid protein production from pre-existing mRNA. Therefore, regulation of translation initiation is likely to be intimately involved in modulating synaptic strength. Our understanding of the translation-initiation process has expanded greatly in recent years. In this review, we discuss various aspects of translation initiation, as well as signaling pathways that might be involved in coupling neurotransmitter and neurotrophin receptors to the translation machinery during various forms of synaptic plasticity.     

Age and sex differences in children’s spatial search strategies

Male and female children, 3, 4, and 5 years old, searched for a sticker that was hidden in 1 of 15 linearly aligned boxes. Two identical bear-shaped landmarks cued the sticker location, which was always in the middle of 3 boxes that separated the two landmarks. The absolute locations of the landmarks and sticker varied across training trials, but the distance in relation to each other remained constant. Training continued until the child chose the correct box first for 3 consecutive trials or for a maximum of 20 trials. Striking age and sex differences emerged in acquisition: The percentage of children who reached criterion increased over age groups to 100% for the boys but stayed at approximately 20% for the girls. A landmark expansion test (with the landmarks moved farther apart) given to children who met criterion revealed that most of these children chose the middle location.     

Second thoughts versus second looks: an age-related deficit in reflectively refreshing just-activated information

Age-related deficits in memory are greater as encoding and retrieval tasks require more reflective (self-generated or executive) processing. One problem in developing more specific models of age-related changes in cognition is that the tasks studied tend to be complex and vary in the combinations of component cognitive processes they recruit. Here we report an age-related deficit in one of the most elementary, but critical, components of reflection: refreshing a just-activated representation. Impairment in such a process potentially has a wide-ranging impact on all higher-order cognition.     

Measuring individual and cultural differences in implicit trait theories

A new measure of implicit theories or beliefs regarding the traitedness versus contextuality of behavior was developed and tested across cultures. In Studies 1 (N = 266) and 2 (N = 266), these implicit beliefs dimensions were reliably measured and replicated across U.S. college student samples and validity evidence was provided. In Study 3, their structure replicated well across an individualistic culture (the United States; N = 249) and a collectivistic culture (Mexico; N = 268). Implicit trait and contextual beliefs overlapped only modestly with implicit entity theory beliefs and were predicted by self-construals in ways that generally supported cultural psychology hypotheses. Implicit trait beliefs were fairly strongly endorsed in both cultures, suggesting that such beliefs may be universally held.     

Speech and language disturbances due to subcortical lesions

Over the last few decades, the number of studies concerning the role of subcortical structures in cognition has increased due to advances in neuroimaging. We describe the language and speech disturbances found in 16 patients with subcortical lesions (9 in basal ganglia and 7 in thalamus), evaluated by CT scan, MRI, and SPECT. Language assessment included the Boston Diagnostic Aphasia Examination, Boston Naming Test, and Token Test. Motor-articulatory alterations predominated in the non-thalamic group; in the thalamic group, there was a higher frequency of language alterations, especially in naming and auditory comprehension; verbal memory and attentional impairments may have contributed to this. We also found hypoperfusion in cortical language areas, and therefore participation of cortical dysfunction cannot be ruled out.     

Effect of multicomponent interventions on caregiver burden and depression: the REACH multisite initiative at 6-month follow-up

Meta-analysis was used to examine pooled parameter estimates of 9 active compared with 6 control conditions of the Resources for Enhancing Alzheimer's Caregiver Health (REACH) project at 6 months on caregiver burden and depressive symptoms. Associations of caregiver characteristics and outcomes were examined. For burden, active interventions were superior to control conditions (p = .022). Also, active interventions were superior to control conditions for women versus men and for caregivers with lower education versus those with higher education. For depressive symptoms, a statistically significant association of group assignment was found for Miami's family therapy and computer technology intervention (p = .034). Also, active interventions were superior to control conditions for Hispanics, nonspouses, and caregivers with lower education. Results suggest interventions should be multicomponent and tailored.