Darren W. Campbell

Sex differences in the activity level of infants

A gender difference in motor activity level (AL) is well established for children, but questions about the existence and nature of an infant sex difference remain. To assess these questions, we applied meta-analytic procedures to summarize 46 infancy studies comprising 78 male–female motor activity comparisons. Our results showed that, as with children, male infants were more active than females. Objective measures of infant AL estimated the size of this difference to be 0.2 standard deviations, though subjective parent-report measures estimated the difference to be smaller. We argue that this early sex difference in activity level is biologically based. However, socialization processes, such as gender-differentiated expectations and experiences, in conjunction with further sex-differentiated biological developments, amplify this early difference to produce the larger gender differences in activity found during childhood. Copyright

Striatal Function in Generalized Social Phobia: A Functional Magnetic Resonance Imaging Study

BACKGROUND Although evidence suggests the involvement of the amygdala in generalized social phobia (GSP), few studies have examined other neural regions. Clinical, preclinical, and dopamine receptor imaging studies demonstrating altered dopaminergic functioning in GSP suggest an association with striatal dysfunction. This is the first functional magnetic resonance imaging (fMRI) study to use a cognitive task known to involve the striatum to examine the neural correlates of GSP. We examined whether subjects with GSP had differential activation in striatal regions compared with healthy control subjects while engaged in a cognitive task that has been shown to activate striatal regions reliably. METHODS Ten adult, unmedicated subjects with a primary DSM-IV diagnosis of GSP and 10 age-, gender-, and education-matched healthy comparison subjects underwent fMRI while performing the implicit sequence learning task. RESULTS The GSP and healthy comparison subjects did not differ significantly on the behavioral performance of the task. Subjects with GSP, however, had significantly reduced neural activation related to implicit learning compared with healthy comparison subjects in the left caudate head, left inferior parietal lobe, and bilateral insula. CONCLUSIONS These findings support the hypothesis that GSP is associated with striatal dysfunction and further the neurobiological understanding of this complex anxiety disorder.

Time-Varying Amygdala Response to Emotional Faces in Generalized Social Phobia

BACKGROUND Individuals with social phobia (SP) have altered behavioral and neural responses to emotional faces and are hypothesized to have deficits in inhibiting emotion-related amygdala responses. We tested for such amygdala deficits to emotional faces in a sample of individuals with SP. METHOD We used functional magnetic resonance imaging (fMRI) to examine the neural substrates of emotional face processing in 14 generalized SP (gSP) and 14 healthy comparison (HC) participants. Analyses focused on the temporal dynamics of the amygdala, prefrontal cortex (PFC), and fusiform face area (FFA) across blocks of neutral, fear, contempt, anger, and happy faces in gSP versus HC participants. RESULTS Amygdala responses in participants with gSP occurred later than the HC participants to fear, angry, and happy faces. Parallel PFC responses were found for happy and fear faces. There were no group differences in temporal response patterns in the FFA. CONCLUSIONS This finding might reflect a neural correlate of atypical orienting responses among individuals with gSP. Commonly reported SP deficits in habituation might reflect neural regions associated with emotional self-evaluations rather than the amygdala. This study highlights the importance of considering time-varying modulation when examining emotion-related processing in individuals with gSP.

Stability in perceived control: implications for health among very old community-dwelling adults.

Objective: Our purpose was to examine how stability/variability in perceptions of control (PC) relate to a variety of health-related variables. Design: PC stability/variability across multiple domains was assessed in a longitudinal design including 318 adults, 72 to 99 years of age. Method: PC and health-related measures were obtained during in-person interviews conducted approximately 3 months apart. PC variability was assessed in relation to self-reported health outcomes (perceived health, chronic health conditions, functional status) and objective measures of physician visits and hospitalizations recorded over a 4-year period in a highly reliable and comprehensive database. Results: PC variability was associated with poorer health, poorer functional status, and more physician visits and hospital admissions, even after statistically controlling for mean PC level and direction-of-change in PC. Implications: Our findings suggest that health and well-being among very old individuals may be compromised by fluctuating levels of PC, or conversely, that stability in PC enhances health.

HAPPY BUT NOT SO APPROACHABLE: THE SOCIAL JUDGMENTS OF INDIVIDUALS WITH GENERALIZED SOCIAL PHOBIA

Background: We examined social approachability judgments in a psychiatric population that frequently experiences interpersonal difficulties and reduced social satisfaction, individuals with generalized social phobia (gSP). Methods: Our objective was to broaden the understanding of the social cognitive tendencies of individuals with gSP by systematically investigating their interpretation of positive facial expressions. We hypothesized that approachability ratings would be lower for positive as well as negative emotional faces in the gSP group compared to the healthy comparison group. Each participant evaluated 24 emotional faces presented on a computer screen. Participants first labeled the faces as either happy, disgust, or angry in emotional expression, and then they rated each faces approachability. Analysis of variance and post hoc analyses were used to identify group, emotion, and group by emotion rating differences. Results: Happy face approachability ratings were higher than disgust and anger in both groups. The central finding was that individuals with gSP rated happy faces as less approachable than the healthy participants and that degree of social anxiety was associated with lower approachability ratings within the gSP sample. Explicit approachability judgments of negative faces did not differ as predicted. Conclusions: Consistent with earlier indirect evidence of interpretation biases of positive social emotional information, this study reveals that individuals with gSP demonstrate explicit, subjective social interpretation biases of overtly positive social feedback. The therapeutic relevance of these results is discussed. Depression and Anxiety, 2009.

Deficit in schizophrenia to recruit the striatum in implicit learning: A functional magnetic resonance imaging investigation

In schizophrenia, explicit learning deficits have been well established although it is less clear whether these patients have deficits in implicit learning (IL). IL is thought to depend on intact striatal functioning. This study examined the hypothesis that schizophrenia patients show deficient recruitment of striatal activation during an IL paradigm, relative to performance-matched healthy comparison subjects. Ten subjects with schizophrenia on atypical antipsychotic medication and 10 age, gender, education, and performance matched healthy comparison subjects underwent fMRI while performing an IL task. On the basis of whole-brain and striatal region-of-interest analyses, we found a relative lack of striatal activation in schizophrenia patients. This result is consistent with convergent evidence of striatal dysfunction in schizophrenia.

Diminished humour perception in schizophrenia: relationship to social and cognitive functioning.

This study attempted to confirm that humour recognition deficits previously found in schizophrenia are specific to the condition and not attributable to other parameters such as depression or anxiety. Secondarily, we explored any possible cognitive or social functioning correlates to humour recognition deficits. A total of 60 participants (20 outpatients with schizophrenia, 20 psychiatric control participants and 20 control participants) underwent a 64-question humour task in addition to a battery of standard cognitive tests and Social Functioning Scales. In order to compare the three groups of participants, we conducted an analysis of variance (ANOVA) and post-hoc t-tests on neuropsychological measures, social functioning measures, and the primary outcome, humour recognition. The schizophrenia group showed significant and substantial deficits in humour recognition compared to the healthy control group, t(38)=5.1, P<0.001, ES=-1.55 and the psychiatric control group, t(38)=3.6, P=0.001. In the schizophrenia group, humour recognition correlated positively with general intellectual functioning (NART) r=.45, P=0.04, social reasoning (WAIS-III Comprehension) r=.54, P=0.01, executive functioning (WCST-CC) r=.69, P=0.001 and social adjustment ratings (SASS scores), r=.54, P=0.02. These findings support the assertion that humour recognition deficits in schizophrenia are specific to the condition and not attributable to other factors such as depression or anxiety. Furthermore, humour recognition deficits in schizophrenia may perhaps be preferentially associated with deficiencies in set shifting and semantic cognition.

Motor activity level and behavioural control in young children

How do young children’s typical levels of physical movement relate to their ability to inhibit task-inappropriate behavioural responses? This question was investigated with a cross-sectional sample of 85 children, 4- to 6-years of age. Children’s typical levels of activity were assessed with actometers, mechanical measures of movement frequency. Multiple measures of contra-habitual task performance, reflecting children’s ability to inhibit the typical response associated with a task and to execute a less typical response, were aggregated. Procedurally similar control tasks, not dependent on the inhibition of behavioural responses, were also assessed. Contra-habitual task performance was positively and uniquely related to activity level, and an age by movement interaction showed that this relation was most reliable among the younger children in our sample. Young children’s motor activity is associated with enhanced, not diminished behavioural control.

A longitudinal analysis of discrete negative emotions and health-services use in elderly individuals.

Objective: To test the hypothesis that everyday, discrete negative emotions—anger, frustration, sadness, and fear—relate to health-service use in later life. Method: Community-dwelling adults (n= 345) ages 72 to 99 were interviewed about the frequency of recently experienced emotions. Physician visits and hospital admissions in the subsequent 2 years were outcomes. Covariates included prior use of health services, chronic illness, functional status, and demographics. Results: Age, education, and gender moderated relations between negative emotions and health care use. More frustration was associated with fewer physician visits among older individuals. Sadness was associated with more hospital admissions for women. Among those with more education, frequent anger was associated with more physician visits. Projected effects of negative emotions resulted in increases in health-service use, ranging from 18% to 33%. Discussion: The interactions indicate the importance of negative emotions and the larger social and developmental context in health care services use among elderly individuals.

The neural basis of humour comprehension and humour appreciation: The roles of the temporoparietal junction and superior frontal gyrus

Psychological well-being and social acumen benefit from the recognition of humourous intent and its enjoyment. The enjoyment of humour requires recognition, but humour recognition is not necessarily accompanied by humour enjoyment. Humour recognition is crucial during social interactions, while the associated enjoyment is less critical. Few neuroimaging studies have explicitly differentiated between the neural foundations of humour comprehension and humour appreciation. Among such studies, design limitations have obscured the specification of neural correlates to humour comprehension or appreciation. We implemented a trichotomous response option to address these design limitations. Twenty-four participants rated 120 comics (90 unaltered with humourous intent and 30 caption-altered without humourous intent) as either funny jokes (FJ), not funny jokes but intended to be funny (NFJ), or not intended to be funny or non-jokes (NJ). We defined humour comprehension by NFJ minus NJ and humour appreciation by FJ minus NFJ. We measured localized blood oxygen level dependent (BOLD) neural responses with a 3T MRI scanner. We tested for BOLD responses in humour comprehension brain regions of interest (ROIs), humour appreciation ROIs, and across the whole-brain. We found significant NFJ-NJ BOLD responses in our humour comprehension ROIs and significant FJ-NFJ BOLD responses in select humour appreciation ROIs. One key finding is that comprehension accuracy levels correlated with humour-comprehension responses in the left temporo-parietal junction (TPJ). This finding represents a novel and precise neural linkage to humour comprehension. A second key finding is that the superior frontal gyrus (SFG) was uniquely associated with humour-appreciation. The SFG response suggests that complex cognitive processing underlies humour appreciation and that current models of humour appreciation be revised. Finally, our research design provides an operational distinction between humour comprehension and appreciation and a sensitive measure of individual differences in humour comprehension accuracy.