Sex-related Differences in Stress Reactivity and Cingulum White Matter.

The prefrontal cortex and limbic system are important components of the neural circuit that underlies stress and anxiety. These brain regions are connected by white matter tracts that support neural communication including the cingulum, uncinate fasciculus, and the fornix/stria-terminalis. Determining the relationship between stress reactivity and these white matter tracts may provide new insight into factors that underlie stress susceptibility and resilience. Therefore, the present study investigated sex differences in the relationship between stress reactivity and generalized fractional anisotropy (GFA) of the white matter tracts that link the prefrontal cortex and limbic system. Diffusion weighted images were collected and deterministic tractography was completed in 104 young adults (55 men, 49 women; mean age = 18.87 SEM = 0.08). Participants also completed self-report questionnaires (e.g., Trait Anxiety) and donated saliva (later assayed for cortisol) before, during, and after the Trier Social Stress Test. Results revealed that stress reactivity (area under the curve increase in cortisol) and GFA of the cingulum bundle varied by sex. Specifically, men demonstrated greater cortisol reactivity and greater GFA within the cingulum than women. Further, an interaction between sex, stress reactivity, and cingulum GFA was observed in which men demonstrated a positive relationship while women demonstrated a negative relationship between GFA and cortisol reactivity. Finally, trait anxiety was positively associated with the GFA of the fornix/stria terminalis - the white matter pathways that connect the hippocampus/amygdala to the hypothalamus. These findings advance our understanding of factors that underlie individual differences in stress reactivity.

Threat-related learning relies on distinct dorsal prefrontal cortex network connectivity.

Conditioned changes in the emotional response to threat (e.g. aversive unconditioned stimulus; UCS) are mediated in part by the prefrontal cortex (PFC). Unpredictable threats elicit large emotional responses, while the response is diminished when the threat is predictable. A better understanding of how PFC connectivity to other brain regions varies with threat predictability would provide important insights into the neural processes that mediate conditioned diminution of the emotional response to threat. The present study examined brain connectivity during predictable and unpredictable threat exposure using a fear conditioning paradigm (previously published in Wood et al., 2012) in which unconditioned functional magnetic resonance imaging data were reanalyzed to assess effective connectivity. Granger causality analysis was performed using the time series data from 15 activated regions of interest after hemodynamic deconvolution, to determine regional effective connectivity. In addition, connectivity path weights were correlated with trait anxiety measures to assess the relationship between negative affect and brain connectivity. Results indicate the dorsomedial PFC (dmPFC) serves as a neural hub that influences activity in other brain regions when threats are unpredictable. In contrast, the dorsolateral PFC (dlPFC) serves as a neural hub that influences the activity of other brain regions when threats are predictable. These findings are consistent with the view that the dmPFC coordinates brain activity to take action, perhaps in a reactive manner, when an unpredicted threat is encountered, while the dlPFC coordinates brain regions to take action, in what may be a more proactive manner, to respond to predictable threats. Further, dlPFC connectivity to other brain regions (e.g. ventromedial PFC, amygdala, and insula) varied with negative affect (i.e. trait anxiety) when the UCS was predictable, suggesting that stronger connectivity may be required for emotion regulation in individuals with higher levels of negative affect.

Mood changes in bulimia nervosa.

Daily measurement of mood, and the occurrence of specific eating behaviours, were assessed concurrently over an eight-week period in a sample of 50 patients meeting diagnostic criteria for bulimia nervosa. Results of observer-rated scales of mood showed a significant reduction of scores, whereas self-assessment of mood showed no change over the study period. Negative mood states, although not severe, were more marked when the specific behavioural symptoms of binge-eating, vomiting, or purging occurred, and they increased as abnormal eating behaviours accumulated. It is suggested that the accompanying dysphoric mood states of bulimia nervosa are likely to be a secondary manifestation related to the presence of abnormal eating symptoms, and that they do no constitute a primary depressive illness.

Bouffée délirante: an examination of its current status.

Bouffée délirante is an historic and unique French diagnostic term for a short-lived psychosis. The key diagnostic features are acute, floridly psychotic symptoms with complete remission. Its use in a Paris hospital has been examined, and it appears that the term is declining in popularity. A case-controlled study indicated that the diagnosis is likely to be given to migrants on first admission. A re-diagnosis of case summaries indicated no particular correspondence of bouffée délirante to any one ICD category. However, the usefulness of having a special diagnostic term for psychosis with a good outcome is discussed.

A case-control study of the aetiology of cryptorchidism.

A study of cryptorchidism was undertaken based on patients identified through the Oxford Record Linkage Study. The cumulative lifetime incidence of archidopexy among males in the study area was estimated to be 3.38%; 88% of orchidopexies were performed on males aged 5 years and over and 32% on those aged 10 and over. In a case-control study with 146 cases ascertained at orchidopexy and 146 matched controls there was a substantially increased risk of cryptorchidism for those who had undergone breech labour. Raised risks of cryptorchidism were found for boys born to mothers who were primigravidas or aged under 20, and a significantly reduced risk was found for boys whose mothers were of B blood group. There was a gradient of increasing risk with decreasing birth weight and a significantly raised risk associated with clinical inguinal hernia. Since cryptorchidism and testicular cancer share several risk factors, it may be profitable to study newly identified risk factors for cryptorchidism in relation to testicular cancer.