Personality in Captive Chimpanzees: Use of a Novel Rating Procedure

We present a new method to assess the personalities of captive chimpanzees (Pan troglodytes). Using individually generated bipolar constructs, experienced observers rated the personalities of chimpanzees on a five-point scale. Each observer chose a subset of his/her own constructs and we performed a separate factor analysis on each set of ratings. The analyses indicate four factors: dominance, sociability, machiavellianism, and anxiety. We propose that this factor structure will be useful in the development of a single rating instrument with which to assess the personalities of captive chimpanzees.     

Orexin deficiency modulates cognitive flexibility in a sex-dependent manner

Cognitive flexibility is an important executive function and refers to the ability to adapt behaviors in response to changes in the environment. Of note, many brain disorders are associated with impairments in cognitive flexibility. Several classical neurotransmitter systems including dopamine, acetylcholine and noradrenaline are shown to be important for cognitive flexibility, however, there is not much known about the role of neuropeptides. The neuropeptide orexin, which is brain-widely released by neurons in the lateral hypothalamus, is a major player in maintaining sleep/wake cycle, feeding behavior, arousal, and motivational behavior. Recent studies showed a role of orexin in attention, cognition and stress-induced attenuation of cognitive flexibility by disrupting orexin signaling locally or systemically. However, it is not known so far whether brain-wide reduction or loss of orexin affects cognitive flexibility. We investigated this question by testing male and female orexin-deficient mice in the attentional set shifting task (ASST), an established paradigm of cognitive flexibility. We found that orexin deficiency impaired the intra-dimensional shift phase of the ASST selectively in female homozygous orexin-deficient mice and improved the first reversal learning phase selectively in male homozygous orexin-deficient mice. We also found that these orexin-mediated sex-based modulations of cognitive flexibility were not correlated with trait anxiety, narcoleptic episodes, and reward consumption. Our findings highlight a sexually dimorphic role of orexin in regulating cognitive flexibility and the need for further investigations of sex-specific functions of the orexin circuitry.     

Psychiatric III-Health of Women and Its Relationship to Obesity and Body Fat Distribution

Objective : Abdominal obesity is associated with serious, prevalent diseases. Previously, psychiatric symptoms and ill-health has been found in this condition in men. The results of a similar study in women is reported herein. Research Methods and Procedures : A cohort of 1464 women, aged 40 years and recruited by systematic sampling, was examined (77.7% participation rate). Items regarding use of anxiolytics, hypnotics, and antidepressive drugs were registered, as well as symptoms of dyspepsia, sleeping disturbances, melancholy, and degree of life satisfaction. Smoking and alcohol consumption, as well as self-measured weight, height, waist, and hip circumferences, were reported, from which body mass index [BMI; weight (kg)/height² (m²), kg/m²] and the waist/hip circumference ratio (WHR) were calculated. Results : In bivariate analyses, BMI was associated with use of anxiolytics, antidepressive drugs, various sleeping disturbances, and a low degree of life satisfaction. After controlling for “the WHR, alcohol, and tobacco use in multivariate analysis, the associations between BMI and use of anxiolytics and sleeping disturbances remained significant. The WHR correlated with dyspepsia, sleeping problems, and use of antidepressive drugs. After adjustments for BMI, smoking, and alcohol, the relationship to dyspepsia and antidepressants remained significant. Discussion : The results suggest that elevated BMI (obesity) and elevated WHR (central fat distribution) are associated in different ways with symptoms of psychiatric ill-health in women. Obesity alone shows no such relationships to psy chiatric ill-health in men, whereas central fat distribution shows independent associations to all of the measured variables studied in this report in women, suggesting gender differences in these associations.