Modulating speed-accuracy strategies in major depression.

BACKGROUND: Depression is associated with deficits in cognitive flexibility. The role of general slowing in modulating more specific cognitive deficits is however unclear. AIM: We assessed how depression affects the capacity to strategically adapt behavior between harsh and prudent response modalities and how general and specific processes may contribute to performance deficits. METHODS: Patients suffering from major depression and age- and education-matched healthy controls were asked to randomly stress either speed or accuracy during perceptual decision-making. RESULTS: Diffusion models showed that patients with depression kept using a less conservative strategy after a trial with speed vs. accuracy instructions. Additionally, the depression group showed a slower rate of evidence accumulation as indicated by a generally lower drift rate. CONCLUSIONS: These data demonstrate that less efficient strategic regulation of behavior in depression is due not only to general slowing, but also to more specific deficits, such as a rigid dependence on past contextual instructions. Future studies should investigate the neuro-anatomical basis of this deficit.

Psychopathological and personality traits underlie decision making in recent onset medication naïve anorexia nervosa: a pilot study.

The Iowa Gambling Task (IGT) analyzes the ability of participants to sacrifice immediate rewards in view of a long term gain. Anorexia Nervosa (AN) in addition to weight loss and body image disturbances is also characterized by the tendency to make decisions that may result in long-term negative outcomes. Studies that analyzed IGT performance in patients with AN were not consistent with each other. Fifteen adolescents with AN and 15 matched controls carried out IGT after being clinically and neuropsychologically evaluated. An interesting generalized estimating equation approach showed that four independent clinical variables, and not the group, explained IGT performances, such as blocks repetition, anxiety, psychogenic eating disorders and self transcendence. The impairment of decision making is not related to the diagnosis of AN, but it is driven by high levels of anxiety and self transcendence. Instead, some psychogenic eating disorders traits, related to illness severity, positively affected IGT performance in the whole sample. IGT impairment in AN found by prior studies could be related to these clinical features which are not always taken into account.

Impaired configural body processing in anorexia nervosa: evidence from the body inversion effect.

Patients with anorexia nervosa (AN) suffer from severe disturbances of body perception. It is unclear, however, whether such disturbances are linked to specific alterations in the processing of body configurations with respect to the local processing of body part details. Here, we compared a consecutive sample of 12 AN patients with a group of 12 age-, gender- and education-matched controls using an inversion effect paradigm requiring the visual discrimination of upright and inverted pictures of whole bodies, faces and objects. The AN patients presented selective deficits in the discrimination of upright body stimuli, which requires configural processing. Conversely, patients and controls showed comparable abilities in the discrimination of inverted bodies, which involves only detail-based processing, and in the discrimination of both upright and inverted faces and objects. Importantly, the body inversion effect negatively correlated with the persistence scores at the Temperament and Character Inventory, which evaluates increased tendency to convert a signal of punishment into a signal of reinforcement. These results suggest that the deficits of configural processing in AN patients may be associated with their obsessive worries about body appearance and to the excessive attention to details that characterizes their general perceptual style.

Decreased hypothalamus volumes in generalized anxiety disorder but not in panic disorder.

BACKGROUND: The hypothalamus is a brain structure involved in the neuroendocrine aspect of stress and anxiety. Evidence suggests that generalized anxiety disorder (GAD) and panic disorder (PD) might be accompanied by dysfunction of the hypothalamus-pituitary-adrenal axis (HPA), but so far structural alterations were not studied. We investigated hypothalamic volumes in patients with either GAD or PD and in healthy controls. METHODS: Twelve GAD patients, 11 PD patients and 21 healthy controls underwent a 1.5T MRI scan. Hypothalamus volumes were manually traced by a rater blind to subjects' identity. General linear model for repeated measures (GLM-RM) was used to compare groups on hypothalamic volumes, controlling for total intracranial volume, age and sex. RESULTS: The hypothalamus volume was significantly reduced (p=0.04) in GAD patients, with significant reductions in both the left (p=0.02) and right side (p=0.04). Patients with PD did not differ significantly (p=0.73). Anxiety scores were inversely correlated with hypothalamic volumes. LIMITATIONS: The small sample size could reduce the generalizability of the results while the lack of stress hormone measurements renders functional assessment of the hypothalamus-pituitary-adrenal axis not feasible. CONCLUSIONS: The present study showed decreased hypothalamic volumes in GAD patients but not in those with PD. Future longitudinal studies should combine volumetric data with measurements of stress hormones to better elucidate the role of the HPA axis in GAD.

Visual body perception in anorexia nervosa.

OBJECTIVE: Disturbance of body perception is a central aspect of anorexia nervosa (AN) and several neuroimaging studies have documented structural and functional alterations of occipito-temporal cortices involved in visual body processing. However, it is unclear whether these perceptual deficits involve more basic aspects of others' body perception. METHOD: A consecutive sample of 15 adolescent patients with AN were compared with a group of 15 age- and gender-matched controls in delayed matching to sample tasks requiring the visual discrimination of the form or of the action of others' body. RESULTS: Patients showed better visual discrimination performance than controls in detail-based processing of body forms but not of body actions, which positively correlated with their increased tendency to convert a signal of punishment into a signal of reinforcement (higher persistence scores). DISCUSSION: The paradoxical advantage of patients with AN in detail-based body processing may be associated to their tendency to routinely explore body parts as a consequence of their obsessive worries about body appearance.