White matter volume alterations in hair-pulling disorder (trichotillomania)

Trichotillomania (TTM) is a disorder characterized by repetitive hair-pulling resulting in hair loss. Key processes affected in TTM comprise affective, cognitive, and motor functions. Emerging evidence suggests that brain matter aberrations in fronto-striatal and fronto-limbic brain networks and the cerebellum may characterize the pathophysiology of TTM. The aim of the present voxel-based morphometry (VBM) study was to evaluate whole brain grey and white matter volume alteration in TTM and its correlation with hair-pulling severity. High-resolution magnetic resonance imaging (3 T) data were acquired from 29 TTM patients and 28 age-matched healthy controls (CTRLs). All TTM participants completed the Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS) to assess illness/pulling severity. Using whole-brain VBM, between-group differences in regional brain volumes were measured. Additionally, within the TTM group, the relationship between MGH-HPS scores, illness duration and brain volumes were examined. All data were corrected for multiple comparisons using family-wise error (FWE) correction at p < 0.05. Patients with TTM showed larger white matter volumes in the parahippocampal gyrus and cerebellum compared to CTRLs. Estimated white matter volumes showed no significant association with illness duration or MGH-HPS total scores. No significant between-group differences were found for grey matter volumes. Our observations suggest regional alterations in cortico-limbic and cerebellar white matter in patients with TTM, which may underlie deficits in cognitive and affective processing. Such volumetric white matter changes may precipitate impaired cortico-cerebellar communication leading to a reduced ability to control hair pulling behavior

Contribution to the feeding ecology of the banded puffer fish Colomesus psittacus (Tetraodontidae) in north Brazilian mangrove creeks

Stomach contents were examined from 102 banded puffer, Colomesus psittacus (Tetraodontidae), caught from intertidal mangrove creeks at diurnal neap tides between June and September, 1997 (early dry season) near Bragança (north Brazil). The study found that C. psittacus were specialized predators of Cirripedia (Balanus spp.) and Brachyuran crabs (Uca spp., Pachygrapsus gracilis) (mean: 58 and 38% by dry weight, respectively), emphasizing a short food chain in the mangrove system. Cirripedia and Brachyura dominated the diet in all size classes, however, the prey spectrum narrowed with fish size. The mean daily consumption of Cirripedia and Brachyura was 6.2% body weight of C. psittacus. On average C. psittacus consumed 100.3 g.ha-1.d-1 of Cirripedia and 178.7 g.ha-1.d-1 of Brachyura (wet weight). The predation on Brachyuran crabs - a significant driver of fluxes of organic matter and energy in the system - provides C. psittacus with an important ecological function in the mangrove food web. A plant-animal interaction is proposed where C. psittacus exerts a mutually beneficial cleaning function on the Aufwuchs (Cirripedia and associated epibiota) of Rhizophora mangle stilt roots. Our results and those of other studies suggest that C. psittacus encounter optimum foraging conditions in the mangrove at high inundations at daylight (spring tide-day) whereas darkness and low inundations are linked to poor foraging conditions (neap tide-night). The C. psittacus resource could be used as an alternative income in the region in terms of i) sustainable catch and filet processing for exports to East Asia, ii) developing certified aquaculture methods for breeding puffers for the aquarium trade

Proximal mappings and moreau envelopes of single-variable convex piecewise cubic functions and multivariable gauge functions

This work presents a collection of useful properties of the Moreau envelope for finite-dimensional, proper, lower semicontinuous, convex functions. In particular, gauge functions and piecewise cubic functions are investigated and their Moreau envelopes categorized. Characterizations of convex Moreau envelopes are established; topics include strict convexity, strong convexity, and Lipschitz continuity

The Beliefs in Trichotillomania Scale (BiTS): factor analyses and preliminary validation

Objectives: The role of cognitions and beliefs in trichotillomania (TTM; hair pulling disorder) has been the subject of only limited investigation. This study aimed to develop and validate the Beliefs in TTM Scale (BiTS). Methods: A pool of 50 items based upon themes identified in previous research was administered online to 841 participants with and without self-reported problematic, non-cosmetic hair pulling behaviours. Results: Exploratory and confirmatory factor analyses conducted in randomly split-halves of the sample supported retention of 14 items comprising three factors: negative self-beliefs, low coping efficacy, and perfectionism. Conclusions: The BiTS demonstrated satisfactory psychometric properties and all three subscales significantly correlated with greater hair pulling severity. Negative self-beliefs predicted hair pulling severity over and above mood symptoms, suggesting the importance of addressing self-construals in psychological treatments for TTM. Validation in a clinician diagnosed sample is required. Practitioner points: Research supports cognitive therapies for treating trichotillomania (hair pulling disorder), although studies investigating the nature and role of cognitions and beliefs in this disorder have been lacking. This study developed and validated a self-report measure of three styles of beliefs most relevant to trichotillomania: negative self-beliefs, low coping efficacy, and perfectionism. Negative self-beliefs predicted the severity of trichotillomania symptoms over and above depression and anxiety, suggesting such cognitions may not necessarily be due to comorbidities. Future research should validate the new measure in a clinician diagnosed sample, and therapies for trichotillomania may be enhanced by targeting shame specifically