Social cognition in cervical dystonia: phenotype and relationship to anxiety and depression.

BACKGROUND AND PURPOSE: Anxiety and depression are common disabling comorbidities in cervical dystonia (CD) and may predispose to social withdrawal and social cognitive impairments. The relationship between social cognition and depressive/anxiety symptoms in CD is under-investigated. METHODS: Forty-six CD patients (40 women; mean age ± SD, 55.57 ± 10.84 years) were administered the following social cognition battery: Affect Naming, Prosody Face and Pair Matching subtests from the Wechsler Adult Intelligence Scale IV and Wechsler Memory Scale IV (social perception), reality-known and reality-unknown false belief reasoning tasks (theory of mind), Empathy Quotient and Social Norms Questionnaire 22 (social behaviour), alongside the Benton Facial Recognition Task (non-emotional facial discrimination). Alongside CD severity, the Hospital Anxiety and Depression Scale measured depressive/anxiety comorbid diagnostic status and severity, and the Liebowitz Social Anxiety Scale assessed social phobia. Social cognition tasks were standardized using published normative data and a cut-off of z < -1.5 for impairment. RESULTS: More than 90% of our CD patients performed normally on social perception and social behaviour tests. Performance on impaired belief reasoning (theory of mind) was impaired in 10 of 46 (21.74%); five of 46 (10.87%) were impaired on the Empathy Quotient. Better performance on the Affect Naming task was associated with comorbid anxiety (η2  = 0.09, medium-to-large effect size) and greater anxiety, depression and social phobia severity. Worse performance on the Empathy Quotient was associated with comorbid depression (η2  = 0.11, medium-to-large effect size) and greater depression severity. CD patients had significantly more difficulties with fearful face identification (P < 0.001). CONCLUSIONS: Greater social perception abilities in CD patients with more severe anxiety and depression suggest efficient modulation and self-adaptation of social cognitive skills.

Characterization of cognition in mild cognitive impairment with and without Parkinson's disease.

•Screening tests can diagnose PD-MCI but do not give detailed cognitive profiles.•Criteria based on a complete neuropsychological battery identify more PD patients with MCI.•The overall cognitive profile is similar in PD-MCI and MCI.•Neuropsychological batteries and definition of impairment cut-offs should be refined.

Heat shock protein 25 expression and preferential Purkinje cell survival in the lurcher mutant mouse cerebellum.

The spatial organization of the mouse cerebellum into transverse zones and parasagittal stripes is reflected during the temporal progression of Purkinje cell death in the Lurcher mutant mouse (+/Lc). Neurodegeneration in the +/Lc mutant is apparent by the second postnatal week and is initially seen in all four transverse zones: the anterior (lobules I-V), central (lobules VI, VII), posterior (lobules VIII, dorsal IX), and nodular (ventral lobule IX and lobule X) zone. However, from postnatal day (P)25-P36, Purkinje cell loss proceeds more rapidly in the anterior zone, followed by the posterior and central zones, and is significantly delayed in the nodular zone. Coronal sections through the +/Lc cerebellum reveal that surviving Purkinje cells are restricted to the paraflocculus/flocculus and the nodular zone and could be detected as late as P146 (approximately 5 months). Within this region, the pattern of preferentially surviving calbindin-immunoreactive Purkinje cells reflects the expression of the constitutively expressed small heat shock protein HSP25 in the wild-type cerebellum. Although the role of constitutively expressed HSP25 in the wild-type cerebellum is not clear, it appears to play a neuroprotective role in the flocculonodular region of the +/Lc mutant cerebellum as the percentage of surviving Purkinje cells that are HSP25-immunopositive significantly increases over time.

Patterned cerebellar Purkinje cell death in a transgenic mouse model of Niemann Pick type A/B disease.

Niemann Pick disease is a family of autosomal recessive disorders characterized by cholesterol accumulation. The most common type is Niemann Pick type A/B (NPA/B), resulting from deficient acid sphingomyelinase activity, which leads to sphingomyelin and cholesterol accumulation. The neuropathology of NPA/B includes widespread neuronal degeneration. An acid sphingomyelinase knockout mouse model of NPA/B (ASMKO) has been developed by the targeted deletion of the acid sphingomyelinase gene. When cerebellar morphology was examined in the ASMKO mouse at postnatal day 60 (P60), a dramatic pattern of longitudinal stripes was revealed in which roughly half the Purkinje cells had died, leaving a highly stereotyped, bilaterally symmetrical array of stripes. Antizebrin II immunocytochemistry revealed that the absent Purkinje cells corresponded exactly to the zebrin II-negative subset, leaving the zebrin II-positive subset apparently intact. By P120, some of the zebrin II-positive Purkinje cells had also been eliminated from the posterior vermis and hemispheres. By P180, all Purkinje cells had been lost from the anterior lobe. Finally at P240, almost all Purkinje cells had disappeared to leave a stereotyped distribution in lobules VI, IX-X and the flocculus and paraflocculus. The temporal pattern of Purkinje cell death demonstrates differential susceptibility of morphologically identical cells that appear to be linked to their molecular phenotypes.

The Dalila effect: C57BL6 mice barber whiskers by plucking.

Group-housed laboratory mice are frequently found with their whiskers and facial hair removed. It has been proposed that dominant mice are responsible for barbering the hair of the recipient (the Dalila effect), and early studies suggest that the hair is removed by nibbling. In the present study, pairs of C57BL6 mice, composed of a barber and recipient, were separated to allow hair to regrow. The animals were then placed together in an observation box and their social behavior was videorecorded. The videorecording was subjected to frame-by-frame analysis. Barbering was found to occur during acts of mutual grooming. During grooming, one member of a mouse pair removed the vibrissae of the conspecific and did so by grasping individual whiskers with the incisors and plucking them out. Although plucking appeared 'painful', recipients were passive in accepting barbering, and even pursued conspecifics for further grooming. Other measures indicated that barbers were heavier than recipients and brain weights were not different. Although cortical barrel fields appeared normal to cytochrome oxidization and zinc staining, Golgi analysis of layer three, barrel-field basilar dendrites indicated changes in cell morphology. The results are discussed in relation to the hypothesis that barbering is an expression of social dominance, the origins of the barbering behavior, and the consequences of barbering on brain function.

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species.

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents. The present study was undertaken to describe limb/paw movements in a variety of common rodents. The movements used for handling sunflower seeds and other foods were videorecorded and analyzed in the guinea pig (Cavia porcellus), Mongolian gerbil (Meriones unguiculatus), Syrian hamster (Mesocricetus auratus), laboratory mouse (Mus musculus), laboratory rat (Rattus norvegicus), gray squirrel (Sciurus carolinensis), red squirrel (Tamiasciurus hudsonicus), Richardson's ground squirrel (Spermophilus richardsonni), prairie dog (Cynomus parvidens), and Canadian beaver (Castor americanus). The results suggested five order-common movements of food handling: (1) locating food by sniffing, (2) grasping food by mouth, (3) sitting back on the haunches to eat, (4) grasping the food using an elbow-in movement, and (5) manipulate the food with the digits. Different species displayed species-typical specializations including (1) bilateral grasping with the paws (gerbil), (2) unilateral grasping with a paw (beaver), (3) unilateral holding (ground squirrels), (4) various grip and digit postures (all species), (5) unilateral object removal from the mouth (gerbil), (6) bilateral thumb holding (squirrels), and (7) simultaneous holding/manipulation of two objects (squirrels). Only the guinea pig did not handle food with its paws, suggesting its behavior is regressive. The existence of a core pattern of paw and digit use in rodents suggests that skilled limb and paw movements originate at least with the common ancestors of the rodent, and likely the common ancestor to rodent and primate lineages, while species-typical movements suggest specialization/regression of limb use has occurred in a number of mammalian orders.

Paw and limb use in skilled and spontaneous reaching after pyramidal tract, red nucleus and combined lesions in the rat: behavioral and anatomical dissociations.

The pyramidal tract and red nucleus send prominent projections to the spinal cord and are thought to co-operate in producing skilled movements. In the present study, skilled reaching for food located on a shelf and spontaneous grasping, handling and eating pieces of pasta were video-recorded and analyzed in control rats, rats with unilateral ibotenic acid lesions of the red nucleus (RN), unilateral pyramidal tract lesions (PT) and combined lesions. The behavioral results suggest that skilled movements are organized as action patterns, easily recognizable and distinctive for each task. In both skilled and spontaneous reaching, PT lesions reduced success more than RN lesions, suggesting a greater role for the PT in guiding limb movements. Both lesions impaired rotatory movements including limb aiming, pronation and supination. RN lesions additionally abolished the arpeggio movement by which the paw is oriented for searching and grasping. Combined lesions were additive as rats lost both rotatory movements and arpeggio. Nevertheless, even after combined lesions, the rats were able to advance the limb, grasp food and withdraw the limb. The sparing following combined lesions suggests that other neural systems as well as compensatory adjustments assist the impaired limb. The results are discussed in relation to the possible distinctive contributions of the rubrospinal and corticospinal tract to the action patterns that comprise skilled movements in rats.