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The three common alleles of the APOEgene, ?2/?3/?4, have been linked to human spatial orientation. We investigated the genetic role of APOEin developmental topographical disorientation (DTD), a lifelong condition that results in topographical disorientation. We genotyped the APOE?2/?3/?4 alleles in a cohort of 20 unrelated DTD probands, and found allele frequencies not statistically different from the those seen in the population as a whole. Therefore, we found no evidence that DTD occurs preferentially on a genetic background containing any particular APOEallele, making it unlikely that these APOEalleles are contributing to the development of DTD.

Visual short-term memory (VSTM) is an important cognitive capacity that varies across the healthy adult population and is affected in several neurodevelopmental disorders. It has been suggested that neuroanatomy places limits on this capacity through a map architecture that creates competition for cortical space. This suggestion has been supported by the finding that primary visual (V1) gray matter volume (GMV) is positively associated with VSTM capacity. However, evidence from neurodevelopmental disorders suggests that the dorsal visual stream is more broadly vulnerable and atypical volumes of other map-containing regions may therefore play a role. For example, Turner syndrome is associated with concomitantly reduced volume of the right intraparietal sulcus (IPS) and deficits in VSTM. As posterior IPS regions (IPS0-2) contain topographic maps, together this suggests that posterior IPS volumes may also associate with VSTM. In this study, we assessed VSTM using two tasks, as well as a composite score, and used voxel-based morphometry of T1-weighted magnetic resonance images to assess GMV in V1 and right IPS0-2 in 32 healthy young adults (16 female). For comparison with previous work, we also assessed associations between VSTM and voxel-wise GMV on a whole-brain basis. We found that total brain volume (TBV) significantly correlated with VSTM, and that correlations between VSTM and regional GMV were substantially reduced in strength when controlling for TBV. In our whole-brain analysis, we found that VSTM was associated with GMV of clusters centered around the right putamen and left Rolandic operculum, though only when TBV was not controlled for. Our results suggest that VSTM ability is unlikely to be accounted for by the volume of an individual cortical region, and may instead rely on distributed structural properties.

Clinical islet cell transplantation has resulted in insulin independence in a limited number of cases. Rejection, recurrence of autoimmunity, and impairment of normal islet function by conventional immunosuppressive drugs, e.g., [...]

Based on rodent data it is estimated that islet engraftment and angiogenesis are completed after 10 to 11 days. We assessed the insulin response to an intra-venous glucose tolerance test [...]

Abstract.Sleep loss is known to severely disturb individuals’ mood and emotion processing. Here, we tested the hypothesis that quality of sleep is predictive of individuals’ performance on a task evaluating emotional empathy. We tested 34 healthy undergraduate students [19 males, mean (SD) age = 21.82 (3.26) years; mean (SD) education = 14.98 (1.91) years] recruited through the University of Calgary research participation system. We collected objective (actigraphy) and subjective (questionnaires and self-reports) sleep measures to characterize individuals’ sleep quality, and asked participants to solve a computerized emotional empathy task. We first performed a dimensionality reduction analysis on the sleep-related measures, which resulted in six principal components, and then ran a stepwise multiple regression analysis to investigate the sleep measures that best predicted participants’ scores on the emotional empathy task. We found that subjective sleep quality, together with sleep phase, best predicted participants’ empathic sensitivity to negative images while they explicitly evaluated the emotions of others (i.e., direct component of emotional empathy). Also, subjective sleep quality resulted to be the best predictor of participants’ arousal state in response to negative images, which is an implicit manifestation of their empathic experience (i.e., indirect component of emotional empathy). In both cases, lower subjective sleep quality was associated with lower empathic sensitivity to negative stimuli. Finally, sleep duration best predicted average empathic responses to stimuli of all valences, with shorter sleep durations associated with lower average empathic responses. Our findings provide evidence of a significant relationship between individuals’ quality of sleep and their ability to share the emotions experienced by others. These findings may have important implications for individuals employed in professions requiring social interaction and empathic experience coupled with schedules that interfere with nighttime sleep.

Previous studies report that acquired prosopagnosia is frequently associated with topographic disorientation. Whether this is associated with a specific anatomic subtype of prosopagnosia, how frequently it is seen with the developmental variant, and what specific topographic function is impaired to account for this problem are not known.

Face perception is a function with significant complexity, reflected in cognitive models that propose a hierarchy of parallel and serial processing stages. Current neuroimaging data also show that face perception involves a core processing network of cortical modules, which are likely specialized for different functions involved in face processing. The core face processing network is further linked to an extended face processing network which is not solely involved in the perception of faces, but rather contains modules mediating the processing of semantic, biographic and emotional information about people. The segregation of these processes within discrete anatomic regions creates the potential for disconnection between regions to generate neuropsychological deficits involving faces. In this review we consider the types of disconnection possible both within the core face processing system and between the core and extended systems, the pattern of deficits that would be considered as evidence of such disconnections, the potential anatomy of lesions that would create them, and whether any cases exist that meet these criteria.