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Mutations in the progranulin gene (GRN) are a common cause of familial frontotemporal dementia. We used a comprehensive neuropsychological battery to investigate whether early cognitive changes could be detected in GRN mutation carriers before dementia onset. Twenty-four at-risk members from six families with known GRN mutations underwent detailed neuropsychological testing. Group differences were investigated by domains of attention, language, visuospatial function, verbal memory, non-verbal memory, working memory and executive function. There was a trend for mutation carriers (n=8) to perform more poorly than non-carriers (n=16) across neuropsychological domains, with significant between group differences for visuospatial function (p<.04; d=0.92) and working memory function (p<.02; d=1.10). Measurable cognitive differences exist before the development of frontotemporal dementia in subjects with GRN mutations. The neuropsychological profile of mutation carriers suggests early asymmetric, right hemisphere brain dysfunction that is consistent with recent functional imaging data from our research group and the broader literature. (JINS, 2014, 20, 1–10)
Direct deposition of graphene from carbon sources on foreign substrates without the use of metal catalysts is shown to be an effective process with several advantages over other growth techniques. Carbon source molecular beam epitaxy (CMBE) in particular provides an additional control parameter in carbon flux and enables growth on substrates other than SiC, including oxidized Si and sapphire. CMBE using thermally evaporated C60 and a heated graphite filament on SiC is reported here. The graphene films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and Hall effect. Graphene films on Si-face SiC grown using the C60 source have Bernal-like stacking and n-type conduction while those grown using the graphite filament have turbostratic stacking and p-type conduction. The sheet concentration for both n- and p-type doping is linearly dependent on film thickness.
We ask if Earth-like planets (terrestrial mass and habitable-zone orbit) can be detected in multi-planet systems, using astrometric and radial velocity observations. We report here the preliminary results of double-blind calculations designed to answer this question.
Good cognitive performance requires adherence to rules specific to the task at hand. Patients with neurological disease often make rule violation (RV) errors, but the anatomical basis for RV during cognitive testing remains debated. The present study examined the neuroanatomical correlates of RV errors made on tests of executive functioning in 166 subjects diagnosed with neurodegenerative disease or as neurologically healthy. Specifically, RV errors were voxel-wisely correlated with gray matter volume derived from high-definition magnetic resonance images using voxel-based morphometry implemented in SPM2. Latent variable analysis showed that RV errors tapped a unitary construct separate from repetition errors. This analysis was used to generate factor scores to represent what is common among RV errors across tests. The extracted RV factor scores correlated with tissue loss in the lateral middle and inferior frontal gyri and the caudate nucleus bilaterally. When a more stringent control for global cognitive functioning was applied using Mini Mental State Exam scores, only the correlations with the right lateral prefrontal cortex (PFC) remained significant. These data underscore the importance of right lateral PFC in behavioral monitoring and highlight the potential of RV error assessment for identifying patients with damage to this region. (JINS, 2009, 15, 354–364.)
The purpose of this study was to examine the relationships between
lobar volumes and set shifting. We studied 101 subjects, including 36
normal controls, 16 patients with probable Alzheimer's disease, 30
patients with frontotemporal dementia (FTD), and 19 patients with semantic
dementia (SD), using a shifting paradigm that carefully controlled for
component abilities. Subjects were administered two conditions of the
Delis–Kaplan Executive Function System (D-KEFS) Design Fluency Test.
In the control condition (DF:Control), examinees generated as many unique
designs as possible in 60 s by drawing lines connecting only unfilled
dots. In the switching condition (DF:Switch), examinees generated designs
by drawing lines alternating between filled and unfilled dots. We used
BRAINS2 software to generate volumes of the right and left frontal,
temporal, and parietal lobes. Partial correlations and multiple
regressions showed that, after controlling for Mini-Mental State
Examination and DF:Control, only the right and left frontal lobe volumes
significantly correlated with the DF:Switch, most clearly in the FTD and
SD groups. Follow-up analyses indicated that frontal contributions to
shifting were not related to working memory. Results highlight the
importance of carefully controlling for component cognitive processes when
studying executive functioning. (JINS, 2007, 13,