Adapted connections on metric contact manifolds

In this paper, we describe the space of adapted connections on a metric contact manifold through the space of their torsion tensors. The torsion tensor is an element of the space of TM-valued two-forms, which splits into various subspaces. We study the parts of the torsion tensor according to this splitting to completely describe the space of adapted connections. We use this description to obtain characterizations of the generalized Tanaka-Webster connection and to describe the Dirac operators of adapted connections.Comment: 25 pages; some remarks added, minor correction

Massive cortical reorganization in sighted Braille readers

The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills

Remembering verbally-presented items as pictures:brain activity underlying visual mental images in schizophrenia patients with visual hallucinations

Background: Previous research suggests that visual hallucinations in schizophrenia consist of mental images mistaken for percepts due to failure of the reality-monitoring processes. However, the neural substrates that underpin such dysfunction are currently unknown. We conducted a brain imaging study to investigate the role of visual mental imagery in visual hallucinations. Method: Twenty-three patients with schizophrenia and 26 healthy participants were administered a reality-monitoring task whilst undergoing an fMRI protocol. At the encoding phase, a mixture of pictures of common items and labels designating common items were presented. On the memory test, participants were requested to remember whether a picture of the item had been presented or merely its label. Results: Visual hallucination scores were associated with a liberal response bias reflecting propensity to erroneously remember pictures of the items that had in fact been presented as words. At encoding, patients with visual hallucinations differentially activated the right fusiform gyrus when processing the words they later remembered as pictures, which suggests the formation of visual mental images. On the memory test, the whole patient group activated the anterior cingulate and medial superior frontal gyrus when falsely remembering pictures. However, no differential activation was observed in patients with visual hallucinations, whereas in the healthy sample, the production of visual mental images at encoding led to greater activation of a fronto-parietal decisional network on the memory test. Conclusions: Visual hallucinations are associated with enhanced visual imagery and possibly with a failure of the reality-monitoring processes that enable discrimination between imagined and perceived events

Health Care Provider Knowledge of the Immunization Schedule and the Contraindications to Vaccinate

The purpose to this study was to determine if the current knowledge of Kent county\u27s health care providers contributed to the under immunization of children less than two years of age. A survey, modified from a previous study done in Los Angeles, was distributed to Family Practice and Pediatrics offices within the greater Grand Rapids area. Several areas of health care provider knowledge were assessed. These included: (1) knowledge of the primary series immunization schedule in both a child on time and delinquent, (2) knowledge of timing between diptheria, tetanus, and pertussis boosters, and (3) knowledge of the contraindications to vaccinate. The results showed an 89% correct response rate for knowledge of the immunization schedule and an 80% correct response rate for knowledge of the contraindications to vaccinate. Overall it was concluded that Kent county health care providers were sufficiently knowledgeable in both areas stated and, therefore, did not significantly contribute to the under immunization of young children

Combining transcranial magnetic stimulation with (f)MRI

Transcranial magnetic stimulation (TMS) is a noninvasive and painless tool for the electrical stimulation of the human cortex (Barker et al. 1985). TMS depolarizes cortical neurons and can evoke measurable electrophysiological and behavioral effects. TMS is usually applied to one cortical area, but can also be given to two or more areas (i.e., multi-site TMS). Single or paired stimuli and short stimulus trains (i.e., high-frequency bursts) provide a means of transiently disrupting ongoing neuronal processing in the stimulated cortex. Repetitive TMS (rTMS) refers to the application of prolonged trains of stimuli, which are either given continuously as long trains at a constant rate (continuous rTMS), or intermittently as repetitive bursts (i.e., intermittent or burst-like rTMS). rTMS can modify the excitability of the cerebral cortex at the stimulated site and also at remote interconnected brain regions, beyond the time of stimulation. Its neuromodulatory effects make rTMS a valuable tool to study the functional plasticity of neuronal networks and may be used therapeutically in patients with neurological and psychiatric disorders