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Visual illusions (VI) in Parkinson’s disease (PD) are generally considered as an early feature of the psychosis spectrum leading to fully formed visual hallucinations (VH), although this sequential relationship has not been clearly demonstrated. We aimed to determine whether there are any overlapping, potentially graded patterns of structural and functional connectivity abnormalities in PD with VI and with VH. Such a finding would argue for a continuum between these entities, whereas distinct imaging features would suggest different neural underpinnings for the phenomena. In this case control study, we compared structural and resting state functional MRI brain patterns of PD patients with VH (PD-H, n = 20), with VI (PD-I, n = 19), and without VH or VI (PD-C, n = 23). 1) PD-H had hypo-connectivity between the ILO and anterior cingulate precuneus and parahippocampal gyrus compared to PD-C and PD-I; 2) In contrast, PD-I had hyper-connectivity between the inferior frontal gyrus and the postcentral gyrus compared to PD-C and PD-H. Moreover, PD-I had higher levels of functional connectivity between the amygdala, hippocampus, insula, and fronto-temporal regions compared to PD-H, together with divergent patterns toward the cingulate. 3) Both PD-I and PD-H had functional hypo-connectivity between the lingual gyrus and the parahippocampal region vs. PD-C, and no significant grey matter volume differences was observed between PD-I and PD-H. Distinct patterns of functional connectivity characterized VI and VH in PD, suggesting that these two perceptual experiences, while probably linked and driven by at least some similar mechanisms, could reflect differing neural dysfunction.

There is substantial evidence that neuromodulatory systems critically influence brain state dynamics; however, most work has been purely descriptive. Here, we quantify, using data combining local inactivation of the basal forebrain with simultaneous measurement of resting-state fMRI activity in the macaque, the causal role of long-range cholinergic input to the stabilization of brain states in the cerebral cortex. Local inactivation of the nucleus basalis of Meynert (nbM) leads to a decrease in the energy barriers required for an fMRI state transition in cortical ongoing activity. Moreover, the inactivation of particular nbM sub-regions predominantly affects information transfer in cortical regions known to receive direct anatomical projections. We demonstrate these results in a simple neurodynamical model of cholinergic impact on neuronal firing rates and slow hyperpolarizing adaptation currents. We conclude that the cholinergic system plays a critical role in stabilizing macroscale brain state dynamics.

COVID-19 and rising student numbers are affecting healthcare education, particularly access to clinical placements. As healthcare education is increasingly supported by technology and non-traditional teaching methods, educational experiences gained through clinical placement also require new approaches. This article explores and discusses the use of a simulated clinical placement for a dietetic student cohort. During this virtual placement, students were able to explore and experience a virtual clinical setting and immerse themselves in a placement experience. A vast range of virtual resources were linked to the online placement portal, including statutory and mandatory training, dietetic resources, patient journeys and interprofessional communication. Advantages of this approach include that all students experience a given situation, unlike in traditional placements where workloads, variety and engagement vary; there is also no risk to patient safety. The aim is to enhance the learning experience to create effective, efficient clinicians. This virtual placement for dietetics is part of a bigger project to develop and evaluate the use of a virtual placement framework in a range of professions. The concept of virtual placement may have been brought forward by the COVID-19 crisis but was inevitable with the move to more technology-enhanced learning tools.

V3 serotyping is a technique for determining HIV‐1 genetic subtype based on the binding of antibodies from patient sera or plasma to synthetic V3 peptides derived from subtype consensus sequences. Variation in the performance of this assay has been attributed to V3 sequence heterogeneity, the degree of which varies with patient disease progression, virus co‐receptor usage, and genetic subtype. This study assessed the performance of a competitive peptide enzyme immunoassay (cPEIA) in samples from HIV‐1 subtype C infected patients with varying disease profiles, including those with syncytium (SI) and non‐syncytium‐inducing (NSI) viruses. Out of 90 sera tested, 94.4% reacted strongly against the subtype C peptide. There was no significant difference in assay sensitivity among samples from advanced AIDS patients in which humoral immune response may be lower, nor among SI viruses which carry changes in the V3 sequence. Four samples were found to be cross‐reactive with other subtypes and one acutely infected patient sample was non‐reactive due to low anti‐gp120 antibody titers. A significantly higher number of samples showed secondary reactivity to subtype A, compared to other subtypes (P< 0.005). In conclusion, the assay was able to identify HIV‐1 subtype C infection with a high level of sensitivity (94%) irrespective of the stage of disease and therefore provides a valuable resource for the large‐scale epidemiological monitoring of the spread of HIV‐1 subtypes in South Africa. J. Med. Virol. 78:1262–1268, 2006. © 2006 Wiley‐Liss, Inc.

The genotypes and biological phenotypes of HIV-1 isolates obtained from 40 perinatally infected children in South Africa were analyzed. This included 15 infants who had HIV-related symptoms, most of whom died within 2 years of birth (rapid progressors), and 25 children who survived between 4 and 9 years with varying signs of disease (slow progressors). Heteroduplex mobility assays and sequence analysis confirmed that within the env and gag regions, all isolates were HIV-1 subtype C. Viral isolates from 14 of the 15 rapid progressors used the CCR5 coreceptor, whereas 1 (02ZARP1) used both the CXCR4 and CCR5 coreceptors. Among the 25 slow progressors, 22 isolates used CCR5 only, 2 used CXCR4 only, and 1 used both CCR5 and CXCR4. Two of the slow-progressing children who harbored CXCR4-using viruses had AIDS. All four CXCR4-using viruses had genotypic changes in the V3 region previously shown to be associated with CXCR4 usage. This cross-sectional study shows that HIV-1 subtype C viruses from both rapid- and slow-progressing perinatally infected children used predominantly CCR5. Similar to adults, CXCR4 usage was uncommon among HIV-1 subtype C isolates from pediatric infections.

Objective: To review all bicycle crash‐related injuries reported to the Oregon Injury Registry for 1989 to compare patterns of injury and other features in adults vs children and adolescents.