Cortex最新文献

Prism adaptation (PA) is a visuomotor adaptation paradigm resulting in transient sensorimotor shifts. Previous work shows PA can cause additional changes in higher-level visuospatial representations in healthy subjects. In patients with neglect symptoms, records of beneficial visuospatial aftereffects of PA form the basis for its usage as a potential rehabilitation strategy. However, results in both patients and healthy subjects are mixed, with recent studies failing to replicate effects of PA on visuospatial representations. Here, we applied a single session of either right or left PA in healthy subjects (N = 85). Sensorimotor, proprioceptive, and visuospatial biases were measured at baseline, immediately after, 30 minutes, and 24 hours after PA. We found that PA has immediate and robust sensorimotor and proprioceptive aftereffects, replicating previous findings. Crucially, we find that despite expected decay, significant residues of sensorimotor aftereffects can last up to 24 h after PA. In contrast, no short or long-term aftereffects were found on visuospatial attention as measured by the grayscale judgment task. This null result was stable when taking the initial bias of attention orientation into account. No relationship was found between the degree of sensorimotor or proprioceptive responsiveness and visuospatial responsiveness. Our results suggest the effects of PA on the sensorimotor system are less transient than previously thought and are still evident after a night of sleep. Importantly, taken together with recently published null results for the visuospatial effects of PA using other tasks, we suggest these effects might be less extensive than previously reported in healthy subjects.

Long-Covid is associated with cognitive deficits in memory, attention, or executive function. However, the associated cerebral structural and functional changes are insufficiently studied to date. We investigated 39 long-Covid patients with (n = 16) and without (n = 23) cognitive impairment. Impairment was defined by a pronounced deficit (-1.5 SD) in at least one cognitive domain including memory, attention, executive function, and verbal fluency. All participants underwent structural and functional resting-state magnetic resonance imaging (MRI). We assessed differences in resting-state networks (within and between networks) between both groups as well as structural differences in total gray matter and subcortical volumes. Both groups did not differ in demographic or disease-related characteristics. Patients with cognitive deficits showed higher functional connectivity (FC) between the default mode network (DMN) and parts of the posterior supramarginal gyrus, angular gyrus and posterior-occipital part of the middle temporal gyrus, compared to those cognitively unimpaired. In addition, inter-network analyses indicated a stronger connectivity between the visual and ventral stream network in those with cognitive impairment. We found no volumetric differences between the two groups. Our results indicate that altered FC with the DMN as well as a stronger connectivity between the visual and ventral stream network in cognitively impaired long-Covid patients are associated with worse cognitive performance and therefore suggests a maladaptive functional change.

Processing speech amongst noise requires sensory and cognitive abilities that are often affected by Huntington's Disease. However, their impact on daily communication remains unclear. We examined the effects of Huntington's Disease on speech-in-noise processing using everyday sentences and words in noise contexts and conditions that mimic different daily life scenarios. In Premanifest (n = 16) and Manifest Huntington's Disease (n = 12) and Control (n = 26) participants, we examined speech discrimination amongst non-demanding and attentionally demanding noise. We also examined how Huntington's Disease affected the ability to use spatial separation cues to disambiguate speech from noise in single-voice masker or multi-talker backgrounds. Finally, we administered a validated questionnaire where participants rated auditory processing difficulties during daily life activities. Sentence-in-noise discrimination was impaired in individuals with Manifest Huntington's Disease in almost all signal-to-noise ratio conditions with the attentionally-demanding masker and amongst the non-demanding noise masker with the most difficult signal-to-noise ratio. Premanifest Huntington's Disease participants had difficulty perceiving speech in some attentionally demanding noise conditions. Spatial cues provided situational benefits to speech processing under attentionally-demanding conditions for participants at all stages of Huntington's Disease, except for the Manifest Huntington's Disease group when stimuli included a single competing speaker. A logistic regression model using speech processing performance as a predictor successfully distinguished healthy control and Premanifest groups with 87.5% accuracy. Stage-dependent impairments in speech processing were observed under naturalistic noise conditions. These results further our understanding and contextualization of communication difficulties experienced by people with Huntington's Disease.