Key points Healthy ageing in man is associated with a decline motor adaptation. Transcranial direct current stimulation (TDCS) over the primary cortex (M1) or lateral cerebellum can improve adaptation young and older adults, but as yet no comparisons of TDCS effects exist between two age groups sites. M1 enhanced both by ∼30% relative to their respective non‐stimulated improved performance adults extent that it compared without stimulation. The study suggests plastic mechanisms activated...

This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD), Parkinson's (PD), atypical parkinsonism, others, leveraging advancements in eye-tracking technology for enhanced diagnostic precision.We delve into different classes eye movements, their clinical assessment, specific abnormalities manifesting these diseases, highlighting nuanced differences shared patterns.For instance, AD...

The accuracy of saccadic eye movements is maintained over the long term by adaptation mechanisms that decrease or increase saccade amplitude. It still unknown whether these opposite adaptive changes rely on common mechanisms. Here, a double-step target paradigm was used to adaptively (backward second step) (forward amplitude reactive saccades in one direction only. To test which sensorimotor transformation stages are subjected changes, we measured their transfer antisaccades sensory and...

The posterior vermis of the cerebellum is considered to be critically involved in saccadic adaptation. However, recent evidence suggests that adaptive decrease (backward adaptation) and increase (forward saccade amplitude rely on partially separate neural substrates. We investigated whether could differentially backward forward adaptation by using transcranial direct current stimulation (TDCS). To do so, participants' saccades were adapted or while they received anodal, cathodal, sham TDCS....

Abstract The cerebellum is a key area for movement control and sensory‐motor plasticity. Its medial part considered as the exclusive cerebellar center controlling accuracy adaptive calibration of saccadic eye movements. However, contribution other zones situated in its lateral unknown. We addressed this question healthy adult volunteers by using magnetic resonance imaging (MRI)‐guided transcranial stimulation (TMS). double‐step target paradigm was used to adaptively lengthen or shorten...

Sensorimotor adaptation restores and maintains the accuracy of goal-directed movements. It remains unclear whether these adaptive mechanisms modify actions by controlling peripheral premotor stages that send commands to effectors and/or earlier processing involved in registration target location. Here, we studied effect saccadic eye movements, a well-established model sensorimotor adaptation, an antisaccade task. This task introduces clear spatial dissociation between actual direction...

Sensorimotor adaptation ensures movement accuracy despite continuously changing environment and body. Adaptation of saccadic eye movements is a classical model sensorimotor adaptation. Beside the well-established role brainstem–cerebellum in reactive saccades (RSs), cerebral cortex has been suggested to be involved voluntary (VSs). Here, we provide direct evidence for causal involvement parietal First, posterior intraparietal sulcus (pIPS) was identified each subject using functional...

Abstract Adults do not learn languages as easily children do. It has been hypothesized that the late-developing prefrontal cortex supports executive functions competes with procedural learning mechanisms are important for language learning. To address this hypothesis, we tested whether a temporary neural disruption of left Dorsolateral Prefrontal Cortex (DLPFC) can improve implicit, word-forms in adults. Young adults were presented repeating audio-visual sequences syllables immediate serial...

Bioassays were performed by commercially available kits on peracetic acid (PAA) solutions, at different concentrations, and secondary effluents (from two wastewater treatment plants) after disinfection bench-scale, considering both samples containing residual active PAA the same where was quenched. Four indicator organisms used: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, Selenastrum capricornutum. The experiments lead to conclude that platyurus is a very sensitive organism,...

When goal-directed movements are inaccurate, two responses generated by the brain: a fast motor correction toward target and an adaptive recalibration developing progressively across subsequent trials. For saccadic system, there is clear dissociation between (corrective saccade production) (primary modification). Error signals used to trigger corrective saccades induce adaptation based on post-saccadic visual feedback. The goal of this study was determine if similar or different error...

Movement accuracy depends crucially on the ability to detect errors while actions are being performed. When inaccuracies occur repeatedly, both an immediate motor correction and a progressive adaptation of command can unfold. Of all movements in repertoire humans, saccadic eye fastest. Due high speed saccades, impairment visual perception during phenomenon called “saccadic suppression”, it is widely believed that adaptive mechanisms maintaining performance depend critically error signals...

Ataxia with Oculomotor Apraxia type 2 (AOA2) is one of the most frequent types autosomal degenerative cerebellar ataxia. The first objective this work was to identify specific atrophy using MRI in patients AOA2. Since increased iron deposits have been reported diseases, our second report signals dentate nuclei Five AOA2 and 5 age-matched controls were subjects a 3T experiment that included 3D turbo field echo T1-weighted sequence. normalized volumes twenty-eight lobules percentage (relative...

Comprehending speech can be particularly challenging in a noisy environment and the absence of semantic context. It has been proposed that articulatory motor system would recruited especially difficult listening conditions. However, it remains unknown how signal-to-noise ratio (SNR) context affect recruitment when to continuous speech. The aim present study was address hypothesis involvement cortex increases intelligibility clarity spoken sentences decreases, because noise lack We applied...

Early detection of the behavioural deficits neurodegenerative diseases may help to describe pathogenesis such and establish important biomarkers disease progression. The aim this study was identify how sensorimotor adaptation upper limb, a cerebellar-dependent process restoring movement accuracy after introduction perturbation, is affected at pre-clinical clinical stages spinocerebellar ataxia type 6 (SCA6), an inherited disease. We demonstrate that initial perturbation significantly...

Perception of our visual environment strongly depends on saccadic eye movements, which in turn are calibrated by adaptation mechanisms elicited systematic movement errors. Current models assume that error signals acquired only after saccade completion, because the high speed execution disturbs processing (saccadic "suppression" and "mislocalization"). Complementing a previous study from group, here we report information presented during saccades can drive further determine critical time...

Procedural learning is a form of memory where people implicitly acquire skill through repeated practice. People with Parkinson’s disease (PD) have been found to motor adaptation, procedural learning, similarly healthy older adults but they deficits in long-term retention. A similar pattern normal on initial exposure deficit retention seen subsequent days has also mirror-reading, non-motor learning. It well-studied fact that disrupting sleep will impair the consolidation memories. Given...

Accuracy of saccadic eye movements is maintained thanks to adaptation mechanisms. The adaptive lengthening and shortening reactive voluntary saccades rely on partially separate neural substrates. Although in daily-life we mostly perform sequences saccades, the effect has been mainly evaluated single saccades. Here, two were recorded before after rightward In 4 sessions, adaptively shortened or lengthened. We found that second saccade sequence always remained accurate compensated for changes...