Aging is associated with a decline in physical functions, cognition and brain structure. Considering that human life is based on an inseparable physical-cognitive interplay, combined physical-cognitive training through exergames is a promising approach to counteract age-related impairments. The aim of this study was to assess the effects of an in-home multicomponent exergame training on [i] physical and cognitive functions and [ii] brain volume of older adults compared to a usual care control group. Thirty-seven healthy and independently living older adults aged 65 years and older were randomly assigned to an intervention (exergame training) or a control (usual care) group. Over 16 weeks, the participants of the intervention group absolved three home-based exergame sessions per week (à 30-40 min) including Tai Chi-inspired exercises, dancing and step-based cognitive games. The control participants continued with their normal daily living. Pre-and post-measurements included assessments of physical (gait parameters, functional muscle strength, balance, aerobic endurance) and cognitive (processing speed, short-term attention span, working memory, inhibition, mental flexibility) functions. T1-weighted magnetic resonance imaging was conducted to assess brain volume. Thirty-one participants (mean age = 73.9 ± 6.4 years, range = 65-90 years, 16 female) completed the study. Inhibition and working memory significantly improved postintervention in favor of the intervention group [inhibition: F (1) = 2.537, p = 0.046, n 2 p = 0.11, working memory: F (1) = 5.872, p = 0.015, n 2 p = 0.02]. Two measures of short-term attentional span showed improvements after training in favor of the control group [F (1) = 4.309, p = 0.038, n 2 p = 0.03, F (1) = 8.504, p = 0.004, n 2 p = 0.04]. No significant training effects were evident for physical functions or brain volume. Both groups exhibited a significant decrease in gray matter volume of frontal areas and the hippocampus over time. The findings indicate a positive influence of exergame training Adcock et al. Effects of Exergame Training in Older Adults on executive functioning. No improvements in physical functions or brain volume were evident in this study. Better adapted individualized training challenge and a longer training period are suggested. Further studies are needed that assess training-related structural brain plasticity and its effect on performance, daily life functioning and healthy aging.

To date the exact neuronal implementation of decision confidence has been subject to little research. Here we explore electroencephalographic correlates of human choice certainty in a visual motion discrimination task for either spatial attention or motor effector cue instructions. We demonstrate electrophysiological correlates of choice certainty that evolve as early as 300 ms after stimulus onset and resemble the primary visual motion representations in early visual cortex. These correlates do not emerge unless or until the subject unambiguously knows which of the competing visual stimuli is actually relevant to behaviour. They extend beyond stimulus presentation up to the motor response but are independent of the motor effector. Our findings suggest that perceptual confidence evolves in parallel with representations of stimulus properties and is dedicated to one specific aspect of the visual world. Its electroencephalographic correlates can be disentangled from representations of sensory evidence, objective discrimination performance and overt motor behaviour.

Choice certainty is a probabilistic estimate of past performance and expected outcome. In perceptual decisions the degree of confidence correlates closely with choice accuracy and reaction times, suggesting an intimate relationship to objective performance. Here we show that spatial and feature-based attention increase human subjects' certainty more than accuracy in visual motion discrimination tasks. Our findings demonstrate for the first time a dissociation of choice accuracy and certainty with a significantly stronger influence of voluntary top-down attention on subjective performance measures than on objective performance. These results reveal a so far unknown mechanism of the selection process implemented by attention and suggest a unique biological valence of choice certainty beyond a faithful reflection of the decision process.

Present pathophysiological concepts of neuropathic tremor assume mistimed and defective afferent input resulting in deregulation of cerebello-thalamo-cortical motor networks. Here, we provide direct evidence of central tremor processing in a 76-year-old female who underwent bilateral deep brain stimulation of the ventral intermedial nucleus of the thalamus (Vim-DBS) because of neuropathic tremor associated with IgM paraproteinemia. Electrophysiological recordings of EEG and EMG were performed in three perioperative sessions: (1) preoperatively, (2) intraoperatively, and (3) 4 days after surgery in both rest and postural tremor conditions. Tremor-related synchronization (coherence) between motor cortex (M1) and muscles (M. extensor digitorum, M. flexor digitorum) was assessed, and additional intraoperative local field potential (LFP) recordings from Vim allowed comprehensive coherence mapping in thalamo-cortico-muscular networks. Directionality of information flow was determined by directed transfer function (DTF) and phase analyses. Stimulation effects on tremor and corticomuscular coherence were assessed and the patient was followed for 12 months on clinical outcome measures (Tremor Rating Scale, CADET-Score). Vim-DBS reduced tremor (59%) and improved motor functionality in daily activities (31%, CADET-A) after 12 months. Intraoperative recordings demonstrated significant coherence in the tremor frequency (4 Hz) between M1 and contralateral muscle, Vim and ipsilateral M1, Vim and contralateral muscle, but not between Vim and contralateral M1. Information flow was directed from M1 to Vim and bidirectional between M1 and muscle and between Vim and muscle, respectively. Corticomuscular coherence at tremor frequency was completely suppressed by Vim-DBS. Our case study demonstrates central oscillators underlying neuropathic tremor and implies a strong pathophysiological rationale for Vim-DBS.

While perceptual learning increases objective sensitivity, the effects on the constant interaction of the process of perception and its metacognitive evaluation have been rarely investigated. Visual perception has been described as a process of probabilistic inference featuring metacognitive evaluations of choice certainty. For visual motion perception in healthy, naive human subjects here we show that perceptual sensitivity and confidence in it increased with training. The metacognitive sensitivity–estimated from certainty ratings by a bias-free signal detection theoretic approach–in contrast, did not. Concomitant 3Hz transcranial alternating current stimulation (tACS) was applied in compliance with previous findings on effective high-low cross-frequency coupling subserving signal detection. While perceptual accuracy and confidence in it improved with training, there were no statistically significant tACS effects. Neither metacognitive sensitivity in distinguishing between their own correct and incorrect stimulus classifications, nor decision confidence itself determined the subjects’ visual perceptual learning. Improvements of objective performance and the metacognitive confidence in it were rather determined by the perceptual sensitivity at the outset of the experiment. Post-decision certainty in visual perceptual learning was neither independent of objective performance, nor requisite for changes in sensitivity, but rather covaried with objective performance. The exact functional role of metacognitive confidence in human visual perception has yet to be determined.

Topesthesia, the recognition of tactile stimulation location on the skin, can be severely affected by neurological injuries, such as stroke. Despite topesthesia being crucial for manipulating objects and interacting with the environment during activities of daily living, deficits cannot be quantitatively captured with current clinical assessments and are, as a consequence, not well-understood. The present work describes a novel automated assessment tool for tactile mislocalization in neurological patients with somatosensory deficits. We present two cases of ischemic stroke patients, describe their tactile localization deficits with the automated assessment, and compare the results to a standard manual clinical assessment. Using the automated assessment tool, it was possible to identify, locate, precisely quantify, and depict the patients' deficits in topesthesia. In comparison, the clinical assessment was not sensitive enough and some deficits would remain undetected due to ceiling effects. In addition, an MRI structural analysis of the lesion supported the existence of somatosensory deficits. This novel and quantitative assessment may not only help to raise awareness of the implications of deficits in topesthesia, but would also allow monitoring recovery throughout the rehabilitation process, informing treatment design, and objectively evaluating treatment efficacy.

Background: Imaging studies point to a posture (finger vs. hand) and domain-specific neural basis of gestures. Furthermore, modulation of gestures by theta burst stimulation (TBS) may depend on interhemispheric disinhibition. Objective/Hypothesis: In this randomized sham-controlled study, we hypothesized that dual site continuous TBS over left inferior frontal gyrus (IFG-L) and right inferior parietal gyrus (IPL-R) predominantly affects pantomime of finger postures. Furthermore, we predicted that dual cTBS improves imitation of hand gestures if the effect correlates with measures of callosal connectivity. Methods: Forty-six healthy subjects participated in this study and were targeted with one train of TBS in different experimental sessions: baseline, sham, single site IFG-L, dual IFG-L/IPL-R, single site IPL-R. Gestures were evaluated by blinded raters using the Test for Upper Limb Apraxia (TULIA) and Postural Imitation Test (PIT). Callosal connectivity was analyzed by diffusion tensor imaging (DTI). Results: Dual cTBS significantly improved TULIA total (F [3, 28] ¼ 4.118, p ¼ .009), but did not affect TULIA pantomime. The beneficial effect was driven by the cTBS over IPL-R, which improved TULIA imitation (p ¼ .038). Furthermore, TULIA imitation significantly correlated with the microstructure (fractional anisotropy) of the splenium (r ¼ 0.420, p ¼ .026), corrected for age and whole brain volume. Conclusions: The study suggests that inhibition of IPL-R largely accounted for improved gesturing, possibly through transcallosal facilitation of IPL-L. Therefore, the findings may be relevant for the treatment of apraxic stroke patients. Gesture pantomime and postural gestures escaped the modulation by dual cTBS, suggesting a more widespread and/or variable neural representation.

, a 68-year-old right-handed man presented hours after acute onset of left hand and leg weakness. During a 6-week period preceding admission he had experienced at least 2 sudden onset episodes of an isolated paresthesia of the left ring finger. Each persisted for approximately 2 minutes and the patient did not seek medical attention for it. He had a history of hypertension and hyperlipidemia, but no previous stroke. Clinical examination showed mild left hemiparesis, symmetric monosynaptic reflexes, and hypesthesia of the left hand, this time affecting all fingers. There were no signs of peripheral nerve lesion-sensitive or motor-and no change of or new paresthesia under provocation tests for entrapment neuropathies. MRI of the head and neck with diffusion-weighted sequences and angiography showed isolated right middle cerebral artery (MCA) stenosis and multiple acute infarctions in its watershed territories, involving the right corona radiata and cortical and subcortical white matter of the right fronto-parieto-occipital lobes (figure, A). Routine blood tests, chest radiography, ECG, long-term ECG, and EEG were normal. Transthoracic echocardiogram indicated beginning hypertensive heart disease, no cardiac thrombus or valvular dysfunction. The following day, he received successful angioplasty and stenting of the symptomatic MCA stenosis (figure, B and C). Treated before publication of the SAMMPRIS 1 trial data, follow-up of this patient to date is without further ischemic events or complications under antiplatelet therapy. Cerebral watershed infarcts typically involve the junction of the distal fields of the nonanastamosing territories of the anterior cerebral artery (ACA), middle cerebral artery, and posterior cerebral artery and account for approximately 10% of cerebral ischemias. 2 Untreated MCA stenosis is associated with a high rate of stroke recurrence 3 and warning TIAs are common. 3 Recognized pathogenetic factors are hemodynamic impairment and microembolism. 2 We report a case of unilateral watershed infarction due to MCA stenosis with prodromal isolated paresthesia of 1 ring finger. Pseudoperipheral sensory-motor deficits due to CNS lesions were described as early as 1909. 4 In a more recent MRI study on cortical infarction with weakness restricted to particular groups of fingers, 5 predominant ulnar finger involvement was closely