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Predicting upcoming sensorimotor events means creating forward estimates of the body and the surrounding world. This ability is a fundamental aspect of skilled motor behavior and requires an accurate and constantly updated representation of the body and the environment. To test whether these prediction mechanisms could be affected by a peripheral injury, we employed an action observation and electroencephalogram (EEG) paradigm to assess the occurrence of prediction markers in anticipation of observed sensorimotor events in healthy and brachial plexus injury (BPI) participants. Nine healthy subjects and six BPI patients watched a series of video clips showing an actor’s hand and a colored ball in an egocentric perspective. The color of the ball indicated whether the hand would grasp it (hand movement), or the ball would roll toward the hand and touch it (ball movement), or no event would occur (no movement). In healthy participants, we expected to find distinct electroencephalographic activation patterns (EEG signatures) specific to the prediction of the occurrence of each of these situations. Cluster analysis from EEG signals recorded from electrodes placed over the sensorimotor cortex of control participants showed that predicting either an upcoming hand movement or the occurrence of a tactile event yielded specific neural signatures. In BPI participants, the EEG signals from the sensorimotor cortex contralateral to the dominant hand in the hand movement condition were different compared to the other conditions. Furthermore, there were no differences between ball movement and no movement conditions in the sensorimotor cortex contralateral to the dominant hand, suggesting that BPI blurred specifically the ability to predict upcoming tactile events for the dominant hand. These results highlight the role of the sensorimotor cortex in creating estimates of both actions and tactile interactions in the space around the body and suggest plastic effects on prediction coding following peripheral sensorimotor loss.

Spatial location is an intrinsic characteristic of the stimulus that influences the execution of the correct response in various tasks. The effect is named Stimulus-Response Compatibility, with the Spatial Compatibility, Simon, and Spatial Stroop tasks being examples of this phenomenon. The Simon effect is modulated if participants perform a previous incompatible spatial compatibility task. This modulation, called transfer-of-learning effect, has been attributed to issociations between long-term memory and short-term memory. It had not yet studied whether this incompatible practice modulates the spatial Stroop effect. In this work, we tested 32 volunteers in an experimental design that allows us to study and separate the Simon and spatial Stroop effects in the same task and test the hypothesis of a generalized transfer-of-learning effect by an incompatible practice. The results indicate that a previous incompatible task modulates only the Simon effect, contradicting the hypothesis of the generalized transfer of learning after an incompatible practice.

We hereby present the first worldwide public digital database centred on adult Traumatic Brachial Plexus Injury (TBPI). This initiative aims at reducing distance between clinical and experimental practice and encouraging data sharing and reuse. Detailed electronic questionnaires made with the free software LimeSurvey were designed to collect patients’ epidemiological, physical and clinical data. The freely available software Neuroscience Experiments System (NES) was employed to support data storage and management. First results of this effort concern data collected from 109 Brazilian adult TBPI patients with varying degrees of functional impairment. The sample is composed by large majority of men (84.4%), mean age of 32.1 (11.3 SD) years old, victims of motorcycle accidents (67%). The similarity of this dataset basic descriptors with those from previous reports in TBPI validates the strategies employed herein. Managing data from diverse provenance in TBPI may allow identifying functional markers related to the patients’ clinical improvement and foster the development of new investigative tools to unveil its mechanisms.

The handedness recognition of visually perceived body parts engages motor representations that are constrained by the same biomechanical factors that limit the execution of real movements. In the present study, we used small plastic cutouts that represented the human hand to investigate the properties of mental images generated during their haptic exploration. Our working hypothesis was that any handedness recognition task that involves body parts depends on motor imagery. Forty-four blindfolded, right-handed volunteers participated in a handedness evaluation experiment using their index finger to explore either the back or palm view of a haptic stimulus that represented the human hand. The stimuli were presented in four different orientations, and we measured the subjects' response times. Our results showed that stimulus configurations that resemble awkward positions of the human hand are associated with longer response times (p < .006), indicating that the haptic exploration of stimuli that represent body parts also leads to motor imagery that is constrained by biomechanical factors.

Background Leprosy is an endemic infectious disease caused by Mycobacterium leprae that predominantly attacks the skin and peripheral nerves, leading to progressive impairment of motor, sensory and autonomic function. Little is known about how this peripheral neuropathy affects corticospinal excitability of handgrip muscles. Our purpose was to explore the motor cortex organization after progressive peripheral nerve injury and upper-limb dysfunction induced by leprosy using noninvasive transcranial magnetic stimulation (TMS). Methods In a cross-sectional study design, we mapped bilaterally in the primary motor cortex (M1) the representations of the hand flexor digitorum superficialis (FDS), as well as of the intrinsic hand muscles abductor pollicis brevis (APB), first dorsal interosseous (FDI) and abductor digiti minimi (ADM). All participants underwent clinical assessment, handgrip dynamometry and motor and sensory nerve conduction exams 30 days before mapping. Wilcoxon signed rank and Mann-Whitney tests were performed with an alpha-value of p, Author Summary Leprosy is an endemic disease caused by Mycobacterium leprae that predominantly attacks both skin and peripheral nerves, resulting in persistent distal hand atrophy and the loss of sensory and autonomic functions. In this study, we employ a noninvasive tool named transcranial magnetic stimulation (TMS) to map the handgrip muscle representation in the primary motor cortex of patients affected by leprosy. The findings of this study support that the decrease or loss of sensory afferent neurons and/or impairment in the strength of peripheral muscles in the ulnar/median territory verified in leprosy patients alters the handgrip function leading to cortical motor reorganization in the corresponding affected hand muscles.