196,172 research outputs found
L’uso degli strumenti di comunicazione telematica fra gli adolescenti
No full textResoconto e interpretazione di un'indagine svolta su un campione di 1400 studenti delle scuole superiori di Bergamo nel 2009 sui temi della comunicazione fra adolescent
FUNCTIONAL EFFECT OF SHORT-TERM IMMOBILIZATION: KINEMATIC CHANGES AND RECOVERY ON REACHING-TO-GRASP
No full textAlthough previous investigations agree in showing significant cortical modifications related to short-term limb immobilization, little is known about the functional changes induced by non-use. To address this issue, we studied the kinematic effect of 10. h of hand immobilization. In order to prevent any movement, right handed healthy participants wore on their dominant hand a soft bandage. They were requested to perform the same reaching-to-grasping task immediately after immobilization, 1. day before (baseline 1) and in other two following days without non-use (baseline 2 and baseline 3). While no differences were found among baseline conditions, an increase of the total duration of reaching movement together with an anticipation of the time to peak velocity were observed in the first trial after immobilization. Interestingly, these initial effects decreased quickly trial-by-trial, following an exponential function till reaching values equal to those observed in the control conditions. The present findings show firstly that the transport phase of the reaching-to-grasp task was affected by a temporary reduction of sensory and motor information. Secondly, a trial-by-trial recovery of the immobilization-related changes, likely driven by the sensory inputs and motor outputs associated to the repetition of the movement has been observed. All together these results confirm a fundamental role of a continuous stream of sensorimotor signals in maintaining motor efficiency and in driving recovery process. © 2012 IBRO
Representing tools as hand movements: Early and somatotopic visuomotor transformations
No full textAbstractThe term affordance defines a property of objects, which relates to the possible interactions that an agent can carry out on that object. In monkeys, canonical neurons encode both the visual and the motor properties of objects with high specificity. However, it is not clear if in humans exists a similarly fine-grained description of these visuomotor transformations. In particular, it has not yet been proven that the processing of visual features related to specific affordances induces both specific and early visuomotor transformations, given that complete specificity has been reported to emerge quite late (300–450ms). In this study, we applied an adaptation-stimulation paradigm to investigate early cortico-spinal facilitation and hand movements׳ synergies evoked by the observation of tools. We adapted, through passive observation of finger movements, neuronal populations coding either for precision or power grip actions. We then presented the picture of one tool affording one of the two grasps types and applied single-pulse Transcranial Magnetic Stimulation (TMS) to the hand primary motor cortex, 150ms after image onset. Cortico-spinal excitability of the Abductor Digiti Minimi and Abductor Pollicis Brevis showed a detailed pattern of modulations, matching tools׳ affordances. Similarly, TMS-induced hand movements showed a pattern of grip-specific whole hand synergies. These results offer a direct proof of the emergence of an early visuomotor transformation when tools are observed, that maintains the same amount of synergistic motor details as the actions we can perform on them
Relationships between focal and equilibrium components during a pointing task beyond arm length
No full text
Ibridamenti: una struttura che connette
No full textSaggio sul blog "Ibridamenti" dell'Università Ca' Foscari di Venezi
- …
