1,721,011 research outputs found
Neuroni mirror nell'area F5 della corteccia cerebrale della scimmia: c'è stata evidenza sperimentale? E nell’uomo?
No full text
A P300 auditory brain-computer interface based on mental repetition
No full textObjective. The current study evaluates an auditory brain-computer interface (BCI) protocol that allows users to mentally choose among 6 options. Methods. The protocol is based on an oddball P300 paradigm. To reduce mental workload, we introduce a change in the typical oddball paradigm task: Instead of passively counting the presented target auditory stimuli, we ask participants to simply mentally repeat them when they occur. In the study, ten healthy participants carried out two calibration sessions respectively with traditional mental count and with the proposed mental repetition and then three free item selection sessions using mental repetition. A comparison has been conducted between off-line count and mental repetition classification accuracies achieved by each participant during the calibration sessions. The mental workload difference between the count and repeat calibration sessions of each participant was evaluated by computing alpha (at Po8) and theta (at Fz) spectral power density (SPD) curves. Results. Nine out of ten participants showed a higher mental workload with the traditional mental count. The repeat activity was preferred by 8 out of 10 participants. The comparison conducted between off-line count and mental repetition classification accuracies shows a slightly worse average behavior for the repeat protocol in the first 8 averaged trials. With the proposed protocol we got an average on-line item-selection information transfer rate (ITR) over 2 trials of 2.35 bits min-1, and an average on-line accuracy over 10 trials of 81.7%. Conclusions. Although off-line classification based on mental count data got slightly better results, the proposed auditory BCI protocol with mental repetition achieved an on-line performance similar to the traditional counting oddball paradigm task but with a lower mental workload. Significance. The results obtained with healthy subjects suggest that the proposed protocol can be a simpler alternative to the mental count, with comparable performance and lower mental load
Localizzazione topografica delle aree corticali motorie e sensoriali coinvolte nel controllo del movimento volontario
No full textIdentifying timescales and possible precursors of the awake to asleep transition in EOG time series
No full textThe emotional control of action: ERP evidence
No full textIt is known that unpleasant emotions con modulate the speed of involuntary movements, yet the effects of aversive stimulation on voluntary motor acts have not been systematically investigated. The effects of aversive stimulation on subsequent movement-related cortical activity were examined using a task involving compatible and incompatible movements. Negative shafts in the timing of two motor event-related potentials were found subsequent to aversive stimulation for compatible movements only. With analogy to the Fear-Potentiated Startle Reflex, a reactive Mechanism affecting covert action, these Fear-Potentiated Movement-Related Potentials (FPMPs) reflect preparation for overt actions performed to cope with particular types of danger. Further analysis revealed a positive deflection in the left frontal cortex prior the execution of incompatible movements, which may reflect inhibitory suppression of externally-triggered imitative tendencies
Real-Time Neuropsychological Testing of Sensorimotor Cognition During Awake Surgery in Precentral and Postsomatosensory Areas
No full textBACKGROUND: For patients undergoing brain surgery, once primary motor and sensory areas are identified by direct electrical stimulation, resection can be performed in the precentral and postsomatosensory areas while monitoring cognition. For this purpose, we developed a real-time neuropsychological testing (RTNT) protocol tapping sensorimotor cognition. METHODS: We retrospectively reviewed a consecutive series of 57 adult patients with tumors in the precentral and postsomatosensory areas who performed the RTNT sequence. The testing protocol used continuously throughout resection for excisions comprised action verbs, mental rotation of body parts, action imagery, action semantics, ideomotor praxis, and short-term memory. RESULTS: The patients' median performance on RTNT tests was significantly lower for mental rotation and action imagery (chi(2) (2) = 55.98, P < 0.001), as well as their minimum value of patients' performance (chi(2) (2) = 85.048, P < 0.001) and their delta calculated between the patients' performance at the first versus the last RTNT run (chi(2) (2) = 14.33, P < 0.05). Patients showing such decreases in performance on action imagery had lesions overlapping on the right precentral and postcentral gyrus, the supplementary motor area, and the superior and inferior parietal lobe. For the mental rotation task, their maximum lesion overlay included the right cingulum/supplementary motor area and left superior and inferior parietal lobe and medial precuneus. The mean resection extent was 91.15% +/- 17.45 and correlated with the number of motor-related positive sites found by the direct electrical stimulation at cortical (r = -0.279, P = 0.020) and white matter (r = -0.417, P = 0.001) level. CONCLUSIONS: The sensory-motor RTNT is performed to assist surgery in the precentral and postsomatosensory areas
- …
