1. We stimulated the motor cortex of normal subjects (transcranial magnetic stimulation) while they 1) observed an experimenter grasping 3D-objects, 2) looked at the same 3D-objects, 3) observed an experimenter tracing geometrical figures in the air with his arm, and 4) detected the dimming of a light. Motor evoked potentials (MEPs) were recorded from hand muscles. 2. We found that MEPs significantly increased during the conditions in which subjects observed movements. The MEP pattern reflected the pattern of muscle activity recorded when the subjects executed the observed actions. 3. We conclude that in humans there is a system matching action observation and execution. This system resembles the one recently described in the monkey.

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ObjectiveTo retrospectively investigate safety and efficacy of nusinersen in a large cohort of adult Italian patients with spinal muscular atrophy (SMA).MethodsInclusion criteria were: (1) clinical and molecular diagnosis of SMA2 or SMA3; (2) nusinersen treatment started in adult age (>18 years); (3) clinical data available at least at baseline (T0-beginning of treatment) and 6 months (T6).ResultsWe included 116 patients (13 SMA2 and 103 SMA3) with median age at first administration of 34 years (range 18–72). The Hammersmith Functional Rating Scale Expanded (HFMSE) in patients with SMA3 increased significantly from baseline to T6 (median change +1 point, p<0.0001), T10 (+2, p<0.0001) and T14 (+3, p<0.0001). HFMSE changes were independently significant in SMA3 sitter and walker subgroups. The Revised Upper Limb Module (RULM) in SMA3 significantly improved between T0 and T14 (median +0.5, p=0.012), with most of the benefit observed in sitters (+2, p=0.018). Conversely, patients with SMA2 had no significant changes of median HFMSE and RULM between T0 and the following time points, although a trend for improvement of RULM was observed in those with some residual baseline function. The rate of patients showing clinically meaningful improvements (as defined during clinical trials) increased from 53% to 69% from T6 to T14.ConclusionsOur data provide further evidence of nusinersen safety and efficacy in adult SMA2 and SMA3, with the latter appearing to be cumulative over time. In patients with extremely advanced disease, effects on residual motor function are less clear.

The effect of unilateral surgical ablations of the postarcuate cortex (area 6) has been studied in the macaque monkey (Macaca irus). Two series of neurological deficits were found: (1) a failure to grasp food with the mouth when presented contralaterally to the lesion and a reluctance to use the contralateral hand; (2) a severe hemi-inattention. This was present in both the somatosensory and visual modalities but, in the latter, was limited to the peripersonal space. Both motor and attentional deficits improved with time. However, when the symptomatology was stabilized, the animals tended to use the ipsilateral hand and, when presented with two stimuli, preferred that ipsilateral to the lesion. Control experiments in which area 8 (frontal eye fields) was ablated unilaterally showed a decrease of eye movements contralateral to the lesion and a neglect of the contralateral hemispace. No somatosensory deficits were found. The visual neglect was more prominent for 'far' space than for that near the animal. The role of area 6 in organizing motor acts and the strict relation between the type of motor deficit and the type of neglect are discussed.

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