Neurofunctional correlates of eye to hand motor transfer.

This work investigates the transfer of motor learning from the eye to the hand and its neural correlates by using functional magnetic resonance imaging (fMRI) and a sensorimotor task consisting of the continuous tracking of a virtual target. In pretraining evaluation, all the participants (experimental and control group) performed the tracking task inside an MRI scanner using their right hand and a joystick. After which, the experimental group practiced an eye-controlled version of the task for 5 days using an eye tracking system outside the MRI environment. Post-training evaluation was done 1 week after the first scanning session, where all the participants were scanned again while repeating the manual pretraining task. Behavioral results show that the training in the eye-controlled task produced a better performance not only in the eye-controlled modality (motor learning) but also in the hand-controlled modality (motor transfer). Neural results indicate that eye to hand motor transfer is supported by the motor cortex, the basal ganglia and the cerebellum, which is consistent with previous research focused on other effectors. These results may be of interest in neurorehabilitation to activate the motor systems and help in the recovery of motor functions in stroke or movement disorder patients.

Phonological, lexical, and semantic errors produced by impairment at the output buffer in a Spanish aphasic patient.

We present a single case of a right-handed female patient, RH, who was categorized as suffering from conduction aphasia. She presented no articulatory problems during spontaneous speech but made a significant number of phonological paraphasias in naming and repetition tasks. The number of errors increased for long words and pseudowords. This pattern of results points to damage in the "Phonological Output Buffer" (POB) as the basis of this disorder. However, this patient did not make mistakes when reading words and pseudowords aloud, even when we introduced a delay between the presentation of the word and its production to test the working memory resources of the phonological buffer. Furthermore, the patient's ability to name objects, repeat words, and write to dictation improved with her degree of familiarity with the items. The damage could be situated at the point where phonemes are selected and ordered to produce words. We posit that the deficits observed in this patient, and the differences encountered between her performance and that of others described in the literature, in particular in reading tasks, can be explained by considering POB damage to be gradual in nature. According to this explanation, the performance of patients with damage to the POB will depend on the amount of information provided by the stimulus (word/nonword), the language particularities (regular/irregular), and the nature of the task demands (repetition, writing, naming, or reading).