Cutaneous Sensibility Changes in Bell's Palsy Patients.

Objective Bell's palsy is a cranial nerve VII dysfunction that renders the patient unable to control facial muscles from the affected side. Nevertheless, some patients have reported cutaneous changes in the paretic area. Therefore, cutaneous sensibility changes might be possible additional symptoms within the clinical presentation of this disorder. Accordingly, the aim of this research was to investigate the relationship between cutaneous sensibility and facial paralysis severity in these patients. Study Design Prospective longitudinal cohort study. Settings Tertiary care medical center. Subjects and Methods Twelve acute-onset Bell's palsy patients were enrolled from March to September 2009. In addition, 12 sex- and age-matched healthy volunteers were tested. Cutaneous sensibility was evaluated with pressure threshold and 2-point discrimination at 6 areas of the face. Facial paralysis severity was evaluated with the House-Brackmann scale. Results Statistically significant correlations based on the Spearman's test were found between facial paralysis severity and cutaneous sensitivity on forehead, eyelid, cheek, nose, and lip ( P < .05). Additionally, significant differences based on the Student's t test were observed between both sides of the face in 2-point discrimination on eyelid, cheek, and lip ( P < .05) in Bell's palsy patients but not in healthy subjects. Conclusion Such results suggest a possible relationship between the loss of motor control of the face and changes in facial sensory information processing. Such findings are worth further research about the neurophysiologic changes associated with the cutaneous sensibility disturbances of these patients.

Contribution of the parafascicular nucleus in the spontaneous object recognition task.

The parafascicular (PF) nucleus, a posterior component of the intralaminar nuclei of the thalamus, is considered to be an essential structure in the feedback systems of basal ganglia-thalamo-cortical circuits critically involved in cognitive processes. The specific role played by multimodal information encoded in PF neurons in learning and memory processes is still unclear. We conducted two experiments to investigate the role of the PF in the spontaneous object recognition (SOR) task. The behavioral effects of pretraining rats with bilateral lesions of PF with N-methyl-D-aspartate (NMDA) were compared to vehicle controls. In the first experiment, rats were tested on their ability to remember the association immediately after training trials and in the second experiment after a 24h delay. Our findings provide evidence that PF lesions critically affect both SOR tests and support its role in that non-spatial form of relational memory.