Explicit and Implicit Responses of Seeing Own vs. Others' Emotions: An Electromyographic Study on the Neurophysiological and Cognitive Basis of the Self-Mirroring Technique.

Facial mimicry is described by embodied cognition theories as a human mirror system-based neural mechanism underpinning emotion recognition. This could play a critical role in the Self-Mirroring Technique (SMT), a method used in psychotherapy to foster patients' emotion recognition by showing them a video of their own face recorded during an emotionally salient moment. However, dissociation in facial mimicry during the perception of own and others' emotions has not been investigated so far. In the present study, we measured electromyographic (EMG) activity from three facial muscles, namely, the zygomaticus major (ZM), the corrugator supercilii (CS), and the levator labii superioris (LLS) while participants were presented with video clips depicting their own face or other unknown faces expressing anger, happiness, sadness, disgust, fear, or a neutral emotion. The results showed that processing self vs. other expressions differently modulated emotion perception at the explicit and implicit muscular levels. Participants were significantly less accurate in recognizing their own vs. others' neutral expressions and rated fearful, disgusted, and neutral expressions as more arousing in the self condition than in the other condition. Even facial EMG evidenced different activations for self vs. other facial expressions. Increased activation of the ZM muscle was found in the self condition compared to the other condition for anger and disgust. Activation of the CS muscle was lower for self than for others' expressions during processing a happy, sad, fearful, or neutral emotion. Finally, the LLS muscle showed increased activation in the self condition compared to the other condition for sad and fearful expressions but increased activation in the other condition compared to the self condition for happy and neutral expressions. Taken together, our complex pattern of results suggests a dissociation at both the explicit and implicit levels in emotional processing of self vs. other emotions that, in the light of the Emotion in Context view, suggests that STM effectiveness is primarily due to a contextual-interpretative process that occurs before that facial mimicry takes place.

Impaired reproduction of second but not millisecond time intervals in Parkinson's disease.

The basal ganglia have been associated with temporal processing in ranges of milliseconds and seconds. However, results from PD patient studies are elusive. Time perception in these patients has been tested with different approaches including repetitive movement tasks (i.e. finger tapping) and cognitive tasks (i.e. time reproduction), and both abnormal and normal performances have been reported for different time intervals. Furthermore, when PD patients were required to learn two target durations in the same session when they were off medication, they overestimated the short duration and underestimated the long duration in the seconds range. This pattern of temporal accuracy was described as a "migration effect" and was interpreted as a dysfunctional representation of memory for time (Malapani, C., Rakitin, B. C., Levy, R., Meck, W. H., Deweer, B., Dubois, B., et al. (1998). Coupled temporal memories in Parkinson's disease: A dopamine-related dysfunction. Journal of Cognitive Neuroscience, 10, 316-331). Here, we controlled the emergence of similar behaviour also during millisecond time processing in PD patients. A time reproduction task was employed in which subjects were required to estimate intervals in millisecond (500ms) and few second (2000ms) ranges. In the first experiment, these intervals were tested in the same session to verify whether the migration effect was present also between time intervals in different millisecond and few second ranges. In a second experiment, they were not intermingled but were tested in two separate sessions to verify whether abnormalities depended on a selective perceptual deficit of the time intervals tested (i.e. millisecond or second ranges). All experiments were performed in both off and on therapy conditions. Our results demonstrated that PD patients showed no deficits in time estimation for time intervals in either the millisecond or few second range when the different time intervals were tested in separate sessions. This negative finding was obtained in both on and off conditions. However, when the different ranges were tested in the same session, we found that PD patients were impaired selectively for time intervals in the seconds range. Our data seem to indicate that time processing in PD patients for time intervals spanning up to 2s is unimpaired and that abnormalities in such temporal scale may emerge only when patients have to deal with different durations, when timing involves further cognitive processes such as memory and attention.

The influence of rTMS over prefrontal and motor areas in a morphological task: grammatical vs. semantic effects.

We investigated the differential role of two frontal regions in the processing of grammatical and semantic knowledge. Given the documented specificity of the prefrontal cortex for the grammatical class of verbs, and of the primary motor cortex for the semantic class of action words, we sought to investigate whether the prefrontal cortex is also sensitive to semantic effects, and whether the motor cortex is also sensitive to grammatical class effects. We used repetitive transcranial magnetic stimulation (rTMS) to suppress the excitability of a portion of left prefontal cortex (first experiment) and of the motor area (second experiment). In the first experiment we found that rTMS applied to the left prefrontal cortex delays the processing of action verbs' retrieval, but is not critical for retrieval of state verbs and state nouns. In the second experiment we found that rTMS applied to the left motor cortex delays the processing of action words, both name and verbs, while it is not critical for the processing of state words. These results support the notion that left prefrontal and motor cortex are involved in the process of action word retrieval. Left prefrontal cortex subserves processing of both grammatical and semantic information, whereas motor cortex contributes to the processing of semantic representation of action words without any involvement in the representation of grammatical categories.