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Abstract: Research data suggest that the amygdala and some related brain structures modulate the processing of emotional visual stimuli even when they are not consciously perceived. In this study, we examined neural responses to investigate whether and how other brain areas anatomically connected to the amygdala might become activated during both overt and covert presentation of conditioned emotional visual stimuli. In the covert presentation, a conditioned angry face was shown for 15ms followed by a neutral masking face (CSmask). In the overt condition, an angry face associated with a painful stimulus (CS+), a happy (H) and a neutral face (N) were presented for 75ms. Based on results of functional magnetic resonance imaging (fMRI) in 10 healthy volunteers, we show evidence that a network of brain structures anatomically connected to the amygdala (including the anterior insula, the fusiform gyrus and the superior temporal sulcus) are involved in the subliminal processing of visual emotional stimuli. Of particular interest was the dissociation between the anterior and posterior insula: the anterior insula responded to both overt and covert presentation of the conditioned stimulus, whereas the posterior insula responded only to the overt presentation of the face associated with a painful electrical stimulation. This response pattern suggests that the anterior insula, the fusiform gyrus and the temporal sulcus cooperate with the amygdala in the unconscious processing of pain-conditioned stimuli. [Copyright &y& Elsevier]

Magnetoencephalography (MEG) includes fast and comfortable recording procedures very suitable for the neurophysiological study of cognitive functions in aged people. In this exploratory MEG study in normal young adults, we tested whether very simple short-term memory (STM) demands induce visible changes in amplitude and latency of surface α rhythms. Two delayed response tasks were used. In the STM condition, a simple cue stimulus (one bit) was memorized along a brief delay period (3.5-5.5 s). In the control (no short-term memory; NSTM) condition, the cue stimulus remained available along the delay period. To make extremely simple the tasks, the explicit demand was visuospatial but the retention could be also based on phonological and somatomotor coding. Compared to the control condition, the amplitude of the α 1 (6-8 Hz) ERD decreased in the left hemisphere, whereas the amplitude of the α 2 (8-10 Hz) and α 3 (10-12 Hz) event-related desynchronization (ERD) increased in right and left parietal areas, respectively. Furthermore, the latency of the α ERD peak was slightly but significantly ( P < 0.05) later in STM compared to control condition. In conclusion, whole-head MEG technology and very simple STM demands revealed significant changes of human neuromagnetic α rhythms in normal young adults. Hum. Brain Mapp 24:184-192, 2005. © 2004 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]