31 research outputs found
Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders
Theories of autism spectrum disorders (ASD) have focused on altered perceptual integration
of sensory features as a possible core deficit. Yet, there is little understanding of the
neuronal processing of elementary sensory features in ASD. For typically developed individuals,
we previously established a direct link between frequency-specific neural activity
and the intensity of a specific sensory feature: Gamma-band activity in the visual cortex
increased approximately linearly with the strength of visual motion. Using magnetoencephalography
(MEG), we investigated whether in individuals with ASD neural activity reflect the
coherence, and thus intensity, of visual motion in a similar fashion. Thirteen adult participants
with ASD and 14 control participants performed a motion direction discrimination task
with increasing levels of motion coherence. A polynomial regression analysis revealed that
gamma-band power increased significantly stronger with motion coherence in ASD compared
to controls, suggesting excessive visual activation with increasing stimulus intensity
originating from motion-responsive visual areas V3, V6 and hMT/V5. Enhanced neural
responses with increasing stimulus intensity suggest an enhanced response gain in ASD.
Response gain is controlled by excitatory-inhibitory interactions, which also drive high-frequency
oscillations in the gamma-band. Thus, our data suggest that a disturbed excitatoryinhibitory
balance underlies enhanced neural responses to coherent motion in ASD
The Power of an Infant\u27s Smile: Maternal Physiological Responses to Infant Emotional Expressions
Infant emotional expressions, such as distress cries, evoke maternal physiological reactions. Most of which involve accelerated sympathetic nervous activity. Comparatively little is known about effects of positive infant expressions, such as happy smiles, on maternal physiological responses. This study investigated how physiological and psychological maternal states change in response to infants\u27 emotional expressions. Thirty first-time mothers viewed films of their own 6- to 7-month-old infants\u27 affective behavior. Each observed a video of a distress cry followed by a video showing one of two expressions (randomly assigned): a happy smiling face (smile condition) or a calm neutral face (neutral condition). Both before and after the session, participants completed a self-report inventory assessing their emotional states. The results of the self-report inventory revealed no effects of exposure to the infant videos. However, the mothers in the smile condition, but not in the neutral condition, showed deceleration of skin conductance. These findings demonstrate that the mothers who observed their infants smiling showed decreased sympathetic activity. We propose that an infant\u27s positive emotional expression may affect the branch of the maternal stress-response system that modulates the homeostatic balance of the sympathetic and parasympathetic nervous systems
Cognitive functions of shift workers: paramedics and firefighters – an electroencephalography study
Neuromodulation Integrating rTMS and Neurofeedback for the Treatment of Autism Spectrum Disorder: An Exploratory Study
Single Pulse TMS-Induced Modulations of Resting Brain Neurodynamics Encoded in EEG Phase
Transcranial magnetic stimulation (TMS) can noninvasively modulate cortical ongoing activity in the human brain. We investigated frequency-specific and state-dependent cortical network by analyzing how modulation of cortical ongoing activity at one cortical area is propagated to the rest of the brain by TMS-EEG recordings. We found frequency-specific and state-dependent changes in propagation of TMS-evoked phase resetting of cortical ongoing activity in the open eye condition and closed eye condition. We discussed the functional significance of state-dependent synchronization networks observed.National Institutes of Health (U.S.) (NIH fellowship F32MH080493)National Institutes of Health (U.S.) (1KLRR025757-01)National Institutes of Health (U.S.) (Grant K24 RR0118875)Harvard Clinical and Translational Science Center (NIH Award UL1 RR 025758)National Center for Research Resources (U.S.)Harvard UniversityBerenson-Allen Center for Noninvasive Brain Stimulatio