Lateralization of the Human Mirror Neuron System
Lisa Aziz-Zadeh,1,2 Lisa Koski,1,5 Eran Zaidel,2,4 John Mazziotta,1,4,5,6,7 and Marco Iacoboni1,3,4
1Ahmanson Lovelace Brain Mapping Center, Neuropsychiatric Institute, 2Department of Psychology, 3Department of Psychiatry and Biobehavioral
Sciences, 4Brain Research Institute, David Geffen School of Medicine, and Departments of 5Neurology, 6Pharmacology, and 7Radiological Sciences,
University of California, Los Angeles, Los Angeles, California 90095
lateralization of the imitation circuitry in humans is unclear. We conducted a functional magnetic resonance imaging study of imitation
of finger movements with lateralized stimuli and responses. During imitation, activity in the inferior frontal and rostral inferior parietal
cortex, although fairly bilateral, was stronger in the hemisphere ipsilateral to the visual stimulus and response hand. This ipsilateral
pattern is at variance with the typical contralateral activity of primary visual and motor areas. Reliably increased signal in the right
superior temporal sulcus (STS) was observed for both left-sided and right-sided imitation tasks, although subthreshold activity was also
observed in the left STS. Overall, the data indicate that visual and motor components of the human mirror system are not left-lateralized.
multimodal action representations.
Key words: motor; sensorimotor; premotor; language; hemisphere; lateralization
Several studies indicate a shared representation for the execution