Eine vergleichende Studie zur zerebralen Repräsentation des Spiegelneuronensystems und der Deutschen Gebärdensprache bei Normalprobanden sowie Gehörlosen

摘要

The mirror neuron system is an observation-execution matching system activated, in humans, during action observation, motor learning, and imitation of action. Furthermore it is hypothesized that the mirror neuron system plays a key role during the evolution of language and provides the necessary link between manual gestures as an early step in communication preceding vocalization. This theory is based on a functional overlap between cerebral systems involved in action observation and those mediating linguistic processing. However, observation of manual actions and decoding of oral linguistic information are bound to different modalities thus not allowing for systematic investigation of network overlap. In the present study we investigated sign language, a natural language sharing both manual output and visual input with action observation, in deaf signers and hearing controls using functional magnetic resonance imaging. We identified a common network for sign language lexem comprehension and action observation in deaf signers and hearing controls involving bilateral frontal and inferior parietal areas including classic language regions. In contrast, differential activations between deaf signers and hearing controls were observed within bilateral posterior temporal and adjacent parietal regions both for the linguistic and the action observation task. The integration of posterior temporal and parietal regions in the dorsal stream for visual spatial and linguistic processing indicates cross-modal plasticity due to auditory deprivation. The data of the present study demonstrated an overlap between functional representations of the mirror neuron system and the language network when tested within the same modality.