ISCA Workshop on Plasticity in Speech Perception (PSP2005)
Senate House, London, UK
The sequencing of auditory information during language perception seems to be modulated by subcortical structures such as the basal ganglia (BG). In particular, syntactic reanalysis processes as reflected in the P600 component of the event-related brain potential (ERP) are affected in patients with lesions  or neurodegenerative change  of the BG during auditory language processing. One critical question is whether this deficit is function specific or not. The role of the BG in language perception has been discussed controversial . However, their involvement in language production , attention and memory , and timing [6,7] find support. Recent work with subcortical patients has demonstrated that external rhythmic auditory stimulation re-elicits the P600 during the presentation of syntactically erroneous sentences . This result is in line with a compensation hypothesis put forward in the motor domain. If a sensory stimulus is predictive (serially or isochronously) the impairment of the BG can be compensated by overactivation in pre-motor areas [9,10]. The current auditory experiment followed up the compensation hypothesis by investigating patients with deep brain stimulation (DBS) of the subthalamic nucleus. If DBS correlates with compensation in pre-motor areas, auditory sequencing should be facilitated and the P600 reelicited. Patients were tested in an on/off paradigm before and after DBS placement, respectively. While the P600 was not elicited by syntactically erroneous sentences before DBS placement, the P600 resurfaced after DBS placement during both the on and off testing. It is important to note that the patients always showed a P300, a component correlated with non-linguistic attentional processes, ensuring their capacity to perceive and understand both task and stimulus material. We conclude that the current data support a compensation hypothesis in the auditory language domain comparable to the motor domain.
Bibliographic reference. Kotz, Sonja / Schwarz, Johannes / Winkler, Dirk / Preul, Christoph / Cramon, D. Yves von / Friederici, Angela D. (2005): "Recovery of syntactic function during auditory language processing following subthalamic nucleus stimulation", In PSP2005, 183 (abstract).