Central processing of auditory information

We are interested in the processing of auditory information in the functional loops of frontal brain regions and how these interact with the central auditory pathway. Recordings from patients with implanted electrodes for deep brain stimulation showed that information during an auditory oddball paradigm and a speech processing paradigm is already processed in subcortical brain areas. Behaviorally relevant signals are transmitted from there to higher-level cortical regions. Since neuronal activity in patients can only be recorded via implanted electrodes in medically defined brain regions, we have established an auditory oddball paradigm in rats. This comprises a target tone, a distractor tone and a standard tone of different frequencies. The neuronal data obtained show that the evoked potentials are comparable to those of patients. We are currently using the oddball paradigm in a behavioral approach to determine the optimal stimulation strategy for central auditory implants.

Hearing loss in adults is considered a risk factor for the development of dementia. However, it is still unclear whether this is due to social withdrawal of the patients or to a change in neuronal networks triggered by the hearing loss with resulting cognitive impairments. In order to investigate this question independently of the actual ability to speak, we are interested in possible changes in behavior and neuronal activity after hearing loss in rats. Initial studies show long-term learning and memory deficits as well as reduced social interactions in deafened adult rats. Since, due to the progressive connectivity of the maturing brain, damage in early developmental stages leads not only to local disturbances but also to malformations of neuronal circuits that may be associated with behavioral deficits and even neuropsychiatric disorders, another approach is to study behavior and neuronal activity after hearing loss in juvenile rats.