You are here: Research groups > Systems Neurophysiology (Schwarz)
Prof. Dr. rer. nat. Cornelius Schwarz
Tel. +49 (0)7071 29 80462
Fax +49 (0)7071 29 5724
Dr. rer. nat. Alia Benali
Dr. rer. nat. Dominik Bruggersergejus.butovas(at)uni-tuebingen.dedominikbrugger(at)fastmail.fm
Dr. rer. nat. Sergejus Butovas
Caroline Bergner (MD project)
Andre Maia Chagas (PhD project)
Petya Georgieva (PhD project)
Bettina Joachimsthaler (PhD project)
puzicha.chr(at)gmx.deChristian Waiblinger (PhD project)
Ursula Pascht (Technician)
1) Active Perception
Perception is an active process. Before actively seeking sensory information, the individual forms an internal hypothesis about its sensory environment. Based on this hypothesis, sensor movements, covert and overt shifts of attention, and selection of explorative strategies, amongst others, are employed to optimize the acquisition of sensory stimuli. Passive perception, on the other hand, only occurs if the individual has no chance to anticipate the sensory event and thus fails to prepare its perceptual system and engage in appropriate explorative behavior. Once an individual acquires sensory data in an active manner, it needs to interpret these data according to its internal hypothesis. In other words, active sensory data must be integrated in a top-down fashion by signals holding the internal hypothesis. For instance, the individual needs to calibrate incoming sensory data according to the movement pattern or attentional mechanisms used, it must update its internal hypothesis based on the new insights gained, and appropriately factor in information obtained from other sensory modi.
We study Active Touch as a model system for Active Perception. Rats perform active palpatory vibrissa movements in order to discriminate surface textures and shapes of objects. The great advantage of this model system is that the easily accessible vibrissal movements can be used as the estimate of the individual's internal hypothesis. A further advantage is the relative simplicity of whisker movements (essentially 1D hair movement around a pivot point in the skin) and the large and accessible whisker representations in the somatosensory and motor cortex. Probing these representations with multi-electrode recordings, while rats perform vibrissa movements and/or tactile detection/discrimination tasks, we investigate how motor signals (carrying the internal hypothesis) modulate tactile processing.
2) Context dependency of cortical microstimulation
It is sought to establish methodological approaches to use CNS-multi-electrode implants for neurological rehabilitation. A microstimulation pulse applied in a CNS structure will generate neuronal activity that is dependent on the context. The context is determined by two sources. A) The spatio-temporal microstimulation pattern itself: it matters if a given pulse is applied in isolation or if it is embedded within a spatio-temporal pulse pattern. B) The functional state of the CNS structure that is to be stimulated: it matters if the structure is engaged in a task or idling (i.e. during sleep) when stimulating it. We aim to employ the Active Touch model system (described above) to determine basic neuronal activity evoked by multi-electrode stimulation in cortical representations of the vibrissal system.
Intrinsic and synaptic mechanisms determining cerebellar nuclei neurons spike output
Although all forms of cerebellar dysfunction are characterized by severe impairment in the timing of muscular activation and consequent uncoordinated movements, the cellular underpinnings of the cerebellum control of movement remains unknown. Our research is focused on the neurons of the deep cerebellar nuclei (DCN) which carry almost all cerebellar output signals and are the main target of the cerebellar cortex signals. Despite their central position in the cerebellar system, the internal micro-circuits and cellular mechanisms determining DCN output are still poorly understood. Moreover, in many types of cerebellar diseases, deep cerebellar nuclei neurons are spared and their function is altered only secondarily to the alterations occurring at the cerebellar cortex. Hence, cerebellar nuclei are a natural place for compensatory mechanisms for diseases affecting the cerebellar cortex. The general aim of this research is to understand the cellular mechanism that control DCNs output. Particularly, three areas are currently investigated:
Finally we are interested in the potential plasticity of the above mentioned mechanisms.