Visual Universitätsmedizin Mainz

Research Interests

Adaptive behavior

The brain's arguably most challenging task is to orchestrate behavior in the face of ever-changing environments. Our main research interests are the psychological and neural mechanisms underlying such adaptive learning processes, with a special emphasis on choice behavior. To that end, we subject experimental animals (rats) to a range of perceptual decision-making tasks. These tasks require the simultaneous consideration of several sources of information, such as sensory evidence for a hypothesis about the state of the world, and the probability of receiving reinforcement when committing to a certain response option. As in the real world, the validity of this information may change over the course of an experimental session. While animals struggle to harvest the maximum possible number of reinforcers, we record extracellular spiking activity in associative forebrain areas to elucidate the hidden variables which enable animals to adapt rapidly (and frequently optimally) to a world full of uncertainty.

Impact of single-neuron stimulation on local neural networks

It is widely held that spike responses of single neurons to sensory stimulation are noisy and uninformative. Contrary to this notion, recent studies showed that electrical activation of single cortical neurons can indeed have behavioral relevance. For example, stimulation of single neurons in rat primary motor cortex generates movements of the facial whiskers, and stimulation of single neurons in somatosensory cortex yields a behavioral response. These studies together suggest that the influence of an individual cortical neuron on the local neural network is stronger than commonly thought. However, the mechanism by which the activity of a single neuron is amplified and propagated through the network to eventually generate behavior is unknown. We aim to elucidate some of the mechanisms underlying the phenomenon of single-cell induced behavioral responses, using juxtacellular recordings and nanostimulation of single neurons in anesthetized, awake, and eventually trained animals.

Sensory processing in the rodent whisker system

The rodent whisker system is a powerful model system to investigate the physiology of perception. In a collaborative project with the Institute of Physiology (Prof. Heiko Luhmann), head-fixed mice are operantly conditioned to perform whisker-based psychophysical detection and discrimination tasks. Using a combination of behavior analysis, multichannel electrophysiology, and optogenetic interventions, we strive to elucidate the neural processes underlying the sensation of touch.

Methods

Operant conditioning
Extracellular single-neuron recordings
Electrical microstimulation
Intracerebral infusion of pharmacological agents
Juxtacellular recordings
Nanostimulation
Cognitive modeling

Postal Address

University Medical Center 

Johannes Gutenberg-University

Institute of Pathophysiology

Focus Program Translational Neuroscience (FTN)

Duesbergweg 6

55128 Mainz, Germany