Ralf Wessel, PhD
Washington University School of Medicine
Department of Ophthalmology and Visual Sciences
Campus Box 8096
660 S. Euclid Ave.
St. Louis, MO 63110
Arguably the biggest goal in modern neuroscience is to gain a deeper and more complete understanding of strongly correlated neural systems, known as microcircuits. A striking phenomenon of strongly correlated neural systems is visual perception. In broad strokes, it is intriguing to hypothesize that visual perception emerges from the interaction between incoming spatiotemporal stimuli and the internal dynamic state of neural networks. Yet, to date, a convincing computational framework for the processing of visual stimuli in neural circuits remains elusive.
To fill this gap, Dr. Wessel’s NeuroPhysics group seeks to delineate principles of visual information processing at the level of spatiotemporal network dynamics in optic tectum and visual cortex. The central component of the NeuroPhysics research program consists of in vitro electrophysiological recordings of cortical activity in the turtle eye-attached whole-brain preparation in response to computer-controlled visual stimulation of the retina. A key innovation of Dr. Wessel’s research lies in adapting quadruple intracellular whole-cell recording and multielectrode array extracellular recording techniques to the unfolded, yet intact, three-layer visual cortex during visual processing. The observed emergent phenomena, including oscillations, synchrony, and neuronal avalanches, are conceptualized using a framework informed by statistical physics and nonlinear dynamics. This synergy of advanced neurotechnology, comparative in vitro physiology, and physics-inspired theory provides a fertile opportunity to test the stated working hypothesis and to advance our understanding of cortical microcircuit function.
- Gabbiani F, Metzner W, Wessel R, and Koch C (1996) From stimulus encoding to feature extraction in weakly electric fish. Nature 384:564-567
- Luksch H, Khanbabaie R, and Wessel R (2004). Synaptic dynamics mediate sensitivity to motion independent of stimulus details. Nature Neuroscience 7:380-388
- Brandt SF, Dellen BK, Wessel R (2006) Synchronization from disordered driving forces in arrays of coupled oscillators. Phys Rev Letters 96: 034104
- Caudill MS, Brandt SF, Nussinov Z, Wessel R (2009) An intricate phase diagram of a prevalent visual circuit reveals universal dynamics, phase transitions and resonances. Phys Rev E 80: 051923
- Lai D, Brandt S, Luksch H, Wessel R (2011) Recurrent antitopographic inhibition mediates competitive stimulus selection in an attention network. J Neurophysiol 105: 793-805