Welcome to the Computational Neuroscience division!
Our group is interested in the question of sensory coding:
How are sensory stimuli represented and processed in nervous systems?
Currently, we mainly work on this questions in two systems:
The tactile system of the leech
Even though the leech seems scary to many people because of it's food preference for warm blood, it is much more sensitive than one would expect for an organism with such a tiny nervous system. When touched, the leech is able to behaviorally discriminate the position of the tactile stimulus as precisely as the human finger tip - even though only 10 sensory cells of three types are located in each segment. Since the leech tactile system shows surprising similarities to the primate perception of touch, this simple invertebrate system can help to analyze fundamental principles of sensory coding and the processing of tactile stimuli.
In our research, we study with a combination of intracellular electrophysiology, voltage-sensitive dyes, data analysis and computational modeling how a minimalistic nervous system can produce precise behavioral reactions to sensory stimulation.
- Pirschel, F., Hilgen, G., & Kretzberg, J. (2018). Effects of touch location and intensity on interneurons of the leech local bend network. Scientific reports, 8(1), 3046
- Fathiazar, E., Hilgen, G., & Kretzberg, J. (2018). Higher Network Activity Induced by Tactile Compared to Electrical Stimulation of Leech Mechanoreceptors. Frontiers in physiology, 9, 173.
- F. Pirschel, J. Kretzberg (2016) "Multiplexed Population Coding of Stimulus Properties by Leech Mechanosensory Cells" The Journal of Neuroscience, 36(13): 3636-3647
- Kretzberg, J, et al. (2016), "Encoding of Tactile Stimuli by Mechanoreceptors and Interneurons of the Medicinal Leech", Frontiers in physiology 7 (2016)
The vertebrate auditory system
Humans and many non-human animals have two ears. Having two ears is highly beneficial for our perception of sounds. When a sound is coming from your left side, the sound wave arriving at your left ear is slightly stronger and slightly earlier than at your right ear. Our brain has special circuits for detecting these subtle differences to find out the location of the sound source. Relevant neurons in these neuronal circuits sense, for example, sound timing differences of far less than one millisecond, which constitutes one of the fastest neural computations happening in the nervous system.
In our research, we analyze, model, and simulate the physiological characteristics of auditory neurons in various vertebrate species, including cats, gerbils, and chickens and owls. Such computational approaches enable us to investigate the cellular mechanisms that underlie the precise auditory information processing and perception of sounds under idealized conditions.
- Ashida, G., & Nogueira, W. (2018). Spike-Conducting Integrate-and-Fire Model. eNeuro, 5(4), ENEURO.0112-18.2018.
- Nogueira W, Ashida G (2018) Development of a model of the electrically stimulated auditory nerve. In: Biomedical Technology, Lecture Notes in Applied and Computational Mechanics P. Wriggers and T. Lenartz (eds.). pp 349-362. Springer International
- Ashida, G., Tollin, D. J., & Kretzberg, J. (2017). Physiological models of the lateral superior olive. PLoS computational biology, 13(12), e1005903.
- Saremi, Amin, et al. "A comparative study of seven human cochlear filter models." The Journal of the Acoustical Society of America140.3 (2016): 1618-1634.
- Ashida, Go, Jutta Kretzberg, and Daniel J. Tollin. "Roles for coincidence detection in coding amplitude-modulated sounds." PLoS computational biology 12.6 (2016): e1004997.