Project B2 – Coding of spatial and temporal information in specialized neural populations
Many species use acoustic communication for mate finding and mate selection. In grasshoppers, specialized interneurons in the metathoracic ganglion extract sound direction and identify the sex, species, and fitness of other grasshoppers from their acoustic communication signals [1-4]. Since the tempo of male and female “songs” is variable due to temperature fluctuations of the sender, the receiver needs to compute time-scale invariant song features [5]. The grasshopper auditory system is thus well suited to study how sensory inputs are processed to create goal-directed behavior.
Objectives and description of the project
The parallel processing of different stimulus aspects in the grasshopper is made possible by a high structural and biophysical diversity across individual metathoracic interneurons [6]. However, it is largely unknown how temporal and spatial aspects of natural stimuli are represented at the population level. Are there clearly separate computational modules or is information processed in a distributed manner? What is the role of feedforward vs. feedback connections? Can we capture the main characteristics of the entire population response by minimal functional models [5]? To answer these and related questions, we will jointly extend our previous studies on auditory receptor neurons, that involved computational modelling and nonlinear dynamics [1,2,7] as well as information theoretical approaches [3,4]. We will also adapt and advance electrophysiological methods including dynamic-clamp and iso-response techniques [2,8]. These closed-loop approaches will allow us to directly test how different stimulus attributes are reflected in the neural response.
[1]: Machens et al. Nat Neurosci 2003. [2]: Gollisch & Herz PLoS Biol 2005. [3]: Machens et al. Neuron 2005. [4]: Eyheribade et al. Front Comp Neurosci 2008. [5]: Creutzig et al. J Neurosci 2009. [6]: Hildebrandt et al. J Neurosci 2009. [7]: Benda & Herz Neural Comp 2003. [8]: Benda et al. Curr Opin Neuro 2007.
