How leeches feel...
Coding in the leech somatosensory System
Although leeches are not everybody´s favorite pet, they have several advantages as model organism to study the processing of sensory information. The nervous system of the leech has a simple structure and is easily accessible. Their behavior is not too complex and many well-defined behaviors are controlled by a low number of individually characterized nerve cells. Hence, there is hope that it will some day be possible to understand the neuronal origin of these behaviors in detail.
One example for such a simple behavior is the local bend reflex. When the mid-body of a leech is touched lightly, the animal bends away locally. This behavior is mediated by a small neuronal network consisting of only 4 sensory cells, approximately 20 interneurons and 4 groups of motorneurons, most of which are individually characterized and located in every midbody ganglion. This network enables the leech to distinguish tactile stimuli which are less than 1mm appart from each other.
Our approach to study sensory information processing and the generation of behavior in leeches is to combine experiments with intracellular recordings and tactile stimulation with model simulation.
- Friederice Pirschel (PhD student, electrophysiology and data analysis)
- Gerrit Hilgen (Postdoc, voltage sensitive dye imaging)
- Elham Fathiazar (PhD student starting 10/2012, analysis of voltage sensitive dye data)