Mucus trail tracking in a predatory snail: olfactory processing retooled to serve a novel sensory modality.

Introduction: The rosy wolfsnail (Euglandina rosea), a predatory land snail, finds prey snails and potential mates by following their mucus trails. Euglandina have evolved unique, mobile lip extensions that detect mucus and aid in following trails. Currently, little is known of the neural substrates of the trail-following behavior.

Electrophysiological properties of motor neurons in a mouse model of severe spinal muscular atrophy: in vitro versus in vivo development.

We examined the electrophysiological activity of motor neurons from the mouse model of severe spinal muscular atrophy (SMA) using two different methods: whole cell patch clamp of neurons cultured from day 13 embryos; and multi-electrode recording of ventral horns in spinal cord slices from pups on post-natal days 5 and 6. We used the MED64 multi-electrode array to record electrophysiological activity from motor neurons in slices from the lumbar spinal cord of SMA pups and their unaffected littermates. Recording simultaneously from up to 32 sites across the ventral horn, we observed a significant decrease in the number of active neurons in 5-6 day-old SMA pups compared to littermates.

Neuronal and network activity in networks of cultured spinal motor neurons.

This is the first report of multielectrode recordings from networks of cultured motor neurons. Neurons isolated from the ventral horns of spinal cords of E15 rats were cultured on MED64 probes. The majority of the neurons in the cultures are positive for neurofilament, choline acetyltransferase, and Hb9, characteristics of motor neurons.

Measuring asymmetric temporal interdependencies in simulated and biological networks.

We use a newly developed metric to characterize asymmetric temporal interdependencies in networks of coupled dynamical elements. We studied the formation of temporal ordering in a system of coupled Rossler oscillators for different connectivity ratios and network topologies and also applied the metric to investigate the functional structure of a biological network (cerebral ganglia of Helix snail). In the former example we show how the local ordering evolves to the global one as a function of structural parameters of the network, while in the latter we show spontaneous emergence of functional interdependence between two groups of electrodes.