Axon Dynamics

Recent years have seen an increase in appreciation for the role that axonal propagation plays in neural coding. In many axons, relatively complex complements of voltage-gated ion channels and neuromodulator receptors render the temporal fidelity of spike propagation dependent on the history of activity.

In consequence, activity patterns can change during conduction between spike initiation sites and synaptic terminals. Spike failures, ectopic spike initiation, and changes in interval structure have all been reported. In a series of publications, we showed that one of the stomatogastric neurons displays substantial activity-dependence of excitability and conduction delays at different time scales, including slow dynamics that outlasts slow changes found in central spike initiation.

In addition, excitability is modulated by dopamine at nanomolar (hormonal) concentrations. We have identified significant parts of the underlying ionic mechanisms and modulatory signaling pathways. Biophysically realistic computational models of the axon replicate the propagation dynamics and allow inferences about the specific contributions of ionic conductances.

We can also show that propagation induced changes in spike patterns, i.e. changes in the temporal neural code, can have dramatic effects on the electrical responses of postsynaptic muscle fibers.

Farzan Nadim​
Office: 973-596-8453    
Lab: 973-596-8290   

Jorge Golowasch​
Office: 973-596-8444
Lab: 973-596-8290 

Dirk Bucher
Office: 973-596-8469
Lab: 973-596-6274