| Definition: |
Spiral neurons are excitatory interneurons located in rhombomere 3 and have contralateral projections that cross the midline forming commissures in rhombomere 3. After crossing the midline the two commissures fuse and project caudally synapsing with the Mauthner neuron. As they enter the axon cap, spiral fiber neurons lose their myelin and wrap around the axon hillock in a stereotyped spiral, where they make both electrical and glutamatergic synapses on the M cell axon close to the M-cell soma and with one another. Spiral neurons produced biphasic excitatory postsynaptic potentials (EPSPs) in the contralateral M-cell with a short latency. |
