B4 MOTONEURON

B4 is a large neuron located on the dorsal surface of each buccal ganglia. It has projections down both ipsi- and contralateral ventral buccal nerves and ipsilateral lateral buccal nerve. The two B4 neurons are electrically coupled with each other as well as with the B4cl and B8 motoneurons. B4 innervates the anterior jugalis muscle in the buccal mass. During feeding cycles, B4 is active during the swallow phase. It is inhibited by protraction phase interneuron N1M and swallow phase interneuron N3p and is electrically coupled with the swallow phase interneurons N3t, N3p and OC. Via these electrical connections, B4 can alter feeding rhythm generation. It receives strong excitation from the modulatory interneuron, CGC. B4 activity can be used to read out whether feeding cycles are fictive appetitive or fictive consummatory.

References

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