Figure 11. Summary of the circuit and its relationship to hindbrain structure.
(A) Diagram of the circuit motif for the left right choice revealed and tested behaviorally in this paper. Relative synaptic strengths are indicated by contact size. Dotted line shows ipsilateral output of the FF. M: Mauthner cell, FF(red): Feedfoward inhibitory neuron. (B) Image of the disposition of the neurons in the hindbrain. The inhibitory neurons (red, FF) lie at the bottom the most lateral of three columns of glycinergic inhibitory neurons (green) marked by arrows. This lateral column contains commissural inhibitory neurons with outputs on both sides of the hindbrain, while more medial columns contain neurons with contralateral (middle column) or ipsilateral outputs (medial column). Scale bar=20 µm. (C) The column containing the FF neurons is one of a series of interleaved glutamatergic and glycinergic columns in the hindbrain. The variety of sensory inputs to the lateral glycinergic column and the shared morphology of the neurons in it raise the possibility that other neurons in the column might also contribute to the laterality of other behavioral responses to sensory inputs by implementing the same circuit motif.