Title | A single oscillating proto-hypothalamic neuron gates taxis behavior in the primitive chordate Ciona. |
Publication Type | Journal Article |
Year of Publication | 2023 |
Authors | Chung J, Newman-Smith E, Kourakis MJ, Miao Y, Borba C, Medina J, Laurent T, Gallean B, Faure E, Smith WC |
Journal | Curr Biol |
Volume | 33 |
Start Page | 3360 |
Issue | 16 |
Date Published | 2023 Jul 18 |
ISSN | 1879-0445 |
Abstract | Ciona larvae display a number of behaviors, including negative phototaxis. In negative phototaxis, the larvae first perform short spontaneous rhythmic casting swims. As larvae are cast in a light field, their photoreceptors are directionally shaded by an associated pigment cell, providing a phototactic cue. This then evokes an extended negative taxis swim. We report here that the larval forebrain of Ciona has a previously uncharacterized single slow-oscillating inhibitory neuron (neuron cor-assBVIN78) that projects to the midbrain, where it targets key interneurons of the phototaxis circuit known as the photoreceptor relay neurons. The anatomical location, gene expression, and oscillation of cor-assBVIN78 suggest homology to oscillating neurons of the vertebrate hypothalamus. Ablation of cor-assBVIN78 results in larvae showing extended phototaxis-like swims, even in the absence of phototactic cues. These results indicate that cor-assBVIN78 has a gating activity on phototaxis by projecting temporally oscillating inhibition to the photoreceptor relay neurons. However, in intact larvae, the frequency of cor-assBVIN78 oscillation does not match that of the rhythmic spontaneous swims, indicating that the troughs in oscillations do not themselves initiate swims but rather that cor-assBVIN78 may modulate the phototaxis circuit by filtering out low-level inputs while restricting them temporally to the troughs in inhibition. |
DOI | 10.1016/j.cub.2023.06.080 |
Alternate Journal | Curr Biol |
PubMed ID | 37490920 |