Development of a neural circuit in the superior colliculus: analysis of the propagation of neuronal excitation from intermediate to superficial layers.
The superior colliculus is important for orientation behaviors, in which visuomotor transformation is performed by the pathway from the superficial layer (SGS) to the intermediate layers (SGI). The opposite pathway (from the SGI to the SGS) also exists, raising the possibility of a feedback circuit, although it could be either negative (inhibitory) or positive (excitatory). In this study, we focused on the development of the feedback circuit. We used optical imaging methods that can measure neuronal population responses directly, as the orientation behaviors are determined by large population activities of superior colliculus neurons. We examined the postnatal development of the propagation pattern of neuronal excitation from the SGI to the SGS using a GABAA receptor antagonist. The optical response propagated within the SGI, but not to the SGS in infant mice that have not opened their eyes. In contrast, in young mice after eye opening, the optical response propagated initially in the SGI and then to the SGS. The GABAA receptor antagonist increased the optical response in the SGS in young mice, as well as that in the SGI in infant mice. Together, these results suggest that axons of SGI neurons terminate to the SGS during development after eye opening.
aDepartment of Human and Artificial Intelligence Systems, Graduate School of Engineering bResearch and Education Program for Life Science, University of Fukui, Fukui cHuman Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 2, Ibaraki, Japan.
Nana
N
Morita
Ryohei P
RP
Hasegawa
Kazuyuki
K
Murase
Hiroshi
H
Ikeda
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005123:Eye; D025461:Feedback, Physiological; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D061848:Optical Imaging; D010852:Picrotoxin / Q000494:pharmacology; D013477:Superior Colliculi / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D013997:Time Factors; D014795:Visual Pathways / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D014796:Visual Perception; D056969:Voltage-Sensitive Dye Imaging
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018691:Excitatory Amino Acid Antagonists; D058785:GABA-A Receptor Agonists; D010852:Picrotoxin