Functional postnatal changes in avian brain regions responsive to retinal slip: a 2-deoxy-D-glucose study

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Avian Biology

Background:

• The nucleus of the basal optic root (nBOR) and lentiform nucleus of the mesencephalon (LM) are avian brain regions involved in processing visual motion for optokinetic eye movements.
• Previous research indicates these nuclei respond to whole-field visual motion stimuli.

Purpose of the Study:

• To investigate the postnatal development of response properties in the nBOR and LM in avian brains.
• To determine how visual motion processing capabilities change during early development in these specific brain areas.

Main Methods:

• Utilized the 2-deoxy-D-glucose (2-DG) method to map brain activity in response to visual stimuli.
• Presented vertical and horizontal whole-field visual motion to one eye in hatchlings and older chicks.
• Analyzed the distribution of 2-DG label in the nBOR and LM to identify activated regions.

Main Results:

• Vertical motion elicited 2-DG labeling in the contralateral nBOR, with distinct dorsal/ventral localization in older birds compared to diffuse labeling in hatchlings.
• Horizontal motion resulted in 2-DG labeling in the contralateral LM and lateral nBOR in both age groups.
• In older birds, temporal-to-nasal motion selectively labeled the LM magnocellularis (LMmc) within the LM, while nasal-to-temporal motion labeled both LM subdivisions.

Conclusions:

• The nBOR and LM exhibit significant postnatal development in their response to visual motion.
• Functional segregation occurs within subdivisions of the nBOR and LM during development.
• These changes may involve intrinsic reorganization in the nBOR and telencephalic projections in the LM.