Flexible cue anchoring strategies enable stable head direction coding in both sighted and blind animals

Area of Science:

• Neuroscience
• Sensory processing
• Spatial navigation

Background:

• Vision is critical for spatial navigation and brain function.
• The effects of vision loss on neuronal encoding of spatial information are not well understood.

Purpose of the Study:

• To investigate how vision loss affects head direction (HD) cells, which are crucial for spatial orientation.
• To explore the role of alternative sensory cues, like olfaction, in maintaining spatial representation in the absence of vision.

Main Methods:

• Electrophysiological recordings were performed on head direction (HD) cells in the thalamus of mice.
• Experiments involved using rd1 mice (a model for photoreceptor degeneration and blindness) and sighted mice placed in darkness.
• Sensory manipulation included the use of olfactory cues and the absence of both visual and olfactory stimuli.

Main Results:

• Head direction (HD) cell tuning remained stable and robust in rd1 mice that became blind.
• Blind mice effectively utilized olfactory cues to maintain stable HD cell tuning.
• Prior visual experience improved HD cell tuning in blind mice compared to congenitally blind animals.
• In the absence of visual and olfactory cues, the HD attractor network persisted, but preferred firing directions drifted.

Conclusions:

• The brain demonstrates remarkable flexibility in using diverse sensory inputs, including olfaction, to maintain spatial representations.
• Visual experience influences the refinement of spatial tuning even after vision loss.
• The head direction (HD) attractor network is resilient but requires sensory input for stable directional output.