Neural and behavioral adaptation to bilateral maps in primary somatosensory cortex

Area of Science:

• Neuroscience
• Sensory Systems
• Neuroplasticity

Background:

• Mice use whiskers for navigation, processed by the primary whisker somatosensory cortex (wS1).
• Normal wS1 function relies on contralateral sensory input via complete axonal crossover.
• Robo3 gene knockout disrupts this crossover, causing abnormal bilateral whisker representation in wS1.

Purpose of the Study:

• Investigate brain adaptation to altered somatotopic maps.
• Examine sensorimotor processing following disrupted whisker input.

Main Methods:

• Utilized Robo3 mutant mice with disrupted axonal projections.
• Assessed performance on a whisker discrimination task.
• Employed unilateral optogenetic inhibition of wS1.
• Conducted single-unit recordings in wS1 and whisker primary motor cortex (wM1).

Main Results:

• Robo3 mutant mice performed comparably to wild-type littermates on whisker discrimination.
• wS1 activity contralateral to the stimulated whisker was crucial for correct reporting.
• Abnormal bilateral whisker responses were observed in wS1 but not in wM1.
• Suggests filtering of aberrant signals along the sensorimotor pathway.

Conclusions:

• The brain can adapt to significant alterations in tactile input.
• Accurate sensorimotor representations are constructed despite disrupted somatotopy.
• Sensorimotor pathways effectively filter abnormal bilateral signals from wS1.