The Role of Interhemispheric Interactions in Cortical Plasticity

Area of Science:

• Neuroscience
• Neuroplasticity
• Sensory processing

Background:

• The brain's hemispheres are often studied independently, with one used as a control for the other.
• This approach may neglect crucial interhemispheric interactions during plasticity studies.

Purpose of the Study:

• To provide direct evidence that cortical plasticity is not a unilateral process.
• To investigate interhemispheric interactions in experience-dependent plasticity.

Main Methods:

• Used 2-[14C] deoxyglucose (2DG) brain mapping in rats.
• Induced experience-dependent plasticity via unilateral whisker deprivation.
• Compared metabolic activity with contralateral stimulation alone versus bilateral stimulation.

Main Results:

• Unilateral whisker deprivation led to a ~45% widening of the sensory representation in the contralateral barrel field (BF).
• Contralateral stimulation alone resulted in <20% representation widening.
• Cortical map remodeling depends partially on the contralateral hemisphere.

Conclusions:

• Cortical plasticity is an integrated process involving interactions between both hemispheres.
• The concept of a "control hemisphere" is challenged, as plasticity in one hemisphere affects the other.
• Findings have implications for understanding learning, rehabilitation, and brain function.