Question

PirB is a receptor for inhibitory proteins like MAG and Nogo that normally cause collapse/inhibition of growth cones. If PirB was blocked, or not present, do you think that would affect visual cortex plasticity after the normal critical period, and if so, in what way? Explain your answer.

Answer 1

Blocking or the absence of the PirB receptor could lead to enhanced neuronal plasticity in the visual cortex beyond the critical period, potentially improving visual learning or recovery from injury but also risking a lack of refinement in neural connections.

Step-by-step explanation:

The PirB receptor is known to bind with inhibitory proteins such as MAG and Nogo, which contribute to the collapse or inhibition of neuronal growth cones. During the critical period of visual cortex development, these inhibitory interactions are important for synaptic pruning and stabilization that ultimately shapes the neural circuits responsible for visual information processing. If PirB is blocked or absent, the normal inhibitory signaling would be disrupted, potentially leading to enhanced neuronal plasticity beyond the critical period. This could manifest as increased capacity for visual learning or recovery from injury, as the usual constraints on neuronal outgrowth and connection strength are lifted. However, this also could lead to a lack of refinement in neural connections, potentially resulting in improper visual processing. Therefore, the absence of PirB could indeed affect visual cortex plasticity in a significant way, potentially allowing for continued plastic changes in the brain that are normally restricted after the critical period has ended.