Figure 3.

Schematic drawing illustrating spine remodeling and maintenance in the mouse motor cortex when a mouse is trained with different forelimb motor tasks sequentially (based on experimental data from [37]). (a) Three spiny dendrites (green) connect with their neighboring axons (yellow) at 6 different synaptic sites (identified as spines and boutons, respectively). (b) New synaptic connections (red) form rapidly during the acquisition phase of learning the first motor task (i.e., a single-pellet reaching task). (c) During the learning consolidation phase of the same motor task, a majority of new synapses formed during learning acquisition are selectively stabilized, while synapses that existed prior to learning are preferentially eliminated (with dotted outlines). This results in a rewiring of the circuit without overall changes in synaptic density. (d) Learning a different forelimb motor task (i.e., a pasta handling task) later in life remodels a different set of synapses (blue).