In the developing cortex, pyramidal neurons are greatly affected by many external influences such as stress (Radley et al., 2006), environmental complexity (Kolb et al., 2003), amphetamines (Crombag et al., 2004) and alcohol exposure (Tu et al., 2008; Whitcher & Klintsova, 2008). Pyramidal neurons vary considerably in dendritic complexity (total length of dendrites, combined with the number of branches and bifurcations) between different layers and cortical regions, suggesting that different structural features may carry different functional loads (Spruston, 2008). In particular, Layer III pyramidal cells in the prefrontal cortex integrate and organize inputs from thalamocortical fibers, originating primarily in the mediodorsal (MD) nucleus (Van Eden, 1986). Furthermore, they influence the axonal competition of glutamatergic neurons originating in the MD nucleus (Wedzony et al, 2005). Thus, changes in dendritic complexity could affect the overall function of pyramidal neurons.
