Figure 7.

Laminar comparison of the relative density of prefrontal neurons projecting to three thalamic nuclei: (A), AM; (B), MD; (C), VA/VL. Asterisks in each scatter plot indicate the position of the average relative density of projection neurons in layers V and VI for all prefrontal areas, separating the plot area in quadrants. Prefrontal areas that cluster in the top left or bottom right quadrant included a higher than average density of projection neurons in layer VI or V, respectively. Prefrontal areas that cluster in the top right or bottom left quadrant included respectively a higher or a lower than average density of projection neurons in both layers VI and V. The slope of the fit (solid lines) shows that MD was targeted heavily by layer VI neurons (steeper slope), VA was targeted equally by both layers V and VI (smallest slope), and AM was targeted mainly by layer VI but also by a significant number of layer V neurons (intermediate slope). The shaded areas in each plot indicate the variation in the density of projection neurons in layer V (X-axis) and layer VI (Y-axis) for each prefrontal area.