Figure 1.

A simplified model of the interactions of microglia (blue), parvalbumin neurons, and pyramidal neurons (gray) across age. Typically, microglia aid in pruning but will switch to an activated form and increase inflammatory factors. Second, cytokines decrease parvalbumin (PV; red) neurons and shift the balance to more excitation. Third, eventually, the neurons are surrounded by perineuronal nets (blue), and plasticity is limited. (Bottom) Voxel placement on the right in adolescent male rats. MRS data of GABA/tCr versus PV levels from the same animals as assayed by Western immunoblot¹⁵². We can detect GABA levels with magnetic resonance spectroscopy (MRS) and compare them to PV levels later. Shown are controls animals (black dots), rats with a history of maternal separation (red dots). Levels of PV were quantified with Western Immunoblot, using our standard methods. The spectrograph and the location of the voxel are on the right. Credit to Dr. Dionyssios Mintzopoulos for the MRS data.