FIGURE 3.

A summary of how training experience affects learning potential. (A) Learning that an environmental event is controllable or predictable depends upon a form of NMDAR-mediated plasticity and is disrupted if glia function is inhibited. Processes initiated during learning (induction) engage a protein synthesis dependent mechanism that maintains the effect over time (memory). Prior experience with controllable/predictable stimulation has a long-term protective/restorative effect that enables instrumental learning and blocks both the learning impairment and EMR induced by VIS. These effects depend upon BDNF and CaMKII. (B) Exposure to uncontrollable/unpredictable shock initiates a process that depends upon the NMDAR, group 1 mGluR, GABA, glia activation, and TNF. These processes induce a protein synthesis dependent mechanism that maintains the effect over time. Prior experience with uncontrollable/unpredictable stimulation inhibits instrumental learning through a process that involves a kappa opioid, TNF, GABA, and the trafficking of GluR2-lacking AMPA receptors. Superscripts indicate whether a neurobiological mechanism is necessary (1) or necessary and sufficient (2).