Imaging glial cell activation with [11C]-R-PK11195 in patients with AIDS.

Glial cell activation occurs in response to brain injury and is present in a wide variety of inflammatory processes including dementia associated with human immunodeficiency virus (HIV). HIV-infected glial cells release cytokines and chemokines that, along with viral neurotoxins, contribute to neuronal damage and apoptosis. The purpose of this study was to determine if glial cell activation in HIV-positive (HIV+) patients could be detected noninvasively, in vivo, using [11C]-R-PK11195 with positron emission tomography (PET).

Sympathetic activity and the underlying action potentials in sympathetic nerves: a simulation.

Understanding the relationship between activity recorded in sympathetic nerves and the action potentials of the axons that contribute to that activity is important for understanding the processing of sympathetic activity by the central nervous system. Because this relationship cannot be determined experimentally and is difficult to predict analytically, we simulated the summed action potentials of 300 axons. This simulation closely resembled actual sympathetic activity and permitted us to know how many action potentials contributed to each burst of simulated sympathetic activity and the durations and amplitudes of each burst.