title: Dynamical reorganization of synchronous activity patterns in prefrontal cortex-hippocampus networks during behavioral sensitization.
abstract: Neural synchrony exhibits temporal variability and, therefore, the temporal patterns of synchronization and desynchronization may have functional relevance. This study employs novel time-series analysis to explore how neural signals become transiently phase locked and unlocked in the theta frequency band in prefrontal cortex and hippocampus of awake, behaving rats during repeated injections of the psychostimulant, d-Amphetamine (AMPH). Short (but frequent) desynchronized events dominate synchronized dynamics in each of the animals we examined. After the first AMPH injection, only increases in the relative prevalence of short desynchronization episodes (but not in average synchrony strength) were significant. Throughout sensitization, both strength and the fine temporal structure of synchrony (measured as the relative prevalence of short desynchronizations) were similarly altered with AMPH injections, with each measure decreasing in the preinjection epoch and increasing after injection. Sensitization also induced decoupling between locomotor activity and synchrony. The increase in numerous short desynchronizations (as opposed to infrequent, but long desynchronizations) in AMPH-treated animals may indicate that synchrony is easy to form yet easy to break. These data yield a novel insight into how synchrony is dynamically altered in cortical networks by AMPH and identify neurophysiological changes that may be important to understand the behavioral pathologies of addiction.
authors: Department of Mathematical Sciences and Center for Mathematical Biosciences.
authors: Sungwoo
authors: S
authors: Ahn
authors: Department of Mathematical Sciences and Center for Mathematical Biosciences, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Leonid L
authors: LL
authors: Rubchinsky
authors: Department of Psychology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA and Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
authors: Christopher C
authors: CC
authors: Lapish
mesh_terms: D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003344:Cortical Synchronization / Q000187:drug effects / Q000502:physiology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D013826:Theta Rhythm / Q000187:drug effects
chemical_list: D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine
keywords: Amphetamine; behavioral sensitization; hippocampus; neural synchrony; prefrontal cortex