Dynamic changes of the endogenous cannabinoid and opioid mesocorticolimbic systems during adolescence:THC effects

Adolescence is a critical phase of active brain development often characterized by the initiation of marijuana (Cannabis sativa) use. Limited information is known regarding the endogenous cannabinoid system of the adolescent brain as well as related neurotransmitters that appear sensitive to cannabis exposure. We recently observed that adult rats pre-exposed to Δ-9-tetrahydrocannabinol (THC) during adolescence self-administered higher amounts of heroin and had selective impairments of the enkephalin opioid system within the nucleus accumbens (NAc) implicated in reward-related behavior. To explore the ontogeny of the cannabinoid and opioid neuronal systems in association with adolescence THC exposure, rats were examined at different adolescent stages during an intermittent THC paradigm (1.5 mg/kg i.p. every third day) from postnatal days (PNDs) 28–49. Rat brains were examined 24 hours after injection at PND 29 (early adolescence), PND 38 (mid adolescence) and PND 50 (late adolescence) and analyzed for endocannabinoids (anandamide and 2-arachidonoylglycerol), Met-enkephalin, cannabinoid CB(1) receptors and µ opioid receptors (µOR) in the NAc, caudate-putamen and prefrontal cortex (PFC). Of the markers studied, the endocannabinoid levels had the most robust alterations throughout adolescence and were specific to the PFC and NAc. Normal correlations between anandamide and 2-arachidonoylglycerol concentrations in the NAc (positive) and PFC (negative) were reversed by THC. Other significant THC-induced effects were confined to the NAc — increased anandamide, decreased Met-enkephalin and decreased µORs. These findings emphasize the dynamic nature of the mesocorticolimbic endocannabinoid system during adolescence and the selective mesocorticolimbic disturbance as a consequence of adolescent cannabis exposure

Effect of misfit strain on the electrocaloric effect in epitaxial SrTiO 3 thin films

77.22.Ej Polarization and depolarization, 77.70.+a Pyroelectric and electrocaloric effects, 77.80.-e Ferroelectricity and antiferroelectricity,

On the Role of Dopamine in Cognitive Vision

Abstract. Although dopamine is one of the most studied neurotransmitter in the brain, its exact function is still unclear. This short review focuses on its role in different levels of cognitive vision: visual processing, visual attention and working memory. Dopamine can influence cognitive vision either through direct modulation of visual cells or through gating of basal ganglia functioning. Even if its classically assigned role is to signal reward prediction error, we review evidence that dopamine is also involved in novelty detection and attention shifting and discuss the possible implications for computational modeling.