Dorsal-CA1 hippocampal neuronal ensembles encode nicotine-reward contextual associations

Natural and drug rewards increase the motivational valence of stimuli in the environment that, through Pavlovian learning mechanisms, become conditioned stimuli that directly motivate behavior in the absence of the original unconditioned stimulus. While the hippocampus has received extensive attention for its role in learning and memory processes, less is known regarding its role in drug-reward associations. We used in vivo Ca2+ imaging in freely moving mice during the formation of nicotine preference behavior to examine the role of the dorsal-CA1 region of the hippocampus in encoding contextual reward-seeking behavior. We show the development of specific neuronal ensembles whose activity encodes nicotine-reward contextual memories and that are necessary for the expression of place preference. Our findings increase our understanding of CA1 hippocampal function in general and as it relates to reward processing by identifying a critical role for CA1 neuronal ensembles in nicotine place preference

RXTE Spectral Observations of the 1996-97 Outburst of the Microquasar GRO J1655-40

Excellent coverage of the entire 16-month 1996-97 outburst cycle of GRO J1655-40 was provided by RXTE. We present a full spectral analysis of these data, which includes 52 PCA spectra from 2.5-20 keV and HEXTE spectra above 20 keV. We also include a nearly continuous ASM light curve with several intensity measurements per day. The data are interpreted in the context of the multicolor blackbody disk/power-law model. The source is observed in the very high, high/soft, and low/hard outburst states. During the very high state, the source exhibits intense hard flares on time scales of hours to days which are correlated with changes in both the fitted temperature and radius of the inner accretion disk. During the high/soft state, the spectrum is dominated by the soft thermal emission from the accretion disk with spectral parameters that suggest approximately constant inner disk radius and temperature. We find that a tight relationship exists between the observed inner radius of the disk and the flux in the power-law component. During intense hard flares, the inner disk radius is observed to decrease by as much as a factor of three on a time scale of days. The apparent decrease of the inner disk radius observed during the flares may be due to the failure of the multicolor disk model caused by a steepening of the radial temperature profile in the disk coupled with increased spectral hardening and not physical changes of the inner disk radius. Assuming that our spectral model is valid during periods of weak power-law emission, our most likely value for the inner disk radius implies a* < 0.7. Such a low value for the black hole angular momentum is inconsistent with the relativistic frame dragging and the `diskoseismic' models as interpretations for the 300 Hz X-ray QPO seen during some of these RXTE observations.Comment: 34 pages including 9 figures and 3 tables. Accepted for publication in the Astrophysical Journal. Our interpretation of the data and the main conclusions have been significantly revise

Stress-induced reinstatement of nicotine preference requires dynorphin/kappa opioid activity in the basolateral amygdala

UNLABELLED: The dynorphin (DYN)/kappa-opioid receptor (KOR) system plays a conserved role in stress-induced reinstatement of drug seeking for prototypical substances of abuse. Due to nicotine\u27s high propensity for stress-induced relapse, we hypothesized that stress would induce reinstatement of nicotine seeking-like behavior in a KOR-dependent manner. Using a conditioned place preference (CPP) reinstatement procedure in mice, we show that both foot-shock stress and the pharmacological stressor yohimbine (2 mg/kg, i.p.) induce reinstatement of nicotine CPP in a norbinaltorphimine (norBNI, a KOR antagonist)-sensitive manner, indicating that KOR activity is necessary for stress-induced nicotine CPP reinstatement. After reinstatement testing, we visualized robust c-fos expression in the basolateral amygdala (BLA), which was reduced in mice pretreated with norBNI. We then used several distinct but complementary approaches of locally disrupting BLA KOR activity to assess the role of KORs and KOR-coupled intracellular signaling cascades on reinstatement of nicotine CPP. norBNI injected locally into the BLA prevented yohimbine-induced nicotine CPP reinstatement without affecting CPP acquisition. Similarly, selective deletion of BLA KORs in KOR conditional knock-out mice prevented foot-shock-induced CPP reinstatement. Together, these findings strongly implicate BLA KORs in stress-induced nicotine seeking-like behavior. In addition, we found that chemogenetic activation of Gαi signaling within CaMKIIα BLA neurons was sufficient to induce nicotine CPP reinstatement, identifying an anatomically specific intracellular mechanism by which stress leads to reinstatement. Considered together, our findings suggest that activation of the DYN/KOR system and Gαi signaling within the BLA is both necessary and sufficient to produce reinstatement of nicotine preference. SIGNIFICANCE STATEMENT: Considering the major impact of nicotine use on human health, understanding the mechanisms by which stress triggers reinstatement of drug-seeking behaviors is particularly pertinent to nicotine. The dynorphin (DYN)/kappa-opioid receptor (KOR) system has been implicated in stress-induced reinstatement of drug seeking for other commonly abused drugs. However, the specific role, brain region, and mechanisms that this system plays in reinstatement of nicotine seeking has not been characterized. Here, we report region-specific engagement of the DYN/KOR system and subsequent activation of inhibitory (Gi-linked) intracellular signaling pathways within the basolateral amygdala during stress-induced reinstatement of nicotine preference. We show that the DYN/KOR system is necessary to produce this behavioral state. This work may provide novel insight for the development of therapeutic approaches to prevent stress-related nicotine relapse

Educational studies of cosmic rays with telescope of Geiger-Muller counters

A group of high school students (XII Liceum) in the framework of the Roland Maze Project has built a compact telescope of three Geiger-Muller counters. The connection between the telescope and PC computer was also created and programed by students involved in the Project. This has allowed students to use their equipment to perform serious scientific measurements concerning the single cosmic ray muon flux at ground level and below. These measurements were then analyzed with the programs based on the 'nowadays' knowledge on statistics. An overview of the apparatus, methods and results were presented at several students conferences and recently won the first prize in a national competition of high school students scientific work. The telescope itself, in spite of its 'scientific' purposes, is built in such a way that it is hung on a wall in a school physics lab and counts muons continuously. This can help to raise the interest for studying physics among others. At present a few (3) groups of young participants of the Roland Maze Project have already built their own telescopes for their schools and some others are working on it. This work is a perfect example of what can be done by young people when respective opportunities are created by more experienced researchers and a little help and advice is given.Comment: 5 figures, 10 page

CHARACTERISTIC OF BODY POSTURE OF THE PARTICIPANTS OF THE EUROPEAN JUNIOR VOLLEYBALL CHAMPIONSHIPS.

The lecture presents methods and results of study of volleyball players posture, age17-18 of different nationalities. The results show change curves in spine and biomechanical parameters under loading influence

Coagulatory defects in type-1 and type-2 diabetes

This research was funded by British Heart Foundation, grant numbers PG/15/9/31270 and FS/15/42/31556.Diabetes (both type-1 and type-2) affects millions of individuals worldwide. A major cause of death for individuals with diabetes is cardiovascular diseases, in part since both types of diabetes lead to physiological changes that affect haemostasis. Those changes include altered concentrations of coagulatory proteins, hyper-activation of platelets, changes in metal ion homeostasis, alterations in lipid metabolism (leading to lipotoxicity in the heart and atherosclerosis), the presence of pro-coagulatory microparticles and endothelial dysfunction. In this review, we explore the different mechanisms by which diabetes leads to an increased risk of developing coagulatory disorders and how this differs between type-1 and type-2 diabetes.Publisher PDFPeer reviewe

Spectral Fits to the 1999 Aql X-1 Outburst Data

We present analysis and spectral fits of the RXTE data from the May/June 1999 outburst of Aql X-1. These data include observations in the rising portion of the hard state, in the soft state, and in the falling portion of the hard state. We show that the data can be fit by a purely thermal Comptonization model for all the observations, but that more complicated models cannot be ruled out. Up to 60% of the corona's power in the soft state may be injected into non-thermal electrons. The soft state data show approximately constant optical depth and coronal temperatures over a range of $\sim10$ in luminosity, while they show evidence for a reduction of seed photon temperature with reduced luminosity and indicate that the characteristic size of the seed photon emitting region is roughly constant throughout the soft state. The hard state before the soft state shows a higher luminosity, higher optical depth, and lower electron temperature than the hard state after the soft state. We find a reduction of the hard (30-60 keV) X-ray flux during a type I burst and show that it requires a total corona energy reservoir of less than $\sim 10^{38}$ ergs.Comment: 10 pages, 7 figues, accepted to A+