The induction of behavioural sensitization is associated with cocaine-induced structural plasticity in the core (but not shell) of the nucleus accumbens

Repeated exposure to cocaine increases the density of dendritic spines on medium spiny neurons in the nucleus accumbens (Acb) and pyramidal cells in the medial prefrontal cortex (mPFC). To determine if this is associated with the development of psychomotor sensitization, rats were given daily i.p. injections of 15 mg/kg of cocaine (or saline) for 8 days, either in their home cage (which failed to induce significant psychomotor sensitization) or in a distinct and relatively novel test cage (which induced robust psychomotor sensitization). Their brains were obtained 2 weeks after the last injection and processed for Golgi–Cox staining. In the Acb core (AcbC) cocaine treatment increased spine density only in the group that developed psychomotor sensitization (i.e. in the Novel but not Home group), and there was a significant positive correlation between the degree of psychomotor sensitization and spine density. In the Acb shell (AcbS) cocaine increased spine density to the same extent in both groups; i.e. independent of psychomotor sensitization. In the mPFC cocaine increased spine density in both groups, but to a significantly greater extent in the Novel group. Furthermore, when rats were treated at Home with a higher dose of cocaine (30 mg/kg), cocaine now induced psychomotor sensitization in this context, and also increased spine density in the AcbC. Thus, the context in which cocaine is experienced influences its ability to reorganize patterns of synaptic connectivity in the Acb and mPFC, and the induction of psychomotor sensitization is associated with structural plasticity in the AcbC and mPFC, but not the AcbS.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73532/1/j.1460-9568.2004.03612.x.pd

Expression of amphetamine sensitization is associated with recruitment of a reactive neuronal population in the nucleus accumbens core

Rationale: Repeated exposure to psychostimulant drugs causes a long-lasting increase in the psychomotor and reinforcing effects of these drugs and an array of neuroadaptations. One such alteration is a hypersensitivity of striatal activity such that a low dose of amphetamine in sensitized animals produces dorsal striatal activation patterns similar to acute treatment with a high dose of amphetamine. Objectives: To extend previous findings of striatal hypersensitivity with behavioral observations and with cellular activity in the nucleus accumbens and prefrontal cortex in sensitized animals. Materials and methods: Rats treated acutely with 0, 1, 2.5, or 5 mg/kg i.p. amphetamine and sensitized rats challenged with 1 mg/kg i.p. amphetamine were scored for stereotypy, rearing, and grooming, and locomotor activity recorded. c-fos positive nuclei were quantified in the nucleus accumbens and prefrontal cortex after expression of sensitization with 1 mg/kg i.p. amphetamine. Results: Intense stereotypy was seen in animals treated acutely with 5 mg/kg amphetamine, but not in the sensitized group treated with 1 mg/kg amphetamine. The c-fos response to amphetamine in the accumbens core was augmented in amphetamine-pretreated animals with a shift in the distribution of optical density, while no effect of sensitization was seen in the nucleus accumbens shell or prefrontal cortex. Conclusions A lack of stereotypy in the sensitized group indicates a dissociation of behavioral responses to amphetamine and striatal immediate-early gene activation patterns. The increase in c-fos positive nuclei and shift in the distribution of optical density observed in the nucleus accumbens core suggests recruitment of a new population of neurons during expression of sensitization

Individual Variations in Maternal Care Early in Life Correlate with Later Life Decision-Making and c-Fos Expression in Prefrontal Subregions of Rats

Early life adversity affects hypothalamus-pituitary-adrenal axis activity, alters cognitive functioning and in humans is thought to increase the vulnerability to psychopathology–e.g. depression, anxiety and schizophrenia- later in life. Here we investigated whether subtle natural variations among individual rat pups in the amount of maternal care received, i.e. differences in the amount of licking and grooming (LG), correlate with anxiety and prefrontal cortex-dependent behavior in young adulthood. Therefore, we examined the correlation between LG received during the first postnatal week and later behavior in the elevated plus maze and in decision-making processes using a rodent version of the Iowa Gambling Task (rIGT). In our cohort of male and female animals a high degree of LG correlated with less anxiety in the elevated plus maze and more advantageous choices during the last 10 trials of the rIGT. In tissue collected 2 hrs after completion of the task, the correlation between LG and c-fos expression (a marker of neuronal activity) was established in structures important for IGT performance. Negative correlations existed between rIGT performance and c-fos expression in the lateral orbitofrontal cortex, prelimbic cortex, infralimbic cortex and insular cortex. The insular cortex correlations between c-fos expression and decision-making performance depended on LG background; this was also true for the lateral orbitofrontal cortex in female rats. Dendritic complexity of insular or infralimbic pyramidal neurons did not or weakly correlate with LG background. We conclude that natural variations in maternal care received by pups may significantly contribute to later-life decision-making and activity of underlying brain structures

Vision and force controlled robot weld bead grinding system

Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1988Bibliography: leaves 117-118.by Alan Benjamin Todtenkopf.M.S.M.S. Massachusetts Institute of Technology, Department of Mechanical Engineerin

A family history /

Typescript containing the family history of the Todtenkopf family from Gross Konarzyn in Pomerania. Also included is a family tree reaching back to the mid-19th century.Bela Schoenfeld, 1996Harry Todtenkopf was born 1907 in Gross Konarzyn. He emigrated to Shanghai and later to the U.S. He died 1985 in New York.Caspari ; Neumanndigitize

A Commentary on the Efficacy of Olanzapine for the Treatment of Schizophrenia: The Past, Present, and Future

Olanzapine is a second-generation atypical antipsychotic with proven efficacy for the treatment of schizophrenia. Approved in 1996, olanzapine is one of the most studied antipsychotics, resulting in a considerable amount of clinical data across diverse patient populations. Despite the fact that olanzapine is associated with a known risk of metabolic side effects, including weight gain, many clinicians continue to prescribe olanzapine for the treatment of schizophrenia with the expectation of additional therapeutic antipsychotic efficacy relative to other first-line atypical antipsychotics. The goal of this narrative is to revisit the role of oral olanzapine in the management of patients with schizophrenia, including those with recently diagnosed schizophrenia ( first-episode ), those with an established schizophrenia diagnosis who experience acute exacerbations, those receiving long-term antipsychotic treatment as a maintenance intervention, and those with suboptimal response to antipsychotic treatment, including treatment resistance. Collectively, data from published literature support the favorable efficacy of olanzapine compared with other first- and second-generation antipsychotics, including lower rates of treatment discontinuation and clinically meaningful improvements in the symptoms of schizophrenia. The development of antipsychotic medications with the favorable efficacy of olanzapine, but with reduced weight gain, could address a major unmet need in the treatment of schizophrenia