Optogenetic Strategies to Dissect the Neural Circuits That Underlie Reward and Addiction.

Optogenetic Strategies to Dissect the Neural Circuits that Underlie Reward and Addiction.

Filed under: Addiction Rehab

Cold Spring Harb Perspect Med. 2012 Oct 6;
Stamatakis AM, Stuber GD

Optogenetic strategies for perturbation of neural circuit function have begun to revolutionize systems neuroscience. Whereas optogenetics has proven to be a powerful approach for studying neural systems, the tools to conduct these experiments are still continuously evolving. Here we briefly summarize available hardware and reagents that can be used for studying behaviors related to reward and addiction. In addition, we discuss recent studies in which these strategies have been applied to study neural circuit function in brain slices as well as awake and behaving animals. Collectively, this work serves as a brief introduction to optogenetic techniques and highlights how these tools can be applied to elucidate the neural circuits that underlie reward processing and addiction.
HubMed – addiction

Abnormal Social Behavior in Nicotinic Acetylcholine Receptor Beta 4 Subunit Null Mice.

Filed under: Addiction Rehab

Nicotine Tob Res. 2012 Oct 4;
Salas R, Fung B, Sturm R, De Biasi M

INTRODUCTION: Tobacco addiction has a strong social component. Therefore, nicotinic acetylcholine receptors (nAChR) may influence social behavior. Because the ?4 nicotinic receptor subunit is important for possibly related behaviors, such as anxiety-like behavior and the effects of nicotine, we studied the social behavior of mice null for the ?4 nAChR subunit. METHODS: To measure social behavior, we used the intruder test for social memory in wild-type and littermate ?4 null mice. In addition, we used a nonsocial olfactory memory test as a control. RESULTS: In the intruder test, ?4 null mice showed social amnesia: Wild-type mice spent less time actively interacting with a younger intruder on Day 2 than on Day 1, but ?4 null mice interacted for a similar time on both days. In the nonsocial olfactory memory test, control littermates and ?4 null mice learnt the associations to a similar extent, showing that the amnesic phenotype in the intruder test is specific for social settings.Conclusions:We conclude that nAChRs that contain the ?4 subunit are important for social behaviors. As those receptors are necessary to observe several effects of nicotine including withdrawal, it is tempting to speculate that the social component of tobacco use is related to the same neuronal circuits responsible for continuing tobacco use in smokers.
HubMed – addiction

Disrupted Cortical Conductivity in Schizophrenia: TMS-EEG Study.

Filed under: Addiction Rehab

Cereb Cortex. 2012 Oct 5;
Frantseva M, Cui J, Farzan F, Chinta LV, Perez Velazquez JL, Daskalakis ZJ

Schizophrenia is conceptualized as a failure of cognitive integration, and altered oscillatory properties of neurocircuits are associated with its symptoms. We hypothesized that abnormal characteristics of neural networks may alter functional connectivity and distort propagation of activation in schizophrenic brains. Thus, electroencephalography (EEG) responses to transcranial magnetic stimulation (TMS) of motor cortex were compared between schizophrenia and healthy subjects. There was no difference in the initial response. However, TMS-induced waves of recurrent excitation spreading across the cortex were observed in schizophrenia, while in healthy subjects the activation faded away soon after stimulation. This widespread activation in schizophrenia was associated with increased oscillatory activities in the proximal central leads and in fronto-temporo-parietal leads bilaterally. A positive correlation was found between increased TMS-induced cortical activation in gamma frequency and positive symptoms of schizophrenia, while negative symptoms were correlated with activation in theta and delta bands. We suggest that excessive activation in response to stimulation in schizophrenia brains may lead to abnormal propagation of the signal that could potentially result in aberrant activity in areas remote from the activation origin. This mechanism may account for the positive symptoms of schizophrenia and could worsen signal to noise deficits, jeopardizing adequate information processing with ensuing cognitive deficits.
HubMed – addiction

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