Spring 2012 Seminar Series in Neuroscience
Location of Seminars: Muenzinger E214 (See map and directions)
|Tuesday Feb 7, 4-5 pm
Dr. Martin P. Paulus,
TITLE: “Decision-Making and Interoception”
Abstract:Why do we eat the dessert now but risk obesity and adverse health issues later? Decision-making is a complex process of assessing options, selecting actions, and evaluating outcomes. Interoception is the sensing and processing of the internal body states resulting in "how you feel" at any moment in time. The insular cortex is an important neural substrate for interoceptive processing and is among the neural substrates that have been observed in imaging studies during decision-making. Although the notion that internal states have profound effects on decision-making was raised by several investigators in the mid-90s, the experimental study of these effects has only begun recently. The fundamental link between interoception and decision-making means that what we choose depends fundamentally on our current state of the body and much less on logical reasoning. We will present brain imaging data that support this claim.
|Tuesday Feb 21, 4-5 pm||Dr. Sarah Watamura, |
TITLE: "Hypocortisolemia in Children: Calling for an Alternative to the Glucocorticoid Cascade Hypothesis"
Abstract: Large epidemiological studies clearly link early and persistent stress exposure to increased lifetime risk for psychological and physical disease. In fact, a study of over 17,000 Kaiser patients demonstrated a 20-year reduction in lifespan associated with severe early life stress. One possible mechanism through which early life stress results in health disparities is via changes in the body's own systems for managing stress resulting in over- or under-activation of these life-preserving systems. Currently, one primary theory of stress effects over time exists and is used to explain both over- and under-active stress systems, the glucocorticoid cascade hypothesis. In this hypothesis, severe stress over time is believed to impair the brain areas that provide negative feedback to the stress response systems ultimately resulting in a system that feeds forward producing increasingly high levels of steroid hormones until ultimately failing to function entirely resulting in hyporesponsiveness (a marker of disease states including post-traumatic stress disorder). This talk will present data demonstrating hypocortisolemia in young children and revisit questions about how and when a hypoactive state results, and most importantly what its consequences are and whether remediation is possible.
|Tuesday Mar 6, 4-5 pm|
Dr. Salome Kurth,
TITLE: “Sleep Electrophysiology – a Mirror of Brain Maturation?”
Abstract: The sleep electroencephalogram (EEG) is the most established method to reliably assess sleep. Slow wave activity (SWA, 1-4.5 Hz) in the scalp EEG is a well established marker of sleep depth, and the best indicator for the homeostatic regulation of sleep. On the neuronal level, surface SWA occurs concurrently with slow fluctuations in neuronal membrane potentials. These slow oscillations occur highly synchronized among populations of cortical neurons. It has been proposed that SWA fulfils a crucial role in synaptic plasticity, and recent animal and human studies point to a close relationship between synaptic potentiation during waking and SWA during sleep. In particular, it is assumed that the more a cortical network undergoes synaptic potentiation (attributable to learning processes) during wakefulness, the more SWA is expressed during subsequent sleep.
New methods provide an opportunity to acquire EEG with high spatial resolution map topographical differences of brain activity. Mapping sleep SWA in children and adolescents reveals that the topographical changes in SWA parallel morphological changes of the cortex. SWA topography may thus serve as a promising neuroimaging tool in the future. Moreover, recent findings suggest that SWA maturation even precedes the structural and functional maturation of the cortex, as measured in cortical thinning (MRI) or improvement of behavioral skills. In line with SWA interference studies in adults that investigate inhibition or boosting of SWA, this might be a hint that deep sleep SWA in humans is actively involved in cortical development that optimizes performance.
|Tuesday, Mar 20, 4-5 pm|
Dr. Klaus Miczek,
TITLE: “Neuropeptide Modulation of Accumbal Dopamine and Social Stress: Models Relevant to Drug Abuse and Depression”
Abstract: I will focus on modeling salient features of depression in female rodents with the purpose of identifying long-term neuroadaptations to complement our studies in males. When confronting a rival female who is lactating, endocrine cyclicity, preference for sweets, exploratory behavior and weight gain are disrupted in the intruder female as indices of anhedonia. The initial neurochemical characterization indicates that continuously socially stressed females show a blunted dopamine response to a cocaine challenge, whereas intermittently stressed females show a more prolonged dopamine response. Our first studies with neuropeptides indicate that socially stressed males can be protected against the sensitizing effects of intermittent stress and the escalation of cocaine self-administration can be prevented by microinjections of CRF R1 antagonists into the ventral tegmental area. We speculate that CRF R1 receptors on dopamine neurons in the ventral tegmental area are critical for the sensitizing and escalating effects of brief episodes of social stress in males and females, and we study at present how these receptor subtypes modulate inescapable social stress.
|Tuesday April 10, 4-5 pm||Dr. Boris Tabakoff, |
TITLE: “Genetical/Genomics Reveal Why Animals (and Humans) Drink Alcohol”
Abstract: The consumption of alcohol is an integral component of the behavior of approximately 70% of the American public. The levels of alcohol consumption are related to alcohol-related problems including accidents, violence, and alcohol dependence. In both non-human animals and humans, heritable factors play a role in one's predisposition to quantities of alcohol consumed on average. We used the genetical/genomics approach (Jensen, RC & Nap, IP. Trends Genetics 17:388 (2001)) combined with phenomics to identify neural systems in mouse, rat, and man that predispose high or low consumption of ethanol. Systems that drive appetitive behavior were identified and particularly the systems controlling GABA release and GABAB receptor mediated events and the systems that internalize and desensitize the GABAB receptor play a prominent role in alcohol drinking behavior.
Tuesday April 24, 4-5 pm
|Dr. Don Cooper,|
TITLE: “The Role of Transient Receptor Potential Channels in Addiction Circuitry”
Abstract: The nonselective TRPC4/5 cation channels have been shown to be present in high abundance in the corticolimbic regions of the brain and play a pictoral role in modulating cellular excitability due to their involvement in intracellular Ca2+-regulation. In this talk, the involvement of TRPC channels in maintaining persistent activity in prefrontal cortical pyramidal neurons as a cellular mechanism of working memory and attention will be discussed. Furthermore, the role of TRPC4/5 channels in mammalian behaviors, such as working memory, addiction and social behavior in rodent models will be presented. Lastly, new work will be presented showing how optogenetics can be a powerful method to control impulse activity on a millisecond time scale in specific neural circuits but may also have serious limitations for establishing the causal elements of complex behaviors.
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