Are 'hot spots' hot spots?

The term ‘hot spot’ emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the implication that volcanism (a) is emplaced by a single, spatially restricted, mongenetic melt-delivery system, assumed to be a mantle plume, and (b) that the source is unusually hot. This model has tended to be assumed a priori to be correct. Nevertheless, there are many geological ways of testing it, and a great deal of work has recently been done to do so. Two fundamental problems challenge this work. First is the difficulty of deciding a ‘normal’ mantle temperature against which to compare estimates. This is usually taken to be the source temperature of mid-ocean ridge basalts (MORBs). However, Earth's surface conduction layer is ∼200 km thick, and such a norm is not appropriate if the lavas under investigation formed deeper than the 40–50 km source depth of MORB. Second, methods for estimating temperature suffer from ambiguity of interpretation with composition and partial melt, controversy regarding how they should be applied, lack of repeatability between studies using the same data, and insufficient precision to detect the 200–300 °C temperature variations postulated. Available methods include multiple seismological and petrological approaches, modelling bathymetry and topography, and measuring heat flow. Investigations have been carried out in many areas postulated to represent either (hot) plume heads or (hotter) tails. These include sections of the mid-ocean spreading ridge postulated to include ridge-centred plumes, the North Atlantic Igneous Province, Iceland, Hawaii, oceanic plateaus, and high-standing continental areas such as the Hoggar swell. Most volcanic regions that may reasonably be considered anomalous in the simple plate-tectonic paradigm have been built by volcanism distributed throughout hundreds, even thousand of kilometres, and as yet no unequivocal evidence has been produced that any of them have high temperature anomalies compared with average mantle temperature for the same (usually unknown) depth elsewhere. Critical investigation of the genesis processes of ‘anomalous’ volcanic regions would be encouraged if use of the term ‘hot spot’ were discontinued in favour of one that does not assume a postulated origin, but is a description of unequivocal, observed characteristics

Developing Baseline Performance in an Animal Model of Learning and Memory

Color poster with text and graphs.This study looked at the chemical and neural mechanisms that underlie learning and memory. A repeated acquisition task was used to develop an animal model of learning and memory.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs

Does Delay Length or Sequence Exposure Affect Repeated Acquisition Performance?

Color poster with text and graphs.Repeated acquisition of response chains is a systematic method used to study learning and memory. Subjects complete sequences of responses in order to earn reinforcers. Subjects must learn the correct sequence of responses for the session through trial-and-error. As the subject completes more correct sequences over session time, the number of errors should be reduced throughout the session. This within-session error reduction is defined as learning. The purpose of this study was to examine learning and memory by establishing baseline error rates for subjects and response sequences.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs

Effects of Duloxetine in Rats Trained to Discriminate Between 2- and 22- hr Food Deprivation

Color poster with text and graphs.Duloxetine inhibits serotonin and norepinephrine transporters, and is clinically used to treat depression, pain, and generalized anxiety disorder. Duloxetine has been shown to reduce food intake in several species. The purpose of this study was to examine the effects of duloxetine in non-restricted rats trained to discriminate between 22- and 2-hour food deprivation to gain better understanding of neurochemicals mediating the discriminative stimulus effects of 22-hour food deprivation.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs

Effects of Duloxetine in Rats Trained to Discriminate Between 2 and 22 hr Food Deprivation

Color poster with text, graphs, and tables.Duloxetine inhibits serotonin and norepinephrine transporters, and is clinically used to treat depression, pain, and generalized anxiety disorder. Duloxetine has been shown to reduce food intake in several species. The purpose of this study was to examine the effects of duloxetine in non-restricted rats trained to discriminate between 22- and 2-hour food deprivation to gain better understanding of neurochemicals mediating the discriminative stimulus e ects of 22-hour food deprivation.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs

Effects of Chlorpromazine in Rats Trained to Discriminate Between 2 and 22 Hr Food Deprivation

Color poster with text, graphs, and tables.Chlorpromazine, a typical antipsychotic, has been shown to have varying effects on food intake. Chlorpromazine is a dopamine antagonist that blocks several dopamine receptors (including D1 and D2). Previous research indicated chlorpromazine (5.0mg/kg) may affect food intake in two time phases. This study looked at the effects of chlorpromazine in a food-deprivation discrimination paradigm that may serve as an animal model of 'hunger'.University of Wisconsin--Eau Claire Office of Research and Sponsored Programs