No description available.

No description available.

abstract: Three experiments used a spatial serial conditioning paradigm to assess the effectiveness of spatially informative conditioned stimuli in eliciting tracking behavior in pigeons. The experimental paradigm consisted of the simultaneous presentation of 2 key lights (CS2 and CTRL), followed by another key light (CS1), followed by food (the unconditioned stimulus or US). CS2 and CTRL were presented in 2 of 3 possible locations, randomly assigned; CS1 was always presented in the same location as CS2. CS2 was designed to signal the spatial, but not the temporal locus of CS1; CS1 signaled the temporal locus of the US. In Experiment 1, differential pecking on CS2 was observed even when CS2 was present throughout the interval between CS1s, but only in a minority of pigeons. A control condition verified that pecking on CS2 was not due to temporal proximity between CS2 and US. Experiment 2 demonstrated the reversibility of spatial conditioning between CS2 and CTRL. Asymptotic performance never involved tracking CTRL more than CS2 for any of 16 pigeons. It is inferred that pigeons learned the spatial association between CS2 and CS1, and that temporal contingency facilitated its expression as tracking behavior. In a third experiment, with pigeons responding to a touchscreen monitor, differential responding to CS2 was observed only when CS2 disambiguated the location of a random CS1. When the presentation location of CS1 was held constant, no differences in responding to CS2 or CTRL were observed. / Dissertation/Thesis / M.A. Psychology 2011

<p> This thesis is concerned with control procedures employed in Pavlovian conditioning, in particular, the "truly random" control. Pilot work indicated that this procedure employed in a CER paradigm resulted in response suppression. Our first objective then was to examine this finding in a more formal experiment, as well as attempting to determine the cause of the observed suppression. In a second experiment, a variable predicted to affect the amount of conditioning within traditional conditioning theory was employed to determine the possible role of this variable in suppression produced by the random control procedure.</p> <p> It was found, in the first experiment, that two variations of the random procedure resulted in suppression in testing. The results of a third group indicated that the suppression was not due to a between-session discriminative function of the CS. A fourth group demonstrated, within contingency logic, inhibitory control, but this group, like the others, showed suppression.</p> <p> In the second experiment, variations of stimulus conditions, none of which made the US contingent on the CS, resulted in marked differences in suppression in testing. Further, significantly different recovery rates of the operant baseline were noted both as a function of the recovery condition and of the CS employed in training.</p> / Thesis / Master of Arts (MA)

No description available.

Memory plays an important role in defining how one behaves. The neurobiological mechanisms of memory have been studied extensively in animal models and the NMDA glutamate receptor has been identified to play an important role in the consolidation and reconsolidation of appetitive memories. Certain memories, depending on what was learned, can function differently and can be more difficult to disrupt based on a number of factors. Currently, no study has examined whether or not a reward-predictive stimulus attributed with incentive value is more difficult to disrupt than a stimulus that functions as a general reward-predictor. To determine the role of the NMDA receptor on memory consolidation with different functioning reward-predictive stimuli rats underwent a Pavlovian conditioned approach, where a post-session NMDA receptor antagonist was administered daily. Furthermore, to determine the role of the NMDA receptor on memory reconsolidation, another set of rats were trained on a Pavlovian conditioned approach task, after training was complete rats were presented with a reward-predictive stimuli followed by an administration of a NMDA receptor antagonist and then re-tested.

Thesis advisor: Gorica D. Petrovich / Thesis advisor: Christina Reppucci / We are interested in exploring the instances in which environmental controls can override physiologic or homeostatic cues, and additionally the areas of the brain that might be implicated in such behavioral effects. For this study, we replicated a previously established behavioral finding in which male and female rats show fear-cue induced inhibition of eating, and that female rats take longer than male rats to extinguish this behavior. We assessed brain activation via Fos-expression in the NTS and DMX in the brainstem and found that males had higher brainstem activation than females during extinction of fear-cue induced inhibition of eating. Additionally, female experimental rats had suppressed activity in the caudal NTS compared to female control rats. The data from this study support our hypotheses that there are distinct activation patterns in the brainstem during the extinguishing of inhibition of eating, and that there are sex differences in these activation patterns. / Thesis (BS) — Boston College, 2013. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Psychology Honors Program. / Discipline: Psychology.

Thesis advisor: Gorica Petrovich / Thesis advisor: Christina Reppucci / In order to understand the neurobiological basis for the phenomenon in which environmental cues override physiological cues to influence the behavioral control of feeding, we utilized an animal model for fear-cue induced inhibition of eating. Female rats that had learned to associate a tone with foot-shocks showed inhibition of eating across three extinction tests, whereas male rats that had received tone-shock pairings extinguished their inhibition of eating after the first test day. We assessed activation of orexin (ORX), a neuropeptide involved in eating and arousal, in the lateral hypothalamic area (LHA) of the brains of male and female control and experimental rats during the final test day. Female rats exhibited greater recruitment of ORX neurons in the LHA than male rats; there was no difference in ORX activation between control and experimental groups of either sex, indicating that ORX is involved in sex differences in fear-cue induced inhibition of eating. / Thesis (BS) — Boston College, 2013. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Psychology.

The experiments reported in this thesis studied the mechanisms of expression of overexpectation of conditioned fear, as measured by freezing. In Stage I, rats were conditioned to fear a tone and a flashing light conditioned stimulus (CS) through pairings with a 0.5 mA, 1 s shock. In Stage II, overexpectation was trained by the reinforcement of a compound of these CSs with a shock of the same magnitude. Two compound ?? shock pairings produced an overexpectation effect, as measured by freezing to presentations of the tone alone, while further Stage II training caused over-training of overexpectation. Expression of the overexpectation effect produced by two compound ?? shock pairings could be prevented by pre-test injection of the benzodiazepine partial inverse agonist FG7142. This effect was dose-dependent and not due to state-dependent memory. Control experiments suggested that it was also not due to any general effect of FG7142 on the Pavlovian freezing response. Freezing to a tone that had been conditioned, but not subjected to any decremental training procedures, was unaffected by administration of FG7142 before either the conditioning or test session. FG7142 also did not affect freezing to a tone that had been subjected to an associative blocking procedure. The hypothesis that overexpectation of conditioned fear may be context-dependent was also tested. However, renewal was not observed. Rats that received Stage II training in a context distinct from the Stage I training context showed equivalent expression of overexpectation regardless of whether testing was conducted in the Stage I or Stage II training context. These results are consistent with the hypothesis that overexpectation, like extinction, leads to the imposition of a GABAA receptor-mediated mask on the fear CR. Moreover, they suggest that this masking of fear is the specific consequence of negative predictive error.

The experiments reported in this thesis studied the mechanisms of expression of overexpectation of conditioned fear, as measured by freezing. In Stage I, rats were conditioned to fear a tone and a flashing light conditioned stimulus (CS) through pairings with a 0.5 mA, 1 s shock. In Stage II, overexpectation was trained by the reinforcement of a compound of these CSs with a shock of the same magnitude. Two compound ?? shock pairings produced an overexpectation effect, as measured by freezing to presentations of the tone alone, while further Stage II training caused over-training of overexpectation. Expression of the overexpectation effect produced by two compound ?? shock pairings could be prevented by pre-test injection of the benzodiazepine partial inverse agonist FG7142. This effect was dose-dependent and not due to state-dependent memory. Control experiments suggested that it was also not due to any general effect of FG7142 on the Pavlovian freezing response. Freezing to a tone that had been conditioned, but not subjected to any decremental training procedures, was unaffected by administration of FG7142 before either the conditioning or test session. FG7142 also did not affect freezing to a tone that had been subjected to an associative blocking procedure. The hypothesis that overexpectation of conditioned fear may be context-dependent was also tested. However, renewal was not observed. Rats that received Stage II training in a context distinct from the Stage I training context showed equivalent expression of overexpectation regardless of whether testing was conducted in the Stage I or Stage II training context. These results are consistent with the hypothesis that overexpectation, like extinction, leads to the imposition of a GABAA receptor-mediated mask on the fear CR. Moreover, they suggest that this masking of fear is the specific consequence of negative predictive error.