<p>Emotion is known to influence multiple aspects of memory formation, which may include the initial encoding of the memory trace, its consolidation over time, and the efficacy of its retrieval. However, prior investigations have tended to treat emotional modulation of episodic memory as a unitary construct, thus conflating the contributions of these different stages to emotion-mediated memory enhancements. The present thesis aims to disentangle the component processes of emotional memory formation and retrieval through a series of studies using cognitive behavioral and functional magnetic resonance imaging (fMRI) methods. In the first 2 studies, neural activity was evaluated during the initial viewing of emotionally arousing and neutral scenes and, in the 3rd study, neural activity during this initial viewing period was compared to that during a recognition memory task. The findings are compatible with the proposal that two distinct networks support successful emotional memory formation: an amygdala-medial temporal lobe (MTL) network that modulates the consolidation of memories over time and a prefrontal-MTL network that translates emotion effects on controlled elaboration into superior memory encoding. The superlative quality of emotional memories is furthermore marked by heightened similarity between neural states at encoding and retrieval, suggesting another line of evidence through which emotion effects can be observed. Taken together, the results presented here highlight the heterogeneity of processes that confer mnemonic advantages to emotionally significant information.</p> / Dissertation

While it is known that primitive, low-level visual stimuli such as abrupt visual onsets or luminance changes can bias attentional orienting without willful intent on the part of the observer, comparatively little is known about how attention functions in rich, dynamic, meaningful contexts, such as those that comprise our everyday lives. The primary motivating hypothesis of this investigation is that, given our intrinsic needs as evolved social organisms, as well as our capability for behavioral flexibility, the attention system should be sensitive not only to low-level stimulus features, but also to complex stimuli that provide behaviorally relevant information. Three separate lines of research will be presented, each one providing a unique perspective on this issue. The first examined attentional orienting to socially relevant stimuli, finding that eye gaze serves as particularly potent cue for attentional orienting, driving the cortical orienting network more robustly than non-social stimuli, and resulting in a larger attention-related modulation of the early visual processing of stimuli appearing at attended locations. The second line of inquiry investigated patterns of eye movements while participants viewed naturalistic navigational scenes, revealing a dynamic interplay of orienting to the various behaviorally relevant aspects of the scene. The third set of studies specifically addressed whether, given the relevance of heading information for guiding navigational behavior, there is evidence that attention can be oriented automatically to the heading point in an optic flow field simulating the patterns of visual stimulation that accompany self-motion. Together, the results converge on the conclusion that attention can be oriented automatically in a dynamic, flexible, and continuous manner on the basis of complex visual stimuli that provide behaviorally relevant information.

Social cognition is a fundamental aspect of human experience that enables us to have relationships with and understanding of other people. Social relationships have been shown to mitigate cognitive decline in old age and benefit cognitive functioning, and the social interaction on which these relationships rely requires an extensive network of cognitive processes, and by extension neural systems, that have not, as of yet, been widely studied in older adults. Nor has the function of these systems been tied to social relationships in the real world. Here, I will compare self-reports of real-world quality and extent of social networks with behavioral and neural measures of other-regard in the laboratory. It is hoped that by so doing we will be able to link social neuroscientific measures in the laboratory with persons’ perceptions of the quality and extent of their social relationships. In this study, other-regard in older adults was operationalized with a reaction-time measure in an implicit turn-taking task, neural measures were provided by dense array EEG, and all participants also completed self-report measures of empathy subscales and of the quality and extent of their social networks. I found that measures of empathic personal distress decreased with increased other-regard (r = -0.36, p = 0.01, beta = 0.47), while increased quality and extent of social networks associated marginally with increased other-regard (r = 0.20, p = 0.11, beta = 0.39). Neural analyses are ongoing and are expected to show differential activation consistent with cognitive processes such as theory of mind, empathy, joint attention, and executive control.

Previous research has shown that cannabidiol (CBD), a non-psychoactive compound in the hemp plant Cannabis sativa, may be useful in treating drug craving, one of the hallmarks of drug addiction. However, the neural mechanism by which CBD attenuates craving is poorly understood. Studies from other laboratories have shown that neuroplastic changes associated with brain NMDA glutamate systems may at least partially serve as a neural mechanism for craving. In the current study, the noncompetitive NMDA receptor antagonist MK-801 maleate was used to induce locomotor sensitization, a form of NMDA glutamate-mediated neuroplasticity, in mice to test the sensitization-attenuating potential of CBD. Separate groups of mice (N=8) received either CBD (1.0 mg/kg, i.p.) or saline thirty minutes prior to an intraperitoneal injection of MK-801 (0.5 mg/kg, i.p.) or saline and tested for locomotor performance in an open field (Induction Trial). Seventy-two hours later all mice, regardless of drug pretreatment, were tested for locomotor activity following a second administration (0.5 mg/kg, i.p.) of MK-801 (Sensitization Trial). Results revealed a significant difference across groups for the Induction Trial, with groups receiving SAL-MK801 and CBD-MK801 significantly more active than SAL-SAL and CBD-SAL groups. Pretreatment with CBD had no effect on the locomotor activating effects of MK-801 during the Sensitization Trial with similar levels of locomotor performance across drug groups. Possibilities for the lack of CBD effects are discussed, as well as implications and future research directions.

Stereotype groups are interrelated. For example, in Australia, New Zealand, and the United States, racial minorities are referred to special education at a much higher rate than are majority racial groups (Tse, Lloyd, Petchkovsky, and Manaia, 2005; Harry, Arnaiz, Klingner, Sturges, 2008). The Stereotype Content Model describes stereotype relationships in terms of an interaction between competence and warmth. Warmth is the more consistent dimension. The nature of competence remains elusive (Fiske, Cuddy, and Glick, 2007; Fiske, Cuddy, Glick, and Xu, 2002). Knowledge of relationships between stereotype groups, which themselves may be effects of bias, could factor into observed competence effects. Disabilities are characterized by objective competence deficits. Disabilities stereotype research allow for more refined models of competence. While competence perception may vary between disabilities, with different domains of competence deficits, unifying disability schemas may also exist. In either case, different competence processes could be inferred. We compared ratings on the Fiske scale (FC, FW), a multimodal competence scale (MMC), a quality of life scale (QL-T), and an overt threat scale (OPT) for five disability groups (DS) and a set of established stereotype (ES) groups. Our MMC analysis indicates the competence dimension and stereotype group interaction was more significant for DS and ES together than for DS alone. This is surprising, because the multimodal competence scale was designed to target specific disability groups. Results indicate there may be some unifying disability schema. Marginally significant differences between disability groups on the QL-T indicate complex relationships between disabilities stereotypes may also exist.

There is extensive evidence that structures in the anterior attentional system (i.e. dorsolateral prefrontal cortex and anterior cingulate) are susceptible to normal aging processes, whereas structural changes in the posterior attentional system are minimal. Using the Stroop priming task, we investigated whether reducing the involvement of the anterior attentional system by pre-cuing the location of the target stimulus would eliminate age differences in interference. Older adults continued to be susceptible to interference when the location cue was ambiguous or invalid, but were less susceptible when the target location of a stimulus was presented with a valid cue.

Objective: A neuroscientific picture-word task was used to investigate semantic and phonological activation spreading in adults who stutter (AWS). Method: Fourteen AWS and 14 adults who do not stutter (AWNS) participated. On each trial, a picture was named at a delay. Sometimes, an attended probe word was heard before naming. Some probes were Semantically-Related to the labels. Those same probes also appeared following pictures with Unrelated labels. N400 ERPs recorded to these two probe types were compared (Semantically-Related versus Unrelated). Other probes were Phonologically-Related to the labels. Those same probes also appeared following pictures with unrelated labels (P-Unrelated). N400 ERPs recorded to these two probe types were compared (Phonologically-Related versus P-Unrelated). Results: AWNS exhibited typical N400 priming effects. AWS exhibited non-robust Semantic N400 priming, and a reverse Phonological N400 priming effect. Conclusions: Results suggest that AWS use attentional control strategies to influence the activation of words in the mental lexicon.

While it is known that primitive, low-level visual stimuli such as abrupt visual onsets or luminance changes can bias attentional orienting without willful intent on the part of the observer, comparatively little is known about how attention functions in rich, dynamic, meaningful contexts, such as those that comprise our everyday lives. The primary motivating hypothesis of this investigation is that, given our intrinsic needs as evolved social organisms, as well as our capability for behavioral flexibility, the attention system should be sensitive not only to low-level stimulus features, but also to complex stimuli that provide behaviorally relevant information. Three separate lines of research will be presented, each one providing a unique perspective on this issue. The first examined attentional orienting to socially relevant stimuli, finding that eye gaze serves as particularly potent cue for attentional orienting, driving the cortical orienting network more robustly than non-social stimuli, and resulting in a larger attention-related modulation of the early visual processing of stimuli appearing at attended locations. The second line of inquiry investigated patterns of eye movements while participants viewed naturalistic navigational scenes, revealing a dynamic interplay of orienting to the various behaviorally relevant aspects of the scene. The third set of studies specifically addressed whether, given the relevance of heading information for guiding navigational behavior, there is evidence that attention can be oriented automatically to the heading point in an optic flow field simulating the patterns of visual stimulation that accompany self-motion. Together, the results converge on the conclusion that attention can be oriented automatically in a dynamic, flexible, and continuous manner on the basis of complex visual stimuli that provide behaviorally relevant information.

The three components model of empathy proposed by Decety and Jackson (2004) is currently the dominant model of empathy. The three components include: 1) the affective component (Simulation Theory), 2) emotional perspective taking, and 3) emotion regulation (self/other distinction). The purpose of the current study was to examine whether empathic perspective taking is dependent on context and to provide a behavioral basis for a follow-up fMRI study. More specifically, we wanted to know how body contexts (e.g. mood) and situational contexts (e.g. perceived fairness of a partner) affect emotional perspective taking. To examine the interaction between mood and perceived fairness of a partner, a 2 (mood group: neutral vs. negative) × 2 (fairness condition: unfair partner vs. fair partner) between-groups experimental design was employed. Mood induction videos were employed for the mood manipulation and participants played either a fair or unfair preprogrammed partner in a modified ultimatum game. After both manipulations, three measures were used to assess perspective taking and several post-game behavioral measures were also employed. Results were obtained from 73 participants (age: 18-22; female = 46, ~18 in each condition). The results demonstrated that participants in the negative mood had more difficulty empathizing with unfair partners and had a greater desire for revenge against them than participants in a neutral mood in the same unfair situations. Therefore, human empathy is not constant, but varies depending on a variety of contexts. We can now use this paradigm for a future fMRI study to investigate the neural substrates underlying this context dependency with a particular emphasis on the frontopolar cortex and the nucleus accumbens.

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