One of the goals of neuroscience is to classify all of the neurons in the brain. Neuronal types can be defined using a combination of morphology, electrophysiology, and gene expression profiles. Gene expression profiles allow differentiation between cells that share similar characteristics. Leveraging the advantage of Berghia stephanieae (Gastropoda; Nudibranchia), which has around 28,000 neurons, I constructed high-throughput single-neuron transcriptomes for its whole brain. I produced a single-cell dissociation protocol and a custom data analysis pipeline for data of this nature. Around 129,000 cells were collected from 18 rhinophore ganglia and 20 circumesophageal ring ganglia (brain), consisting of the cerebropleural, pedal, and buccal ganglia. Messenger RNA libraries were constructed using the 10X Genomics’ Chromium platform. After library preparation, around 1,000 cells were recovered and sequenced. The HTStream package was utilized to trim off unwanted sequences from the raw reads and remove PCR duplicates and other contamination, then the salmon alevin package was employed to construct gene-by-cell matrices containing all the transcripts for each gene in each cell. The Seurat pipeline was used to extract this expression data from the matrices, normalize it, and perform dimensionality reduction. The cells were clustered based on similarities in their gene expression profiles. The cells formed eight clusters on a UMAP graph, each having distinct marker genes. Additionally, one cluster was composed of almost exclusively cells from the rhinophore ganglia, accounting for 30% of all rhinophore ganglion cells in the sample. Cells from the rhinophore ganglia are as heteregenous as cells from the rest of the brain, with cells forming six clusters. Cell populations that express the same neurotransmitter were identified for a wide range of both small-molecule neurotransmitters and neuropeptides. In a separate project, the locomotion of Berghia was recorded over 9 days with 2 lighting regimes: LD first and DD first. The results suggest that locomotion of Berghia is governed by circadian clock and that Berghia is nocturnal. Hunger state likely plays a role in modulating this circadian rhythm.

Economic pressure and concomitant financial stress have been associated with mental and physical health problems, conflict, and poorer education and employment outcomes. Moreover, financial stress can be seen in specific hardships (e.g., food insecurity) and lead to maladaptive attempts to regulate emotions stemming from financial stressors. Women may be more vulnerable to consequences of food insecurity and attempts to regulate emotions with eating than men. Thus, the current study examined the impact of a randomized financial stress induction on affect and snack food choice while accounting for the influence of food insecurity and gender. Participants included 269 validly responding individuals. Participants completed a measure of implicit affect prior to as well as following random assignment to one of three possible financial stress inductions with varying levels of stress. Participants then predicted the food items they would eat and their overall desired for a specific food from an array of unhealthy snack foods items. Food insecurity was associated with higher stress response to the stress induction, which was experimentally shown to increase negative affect. Positive affect after the stress induction associated with increased desire for snacks among females but not their male counterparts. Additionally, female participants with difficulties with emotion regulation reported higher desire for snacks as compared to their male peers. Future research should include examination of emotion regulation, food insecurity, and gender differences.

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The 2 goals of the present investigation were to 1) examine the reliability of the Children’s Behavior Questionnaire: Short Form (CBQ) in a sample of 4-7 year-old children from the Ukraine and 2) compare those children’s temperament profiles to a) one another when the form was administered in 2 different languages and b) their American counterparts from the CBQ standardization sample. Three waves of data were collected from the parents of 167 children residing in Kiev, Ukraine. Internal reliability analyses showed good internal consistency of the instrument. Comparative analyses conducted both within and between cultures showed similarities and differences across the 15 CBQ dimensions. The observed differences were in the predicted directions: Ukrainian children were rated higher than American children on dimensions reflecting negative affectivity. However, the language of the instrument was a mitigating factor. This finding supports the possibility that parental ethnotheories are embedded in specific languages.

Casual sex is common on college campuses and is potentially relevant to a person's self-esteem. Unfortunately, data are mixed regarding how self-esteem is influenced by casual sex. This thesis is an attempt to understand how casual sex influences women's self-esteem through a series of questionnaires. Three hypotheses were of interest. The first predicted that sociosexuality and desire would explain casual sex engagement. Second, that casual sex behaviors and attitudes would predict self-esteem. Third, looking only at those who engaged in casual sex; casual sex attitudes and affect would predict self-esteem. Using hierarchical regression, results indicated that there was a curvilinear effect for sociosexuality on number of casual sex partners. Results for the second hypothesis showed an interaction between behavior and attitudes to predict selfesteem. Finally, for hypothesis three, results showed a moderation effect for attitudes on negative affect regarding overall casual sex experience and self-esteem.

Cannabis is widely consumed by humans for pharmacological effects that are mediated by THC, though there is little evidence that THC is a primary reinforcer in non-human animal models. We hypothesized that THC may have potent reinforcement enhancing effects, comparable to other drugs (e.g., nicotine and caffeine) which are also widely consumed by humans, but difficult to establish as primary reinforcers in non-humans. In three experiments with male and female rats saccharin (SACC) or a visual stimulus (VS) served as reinforcers for operant behavior. We explored several pharmacological parameters of THC on responding for SACC or VS, including THC dose, intervals between THC injections and testing, and intervals between test sessions. THC acts as a reinforcement enhancer for both SACC and a VS across a range of doses and intervals. Daily THC injections systematically reduced behavior, possibly due to accumulation of THC bioavailability.

In this dissertation, the relationship between flow state, serious games, and learning was examined. Serious games, which are games that convey something other than enjoyment (e.g., learning), are increasingly popular platforms for research, training, and advertisement. The elements that make serious games useful to researchers, trainers, and practitioners are closely linked to those that make up the positive psychology construct of flow state. Flow state describes an optimum experience that is encountered when a variety of factors are met, and is characterized by high focus, engagement, motivation, and immersion. While flow state is often discussed in the serious games literature, in-depth empirical examinations of flow state remain elusive. In this dissertation I addressed this need by conducting a thorough literature review of flow, serious games, and game-based learning in order to propose a new model of flow in games. Two studies were conducted in support of this model. The first experiment consisted of the creation and validation of a play experience scale. Based on the data from 203 Study 1 participants, the Play Experience Scale was validated for use with video games. The 14-item version of the Play Experience Scale was composed of the components of freedom, lack of extrinsic motivation, autotelic experience, and direct assessment of play. The scale was reliable, with a calculated α of .86. In the second study, the newly developed scale was used alongside an immune system serious game to examine the impact of play, in-game performance, and emotional experience on flow in games. In an effort to provide a more symmetrical version of the scale, two items were added to the scale, iii resulting in a 16-item revision. Based on the empirical results obtained from Study 2’s 77 participants, the proposed model of flow in games was revised slightly. Though Study 2 only examined a subset of the overall model of flow in games, the evidence suggested the model was a good theoretical match. Further, the two added items of the Play Experience Scale were valid, providing a final 16-item version of the scale. Play and in-game performance were key predictors of game-based learning. Additionally, play, video game self-efficacy, and emotional experience exhibited a reciprocal relationship with flow state. Implications for serious game development, scientific research into games and learning, and industry testing of game playability were provided. Following these implications, conclusions were presented alongside suggestions for further research.

The purpose of the present study was to investigate whether developmental researchers were influenced in the laboratory by the characteristics of children who participate in their research. I hypothesized that experimenters, as social partners, would adapt their speaking and other behaviors to the child’s perceived temperamental profile and language proficiency. I specifically focused on whether experimenters would adhere to the experimental laboratory procedure of two elicited imitation tasks, Feed Bear and Make a Rattle, in an archival dataset. Participants included 61 primarily white 15-month-olds. Coders transcribed infant directed speech (IDS) and analyzed transcriptions for total words, words per sentence, and percentage of words with six or more letters. The present study revealed differential correlational findings across temperamental dimensions, experimenter IDS, and elicited imitation tasks. An investigation of this kind provides new information concerning procedural fidelity and how experimenters may be influenced by their child research participants.

<p>Trajectory formation is an important quality of human movement wherein the analysis of its kinematic structure often permits inferences regarding the underlying sensorimotor organization. The studies reported herein aimed to reveal how task-specific encoding of saccades contribute to two movement models. We first examined saccades for changes in the evidence for online spatial corrections in response to different instances of visual tracking. Results from our first study indicated the sensorimotor operations associated with making timed series responses permitted unhindered operation of online corrections in predictive saccades. These saccades imposed a demand on spatial working memory without suffering diminished corrections typical of single delayed memory-guided saccades. Next, we queried the role of ventral stream visuomotor processing, as well as the contribution of basic stimulus features to explaining known modulations of online saccadic corrections. Our results are consistent with the explanation that ventral stream contribution to target metrics influence trajectory kinematics, but did not induce diminished online corrections if vision of that illusory target was available at saccade onset. Using another movement task, we examined how different saccadic tracking behaviours dissociated the contribution of various sensorimotor operations involved in oculomotor preparation and execution to eye-hand coupling. By observing changes in manual trajectory in an oculo-manual task, we contrasted the effects of saccadic tracking in predictive and reactive modes, overt and covert, horizontal and vertical, spatially congruent or perpendicular axes of primary motion relative to eye-hand coupling. From these data we concluded that saccadic encoding induced execution-dependent coupling, and optionally motor planning-dependent coupling when task constraints specified temporal synchrony between eye and hand movements. Moreover, eventual motor execution was a prerequisite for the emergence of oculomotor planning-dependent coupling effects. This implied no apparent contribution to the coupling dynamic as an exclusive function of shifts in the spatial allocation of attention without oculomotor output.</p> / Doctor of Philosophy (PhD)

<p>Evidence suggests that a change in the firing rate of dopamine (DA) cells is a major neurobiological correlate of learning. The Temporal Difference (TD) learning algorithm provides a popular account of the DA signal as conveying the error between expected and actual rewards. Other accounts have attempted to code the DA firing pattern as conveying surprise or salience. The DA mediated cells have also been implicated in several neuropsychological disorders such as obsessive compulsive disorder and schizophrenia. Compelling neuropsychological explanations of the DA signal also frame it as conveying salience. A model-based reinforcement learning algorithm using a salience signal analogous to dopamine neurons was built and used to model existing animal behavioral data.</p> <p>Different reinforcement learning models were then compared under conditions of altered DA firing patterns. Several differing predictions of the TD model and the salience model were compared against animal behavioral data in an obsessive compulsive disorder (OCD) model using a dopamine agonist. The results show that the salience model predictions more accurately model actual animal behavior.</p> <p>The role of context in the salience model is different than the standard TD-learning algorithm. Several predictions of the salience model for how people should respond to context shifts of differing salience were tested against known behavioral correlates of endogenous dopamine levels. As predicted, individuals with behavioral traits correlated with higher endogenous dopamine levels are far more sensitive to low salience context shifts than those with correlates to lower endogenous dopamine levels. This is a unique prediction of the salience model for the DA signal which allows for better integration of reinforcement learning models and neuropsychological frameworks for discussing the role of dopamine in learning, memory and behavior.</p> / Doctor of Science (PhD)