Decision Making by the Prefrontal Cortex And the Role of Dopamine in Pyramidal Neuron Function

There were two primary focuses of this research. The first aim was to investigate how students’ perception toward the flipped classroom and video learning correlate to their characteristics including their demographics, first generation status, English language learner status, Grit level, motivation types, quality of peer collaboration, and social self-efficacy. Our data indicated that there is significant correlation between student’s motivation status and attitude toward learning from video lectures. The intrinsically motivated students have a higher attitude toward learning from video. This study also demonstrates that participants with high Grit scores performed better than the participants with low Grit scores. The second aim was to investigate the effect of D3R activation on resonance frequency and sag amplitude in type I layer V medial prefrontal cortical pyramidal neurons. Because dopamine D3R is a relatively hot area of research, I first completed an extended literature review on D3R cellular mechanisms and roles in many neuropsychiatric diseases. Then I explored the effect of D3R agonists on type I layer V pyramidal neurons. I used two types of novel Dopamine D3R agonists in this study. I found that D3R agonist application inhibited the sag amplitude and resonance frequency in type I layer V mPFC pyramidal neurons. This work shed light on previously unknown cellular mechanisms on the effect of dopamine D3R activation on intrinsic electrical properties of type I layer V pyramidal neurons. The concentrations of both agonists used was 10 uM, at these concentrations; the drugs should saturate the D3R in our cortical slices. Further dose response experiments are needed to determine the concentration range of D3R agonists that could facilitate usage in future research

Unicorn, hare, or tortoise? Using machine learning to predict working memory training performance

People differ considerably in the extent to which they benefit from working memory (WM) training. Although there is increasing research focusing on individual differences associated with WM training outcomes, we still lack an understanding of which specific individual differences, and in what combination, contribute to inter-individual variations in training trajectories. In the current study, 568 undergraduates completed one of several N-back intervention variants over the course of two weeks. Participants\u27 training trajectories were clustered into three distinct training patterns (high performers, intermediate performers, and low performers). We applied machine-learning algorithms to train a binary tree model to predict individuals\u27 training patterns relying on several individual difference variables that have been identified as relevant in previous literature. These individual difference variables included pre-existing cognitive abilities, personality characteristics, motivational factors, video game experience, health status, bilingualism, and socioeconomic status. We found that our classification model showed good predictive power in distinguishing between high performers and relatively lower performers. Furthermore, we found that openness and pre-existing WM capacity to be the two most important factors in distinguishing between high and low performers. However, among low performers, openness and video game background were the most significant predictors of their learning persistence. In conclusion, it is possible to predict individual training performance using participant characteristics before training, which could inform the development of personalized interventions

Getting Gritty with It: An Examination of Self-Directed Learning and Grit Among Doctoral Students

Extant literature suggests studying for a doctorate requires not just the growth of intellectual and technical skills and abilities, but also progressively developing more noncognitive attributes. Two noncognitive factors with demonstrated relationships with academic outcomes include self-directed learning and grit. Self-directed learning (SDL) is defined as the process of initiating, maintaining, and evaluating one’s own learning, as well as the individual characteristics – such as control, initiative, self-efficacy, and motivation – of the learner who engages in self-directed learning (Brockett & Hiemstra, 1991; Stockdale, 2003). Grit, identified as a noncognitive trait by Duckworth, Peterson, Matthews, and Kelly (2007), is defined as “perseverance and passion for long-term goals” (p. 1087). While various studies have examined these factors separately, none has explored the relationship between SDL and grit among doctoral students.The purpose of this study was to examine the relationships among SDL, grit, and progression toward degree among doctoral students. Participants (N = 118) were doctoral students in a college of education, health, and human sciences at a large, R1 public institution in the southeastern United States. Participants completed the PRO-SDLS (Stockdale, 2003), measuring SDL, and the Grit-S (Duckworth & Quinn, 2009), measuring grit, as well as age, gender, employment status, enrollment status, and stage in degree. Correlational tests and independent samples t-tests were conducted to identify significant relationships and differences, respectively, among these variables.A very strong, significant positive relationship was found between SDL and grit (r = .70, p\u3c.001). Significant positive relationships also were found among the PRO-SDLS four factors (initiative, control, self-efficacy, and motivation) and the Grit-S two factors (consistency of interest and perseverance of effort). SDL and age were found to be significantly positively related (r = .23, p = .013), suggesting older participants were more self-directed. Grit was found to be significantly different by gender t(116) = 2.33, p = .021, as women participants were significantly grittier than men participants.Implications for practice include introducing SDL and grit as noncognitive learner characteristics to doctoral students, as well as designing doctoral education to foster self-direction and grittiness. Recommendations for future directions for research are also addressed

Learning and plasticity in adolescence

Adolescence is the period of life between puberty and relative independence. It is a time during which the human brain undergoes protracted changes - particularly in the frontal, parietal and temporal cortices. These changes have been linked to improvements in cognitive performance; and are thought to render adolescence a period of relatively high levels of plasticity, during which the environment has a heightened impact on brain development and behaviour. This thesis investigates learning and plasticity in adolescence in four experimental studies. Study 1 examined age differences in face cognition, a key component of social cognition, by testing face perception and face memory performance in 661 participants aged 11 - 33. Study 2 tested whether the effects of social exclusion are age-dependent by measuring cognitive performance after social exclusion in 99 participants between ages 10 - 38. For Study 3, 663 participants aged 11 - 33 were asked to complete 20 days of cognitive training to probe whether the effects of cognitive training are also age-dependent. Study 4 investigated the neural correlates of academic diligence in 40 girls aged 14 - 15, using functional and structural neuroimaging. The research in this thesis demonstrates protracted development of cognitive functions in adolescence, consistent with previous studies. It highlights adolescence as a window of opportunity for learning but also as a vulnerable phase during which the brain is particularly susceptible to harmful effects of social exclusion. Finally, it highlights that individual variability in self-control and underlying frontal systems may be related to academic diligence, and thus educational outcomes

Longitudinal associations between structural prefrontal cortex and nucleus accumbens development and daily identity formation processes across adolescence

We tested whether adolescents with daily high identity uncertainty showed differential structural brain development across adolescence and young adulthood. Participants (N = 150, MageT1 15.92 years) were followed across three waves, covering 4 years. Self-reported daily educational identity and structural brain data of lateral prefrontal cortex (lPFC)/anterior cingulate cortex (ACC), medial PFC, and nucleus accumbens (NAcc) was collected across three waves. All hypotheses were pre-registered. Latent class growth analyses confirmed 2 identity subgroups: an identity synthesis class (characterized by strong commitments, and low uncertainty), and an identity moratorium class (high daily identity uncertainty). Latent growth curve models revealed, on average, delayed maturation of the lateral PFC/ACC and medial PFC and stable NAcc. Yet, adolescents in identity moratorium showed lower levels and less decline in NAcc gray matter volume. Lateral PFC/ACC and medial PFC trajectories did not differ between identity subgroups. Exploratory analyses revealed that adolescents with higher baseline levels and delayed maturation of lateral PFC/ACC and medial PFC gray matter volume, surface area, and cortical thickness reported higher baseline levels and stronger increases of in-depth exploration. These results provide insight into how individual differences in brain develop

Learning to focus and focusing to learn : more than a cortical trick

The consequence of many psychiatric and neurodegenerative disorders, such as Parkinson’s disease and schizophrenia, is an impairment in ‘executive functioning’; an umbrella term for several cognitive processes, including the focussing and shifting of attention and the inhibition of responding. The ability to form an ‘attentional set’ involves learning to discriminate qualities of a multidimensional cue, and to subsequently learn which quality is relevant, and therefore predictive of reward. According to recent research, the subthalamic nucleus (STN) and possibly the adjacent zona incerta (ZI) may mediate the formation of attentional set. Dysregulation of the STN as a result of Parkinson’s disease contributes to characteristic motor symptoms, and whilst deep-brain stimulation of this region may treat gross motor impairments, it may also impair cognition. The work in this thesis aimed to expand our understanding of the mechanisms of attentional set-formation, and the role of the STN in this process. This thesis evaluates new methods for examining set-formation in the attentional set-shifting task; rather than inferring this behaviour solely from the cost of shifting set, modifications to the task design in Chapters 3 & 4 explored several hypotheses designed to exploit a deficit in this behaviour. Chapter 6 revealed that inhibition of this region with designer receptors leads to a disruption in attentional selectivity, which compromises the ability to form an attentional set. This manifested as an inability to parse relevant information from irrelevant, and instead, animals learned the stimuli holistically. The findings in this thesis also suggested that reversal and attentional shifting processes do not operate independently, but rather in a hierarchy, and that consequently, the STN is a region that may be crucial in selecting appropriate responses during associative learning that leads to the formation of an attentional set

Motivation Contagion at School: Do Friends Show Similar Motivation in Behaviour and Brain?

It has been shown that the motivation of students’ is related to academic achievement. However, while research on the socio-cognitive factors that contribute to students’ motivation is increasing, limited attention has been placed on the impact of their real social networks and peer interactions. Therefore, this thesis investigated the spread of motivation between friends i.e. motivation contagion, within a real school environment. To identify the impact of friendships on levels of academic motivation, a longitudinal research study was performed, measuring individual levels of motivation, and social network connections. Additionally, an fMRI study was carried out to establish if observed behavioural similarity could also be identified in brain activation. In Chapters 2 and 3, I examined similarity of motivation between friends using cross-sectional data. Additionally, students network position was also examined, to establish whether being better socially connected is related to levels of individual motivation. In Chapter 4, longitudinal models were constructed in order to break down similarity into its component parts; selection and influence. Chapter 5 includes the fMRI study detailed above, taking measures of brain activity in response to reward and correlating them with the same responses of those with whom they had social connections. Across chapters, the results were varied and in all cases the hypotheses were partially supported. Similarity between friends was observed in some measures of motivation, but not in others. In terms of motivation contagion, results indicated that selection effects were more pervasive than influence effects, suggesting that friendships are more often formed on the basis of similarity, rather than becoming similar over time. Finally, friendship pairs showed similarity in striatal activation in the brain in response to the cue phase of a rewarding task, but the results varied across two samples. The findings are considered from various perspectives including developmental and methodological considerations. Further, application to educational practice is also discussed. Overall, this thesis provides an original contribution by combining psychology, education and neuroscience to provide new insights into the dynamic nature of friendships in the context of school life