Browsing by Author "Friedman, Bruce H."
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- The Ability of Speaking Rate to Influence Infants' Preferences for Infant-Directed SpeechCooper, Jamie S. (Virginia Tech, 1999-09-07)Much research has examined how rate affects visual preferences in human infants and auditory preferences in avian infants. In the visual domain, it seems that human infants prefer stimuli (e.g., flashing displays) presented at faster relative rates. Research using avian species has shown that ducklings, for example, prefer their species- specific maternal call only when it is presented at values close to the species-typical mean. These studies have shown that experience affects ducklings' preferences for rate in auditory events. Researchers in the areas of human infant preferences for visual rate and avian infant preferences for auditory rate have suggested that an effective window of frequencies exists for which infants show maximal attention. Unlike these two areas, little research has addressed how rate affects human infants' preferences for auditory events. A study by Cooper and Cooper (1997) was the first to find that infants attend to rates of speaking infant directed (ID) speech. Specifically, infants preferred ID speech at its normal rate to ID speech at a faster rate. The present study was intended to further investigate how rate of speaking affected infants' preferences for ID speech. More specifically, this study sought to determine whether a window of effective rates also exists for infant preferences for rate in ID speech. Using an infant-controlled preference procedure, 20 six- to eight-week old infants were presented with ID-normal speech (ID speech as its normal rate) and ID- slow speech (ID speech slowed to half the normal rate). It was found that infants looked longer to a visual display when it was paired with ID-slow speech than when it was paired with ID-normal speech. How these results relate to research and theory on visual rate preferences in human infants and auditory rate in avian species is discussed, as well as future directions for this line of research.
- Affect Intensity and Perceptions of Arousal in a Subclinical Level of Psychopathy Termed Aberrant Self-PromotionCyterski, Trina Doran (Virginia Tech, 1999-04-07)The purpose of this study was to answer questions about affect intensity and self-perceived arousal differences in aberrant self-promoters (ASPs) and in individuals high and low in affect intensity (AI). Participants in the study completed a task asking them to respond as quickly and accurately as possible to letter strings presented for 200ms on a computer screen. They completed the task once with letter strings that formed words with an emotional valance and a second time with neutral-valence words. After each task, participants made self-reports of Energy and Tense dimensions of arousal as measured by the Activation-Deactivation Adjective Checklist. As first formulated, the study examined 4 groups of n̲ = 30 (ASPs, non-ASP controls, high-AIs, and low-AIs). Results showed that, as hypothesized, ASPs scored significantly lower than high-AIs on the Affect Intensity Measure (AIM). Other hypotheses were not supported by analyses of the original four groups. However, because about 1/3 of the ASPs exhibited high AIM scores, ASPs were divided into primary and secondary types: (a) those who scored low and (b) those who scored high on the AIM. Subsequent post hoc analyses, based on the hypotheses that had not been supported initially, were conducted on five groups of n̲ = 7. The study found that low-AI ASPs reported significantly lower arousability levels than high-AIs. Results also showed that controls, high-AIs, and low-AIs all reacted significantly more slowly to emotional words than to neutral words. Low-AI ASPs failed to demonstrate this response-time slowing, indicating that, like psychopaths, ASPs may process positive, negative, and neutral stimuli similarly. Additional results indicated that low-AI ASPs decreased both energetic and tension arousal levels after the emotional word task, compared to the neutral word task, whereas high-AIs reported corresponding increases in these types of arousal. These findings support Larsen and Diener's (1987) theory regarding arousal differences in high- and low-AIs. Implications of these findings are discussed in terms of a weak Behavioral Inhibition System (Gray, 1987).
- Anger Expression, Harassment, and Evaluation: Cardiovascular Reactivity and Recovery to Mental StressVella, Elizabeth Jane (Virginia Tech, 2005-05-10)Anger and hostility have been attributed as early risk factors of coronary heart disease (CHD). However, many inconsistencies exist in the literature linking both of these constructs to CHD, as well as to cardiovascular reactivity (CVR) to stressors likely to give rise to CHD. A potential moderating influence discussed in the CVR literature concerns the issue of anger provocation, whereas assessment of the ability to evaluate the source of provocation may moderate the recovery process. The current study adopts a multivariate approach to assess the interactive effects of dispositional anger in predicting the CVR and recovery to mental arithmetic (MA) stress with and without harassment in 47 male undergraduate psychology students. Results revealed anger out (AO) to be associated with high vagal and low frequency power suppression in response to the MA task with harassment. Exposure to experimenter evaluation was associated with attenuated diastolic blood pressure recovery and facilitated vagal recovery in high AO subjects, whereas the opposite pattern was apparent for low AO subjects. The general findings suggest that trait anger interacts with situational influences to predict CVR and recovery to stressors.
- Auditory-Visual System Interactions: Perinatal Visual Experience Affects Auditory Learning and Memory in Bobwhite Quail Chicks (Colinus virginianus)Columbus, Rebecca Foushee (Virginia Tech, 1998-10-19)Early perceptual learning capacity has been shown to correspond with the relative status of emergent sensory systems throughout prenatal and postnatal development. It has also been shown that young infants can learn perceptual information during perinatal development. However, the exact nature of the relationship between prenatal and postnatal perceptual development and the role of early experience on learning ability have yet to be examined. The present study examined how auditory learning capacity in bobwhite quail chicks is affected by the interrelationship between the developing auditory and visual systems in late prenatal/early postnatal development. Chicks were provided with auditory information during the period immediately prior to or the period following hatching. In addition, visual experience was either provided or attenuated during both the prenatal and postnatal periods. Findings revealed that chicks postnatally exposed to 10 min/hr of maternal auditory stimulation in lighted conditions required 72 hr exposure to the call in order to learn that bobwhite maternal call (Experiments 1A and 1B). Control chicks who experienced the prenatal egg-opening procedure demonstrated no naive preference for two individual variants of the bobwhite maternal assembly call (Experiment 2). However, embryos who received 10 min/hr of prenatal visual stimulation, or who were reared in prenatal darkness successfully learned a maternal call with only 24 hr of postnatal exposure (Experiments 3A and 3C). Embryos who received prenatal visual and postnatal darkened rearing conditions (a mismatch between prenatal and postnatal experience) showed deficits in postnatal auditory learning (Experiment 3B). Embryos who were exposed to 10 min/hr of prenatal maternal auditory stimulation and 10 min/hr of nonconcurrent visual stimulation remembered the maternal call into later ages of postnatal development than in previous studies when reared in lighted or darkened postnatal conditions (Experiments 4A and 4B). However, when all prenatal and postnatal visual experience were both removed from embryos' and chicks' environments, deficits in prenatal auditory learning and postnatal memory were observed (Experiment 4C). These results indicate that prenatal and postnatal learning in bobwhite quail occur differently, that mismatches in prenatal and postnatal experience interfere with postnatal auditory learning, and that prenatal learning and postnatal memory are affected by the amount of visual stimulation present within chicks' environmental milieu. In the broader scheme, these results provide further evidence that the auditory and visual systems are linked during early development and support an ecological perspective of learning and memory.
- The Autonomic Characteristics of Defensive Hostility: Reactivity and Recovery to Active and Passive StressorsVella, Elizabeth Jane (Virginia Tech, 2003-04-16)Defensive hostility has been attributed as an early risk factor of coronary heart disease. The autonomic characteristics of high defensive, high hostile (HD) and low defensive, high hostile (LD) men and women were assessed with a variety of cardiovascular (CV) measures. Reactivity and recovery to an active laboratory stressor (video game, VG) and a passive laboratory stressor (hand cold pressor, CP) of 15 HD men, 16 LD men, 16 HD women, and 16 LD women were recorded. It was predicted that the CV patterning associated with the HD participants would display more sympathetic and less vagal control as well as the least pronounced recovery from the stressors in comparison to LD participants. Results revealed differential CV responses to the lab tasks by group. HD women displayed consistently high levels of low frequency power heart rate variability (HRV) during baseline and across conditions. HD men exhibited significantly pronounced heart rate reactivity and reduced high frequency power HRV to the CP task in comparison to LD men. Interestingly, LD women displayed weaker blood pressure (BP) recovery to the VG in comparison to HD women, whereas the opposite pattern was observed in BP recovery to the CP. These results suggest that defensiveness and sex may moderate the CV reactivity and recovery to different types of stressors in hostile participants.
- Autonomic Differentiation of Emotions: A Cluster Analysis ApproachStephens, Chad Louis (Virginia Tech, 2007-09-25)The autonomic specificity of emotion is intrinsic for many major theories of emotion. One of the goals of this study was to validate a standardized set of music clips to be used in studies of emotion and affect. This was accomplished using self-reported affective responses to 40 music pieces, noise, and silence clips in a sample of 71 college-aged individuals. Following the music selection phase of the study; the validated music clips as well as film clips previously shown to induce a wide array of emotional responses were presented to 50 college-aged subjects while a montage of autonomic variables were measured. Evidence for autonomic discrimination of emotion was found via pattern classification analysis replicating findings from previous research. It was theorized that groups of individuals could be identified based upon individual response specificity using cluster analytic techniques. Single cluster solutions for all emotion conditions indicated that stimulus response stereotypy of emotions was more powerful than individual patterns. Results from pattern classification analysis and cluster analysis support the concept of autonomic specificity of emotion.
- Autonomic Patterns of Emotion across Multiple ContextsMcginley, Jared J. (Virginia Tech, 2015-06-17)Research on the autonomic specificity of emotion has spanned several decades. Even though considerable evidence exists for supporting autonomic specificity for discrete emotion states (Kreibig, 2010), there is still an active debate, and conflicting explanations, for these findings (Quigley and Barrett, 2014). There have been several studies employing multivariate pattern classification analytic techniques and calls for those types of studies are still prevalent (Kragel and LaBar, 2014). Although many studies have explored the autonomic specificity of emotions, few have explored what effects the induction methods, themselves, have had in inducing the autonomic change. Autonomic specificity of induction methods might be a meaningful, and confounding, phenomenon in this literature. Based on this unknown variable, the current experiment was designed to see if methods for emotion elicitation could be meaningfully captured by these same pattern classification techniques. This was accomplished using three separate emotion-elicitation methods to elicit five separate emotions. A sample of 64 college-aged students watched film clips, read imagery scripts, and recalled personal memories for five discrete emotions. Using discriminant analysis, the evidence from the current study lent less support for autonomic specificity of emotion than past experiments, and lends some support for providing future exploration into autonomic change that is related to methods for induction. Potential confounds and task fatigue effects are discussed.
- Behavioral and Psychophysiological Responses of 4-month-old Infants to Differing Rates of Infant Directed SpeechMcIlreavy, Megan E. (Virginia Tech, 2003-05-09)Infants of various ages across the first postnatal year have shown behavioral preferences (i.e., more attention) to visual displays when looking resulted in the presentation of Infant-Directed Speech (IDS) compared to Adult-Directed Speech (ADS). Although IDS differs from ADS on a variety of measures, most research has focused on various pitch characteristics (i.e., IDS is higher in absolute pitch and more variable in pitch across utterance length). Work from our lab has found that when the pitch characteristics of IDS were held constant, but the temporal features were manipulated, younger (but not older) infants attended more to slower rates of IDS, even though it was unlikely that they had heard such speech (when speech is spoken at this slow rate, the fundamental frequency cannot be maintained). The purpose of this study was to expand our investigation of how speaking rate affects infant attention by adding the physiological measure of heart rate to our protocol. Of specific interest was whether infants would show differential amounts of heart-rate (HR) decelerations as a function of rate (i.e. greater decelerations to slowed speech). 4-month-old infants were tested with normal IDS (unaltered rate) and slow IDS (rate was twice as slow as normal). Behaviorally, infants did not differentially attend to a display as a function of speech type. Psychophysiologically, infants showed more pronounced HR decelerations to slow than to normal IDS. The discrepancy between measures of attention is discussed, especially with regard to the organization of attention in infants of this age.
- Behavioral Inhibition/Activation and Autonomic Control of the Heart: Extending the Autonomic Flexibility ModelChristie, Israel C. (Virginia Tech, 2005-05-09)The autonomic flexibility model has proven to be a useful theoretical tool relating reductions in physiological variability found to accompany anxiety and concomitant reductions in behavioral (e.g., cognitive and emotional) flexibility. The present study aimed to extend the autonomic flexibility model through the inclusion of individual differences in the sensitivity of the independent motivational systems presumed to underlie anxiety and impulsivity, namely the behavioral inhibition and activation systems (BIS/BAS; Gray, 1994). Contrary to the predicted inverse relationship between BIS sensitivity and measures of physiological variability, findings suggest BAS sensitivity is associated with increased trait-like vagally mediated heart rate variability across diverse tasks as well as greater flexibility in responding within tasks. Numerous BIS*BAS interactions emerged as significant predictors of trait reactivity. Results are discussed in terms of the interface between (1) mesolimbic dopaminergic projections to the nucleus accumbens and (2) the network of central nervous system structures believed to play a large role in controlling peripheral physiology.
- Cardiovascular Activity During Laboratory Tasks in Individuals with High and Low WorryKnepp, Michael Matthew (Virginia Tech, 2007-05-09)Anxiety and worry have been related to exaggerated cardiovascular reactivity and delayed recovery to laboratory stressors, and to increased risk of cardiovascular disease. This study examined cardiovascular responses in high and low worriers to a range of laboratory tasks. The aim of this study was to determine if there is a task-specific relationship between worry and aberrant cardiovascular responding. Forty-one undergraduate women were recruited online to form low and high worry groups by use of the Penn State Worry Questionnaire. Four common laboratory tasks and two conditions designed to elicit worry and relaxation were used: hand cold pressor, mental arithmetic, orthostatic position, supine position, worry imagery, and relaxation imagery. Heart rate, heart rate variability, impedance cardiography, and blood pressure indices were collected to assess task reactivity and recovery, particularly in relation to autonomic nervous system activity. The high worry group had significantly higher heart rates throughout the study. The low worry group presented increased cardiovascular recovery to various tasks. The high worry group during task and post-task periods also increased parasympathetic withdrawal and sympathetic activation. The results of the study suggest that high worriers have decreased vagal control of the heart. The implications of this study suggest a potential link between the post-task period in high worriers and cardiovascular disease. Further research is recommended.
- Cardiovascular Reactivity to and Recovery from Laboratory Tasks in Low and High Worry WomenKnepp, Michael Matthew (Virginia Tech, 2010-03-23)Anxiety and its cognitive component of worry have been related to exaggerated cardiovascular reactivity and delayed recovery to laboratory stressors, and to increased risk of cardiovascular disease. Previous research on the anxiety-cardiovascular system relationship, including data from Knepp and Friedman (2008), are included to support this project. Two experiments were completed during the course of this study. The first consisted of two peripheral-based body positioning tasks. The second experiment used an active versus passive sympathetic stress task paradigm (mental arithmetic, hand cold pressor). Subjects were nonsmokers free of cardiovascular and neurological disease. Trait worry was examined through the Penn State Worry Questionnaire (PSWQ). Blood pressure recordings and cardiac recordings through ECG and ICG were done in each experiment during seven epochs: an anticipatory baseline with three baselines preceding and three recovery periods following each task. Repeated measures analysis was run on all cardiovascular measures. In the first experiment, high worriers had worsened blood pressure reactivity to task. The second experiment found that high worriers had increased stroke volume across all epochs. There were mixed findings in the studies relating to subjects acclimated to the laboratory experience. Future directions of research relating anxiety, worry, and cardiovascular risk factors are discussed.
- Challenging frontal lobe capacity using lateralized vestibular stress: A functional cerebral systems approach to a clinical risk for fallsCarmona, Joseph (Virginia Tech, 2011-10-12)A conceptual model was originally proposed that linked the vestibular modality with executive domains by means of a functional cerebral systems framework. The claim was that frontal regions exert regulatory control over posterior systems for sensation and autonomic functions in a dense, interconnected network with right hemisphere specialization. As a preponderance of evidence demonstrates that a design fluency task is often associated with right frontal functioning, it was hypothesized that proficiency on a design fluency task would yield differences in QEEG and skin conductance after vestibular activation. Fifty-eight total (29 high- and 29 low-fluent performers on the Ruff Figural Fluency Test were subjected to 20 whole-body passive rotations about the neuroaxis at a constant rate of approximately 120 degrees per second. EEG and skin conductance levels were recorded prior to and post-rotation. Analyses were conducted on delta (1-4 Hz.) and beta (13-21 Hz.) frequencies. Overall, delta activity increased from baseline to post-rotation with higher levels at frontal sites, however no group differences were found across conditions. Regarding beta activation, high design fluency was associated with increased beta activation at the right temporal site (T6). In contrast to expectations, beta activity diminished from baseline to post-stress over both groups. Skin conductance levels increased from baseline to post-stress. Methodological considerations are discussed regarding gender issues and procedures of the experiment. The results indicate that vestibular disorientation yields systematic delta changes in the frontal regions, but that future refinements to the vestibular stressor may elicit QEEG and skin conductance differences in fluency groups.
- Cognitive Biases and Autonomic Responding in Anxiety and DepressionSantucci, Aimee Kristin (Virginia Tech, 2001-03-29)The present study addressed cognitive biases in anxiety and depression using the emotional Stroop task, and explored both the affective space and autonomic underpinnings of these disorders. In previous studies, anxiety has been associated with both an attentional bias toward threat information and low cardiac vagal control, as reflected in heart rate variability (HRV) indices. Depression has been linked to a memory bias for negative information; however, findings of low HRV for depression are mixed. The high comorbidity of these disorders renders such findings as difficult to interpret. In the present study, it was hypothesized that the negative affect groups (anxious, depressed, comorbid anxious/depressed) would have lower vagally mediated HRV across tasks compared to the control group and that the anxiety and depression groups would show biases for group specific words on the Stroop task. Results for the Stroop tasks generally support previous findings of an attention bias in anxiety. The comorbid anxiety/depression group generally showed lower vagal control across tasks compared to the other groups, although comparisons between the "pure" anxiety and depression groups and the controls were not significant. It is suggested that this is because the comorbid group had higher depression and anxiety than either of the "pure" groups.
- Comparison between the Effects of Acute Physical and Psychosocial Stress on Feedback-Based LearningYang, Xiao; Nackley, Brittany; Friedman, Bruce H. (MDPI, 2023-07-26)Stress modulates feedback-based learning, a process that has been implicated in declining mental function in aging and mental disorders. While acute physical and psychosocial stressors have been used interchangeably in studies on feedback-based learning, the two types of stressors involve distinct physiological and psychological processes. Whether the two types of stressors differentially influence feedback processing remains unclear. The present study compared the effects of physical and psychosocial stressors on feedback-based learning. Ninety-six subjects (Mage = 19.11 years; 50 female) completed either a cold pressor task (CPT) or mental arithmetic task (MAT), as the physical or psychosocial stressor, while electrocardiography and blood pressure were measured to assess cardiovascular stress reactivity (CVR). Self-ratings on the emotional valence of the stressors were also obtained. A probabilistic learning task was given prior to and after the stressors. Accuracy in selecting positive (Go accuracy) and avoiding negative stimuli (No-go accuracy) were recorded as learning outcomes. Repeated measures ANOVA and multiple regressions were used to compare the effects of two stressors and examine the effects of CVR and valence on the learning outcomes. The results showed that although the effects of CPT and MAT on feedback processing were not different, CVR and valence influenced Go and No-go accuracy, respectively. The results suggest that stress-modulated feedback-based learning involves multiple pathways and underscore the link between CVR and reward sensitivity. The findings have clinical implications and may contribute to a better understanding of human behavioral systems.
- Comparison of Functional Connectivity in the Prefrontal Cortex during a Simple and an Emotional Go/No-Go Task in Female versus Male Groups: An fNIRS StudyNguyen, Thien; Condy, Emma E.; Park, Soongho; Friedman, Bruce H.; Gandjbakhche, Amir H. (MDPI, 2021-07-09)Inhibitory control is a cognitive process to suppress prepotent behavioral responses to stimuli. This study aimed to investigate prefrontal functional connectivity during a behavioral inhibition task and its correlation with the subject’s performance. Additionally, we identified connections that are specific to the Go/No-Go task. The experiment was performed on 42 normal, healthy adults who underwent a vanilla baseline and a simple and emotional Go/No-Go task. Cerebral hemodynamic responses were measured in the prefrontal cortex using a 16-channel near infrared spectroscopy (NIRS) device. Functional connectivity was calculated from NIRS signals and correlated to the Go/No-Go performance. Strong connectivity was found in both the tasks in the right hemisphere, inter-hemispherically, and the left medial prefrontal cortex. Better performance (fewer errors, faster response) is associated with stronger prefrontal connectivity during the simple Go/No-Go in both sexes and the emotional Go/No-Go connectivity in males. However, females express a lower emotional Go/No-Go connectivity while performing better on the task. This study reports a complete prefrontal network during a simple and emotional Go/No-Go and its correlation with the subject’s performance in females and males. The results can be applied to examine behavioral inhibitory control deficits in population with neurodevelopmental disorders.
- Computational and Human Learning Models of Generalized UnsafetyHuskey, Alisa Mae (Virginia Tech, 2020-08-20)The Generalized Unsafety Theory of Stress proposes that physiological markers of generalized stress impair learning of safe cues in stressful environments. Based on this model, chronic problems inhibiting physiological arousal lead to a heightened perception of threat, which involves experiencing anxiety symptoms without any obvious precipitating stressful or traumatic event. This investigation aims to determine the impact of stressor- versus context-related emotional learning on generalized unsafety, using a Pavlovian threat-conditioning paradigm. The difference in learning threatening cues ([CS+] paired with an aversive stimulus) compared to safety cues ([CS-] not paired with an aversive stimulus) was used as a proxy measure of generalized unsafety, as conceptualized by the GUTS model. This difference is expected to be moderated by individual differences in tonic cardiac regulation (i.e. heart rate variability). Lastly, a temporal-differences learning model was used to predict skin-conductance learning during stressor, stressor context and general contexts to determine which best predicts Pavlovian learning. TD learning is expected to better predict skin-conductance in individuals with higher fear inhibition in comparison to those with low fear inhibition.
- Controlling for Acute Caffeine Intake in Cardiovascular Reactivity ResearchGrant, Shara Soyini (Virginia Tech, 2016-04-08)Caffeine substantially affects cardiovascular functioning, yet wide variability exists in caffeine control procedures in cardiovascular reactivity (CVR) research. This study was conducted in order to identify a minimal abstention duration in habitual coffee consumers whereby CVR is unconfounded by caffeine; Six hours was hypothesized (average half-life). Thirty nine subjects (mean age: 20.9; 20 Women) completed a repeated measures study involving hand cold pressor (CP) and memory tasks. Caffeinated and decaffeinated coffee were administered. The following CV indices were acquired during baseline, task, and recovery epochs prior to coffee intake, 30 minutes-, and six hours post-intake: Heart rate (HR), high frequency heart rate variability (hfHRV), root mean squared successive differences (RMSSD), systolic and diastolic blood pressures (SBP, DBP), mean arterial pressure (MAP), pre-ejection period (PEP), left ventricular ejection time (LVET), and total peripheral resistance (TPR). Results support the adequacy of a six-hour abstention in controlling for caffeine-elicited CVR changes. The current study contributes to methodological endeavors in psychophysiology. Further investigations are crucial in establishing ideal caffeine controls, which would promote increasingly valid and reliable cross-study results.
- Defensive Neurophysiological Response: Exploring the Neural and Autonoic Correlates of Social BehaviorPatriquin, Michelle Anne (Virginia Tech, 2013-04-01)Current literature suggests neurological (i.e., insula, amygdala) and autonomic (i.e., respiratory sinus arrhythmia; RSA) markers of language, social, and behavioral challenges in autism spectrum disorders (ASD; Bal et al., 2010; DiMartino, Ross, et al., 2009; Lorenzi, Patriquin, & Scarpa, 2011; Patriquin, Scarpa, Friedman, & Porges, 2011), that hypothetically reflect a defensive neurophysiological circuit (i.e., hyper-arousal within the central and autonomic nervous systems). It is unknown how this neurophysiological state contributes to difficulties in ASD. Therefore, the current study quantified peripheral and central nervous system activity and investigated how this neurophysiological circuit may be related to different social and behavioral patterns that characterize ASD. Participants with (n = 16) and without (n = 30) ASD listened to classical music while brain (via functional magnetic resonance imaging) and autonomic (via pulse oximeter and plethysmogram) data were collected. Results indicated that decreased insula and amygdala activity during physiological hyper-aroused states predicted symptoms associated with ASD, and predicted higher levels of comorbid anxiety, stress, and depression. Contrary to hypotheses, no baseline RSA or amygdala differences were noted between ASD and controls groups, suggesting that adults with ASD may have developed effective coping strategies for reducing physiological threat responses. It will be important for future studies to continue to explore and clarify the neural connections of peripheral nervous system activation in individuals with and without ASD, including extending this research to children.
- Development of Neuroconnectivity and Inhibitory Control: Relation to Social Cognition in Late ChildhoodBroomell, Alleyne Patricia Ross (Virginia Tech, 2019-05-03)Social cognition is a set of complex processes that mediate much of human behavior. The development of these skills is related to and interdependent on other cognitive processes, particularly inhibitory control, which allows for willful suppression of dominant responses. Many aspects of social behavior rely on inhibitory control to moderate impulsive or socially inappropriate behaviors and process complex perspective-taking. Furthermore, the brain regions associated with inhibitory control and social cognition overlap functionally and structurally. I review neurodevelopmental literature to suggest that social cognition is developmentally dependent on inhibitory control and that the neural foundations of both these skills are measurable in infancy. I tested this model using growth curve and structural equation modeling and show that 10-month, but not 5-month, frontotemporal coherence predicts social cognition in late childhood through preschool inhibitory control. These findings provide insight into the neurodevelopmental trajectory of cognition and suggest that connectivity from frontal regions to other parts of the brain is a foundation for the development of these skills.
- Differentiation between the Effects of Physical and Psychosocial Stress on a Feedback-based Learning TaskYang, Xiao (Virginia Tech, 2017-07-12)Feedback-based learning is a process in which decisions are made based on the previous feedback. This learning process is influenced by acute stress. However, different laboratory stressors elicit different physiological response patterns, which may influence feedback processing differently. Moreover, individual differences in stress reactivity may be associated with reward sensitivity. Therefore, the present study investigated the effects of psychosocial and physical stress on feedback-based learning. The relationship between stress reactivity and reward sensitivity was also examined. Ninety-two college-aged subjects were assigned into the mental arithmetic (MA) task or the cold pressor task (CPT) group. All subjects performed a feedback-based learning task prior to and after the stressor. Cardiovascular reactions, stress experiences, and learning outcomes were recorded during tasks. Trait differences in behavioral inhibition and activation (BIS/BAS) were also measured. Results indicated different patterns of cardiovascular reactions to the MA and CPT. Learning outcomes were differentially influenced by the MA and CPT. Moreover, subjective stress scores were negatively correlated with the learning rate in the pre-stress learning task. Additionally, BAS Drive subscale score was related to the processing of positive feedback. The results suggested that physical and psychosocial stress influence learning through distinct neural mechanisms and psychological processes. Motivational processes underlie the relationship between stress reactivity and reward sensitivity. This study extended research on stress and learning, and the findings have applied implications in various areas.