Mind the social feedback : effects of tDCS applied to the left DLPFC on psychophysiological responses during the anticipation and reception of social evaluations

The left dorsolateral prefrontal cortex (lDLPFC) is implicated in anticipatory (i.e. during anticipation of emotional stimuli) and online (i.e. during confrontation with emotional stimuli) emotion regulatory processes. However, research that investigates the causal role of the lDLPFC in these processes is lacking. In this study, 74 participants received active or sham transcranial direct current stimulation (tDCS) over the lDLPFC. Participants were told strangers evaluated them. These (rigged) social evaluations were presented, and in 50% of the trials, participants could anticipate the valence (positive or negative) of the upcoming social feedback. Pupil dilation (a marker of cognitive resource allocation) and skin conductance responses (a marker of arousal) were measured. The results indicate that active (compared to sham) tDCS reduced arousal during the confrontation with anticipated feedback but only marginally during the confrontation with unanticipated feedback. When participants were given the opportunity to anticipate the social feedback, tDCS reduced arousal, irrespective of whether one was anticipating or being confronted with the anticipated feedback. Moreover, tDCS reduced cognitive resource allocation during anticipation, which was associated with resource allocation increases during the subsequent confrontation. Altogether, results suggest that the lDLPFC is causally implicated in the interplay between anticipatory and online emotion regulatory processes

Measuring cognitive load and cognition: metrics for technology-enhanced learning

This critical and reflective literature review examines international research published over the last decade to summarise the different kinds of measures that have been used to explore cognitive load and critiques the strengths and limitations of those focussed on the development of direct empirical approaches. Over the last 40 years, cognitive load theory has become established as one of the most successful and influential theoretical explanations of cognitive processing during learning. Despite this success, attempts to obtain direct objective measures of the theory's central theoretical construct – cognitive load – have proved elusive. This obstacle represents the most significant outstanding challenge for successfully embedding the theoretical and experimental work on cognitive load in empirical data from authentic learning situations. Progress to date on the theoretical and practical approaches to cognitive load are discussed along with the influences of individual differences on cognitive load in order to assess the prospects for the development and application of direct empirical measures of cognitive load especially in technology-rich contexts

Depressed Adolescents’ Pupillary Response to Peer Acceptance and Rejection: The Role of Rumination

Heightened emotional reactivity to peer feedback is predictive of adolescents’ depression risk. Examining variation in emotional reactivity within currently depressed adolescents may identify subgroups that struggle the most with these daily interactions. We tested whether trait rumination, which amplifies emotional reactions, explained variance in depressed adolescents’ physiological reactivity to peer feedback, hypothesizing that rumination would be associated with greater pupillary response to peer rejection and diminished response to peer acceptance. Twenty currently depressed adolescents (12–17) completed a virtual peer interaction paradigm where they received fictitious rejection and acceptance feedback. Pupillary response provided a time-sensitive index of physiological arousal. Rumination was associated with greater initial pupil dilation to both peer rejection and acceptance, and diminished late pupillary response to peer acceptance trials only. Results indicate that depressed adolescents high on trait rumination are more reactive to social feedback regardless of valence, but fail to sustain cognitive-affective load on positive feedback

Associations Between Pupillary Response Patterns to Emotional Faces and Self-Reported Social Anxiety

The present study examined associations between self-reported social anxiety (SA) and patterns of pupillary response to emotional faces that provided feedback to college student participants (n = 59) about their performance on a reaction time task. I hypothesized that self-reported SA would predict pupil dilation profile (peak, duration, and latency) in response to feedback stimuli of varying intensities (i.e., low vs. high intensity happy and angry). Results showed no evidence of significant associations between peak and sustained pupil diameter measures and SA; however, at 0.5 seconds post-stimulus onset, SA and pupil diameter were negatively associated, such that smaller pupil diameter was associated with higher levels of SA. This pattern could be consistent with a blunted autonomic response to affective cues; examination of concurrent eye-tracking data would provide a test of this possibility. The present study lays crucial groundwork for future assessments utilizing pupil diameter as a parsimonious tool

Psychophysiological indices of recognition memory

It has recently been found that during recognition memory tests participants’ pupils dilate more when they view old items compared to novel items. This thesis sought to replicate this novel ‘‘Pupil Old/New Effect’’ (PONE) and to determine its relationship to implicit and explicit mnemonic processes, the veracity of participants’ responses, and the analogous Event-Related Potential (ERP) old/new effect. Across 9 experiments, pupil-size was measured with a video-based eye-tracker during a variety of recognition tasks, and, in the case of Experiment 8, with concurrent Electroencephalography (EEG). The main findings of this thesis are that: - the PONE occurs in a standard explicit test of recognition memory but not in “implicit” tests of either perceptual fluency or artificial grammar learning; - the PONE is present even when participants are asked to give false behavioural answers in a malingering task, or are asked not to respond at all; - the PONE is present when attention is divided both at learning and during recognition; - the PONE is accompanied by a posterior ERP old/new effect; - the PONE does not occur when participants are asked to read previously encountered words without making a recognition decision; - the PONE does not occur if participants preload an “old/new” response; - the PONE is not enhanced by repetition during learning. These findings are discussed in the context of current models of recognition memory and other psychophysiological indices of mnemonic processes. It is argued that together these findings suggest that the increase in pupil-size which occurs when participants encounter previously studied items is not under conscious control and may reflect primarily recollective processes associated with recognition memory

Physiological Correlates of Working Memory Behavior for Cognitive Efficiency: implications for concussion management

Cognitive efficiency—characterized via robust behavioral and physiological response dynamics, may provide clinically meaningful information with respect to dynamic concussion injury response and return to play considerations. Moreover, a feasible and ecologically valid method to assess dynamic behavioral and physiological metrics is also needed to best characterize cognitive efficiency in athletes and soldiers at a greater risk for concussion. This project was designed to examine the clinical utility and feasibility of a cognitive efficiency assessment designed to be completed within a virtual reality environment, which may hold significant implications for improved concussion clinical management. As such, we aimed to first further understand the relationships between heart rate variability and pupillary response as physiological correlates of digit-span task behavior in the context of cognitive efficiency, then to examine the effects of prior concussion on these responses. Additionally, we applied innovative, reliably sound, and validated psychophysiological methods using a feasible instrumentation option (virtual reality headset with pupillometry and heart rate monitor watch and strap). We feel these methodological considerations allowed us to best address our study aims and inform future directions of this line of inquiry to have direct ecologically valid applications. Collegiate club sports athletes, (N=59; 40% with a concussion history; age = 20.48 ± 1.86 years; 58% male), completed a backwards digit-span task (20 trials) in a virtual reality environment while recording pupil size. Linear mixed effects models showed a significant effect of cognitive load (digit sequence-length) on pupillary response (F4,232=3.67, p=0.006). Negligible effects were seen in task performance, heart rate variability or concussion history p<0.05 Pupillary response shows potential in informing cognitive load and efficiency in applied settings, using VR and eye tracking technology. Future investigations should consider participants’ concussion history variability.Doctor of Philosoph