Graduate Research Day

Graduate Research Day - February 11, 2021

Graduate Research Day 2021 will be held on the Airmeet.com platform.
The link to the conference is:

Schedule

9:30-10:05 AM Keynote 1: Dr. Mayu Nishimura

• Title

10:05-10:50 AM Symposium 1

Tovah Kashetsky

Effect of Experience on Collective Decision-Making and Social Organization
Tovah Kashetsky, Grant Doering, and Reuven Dukas

Expertise built from experience allows individuals to perform significantly better than novices on a complex task. Social groups can also demonstrate expertise. Within social groups, collective decision-making is crucial for maintaining cohesion, but it is unknown whether a group’s collective decision-making skills can improve with experience. To investigate this, we tested whether repeated experience with choosing between multiple nests during emigration in house-hunting ants (Temnothorax ambiguus) would improve the speed and efficiency with which colonies reach consensus. We hypothesize that experience with decision-making would improve colony performance on future decisions. We first ran preliminary experiments to quantify nest features that colonies prefer in order to construct artificial nests of varying attractiveness. We will provide 20 colonies experience with a choice between a good- and poor-quality nest during emigration, and 20 colonies with no choice during emigration (a single nest). Lastly, we will test all colonies to decide between a good- and poor-quality nest during a final emigration. So far, we found that colonies with experience decision-making do indeed appear to be faster and more efficient at decisions than colonies without experience decision-making. We will also run a social network analysis on 3 colonies from both groups to examine temporal changes in social organization. This will provide us with a mechanistic explanation for how improvements in collective decision-making arise from the actions of individuals. Studying decision-making in ants will allow us to achieve an improved understanding of the development and mechanisms behind expertise.

Hanna Haponenko

Depth-specific IOR effect when attention shifts from far to near space relative to viewer
Hanna Haponenko, Hong Jin Sun

Inhibition of return (IOR) is a phenomenon where responses to a peripheral target are delayed if the target appears more than 300ms in the same location as a previous cue. IOR has been extensively shown to operate in 2D scenes. It is not fully understood whether IOR is determined by relative location between cue and target in retinal coordinates or world coordinates. Such a question can be studied by examining IOR in 3D scenes. We compared IOR when cues and targets appeared at same or different depth planes and when depth information was provided by monocular cues. When the cue and target appeared at different depths, a vertical offset was created on-screen, a potential confound to depth perception. We removed the contribution of this confound by contrasting the 3D condition with a 2D control condition that matched cue and target positions but removed all context simulating 3D space. Results showed that IOR magnitude decreased for the different-depth condition compared to the same-depth condition in 3D displays. IOR magnitude also decreased as a function of vertical offset in corresponding 2D displays. Most importantly, such magnitude reduction in 3D displays was higher than that in the 2D displays, but only when the difference in depth was caused by the target appearing at a nearer position compared to the cue. We thus have identified a depth-specific IOR effect in a setting strictly comprised of monocular depth cues, which occurs only when attention shifts from far to near space relative to the viewer.

Joanna Spyra

Memory for global musical structures: Dissecting musical features for their contribution to memory for nonadjacent tonal centers
Joanna Spyra & Dr. Matthew Woolhouse

Memory for musical keys is exceptionally poor. Studies have found that participants maintain a memory for key for only 11-20 seconds after key-change occurs. But music is a complex stimulus with many features; how do these features, such as rhythmical activity or timbre, contribute to the maintenance of memory for past musical sequences? In the Digital Music Lab, we employ a paradigm called “nonadjacent key relationships” to tease apart these musical features and examine their unique effects on memory for key. This paradigm divides stimuli into three sections: (1) a key-defining nonadjacent section, (2) an intervening section in a different key, and (3) a probe cadence either in the original key or in a third key (forming an ABA or CBA relationship between the three sections). Participants are asked to rate the probe for its goodness-of-completion, the idea being that if a memory for the original key remains—despite intervening information—participants will rate the ABA condition higher than the CBA condition. Using this as a baseline, we can manipulate various musical features and compare the strength of completion ratings. If a feature boosts memory, goodness-of-completion should receive a similar boost when compared to CBA conditions. Indeed, this is a pattern we found in many musical features. Results confirm that though memory for key itself may be weak, it is supported by common features we use in music composition every day.

11:00-11:45 AM Symposium 2

Emily Wood

Body sway reflects nonverbal communication in a string quartet learning to play unfamiliar music together
Emily Wood, Dobri Dotov, Andrew Chang, Dan Bosnyak, Lucas Klein & Laurel Trainor

Ensemble musicians must anticipate their partners’ actions to coordinate playing a piece together. To achieve this, musicians attend to sensorimotor signals embedded in their partners’ body sway movements. Indeed, a musician’s body sway movements reveal their upcoming intent regarding phrasing, tempo, and dynamics, which helps their partners anticipate how and when to play next. We have previously measured the body sway of expert musicians in small ensembles with motion capture, and used Granger Causality (GC) to calculate bidirectional influence, or information flow, between the body sway of each musician in the ensemble. We showed that information flow was greater from assigned leaders to assigned followers than vice versa, and that group information flow was greater when musicians played with emotional expression than without. Here, we show how information flow changes in an ensemble that learns to play unfamiliar music together. A professional string quartet came into the LIVELab and played two unfamiliar pieces of music together eight times in succession while body sway motion data was recorded. Linear mixed effect modelling showed that information flow within the group decreased significantly across trials for both pieces, suggesting that musicians relied on body sway to help them play together when the pieces were most novel (trial 1), but this reliance decreased as they gained familiarity with playing the pieces together. We are currently completing cross-correlation analyses to examine how the similarity of group body sway movements changes across trials. Overall, our studies show that body sway reflects nonverbal communication in musical ensembles.

Wei (Vivian) Fang

Dominance pulls faces closer
Wei Fang, Cristina I. Galusca, Zhe Wang, Yu-Hao Sun, Olivier Pascalis, Naiqi G. Xiao

Perceived social traits, such as dominance and trustworthiness, affect other people’s behaviors. While the impact of social traits has been consistently found in high-level cognitive processing, it is unclear whether social traits also modulates perceptual processing of faces. To this end, we investigated how facial dominance affects the perceived distance of faces. We used an implicit but highly robust perceptual illusion to measure the perceived distance: when two identical faces are presented vertically (one above the other), relative to the top face, the bottom one appears closer. Observers exhibit a strong bias to indicate the bottom face is bigger.
We examined how facial dominance influences the perceived distance with a set of computer-generated Dominant and Submissive faces. If facial dominance makes faces perceived closer, participants will likely report the bottom one is bigger. To probe the generality of this effect, we tested this effect in Canada, China, and France (N = 30/country) with faces from three races (African, Asian, and Caucasian).
Across the three countries, participants showed a significant bias in choosing the bottom face as the bigger (Mean bottom responses = 72.03%, p < .001), replicating the illusion. Moreover, Dominant faces led to a stronger illusion than Submissive faces (p = .009), suggesting that facial dominance led faces to be perceived closer. No effect of face race or country were found.
As facial dominance is often associated with negative signals, our finding suggests an evolutional mechanism in the visual system, which amplifies dangerous signals in the environment.

Hannah M. Anderson

Variation and correlations of behavioral lateralization
Hannah M. Anderson, David N. Fisher, Brendan L. McEwen, Justin Yeager, Jonathan N. Pruitt, James B. Barnett

Sensory and behavioral laterality, or “handedness,” is widespread across the animal kingdom and is thought to increase neural efficiency and dual information processing. Historically, research on behavioral lateralization has focused on among-individual variation, but the importance of within-individual variation in behavior is being increasingly acknowledged. Among-individual laterality correlations can indicate both neural multitasking or linkage of stimuli and/or behaviors; however, within-individual correlations of lateralization have yet to be explored experimentally. We adopted a multivariate approach to investigate lateralization at both the population and individual level in two species of terrestrial frog: the poison frog Ameerega bilinguis and their Batesian mimic Allobates zaparo. In contrast to other research on the subject we found no evidence for among-individual correlations but did find evidence for within-individual correlations, a previously unexplored form of lateralization. We discuss possible meanings for these results and their broader implications to both lateralization and broader behavioral research.

1:00-2:00 PM Symposium 3

Leigh Greenberg

Visualizing critical information for the perception of androgyny
Leigh Greenberg, Patrick J. Bennett, Allison B. Sekuler

Androgynous face stimuli typically are generated by morphing strongly masculine and strongly feminine faces, based on an assumption that androgynous faces are equally masculine and feminine. Our past work challenged that assumption, finding that faces could be perceived simultaneously as androgynous and strongly gendered. The current study uses a reverse correlation technique (Dotsch & Todorov, 2011) to examine the stimulus characteristics that make a face look more or less androgynous. Observers viewed a pair of male or female faces embedded in Gaussian white noise and chose the face that appeared more androgynous. The two noise fields varied across trials, but were anti-correlated within each trial. Noise fields were sorted based on observer responses and averaged to create a Classification Image (CI) and antiCI. Preliminary results showed that the spatial structure in the CI was related to perceived androgyny: when the CI and antiCI were added to the base face images, the base+CI was clearly more androgynous than the base alone or the base+antiCI. Currently, we are investigating the similarity of CIs obtained from different observers and from different base male and female faces. To verify our findings, we plan to have new observers view CI and antiCI pairs and judge which is more androgynous. We also plan to use this technique to create additional CIs that represent concepts related to androgyny, such as masculinity and femininity. The results of these studies will shed light on our understanding of how the visual system processes face gender information.

Jesse Pazdera

Pitch induces illusory percepts of time
Jesse K. Pazdera, Laurel J. Trainor

Accurate tempo-tracking in auditory perception helps us to direct our attention to critical moments in speech and music. However, past research suggests that perceived tempo can be influenced by other, nontemporal features of an auditory stimulus. For example, people tend to rate music as faster when it is played in a higher octave than when it is played in a lower octave. It has therefore been suggested that pitch height alters tempo perception. However, previous studies have typically compared only one lower register with one higher register, leaving pitch height confounded with other factors like cochlear sensitivity that also change across octaves. My research this year has focused on mapping out these illusory tempo effects over six octaves to disambiguate these factors and better understand how tempo perception varies across the broader range of human hearing. These findings will help us to develop theories as to why seemingly unrelated acoustic information is capable of affecting time perception, and they may teach us something new about how our brains process time. In this talk I will discuss the results of a few of our latest experiments, as well as our working theory as to how pitch induces illusory percepts of time.

Brendan McEwen

Camouflage, conspicuousness, & antipredator behaviour in an Amazonian poison frog & non-toxic mimic
Brendan L. McEwen, Isaac D. Kinley, Hannah M. Anderson, Justin Yeager, Jonathan N. Pruitt, James B. Barnett

The Amazonian rainforest is a dynamic environment brimming with predation threats, and prey species occupying these habitats are under immense pressure to reduce these pressures on their survival. While some species avoid detection through cryptic strategies, i.e. camouflage, others aim to make their presence known to predators by signaling toxic defenses with bright colouration – an evolutionary strategy known as Aposematism. Conventional wisdom would suggest that camouflage and aposematism are mutually exclusive survival strategies, but emerging evidence suggests that aposematic species may simultaneously be cryptic to predators under certain conditions. Aposematic species’ signaling can be parasitized and co-opted by non-toxic species through Batesian Mimicry, affording predator avoidance to these non-defended species. However, mimics are often imperfect in ways that may affect how conspicuous they are to would-be-predators. Further, even while mimicking a toxic species, mimics are under much greater predation threat than their models and may need to behave differently in the face of danger. We examined differences in conspicuousness between the toxic Amazonian frog Ameerega bilinguis and its non-toxic mimic Allobates zaparo using simulated predator vision and human detectors. We then attempt to associate these differences in detectability to differences in antipredator behaviour trials performed in their natural habitat. We find that components of body colouration leads the non-toxic mimic A. zaparo to be more conspicuous than its toxic model A. bilinguis to both simulated predator visual systems and human detectors, and find evidence for a behavioural antipredator adaptation in A. zaparo to compensate for its lack of chemical defense.

Elizabeth Phillips

A vocal-melodic theory of the evolutionary origins of musical scales
Elizabeth Phillips, Steven Brown

The predominant theory of the origin of musical scales stems from the observation that some musical intervals are related to frequency ratios present in the natural harmonic series. From the time of the ancient Greeks onward, harmonicity theory has influenced the practice of instrumental tuning in Western music. However, the voice is the most ancestral and universal pitched instrument and it cannot be pre-tuned the way that instruments can. As a result, sung notes are notoriously imprecise in their tuning properties. In the present study, we analyzed the precision and tuning of notes from vocal melodies – from both European folk and non-Western indigenous traditions – relative to flute melodies of both folk and classical European origin. The results showed that, whereas Western instrumental melodies conformed somewhat to harmonicity, vocal melodies showed significant pitch imprecision and a general disregard for harmonic tuning principles. Importantly, these vocal effects were present regardless of culture, suggesting that they arise from physiological limitations in the vocal-production mechanism. These results highlight striking differences in the pitch-class properties of the voice and musical instruments. Given that song is the most ancestral form of pitched music, these results point to shortcomings in the harmonicity theory and thus call for the development of a vocal-melodic theory of the origin of musical scales. This evolutionary theory should be built cross-culturally, by investigating how the biological- and cultural-evolution mechanisms constraining all vocal music may consistently shape musical scale structure.

2:00 - 2:45 PM Poster Session

Rachael Finnerty

Online Group Music Therapy: A proactive approach
Rachael Finnerty, Laurel Trainor

This research explores the efficacy of online group music therapy as a proactive intervention for university students to manage stress and anxiety in comparison to the standard of care, verbal counseling. Students are randomly assigned to one of: 1) online active group music therapy, 2) online receptive group music therapy, 3) online group verbal therapy, 4) wait-listed control group, 5) no-intervention control group. Demographic information, music background and the Ten Item Personality Index are collected. Before and after each online therapy session, students rate their stress (Likert scale), complete the State-Trait Anxiety Inventory (State) questionnaire and provide heart rate variability using a phone app. The online therapy groups run once a week for six-weeks. All participants complete the WHO-Quality of Life (short-form), the Perceived Stress Scale and provide a hair sample for cortisol analysis before and after the six-week intervention. We expect stress and anxiety to decrease in all three online therapy groups from before to after each session as well as from before to after the six-week intervention, whereas we expect little change in the two control groups. Data collection is ongoing in cohorts of 50 (10 per group), with a goal to test 200 participants. The efficacy of online group music therapy will be compared to the verbal standard of care. If online group music therapy is effective, it could become a relatively low-cost proactive approach to managing stress and anxiety, lowering the strain on health care supports on campuses, and enhancing overall student well-being.

Cindy Tran

Learning conversations in the operating room: The impact of new surgical coaching tool
Cindy Tran, Jennifer Zering, Kathleen Howcraft, Ranil Sonnadara

Introduction: Despite evidence positioning coaching techniques as a central component of competency-based medical education (CBME), implementations of coaching are highly heterogenous in medical education to date. In the present study, we explored the impact of a new surgical coaching checklist on teaching and learning experiences in the operating room (OR). Method: Eight staff and eight surgical trainees used the new coaching checklist for four weeks. Following this, they participated in individual interviews. Questions explored experiences with the coaching tool, barriers and facilitators to use of the tool, and perceived effectiveness of the tool. Interviews were transcribed verbatim and analyzed for themes.
Results: Staff and trainees reported that the checklist was helpful, providing opportunities for persistent interactions, facilitating more direct feedback, and creating a consistent, structured framework for teaching in the OR. The tool was most effective when both parties believed its use would add value to the teaching encounter. Lack of preparation, individual teaching preferences, inability to communicate openly, and competing time demands impeded usage of the tool.
Conclusions: The surgical coaching tool fosters good educational practice and more positive teaching and learning experiences, encouraging a more collaborative teaching environment. The adoption of coaching techniques continues to become increasingly important as more programs shift towards CBME curriculums. Future work will further explore how the tool will help provision and interpretation of meaningful feedback and improving the culture around assessment in CBME.

Seyedbehrad Dehnadi

Exploration of the Bayesian Model of Tactile-Spatial Perception
Seyedbehrad Dehnadi, Daniel Goldreich, Jonathan Tong, Lux Li

Our brains are remarkable at producing an accurate perception of the world from the noisy and ambiguous sensory information they receive. The process by which sensory neurons encode physical stimuli as neural signals is relatively well understood. However, much less is known on how the brain infers stimuli from these signals. While it is accepted that this inference is based on a series of assumptions the brain makes about the world, the details of this inference process require further investigation.
A promising computational model of the brain that can optimally explain the inference process is the Bayesian model. This statistical model proposes that perception is a dynamic process that combines stimulus information with our past experiences. While this model has been effective in replicating human performance on visual and auditory-based perceptual decision-making tasks, it has scarcely been applied in studies of tactile perception. As a result, it is not known if the Bayesian model of perception is generalizable to all senses.
My thesis explores whether a Bayesian observer with access to cortical firing rates could replicate human perception on tactile spatial tasks. So far, we have been able to broadly replicate human performance on Adaptation Induced Repulsion Illusion, Classic Two-Point Discrimination task, Two-Point Discrimination task and Classic Two-Point Discrimination task. We are planning to investigate other tactile experiments and derive prediction based on our model. We hope that our model will deepen the basic scientific understanding of perceptual processing and be beneficial in the construction of neuroprosthetics involving tactile perception.

Konrad Swierczek

Predicting the dynamic perception of musical key: a cognitive model
Konrad Swierczek, Matthew Woolhouse

Musical key, a set of salient pitches within a piece of music, is a central part of experiencing western tonal harmony: even casual listeners are adept at detecting key. Traditional music-theoretic and earlier psychological models evaluate the key of a piece by diatonic-set membership or arbitrary functional labels. While this approach is effective when modelling largely diatonic music, it is less effective in relation to western chromatic music, i.e. repertoire that uses all twelve pitch classes. Indeed, chromaticism has become such a ubiquitous part of the western musical tradition, including pop, that it may even contribute to the formation of key. If the perception of key is not simply the product of diatonic scale membership, what other factors might influence how it arises? We hypothesize that tonal attraction (the perception of pull, push, inertia, and resolution in music) is, in part, responsible for the formation of major and minor key tonal hierarchies: unambiguously directed attraction promotes the perception of a key, while ambiguously directed attraction does not. The proposed formal model of musical key uses “interval cycle proximity” (a cognitive grouping mechanism), rare-interval/diatonic similarity, short-term memory, and psychoacoustic factors to predict the dynamic perception of key across a piece of music by encultured listeners. Since the model is based on cognitive and sensory processes rather than functional labels, it is particularly effective at interpreting previously ambiguous passages of music where a key is either obscured or is in conflict with music theory.

Emma Marsden

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Carly McIntyre-Wood

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Peter Najdzionek

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Maya Flannery

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Jiali Song

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3:00 - 3:30 PM Lightning Talks

Vidhi Patel

Elucidating the Neuroprotective Mechanisms of Phytocannabinoids
Vidhi Patel & Ram Mishra

Background: Neurodegeneration is the gradual loss of neuron structure or function, including neuronal death. A cause of neurodegeneration is the persistent activation of the unfolded protein response (UPR), which leads to cell death caused by endoplasmic reticulum (ER) stress. Cannabinoids, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), were neuroprotective in cellular and animal models of neurodegeneration due to their antioxidant and anti-inflammatory properties. However, there is limited evidence on the role of THC and CBD in ER stress mediation.
Objective: To investigate the neuroprotective mechanisms of THC and CBD using a cellular model of ER stress. Cell viability and the gene expression of UPR proteins will be measured to investigate the effects of treating with cannabinoids prior to exposure to ER stress.
Results: Cell viability increased significantly with THC or CBD pre-treatment but was not significantly altered when the cannabinoids were combined. There was a significant increase in the gene expression of an ER chaperone (GRP78), neurotrophic factor (MANF), and an anti-apoptotic gene (BCL-2) with cannabinoid pre-treatment before ER stress induction.
Significance: These results suggest that exposure to cannabinoids before ER stress induction may shift the UPR to a more adaptive response compared to the terminal UPR response that results in neuronal death. Understanding the role of ER stress in the neuroprotective properties of cannabinoids will provide greater detail about the underlying mechanisms of neurodegeneration and the potential of using cannabinoid treatments to mitigate neurodegeneration.

Lucas Klein

Can machine learning help us understand the musical cocktail party problem?
Lucas Klein & Laurel Trainor

"The ability to allocate attention selectively to one of many sound streams underlies the so-called ‘cocktail party problem.’ Previous research has shown that multi-variate analysis of single-trial electroencephalography (EEG) recordings can be used to identify the attended speech stream in multi-speaker environments. However, few studies have applied this method using naturalistic music stimuli, despite the importance of selective listening for hearing and playing music. For example, orchestra conductors must learn to listen to one section over another, ensemble musicians listen for cues in each other’s playing, and duettists must be able to distinguish their own playing from their partners’.
Cortico-Acoustic Correlation (CACor), a measure of synchronization between the audio stimulus and EEG projections derived using regression filters, has been applied successfully to single-trial data. The spectrogram reconstructed from EEG signals during listening to the attended stream solo was more highly correlated with the audio stimulus than that reconstructed from the unattended stream. Here, we propose to adopt a stimulus reconstruction method to decode auditory selective attention to one of two instruments concurrently playing the high and low parts of a series of contrapuntal melodic sequences.
A model that can successfully identify the target of attention during music listening could inspire a host of new tasks aimed at understanding attentional mechanisms involved in live performance. By collecting EEG while multiple musicians perform and again while they listen to recordings, algorithms could be trained to decode each musician’s attention to each other’s sound as they play.

Jamie Cochrane

Effects of varying facial region visibility on perception
Jamie Cochrane, Leigh Greenberg, Solmaz Vakili

With the current need for constant mask-wearing, many are asking how facial covers will hinder perception. Facial perception is a vital part of social interactions. With that, a recent study by Freud et al. 2020 found [that?] masks significantly hinder face recognition. This finding is somewhat conflicting with other data that suggest that the horizontal eye region is the crucial area for face recognition (Gold, Sekuler, & Bennett, 2004; Sekuler, Gaspar, Gold, & Bennett, 2004). Ideally, if the eye region is preferentially important to facial recognition, masks would not meaningfully hinder perception. Therefore, further investigation is needed to conclude the effects of masks. This study plans to explore the potential detriment a mask can have on one's immediate recognition. Previously, masked facial recognition studies have focused on memory performance, using such methods as the Cambridge face memory task. To remove memory as a confound, this investigation will implement a five-alternative forced-choice task. Participants will fixate on a target face for half a second before the stimuli changes to five alternative faces. The participants must choose the alternative face that matches the target. For comparison, two groups plus a control will be used, varying the method of lower facial visibility: one full-face control, one masked group, and one lower facial removal group. Based on the previous knowledge, it is hypothesized masks will hinder performance, but to what extent is unknown.

Janice Yan

Exploring the social consequences of sexual conflict using bedbug social networks
Janice Yan & Reuven Dukas

Bedbugs (Cimex lectularius) are an ideal model for studying the social implications of sexual conflict because of their notably harmful mode of copulation – traumatic insemination. Repeated traumatic inseminations reduce female longevity and lifetime reproductive output due to the energetic costs of wound healing and increased likelihood of infection. As a result, we expect the high fitness costs associated with repeated traumatic matings to result in divergent social preferences between the sexes. To investigate the impact of sexual harassment on social structure, we devised a novel experimental arena that provides bedbug populations with several high-quality shelters as well as an artificial “host” to facilitate natural foraging behaviour. Using a combination of video-recordings and live observation, we will track sexual and social interactions between individually marked bedbugs over several days. With this data, we can use social network analysis to analyze and visualize bedbug social structure and assess various predictions about how the presence of intense sexual conflict influences animal sociality. We will be examining the prediction that female bedbugs engage in less social interactions overall and occupy more peripheral network positions compared to males as well as whether females preferentially seek associations with other females as a strategy to reap the benefits of group-living while mitigating the costs of unsolicited sexual attention.

James Mirabelli

An Investigation of Associations between Auditory-Verbal Hallucinations, Trauma, and Executive Dysfunction in Borderline Personality Disorder
James Mirabelli

Auditory-verbal hallucinations (AVH) appear in 25 to 50% of those with Borderline Personality Disorder (BPD). However, little is known about the etiology and treatment of AVH within a BPD context. The current study aims to investigate the relation between post-traumatic stress disorder (PTSD) symptoms, executive dysfunction (ED), and AVH in BPD. Traumatic memory intrusions and ED appear in both BPD and PTSD. In both incidence and content, AVH are related to traumatic experiences in BPD. Similarly, PTSD presence and symptom severity, particularly intrusions, are associated with AVH in PTSD samples. Furthermore, PTSD and ED severity are related within PTSD. Deficits in source monitoring—an executive function governing perception of memory and thought origin—may impede perception of intrusions as internally generated. It is therefore hypothesized that PTSD symptoms relate to AVH in BPD directly through decontextualized intrusions as AVH content, and indirectly through ED-related source monitoring deficits allowing intrusions to manifest as AVH. BPD-diagnosed outpatients will complete questionnaires assessing PTSD severity and AVH presence. All participants will complete computerized neurocognitive ED measures. AVH-present participants will be assessed for AVH severity. ED and PTSD severity will be compared between the AVH-present and absent groups, and ED will be assessed as a mediator between PTSD and AVH severity in the AVH-present group. AVH interfere with BPD treatment, and are associated with poorer clinical outcomes and exacerbated suicidality. Therefore, there is an urgent need to investigate AVH in BPD. This study will potentially provide the first psychotherapeutic treatment target for AVH in BPD.

Prizes

Top three:

• Oral Presentation: $75
• Poster Presentation: $75
• Lightning Talks: $50

Winners to be announced...