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Browsing by Author "Hassall, Cameron D."

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    An analysis of electroencephalogram (EEG) with machine learning
    (2024) Emery, Jesse; Phan, Nhi; Jime, Isra; Cobzas, Dana; Hassall, Cameron D.
    Our capstone project was done in collaboration with Dr. Cameron Hassall from the Psychology department at MacEwan University. Our data was based on one of Dr. Hassall’s papers on “Task-level value affects trial-level reward processing” (Hassal, C, 2022), where he wanted to determine if the Anterior Cingulate Cortex was responsible or involved in decision making. To determine this, a task sequence was carried out 427 times using 12 participants over a 52 minute period. While the participants completed these tasks, brain activity was being measured using an electroencephalogram (EEG). For our project, the goal was to train a machine learning model to accurately classify an EEG event after training on past events. In greater detail, we focus on the brain signal when the participant hit the left or right button in response to the stimulus which are colored shapes.
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    The neural correlates of continuous feedback processing
    (2023) Hassall, Cameron D.; Yan, Yan; Hunt, Laurence T.
    Feedback processing is commonly studied by analyzing the brain's response to discrete rather than continuous events. Such studies have led to the hypothesis that rapid phasic midbrain dopaminergic activity tracks reward prediction errors (RPEs), the effects of which are measurable at the scalp via electroencephalography (EEG). Although studies using continuous feedback are sparse, recent animal work suggests that moment-to-moment changes in reward are tracked by slowly ramping midbrain dopaminergic activity. Some have argued that these ramping signals index state values rather than RPEs. Our goal here was to develop an EEG measure of continuous feedback processing in humans, then test whether its behavior could be accounted for by the RPE hypothesis. Participants completed a stimulus–response learning task in which a continuous reward cue gradually increased or decreased over time. A regression-based unmixing approach revealed EEG activity with a topography and time course consistent with the stimulus-preceding negativity (SPN), a scalp potential previously linked to reward anticipation and tonic dopamine release. Importantly, this reward-related activity depended on outcome expectancy: as predicted by the RPE hypothesis, activity for expected reward cues was reduced compared to unexpected reward cues. These results demonstrate the possibility of using human scalp-recorded potentials to track continuous feedback processing, and test candidate hypotheses of this activity.
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    One hundred years of EEG for brain and behaviour research
    (2024) Mushtaq, Faisal; Welke, Dominik; Gallagher, Anne; Pavlov, Yuri G.; Kouara, Layla; Bosch-Bayard, Jorge; van den Bosch, Jasper J. F.; Arvaneh, Mahnaz; Bland, Amy R.; Chaumon, Maximilien; Borck, Cornelius; He, Xun; Luck, Steven J.; Machizawa, Maro G.; Pernet, Cyril; Puce, Aina; Segalowitz, Sidney J.; Rogers, Christine; Awais, Muhammad; Babiloni, Claudio; Bailey, Neil W.; Baillet, Sylvain; Bendall, Robert C. A.; Brady, Daniel; Bringas-Vega, Maria L.; Busch, Niko A.; Calzada-Reyes, Ana; Chatard, Armand; Clayson, Peter E.; Cohen, Michael X.; Cole, Jonathan; Constant, Martin; Corneyllie, Alexandra; Coyle, Damien; Cruse, Damian; Delis, Ioannis; Delorme, Arnaud; Fair, Damien; Falk, Tiago H.; Gamer, Matthias; Ganis, Giorgio; Gloy, Kilian; Gregory, Samantha; Hassall, Cameron D.; Hiley, Katherine E.; Ivry, Richard B.; Jerbi, Karim; Jenkins, Michael; Kaiser, Jakob; Keil, Andreas; Knight, Robert T.; Kochen, Silvia; Kotchoubey, Boris; Krigolson, Olave E.; Langer, Nicolas; Liesefeld, Heinrich R.; Lippé, Sarah; London, Raquel E.; MacNamara, Annmarie; Makeig, Scott; Marinovic, Welber; Martínez-Montes, Eduardo; Marzuki, Aleya A.; Mathew, Ryan K.; Michel, Christoph; Millán, José D. R.; Mon-Williams, Mark; Morales-Chacón, Lilia; Naar, Richard; Nilsonne, Gustav; Niso, Guiomar; Nyhus, Erika; Oostenveld, Robert; Paul, Katharina; Paulus, Walter; Pfabigan, Daniela M.; Pourtois, Gilles; Rampp, Stefan; Rausch, Manuel; Robbins, Kay; Rossini, Paolo M.; Ruzzoli, Manuela; Schmidt, Barbara; Senderecka, Magdalena; Srinivasan, Narayanan; Stegmann, Yannik; Thompson, Paul M.; Valdes-Sosa, Mitchell; van der Molen, Melle J. W.; Veniero, Domenica; Verona, Edelyn; Verona, Edelyn; Voytek, Bradley; Yao, Dezhong; Evans, Alan C.; Valdes Sosa, Pedro
    On the centenary of the first human EEG recording, more than 500 experts reflect on the impact that this discovery has had on our understanding of the brain and behaviour. We document their priorities and call for collective action focusing on validity, democratization and responsibility to realize the potential of EEG in science and society over the next 100 years.
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    Reward positivity affects temporal interval production in a continuous timing task
    (2024) Yan, Yan; Hunt, Laurence T.; Hassall, Cameron D.
    The neural circuits of reward processing and interval timing (including the perception and production of temporal intervals) are functionally intertwined, suggesting that it might be possible for momentary reward processing to influence subsequent timing behavior. Previous animal and human studies have mainly focused on the effect of reward on interval perception, whereas its impact on interval production is less clear. In this study, we examined whether feedback, as an example of performance-contingent reward, biases interval production. We recorded EEG from 20 participants while they engaged in a continuous drumming task with different realistic tempos (1728 trials per participant). Participants received color-coded feedback after each beat about whether they were correct (on time) or incorrect (early or late). Regression-based EEG analysis was used to unmix the rapid occurrence of a feedback response called the reward positivity (RewP), which is traditionally observed in more slow-paced tasks. Using linear mixed modeling, we found that RewP amplitude predicted timing behavior for the upcoming beat. This performance-biasing effect of the RewP was interpreted as reflecting the impact of fluctuations in reward-related anterior cingulate cortex activity on timing, and the necessity of continuous paradigms to make such observations was highlighted.