People in the Lab
I have two research streams that rely on similar technologies:
(1) What happens in the human brain when people perform simple challenge tasks requiring an increase in attention? This happens whenever a task increases in difficulty, or they make an error, or get unexpected feedback. The result is an activation in the medial frontal cortex monitoring region, especially the anterior cingulate. I use EEG/ERPs to monitor these brain responses. Human brains react to a disappointing outcome with what are called medial frontal negativities, the easiest of which to measure is the error-related negativity (ERN) which is easily recorded when someone realizes they have made an error. Several aspects of my current research focus on this phenomenon in different contexts. I use this (and other ERP measures, such as the visual P1 and N170 ERP components) to test neuropsychological models involving the following factors:
(a) Personality individual differences: Of particular interest to me are personality characteristics such as risk-taking and sensation-seeking personality styles, responses to rewards and punishments (including harm-avoidance), and the degree of the person’s empathy and obsessive-compulsiveness. We have found these relate to various ERP components, including the medial frontal negativity.
(b) Developmental differences: The prefrontal cortex of the adolescent brain is still rapidly maturing, and so does its production of ERPs. I am examining the relation between brain maturation and the production of various ERPs, and what cognitive or personality characteristics account for the individual differences in this growth. Of special interest is the relation between these brain responses and the adolescent's propensity to engage in high-risk behaviours and to show good vs poor emotional self-regulation.
(c) Child and adolescent mental health: The growth and function of the medial prefrontal cortex and its relation to well-being and mental health is central to another set of studies, focusing on adolescents. These look at aspects of traits outlined in (a) and (b) above, but in the clinical end.
(2) Another research stream involves rapid cognitive information processing, such as word reading and object and face perception. In both cases, early responses from the visual cortex are easily recorded with ERPs. We are relating word-reading ERPs to the individual's reading and fluency skills, and object-perception ERPs to meaning processes, and examining how these relate to attention control functions of the anterior cingulate and medial frontal cortex.
Sleep, Sleepiness, Sleep Deprivation, Performance while Sleepy, Event Related Potentials (ERPs), Risk Assessment during Sleepiness
I am interested in how the brain functions and how well people perform while sleepy. My recent research has looked at :
- 1) the effect of 20 hours of sleep deprivation on several EEG and ERP (P300, CNV, ERN, Pe) indices of brain functioning, attention and performance monitoring and how they relate to behavioural performance
- 2) the effect of habituation on an event-related potential component (P300) thought to be reflective of attention
- 3) unintentional sleep onset (falling asleep while intending to remain awake).
Future research may involve combining sleep deprivation and mild intoxication as
Lab Technician, BA Visual Arts, BA Psychology, MA Psychology (Behavioural Neuroscience)
My research interests center on the relative contribution of top-down and bottom-up processes in perception. More specifically, what is the earliest junction of a perceptual path that can be altered by mental context manipulations? For example, when presented with multiple instances of an identical stimulus, how do brain responses vary from presentation to presentation, and how far down the sensation-to-perception-to-representation continuum can these variations take place? Further, what factors (such as arousal, attention, task demands, expertise, etc.) contribute to changes in the relative influence of top-down and bottom-up processes in perception?
In addition, as a technician I am developing analysis tools for exploring and testing complex patterns in EEG signals, including Matlab tools compatible with EEGLab and High Power Computing facilities (e.g SHARCNet) for automated artifact detection, pattern detection in continuous or segmented data, batch processing and robust bootstrap testing.
As the lab coordinator, I train and assist students with their data acquisition and processing, from study design to applications for ethical clearance. We work with both the EGI system and BioSemi. We use a wide array of programs for analyzing data, from Brain Vision Analyzer, EEGLab and ERPScore. I have organized the booking and collected data for studies involving community participants, ranging from teenagers, to senior adults.
Risk-taking behaviour is generally considered maladaptive and can be observed in variety of populations. However, some populations and individuals are thought to be more vulnerable to such behaviours. My MA research focuses on testing a model of reward-related behaviour through the development of two gambling paradigms that will allow us to identify and investigate differences in event-related potentials (ERPs) at various stages of the proposed model. Additionally, I will be looking at variability of these ERPs as a function of individual differences in order to examine the role of personality factors in risk-taking behaviour. In the future, we plan to use the developed paradigms to investigate developmental factors that are associated with vulnerability to risk-taking behaviour.
Over the course of my PhD I have been, and continue to, investigate the neurophysiological and genetic correlates of adolescent self-regulation abilities. To achieve these goals I employ EEG/ERP techniques to collect data on the neural markers of attentional control (one aspect of self-regulation). I am interested in early (bottom-up) control of attention (e.g., the P50 ERP component) as well as later (top-down) control of attention. I also collect data on adolescent’s self-regulatory skills as they play out in the real world. Lastly, I collect genetic material for investigating allelic variations that might be associated with the above. I have a particular interest in genes that are related to the dopamine and serotonin systems. I am currently supervised by Dr. Sid Segalowitz in the Behavioural Neuroscience stream.
Stefon Van Noordt
My research examines the functional role of the ACC (and medial prefrontal cortex in general) in performance monitoring using EEG/ERP technology. Currently, we are focusing on the role of the ACC in task-switching, specifically in terms of whether the ACC is sensitive to stimulus cues that signal changes in response contingencies. The ultimate goal is to better understand the functional significance of ACC responses within a coordinated network of brain regions that support behavioural control. Methodologically, my research incorporates a variety of signal processing tools and analytical approaches including time-frequency decomposition, independent components analysis, as well as bootstrapping and robust estimation techniques for testing effects in single subjects and single trials. In addition, I frequently utilize Shared Hierarchical Academic Research Computing Network (SHARCNet) to implement these tools of signal processing and hypothesis testing.
Other research interests I am pursuing include the neuropsychological and psychophysiological correlates of (i) sociopolitical attitudes, (ii) mild head injury in university students, (iii) reward processing across development, and (iv) affect/arousal in performance monitoring.
For my master’s thesis I examined early ERP correlates of emotional face processing (i.e., P1, N170/VPP) as they related to psychopathic personality traits in a subclinical, undergraduate sample. More generally, I am interested in studying the neural mechanisms that underlie the affective abnormalities commonly observed in individuals high in psychopathy. Moreover, the field has increasingly begun to conceptualize psychopathy as a developmental disorder, with evidence of callous-unemotional traits in children as young as five. As such I am also interested in how these abnormalities develop throughout childhood and adolescents. For the purpose of my doctoral dissertation I plan to focus on early ERP components (e.g., P1 to N250) as potential markers of abnormal attention allocation during affective information processing in aggressive adolescents high in callous-unemotional traits. Moreover, I intend to further examine the role that executive functioning ability plays in both neural and behavioural measures of affect processing, as it has been proposed that high executive control may contribute to the legal “success” of psychopathic individuals (e.g., avoiding conviction).
Xin (Reno) Zheng
I am currently doing my Ph.D. in psychology at Brock University, with a major concentration on behavioral neuroscience. My research is focused on cortical neural activations during visual recognition of complex stimuli, including words, faces and objects. To address this issue, I am following two approaches. With a “bottom-up” approach, we center on the properties of visual stimuli themselves and study the effects of such factors as word frequency and facial features on visual recognition. In contrast, with a “top-down” approach, we focus on how a person’s mental state (e.g., attention or appraisal of social/cognitive context) may affect visual recognition. At any particular moment, since an individual’s visual experience of the surrounding environment is constantly influenced by these “bottom-up” and “top-down” factors, it is essential to take both into account in order to have a more comprehensive unde
Undergraduate Thesis Student
First, I am dedicated to learning the current computer software systems (e.g., MATLAB, EEGLAB, DMAT, sLORETA, ERPScore, E-Prime, BESA) with the intention of helping others in the lab explore their data to the fullest. This is done under the supervision of Dr. Sid Segalowitz. Second, I will be spending the upcoming years studying the time-course and constituents of top-down modulation on expert level, bottom-up processing (faces). Specifically, I will be exploring the N170 and D220 (P200) in the context of sleep deprivation (SD) to see how and if they are differentially affected. These components index automatic (N170) and manual (D220) processing in the brain (see Philiastides et al., 2006). Thus, they offer a dichotomous and specific approach to the exploration of SD on cognition. Further, I am interested in the individual differences in noise sensitivity that have been observed in relation to these components (Rousselet, 2011), and how SD alters (perhaps amplifies) these differences. This is done under the supervision of Dr. Tim Murphy.
I’m interested in understanding language processing and how semantic information (what a word or phrase means to us) is represented in the mind and how it is retrieved. My current work is investigating this topic in the context of compound words (two words that are joined together to create a single word). Sometimes, both “constituent” words tell us a lot about the overall meaning of the word (e.g., bedroom: we know this is a room in which a bed is located). In these cases, both constituents can be considered transparent. Sometimes, however, the two constituent words tell us nothing about the meaning of the compound (e.g., deadline: neither dead nor line tell us anything about what a deadline is). Here, both constituents can be considered opaque. Given the clear differences in immediate semantic information offered by compound words that vary in semantic transparency, we can use ERPs to gain insight into how fast, and by what mechanism, the brain retrieves semantic information.
Jazmine Rei Que
Undergraduate Thesis Student
I am a fourth year neuroscience honours student completing my undergraduate thesis with Dr. Sid Segalowitz. My current research project involves the ERP correlates of inhibition and face processing, and the cognitive paradigms used to analyze them. Specifically, I am looking at two early ERP components related to face processing: the P100 and the N170, as well as two ERP components unique to response inhibition in a Go/Nogo task: the N2 and the P300.
Undergraduate Thesis Student
In my honours thesis I am examining electrophysiological evidence of personality. Specifically, I am interested in exploring the relationship between two personality types and performance monitoring, via event-related potentials (ERPs). This is done under the supervision of Dr. Tim Murphy.
Undergraduate Thesis Student
I am currently working on my undergraduate thesis with Dr. Tim Murphy and'we are examining electrophysiological activity as it relates to gambling behaviours. Specifically, we are examining an ERP component referred to as feedback related negativity, which is associated with unexpected events. We want to know how this component relates to consecutive wins and losses in a gambling task across a variety of personality traits. This will be investigated using both an alert and a sleep-deprived condition.