Dear all,
On Friday, November 23, Dr. Heungsun Hwang from McGill's Psychology will be speaking about structural equation modeling for genetic, brain, and cognitive data (title & abstract below). As usual, the talk will span from 12-1 PM in room 735 of 2001 McGill College Avenue. Everyone is welcome.
For a full schedule of talks this term, please visit https://www.mcgill.ca/psychology/events-colloquia-0/brownbag-series.
To be added to the cognitive list serve and get day-of updates & information about additional talks, please visit http://mx0.psych.mcgill.ca/mailman/listinfo/coggroup.
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Imaging genetics structural equation modeling for investigating associations among genetic, brain, and behavioural/cognitive phenotypes
Heungsun Hwang (Psychology, McGill)
Researchers in statistical science have increasingly been able to access both genetic and neuroimaging data collected from the same individuals, enabling to investigate genetic influence on the variation of brain function which is in turn associated with behavioural or cognitive variation. This emerging field, called imaging genetics, aims to integrate genetic and neuroimaging data with behavioural or cognitive outcomes to identify the neuromechanisms linked to individual differences in psychiatric disorders or cognitive tasks. Despite its great potential for studying disease- or task-specific “gene-brain-behaviour/cognition (G-B-B/C)” relationships, imaging genetics is faced with an ever-increasing need for statistical tools to examine these relationships in a more unified and confirmatory manner, while taking into account biological complexities (e.g., genetic networks, gene-gene interactions, gene-environment interactions, etc.) and methodological issues (e.g., high dimensionality and multicollinearity) embedded in genetic and neuroimaging data. Thus, we develop a general statistical tool, named Imaging Genetics Structural Equation Modeling (IGSEM), which allows researchers to specify various biologically plausible G-B-B/C relationships based on previous theories and knowledge, and examine the relationships in a more confirmatory manner. We will provide a non-technical description of IGSEM and its illustrative applications to PTSD and depression data.
Dear all,
On Friday, November 16, Dr. Natasha Rajah from McGill's Psychiatry/Psychology and Director of the Douglas Brain Imaging Center will be speaking about age-related differences in episodic memory-related brain function (title & abstract below). As usual, the talk will span from 12-1 PM in room 735 of 2001 McGill College Avenue. Everyone is welcome.
For a full schedule of talks this term, please visit https://www.mcgill.ca/psychology/events-colloquia-0/brownbag-series.
To be added to the cognitive list serve and get day-of updates & information about additional talks, please visit http://mx0.psych.mcgill.ca/mailman/listinfo/coggroup.
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Age-related differences in episodic memory-related brain function
Dr. Natasha Rajah
Associate Professor, Department of Psychiatry
Associate Member, Department of Psychology
Director, Douglas Brain Imaging Centre
McGill University
Age differences in brain activity have been reported during both encoding and retrieval of past events. Yet, it remains unclear whether these differences are due to age, performance, or age*performance effects. In the current presentation, I will discuss our results from an event-related fMRI study of spatial and temporal context encoding and retrieval in the adult lifespan in which we examined age and performance effects. We conducted a multivariate behavior partial least squares (B-PLS) analysis of fMRI data to differentiate age (as a continuous variable), performance (accuracy) and age*performance effects on brain activity across the adult lifespan. This analysis identified three significant effects: 1) activity in fusiform, middle occipital temporal and inferior parietal cortices increased with age and decreased with performance; 2) Dorsolateral prefrontal cortex (DLPFC) and limbic activity increased with age at encoding, and increased with performance at retrieval; and 3) Right ventrolateral prefrontal and bilateral hippocampus (HC) increased with age during retrieval and was differentially related to performance during encoding versus retrieval. We then conducted a seed voxel PLS analysis to test the hypothesis that age-related increases in DLPFC and posterior HC activity may be related to altered patterns of functional connectivity between these two brain areas, and with ventral visual and fronto-parietal areas. Our findings show that advanced age was related to increased positive connectivity amongst DLPFC, posterior HC, ventral visual and parietal regions. In contrast younger adults exhibited positive connectivity between DLPFC, ventral visual and parietal regions, and negative connectivity between these regions and posterior HC. We conclude that age-related increases in positive DLPFC-HC connectivity may reflect unconstrained encoding and retrieval, which negatively impact memory performance in older adults.
Dear all,
On Friday, November 2, Dr. Aparna Nadig from McGill's School of Communication Sciences and Disorders will be speaking about bilingualism and executive functions in children with autism (title & abstract below). As usual, the talk will span from 12-1 PM in room 735 of 2001 McGill College Avenue. Everyone is welcome.
For a full schedule of talks this term, please visit https://www.mcgill.ca/psychology/events-colloquia-0/brownbag-series.
To be added to the cognitive list serve and get day-of updates & information about additional talks, please visit http://mx0.psych.mcgill.ca/mailman/listinfo/coggroup.
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Proficient bilingualism and children with autism – is it possible? Can it alleviate executive function difficulties?
Dr. Aparna Nadig, McGill SCSD
Children with autism often experiences language delays. In this context, it is a common belief that bilingualism may be too challenging for them and may harm their language development. (1) We examined whether proficient bilingualism is possible in school-age children with autism growing up in Montreal, by assessing their language skills as well as by examining the relationship between their amount of language exposure and skills in that language. Our findings demonstrate that proficient bilingualism is possible for some children with autism. (2) Children with autism demonstrate significant executive function (EF) difficulties. Enhanced EF performance has been reported in typically-developing bilingual children relative to monolinguals. We hypothesized that proficient bilingualism may alleviate EF impairments in autism, and tested this using set-shifting and verbal fluency tasks. In both cases, proficient bilinguals with autism outperformed well-matched monolinguals with autism. These findings build on previous research demonstrating that bilingualism is not detrimental for language development in autism. Moreover, they provide novel evidence indicating that bilingualism may even hold benefits with respect to mitigating some executive function impairments in this population.
