BrainsCAN Fellows

Research Information:
Anxiety disorders affect millions of Canadians, impairing their mental, physical, and social lives. Existing
pharmacotherapies used to treat anxiety disorders can have serious side-effects, including drug dependence and cognitive impairments. Recent research has suggested that cannabis derived compounds, particularly cannabidiol (CBD), may provide an alternative therapy for anxiety disorders. Using a model of general anxiety, this project aims to identify the neural systems associated with anxiety by employing neural recordings and advanced imaging techniques. Furthermore, we will assess the effectiveness of CBD, and other cannabis-derived substances, to treat anxiety and the associated cognitive impairment. These studies will improve our understanding of the mechanisms of anxiety disorders and the associated cognitive disorders. Additionally, this research will greatly aid in the development of safer and more effective pharmacotherapies.

Research Information:
Hearing loss affects > 40% of people aged 50 or older and increases their risk for additional health problems (e.g., depression, cognitive decline). Diagnosis of hearing impairment relies on measuring sensitivity for at‐threshold sounds, but it fails to capture problems older people experience with suprathreshold sounds. For example, many people perceive sounds at moderate intensities to be unpleasantly loud (‘hypersensitivity’), which may result in individuals being easily distractible and avoiding social situations. This project is a multi‐site collaboration involving three labs at Western University and one lab at Purdue University that will study impaired neural adaptation and its relation to hypersensitivity to sound in rats and humans. Understanding the physiological underpinnings of suprathreshold deficits is the first step to effective diagnosis and treatment.

 

Publications: 
Journal of Neuroscience: Aging Affects Adaptation to Sound-Level Statistics in Human Auditory Cortex; Media: Study: ‘Sound’ differences between age groups

Research Information:
The sustained and excessive consumption of calorie-dense foods is the leading cause of preventable chronic disease and premature death worldwide. Limiting the consumption of these foods is therefore essential to maintain optimal health. However, in the modern food-rich environment, maintaining a healthy diet has become a difficult endeavor. The environment is saturated with unhealthy ultra-processed calorie-dense foods (those high in saturated fats and sugar), and these foods are often cheaper than their healthier counterparts. This is coupled with omnipresent cues, in the form of media advertisements, to consume these foods. While some individuals find it really difficult to control calorie-dense food consumption in this environment, others are more adept. My research seeks to understand why some individuals are more prone to overconsumption than others. Specifically, my body of research seeks to understand the neural circuits underlying vulnerability to over consumption, with the particular focus on how the prefrontal cortex regulates reward circuits in the brain to modulate consumptive behaviours across developmental contexts. By delineating these neurobiological processes, we will be able to identify the subtle cognitive and neural markers that increase the propensity to overeat. This would enable researchers and clinicians to identify those individuals that may be more likely to respond to a given intervention and provide the foundational work necessary to develop novel evidence-based interventions.

 

Publications: 
Trends in Cognitive Sciences: Review suggests a reciprocal relationship between obesity and self-control

Research Information:
Auditory cortex (AUD) is critical to our perception of spoken language, and the crossmodal plasticity that follows hearing impairment to improve visual perception impedes hearing restoration. Hearing impairment makes it impossible to functionally localize AUD with noninvasive magnetic resonance imaging (MRI) methods in order to understand the crossmodal plasticity that follows deafening. Structural MRI (sMRI) methods are thus needed to study the reorganization of AUD as it undergoes crossmodal plasticity following hearing impairment. Current imaging studies are increasingly using myelin to map the brain because MRI methods can measure how it restricts the movement of water. My previous work has shown that subregions of AUD differ markedly in quantitative myelin content, and recent imaging work confirms this agreement using structural and functional MRI in humans. This project establishes the precision of myelin as a structural marker of AUD in an animal model and then pilots the use of this method to study crossmodal reorganization in humans with hearing impairment. These results will fill a major gap in our understanding of the mechanisms of crossmodal plasticity by developing, validating, and applying the first structural marker of AUD to study the brain as it undergoes reorganization following hearing impairment.

Research Information:
Up to 20% of pregnant women self-report using cannabis during pregnancy. With recent decriminalization and progressive legalization of recreational cannabis in North America, this figure is projected to increase. While the THC component of cannabis has been shown to impair fetal growth in clinical populations and animal models, our understanding of the developmental effects, and associated neural pathways, of maternal cannabis consumption is currently lacking. This project will address this knowledge gap in a model of prenatal cannabis exposure. Specifically, the effects of cannabis constituents on cognition (e.g. learning and memory) will be investigated at the levels of behaviour, neural pathways, and brain structures. The goal of this project is to improve postnatal developmental outcomes and inform public awareness of the risks associated with prenatal cannabis consumption.

Research Information:
The early life period sees rapid and fundamental maturational changes in the structure and function of the brain. These alterations include cortical reorganization, synaptic pruning and myelination, with varying time courses across development. This project will determine the impact of diet on functional brain network structure essential for cognition. The outcomes of this project will provide the basis for significantly reducing the impact of diet-induced cognitive decline through health recommendations in the clinic and public policy regarding diets.

 

Publications: 
Trends in Cognitive Sciences: Review suggests a reciprocal relationship between obesity and self-control

Research Information:
Oculomotor tasks have long been used as an index of cognitive control dysfunction in neuropsychiatric conditions (e.g., schizophrenia) in humans. Much of the understanding of this oculomotor circuitry has come from saccadic eye movement tasks – neuropsychiatric diseases, however, are difficult to model. With the advent of transgenic and optogenetic techniques, the use of saccadic tasks in preclinical NHP models of human brain diseases has tremendous potential for detecting the underlying disease-related pathophysiology of these debilitating brain disorders. To that end, this project involves the development of protocols for awake-behaving NHP functional magnetic resonance imaging at ultra-high field – by using saccadic tasks during fMRI acquisition, we can identify functional network topologies in NHPs that are homologous with the human brain. Understanding the functional organization of the NHP oculomotor circuitry will be important as researchers leverage the genetic similarity of NHPs to model human neuropsychiatric diseases.

Research Information:
Speech is arguably the most important form of human communication. Since the goal of speech production is the transfer of information, speech production must be carefully regulated to ensure the desired information is conveyed. During speech production sensory feedback, such as auditory feedback, plays an important role in maintaining the fluidity of speech, as it allows speech motor movements to be monitored and production errors to be detected and corrected. A major focus of my research program is investigating how the role of sensory feedback in the control of speech changes throughout development in individuals with and without autism spectrum disorder. I am also interested in how the ability to extract and utilize the information contained in sensory feedback influences the development of higher-order cognitive processes such as speech communication, emotion regulation, and social competence.

Research Information:
The recognition of speech is fundamental for so many day-to-day activities that we often take this skill for granted, particularly in adverse listening conditions (e.g., maintaining a conversation in a crowded café). Reducing listening effort in these challenging environments is important for improving the quality of life for individuals across ages, and one promising means of achieving this goal is through developing perceptual expertise related to talker identity. Voices of friends or family members are substantially more intelligible than unfamiliar voices and are less susceptible to interference by competing sounds, indicating that they are less cognitively demanding and thus may reduce listening effort. Yet, a systematic understanding of how perceptual familiarity develops and leads to improved speech intelligibility is lacking. Thus, the overarching goal of this project is to determine how we develop familiarity with voices to realize maximal benefits to intelligibility. This goal will be informed by recent advances in our understanding of perceptual learning mechanisms as well as the neurobiology of sleep-dependent memory consolidation.

Research Information:
Reaching movements are critical actions for everyday life that involve processing sensory feedback from muscles, joints, and skin across muliple parts of the cerntal nervious system – initially within spinal pathways that act quickly but have limited processing capabilities, and then within cortical pathways that act slower but can produce very sophisticated motor commands. I am interested in testing whether the cortical pathways that process this type of sensory feedback “understand” the processing capabilities of spinal pathways. In the work supported by my BrainsCAN Fellowship, I will experimentally impair the spinal pathway’s ability to process sensory feedback to support reaching movements and test whether the sensory processing that occurs in cortical pathways compensates for the induced spinal dysfunction. It is my hopes that this work will provide insight into how the different areas of the central nervous system work together to processes the sensory information that is important for controlling movement, and then use these insights for improving rehab programs for various situations, including peripheral nerve injury, spinal cord injury and limb amputation.

 

Publications: 
Nature Neuroscience: Spinal stretch reflexes support efficient hand control; Media: Spinal cords contribute to complex hand function

Research Information:
One quarter of the population has such difficulty learning mathematics that it impairs their ability to use information effectively in adult life. What causes some students to struggle with math? Brain imaging research has begun to shed light on how the brain processes numerical information. However, little is known about how this information is integrated across the brain systems important for math learning, such as memory and attention. With this fellowship, I will conduct a series of studies that provide detailed information about the brain mechanisms that support math skills. First, using ultra-high field 7T magnetic resonance imaging (MRI), I will begin to answer questions about how the brain solves math problems at the individual level. This is an important advance because behavioural research shows that children with math learning difficulties are very different from one another. Second, I will investigate the possibility of subtypes of math learning disability with children who have been identified to need math remediation. To do this, I will identify subgroups of individuals with similar cognitive profiles and compare neural signatures of these cognitive profiles. Research in this area will pave the way to improved pedagogical techniques, diagnosis of learning disabilities, and remediation of deficits.