Performing under pressure: The impact of realistic, imminent, and uncertain threats on human cognition and the brain

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Our long-term goal is to define how the human brain manages emotionally salient information and stress to optimize performance. We have found that not all aspects of human cognition respond to emotion and stress the same way. Some skills are improved by emotion, others are disrupted, and still others are unaffected. Although we know how some cognitive functions respond to stress or emotion, there are many more that we have not examined. It is important to understand how the brain and mind operates under emotional stress because error in emotional contexts (e.g., air-traffic control, emergency response, military) can have particularly grave consequences. The objective of this study is to determine how the introduction of potential threats influence different aspects of cognition and perception in humans. We will take a cognitive neuroscience approach, using functional magnetic resonance imaging (fMRI) to measure brain function, psychophysiological techniques to measure arousal, and behavioural techniques to measure performance and cognitive function. We will pursue 3 specific aims: Aim 1: Contrast the impact of realistic 2- and 3- dimensional threatening stimuli on emotional responding, perception, habituation and adaptation. In order to assess the impact of threats on the human brain it is important to have realistic stimuli. It has recently been shown that 3D stimuli influence brain and behaviour in fundamentally different ways than 2D stimuli. Yet, almost everything we know about how the human brain responds to threatening stimuli has been conducted using 2D stimuli. We have developed 3D images of threatening species and will examine the impact they have on human performance and the brain.Aim 2: Determine the opposing effects of auditory versus visual threatening stimuli on cognition and perception. Recently, we have shown that whereas presenting threatening visual stimuli (e.g., snakes) during an object detection task disrupts performance, presenting threatening sounds can actually improve performance for reasons that are poorly understood. We will use fMRI and behavioural experiments to determine the neurocognitive basis behind these and other poorly understood effects. Aim 3: Delineate the impact of fear and anxiety on dissociable cognitive functions. Fear and anxiety are distinct emotions that are mediated by slightly different brain mechanisms. Both can be provoked through the use of shocks: unpredictable shocks (for anxiety) or predictable shocks (for fear). We will determine the impact of each on different cognitive functions that we hypothesize vary in their susceptibility to the distracting effects of stress and emotion.