The lab is devoted to examining the Cognitive Neuroscience of Human mental functions. Well founded cognitive theories are tested using several complimentary research methodologies including, (a) task dissociations in neurologically damaged patients and healthy controls, (b) human electro and magneto encephalograhic recordings (EEG and MEG), (c) functional Magnetic Resonance Imaging (fMRI), and (d) structural MRI, including diffusion tensor imaging.

The field of human memory research has been dominated by the view that multiple brain/cognitive systems support different aspects of what we remember. These systems have been characterized in many ways – implicit, explicit, episodic, semantic, procedural and motor. While a lot of work has emphasized the independence of these systems, more recently these systems are viewed as operating simultaneously, sometimes in cooperation and sometimes in competition, to produce the most efficient way to accomplish a task. We have been working with this prospective to examine –

1 – The role of response and decision learning in implicit memory tasks
2 – The influence of the context of learning on the system that maximizes performance
3 – The role of a multisystem query in the evaluation of the accessibility of memories

1. Memory and Aging
Meta memory refers to the monitoring and awareness of one's memory ability. Current research has shown that metamemory functioning in older adults is impaired in some domains, particularly those that require combinations of newly learned episodic details, while not in others. Using functional MRI we have been examining the neuroanatomical underpinnings of memory monitoring tasks, and the changes in both behavior and function that occur as a result of normal aging. In addition, we've been using structural MRI techniques including T1-weighted SPGR, diffusion tensor imaging, and perfusion scanning to relate structural changes to changes in task performance in a normally aging population.

2. Sleep Deprivation Studies
Long periods of sleep deprivation are often a way of life for persons providing essential services, including medical and military personnel. Using fMRI and EEG we have been examining the cognitive effects of sleep deprivation across a broad spectrum of process from simple attention to complex decision-making. In addition, we are using high resolution T1 weighted MRI and diffusion tensor imaging (DTI), to uncover individual differences in brain structure that predict cognitive vulnerability to sleep deprivation. DTI pdf

3. Visual Attention Studies
The ability to selectively attend to objects in visual space is crucial to monitoring of and navigation through one?s environment, abilities crucial to performance of most daily life activities. Currently, we are using EEG-based neuroimaging measures to investigate the cognitive and brain processes underlying selective visual attention, as well as those neurocognitive processes that differentiate between voluntary allocation of attention and attentional allocation involuntarily driven by stimuli in the environment.

4. Depression Vulnerability
Depression vulnerable individuals appear to have considerable difficulty regulating emotional information through selective attention to negative stimuli. Current theories of emotion regulation implicate two neural systems in the regulation of emotional information: a ventral and a dorsal system. The ventral system gives rise to the autonomic responses to emotion cues and evaluating the contexts of those cues giving rise to the production of affective states while the dorsal system is important for the performance of executive control functions that provide cognitive regulation of affective states. We have proposed a model of emotional experience and control that includes two cortical regions, lateral and medial prefrontal cortices, and one subcortical region, the amygdala. The role of the vlPFC in the cognitive control of emotion is being examined using in a modified version of Posner exogenous cueing task utilizing emotional face stimuli. In fMRI and EEG we are exploring the neural responses associated down-regulation of automatic responses and shifting attention away from emotional stimuli. DTI pdf