The Neural Mechanisms of Consciousness (2015 - present)
The precise spatial and temporal dynamics for the neural mechanisms of consciousness are unknown. My work utilizes intracranial, depth, and scalp EEG and fMRI to investigate the spatio-temporal cortical and subcortical characteristics of human, normal visual consciousness. Our recent findings suggest that visual consciousness involves early sensory cortex signal followed by a transient pulse of neuromodulatory signal from subcortical arousal regions (e.g., thalamus and midbrain) and, finally, broad cortical propagation in parietal attention and prefrontal cortex networks. I am also using pupillometry and machine learning to covertly detect consciousness (Herman et al., 2019; Kronemer et al., in preparation).
Motor Network Regulation of Cognition and Mood State (2013 - present)
Cognitive and motor neural networks are often considered spatially and functionally isolated. There is growing evidence that regions previous thought to be dedicated to motor function (e.g., cerebellum) also engage in a variety of non-motor outputs, including cognition and mood regulation. In a study involving transcranial magnetic stimulation, we showed that disrupting function of the motor cortex impairs working memory performance, particularly when participants utilized motor strategies for rehearsal (e.g., motor traces; Liao et al., 2014). These results suggest a functional link between cognitive and motor networks in working memory. Moreover, we developed a novel clinical questionnaire to study mood-related symptoms in patients with cerebellar ataxia. Results reveal mood changes (e.g., depression) in ataxia that correspond with cerebellum degeneration (Kronemer et al., in preparation).
Chronic HIV and Impairment of Cognitive and Motor Function (2013 - 2017)
Antiretroviral medications allow people to live decades with HIV, but the consequences of chronic HIV are still under investigation. Our research revealed that HIV patients have motor-cognitive impairment even among patients who are identified as neurocognitively normal on clinical exams (Kronemer et al., 2017). Moreover, HIV patients are sensitive to reward particularly if they self-reported premorbid impulsiveness near the time of contracting HIV. These results suggest a link between HIV-risk taking behaviors and reward sensitivity.