The most general hypothesis that guides research in my laboratory is that emotional disorders (such as anxiety disorders and mood disorders) arise from dysfunction of regulatory mechanisms that normally govern emotional processes. From this perspective, I conduct fMRI, cognitive, and psychophysiological studies of affective processes in patients with these disorders and normal volunteers. FMRI provides new opportunities for generating and testing models of the neural systems that underlie various aspects of human emotional functioning. Our studies of the posterior cingulate cortex have shown this region to be consistently activated during the evaluation of emotionally salient stimuli. Several lines of evidence support our hypothesis that this region plays a role in the enhanced memory for emotional information. FMRI and behavioral studies in progress aim to describe the cognitive features of this memory enhancement and the network of brain regions that mediates it. Clinical studies will examine this cognitive-emotional interaction in patients with emotional disorders. Other investigations of emotion include studies to identify brain regions with transient versus sustained activation during sustained subjective emotional responses, brain regions that demonstrate habituation versus sensitization to repeatedly presented emotional stimuli, and studies of hemispheric laterality effects on emotional memory.

Patients who experience repeated, spontaneous panic attacks consistently demonstrate an exaggerated lactic acid response in the brain during systemic alkalosis. Magnetic resonance spectroscopy has the potential to test competing hypotheses regarding the mechanism of this effect and to determine if this abnormality has a role in the pathogenesis of panic disorder. Our lab will conduct MR spectroscopy studies of brain lactic acid metabolism in patients with panic disorder.

Publications:

Maddock, R.J., Garrett, A.S., Buonocore, M.H. Remembering familiar people: The posterior cingulate cortex and autobiographical memory retrieval. Neuroscience. 104: 667-676, 2001.

Maddock, R.J., Garrett, A.S., Buonocore, M.H. Posterior cingulate cortex activation by emotional words: FMRI evidence from a valence decision task. Human Brain Mapping. 18:30-41, 2003.

Maddock, R.J., Buonocore, M.H., Kile, S.J., Garrett, A.S. Brain regions showing increased activation by threat- related words in panic disorder. Neuroreport. 14:325-8, 2003.

Hargrave R, Maddock RJ, and Stone V. 2001. Impaired recognition of facial expressions of emotion in Alzheimer’s disease.. Journal of Neuropsychiatry and Clinical Neurosciences. 14: 64-71, 2002

Maddock RJ. 2001. The lactic acid response to alkalosis in panic disorder: An integrative review. Journal of Neuropsychiatry and Clinical Neurosciences. 13:22-34, 2001.

Garrett, A.S., Maddock, R.J. Time-Course of the Subjective Emotional Response to Aversive Pictures: Relevance to FMRI studies. Psychiatry Research: Neuroimaging. 108:39-48, 2001

Maddock RJ. 1999. Retrosplenial cortex and emotion: New insights from functional imaging studies of the human brain. . Trends in Neurosciences. 22:310-316