Alexander A. Stevens, Ph.D.
Positions
Assistant Professor, Department of Psychiatry
Assistant Professor, Department of Behavioral Neuroscience
Contact
stevenal@ohsu.edu; Phone: 503-494-0358; Lab Phone: 503-494-6494; Office: MNP Suite 1505 rm 1516; Mail Code: UHN80R1
Research Interests
fMRI, Auditory Perception, Blindness, ADHD, Attention, Working Memory
Preceptor Rotation Availability
Dr. Stevens might be available for preceptor rotations. Please contact him directly to inquire.
Mentorship Availability
Dr. Stevens might be available for mentorship. Please contact him directly to inquire.
Research Areas
- Working Memory and selective attention in Adult Attention Deficit Hyperactvity Disorder and its neural correlates.
- Selective training effects on working memory capacity and intellectual abilities.
Education
B.A. (1986) University of Rochester
M.A. (1991) Experimental Psychology, University of New Hampshire
Ph.D. (1995) Experimental Psychology, University of New Hampshire
Postdoctoral Associate, Department of Diagnostic Radiology, Yale University School of Medicine
NIMH Postdoctoral Fellow, Child Study Center, Yale University School of Medicine.
Research Summary
Our work focuses on auditory perception attention and memory and its underlying neural organization. We are currently working in three areas related to attention and memory: First, through a collaboration with Ed Awh at the University of Oregon, we are attempting to identify specific cognitive mechanisms that are disrupted in ADHD. This line of inquiry involves determining the relationship between perceptual abnormalities, attention and working memory in healthy individuals as well as in individuals diagnosed with attention deficit disorders.
Second, We are interested in how experience affects auditory perceptual abilities. Our recent studies have examined the influence of blindness on the functional properties of auditory and visual cortices, and specific auditory perceptual abilities. We employ behavioral testing and psychoacoustic techniques to examine the mechanisms of perception, along with functional magnetic resonance imaging (fMRI) to elucidate their neural correlates. We are now beginning studies on a 7 Tesla human MR system to be able to study trial-by-trial effects of learning and attention.
We have recently started a third lne of work examining how specific cognitive training alters different aspects of cognitive including fluid intelligence. We are specifically trying to determine if altering working memory capacity is possible, and if so what leads to its alteration. Because rpevious research has demonstrated that training with compex working memory tasks which require executive functions produce changesin measures of fluid intelligence, we are trying to understand what specific components of cognitive training are critical, and what neural systems are changed by the training.
Selected Recent Publications
Stevens, AA., Weaver, K (2005). Auditory perceptual consolidation in the blind. Neuropsychologia. 43(13),1901-1910.
Weaver, K., Stevens, AA. (2007) Attention and sensory interaction in Occipital Cortex in the Early Blind. Journal of Cognitive Neuroscience, 19(2), 1-16.
Garg, A. Schwartz, D, Stevens, AA. (2007) Frontal eye field activity during auditory spatial attention in early blind. Neuropsychologia, Neuropsychologia, 45, 2307-2321.
Stevens AA, Snodgrass, M, Weaver, KW, Schwartz, D. (2007). Enhancement of auditory temporal processing in congenital blindness related to brain preparatory activity. Journal of Neuroscience, 27,10734-41.
