Hemispheric differences in memory search.
Repository Usage Stats
Recent evidence suggests that memory demands contribute to visual field (VF) differences in tachistoscopic recognition. The present experiment examined VF differences in a memory-search paradigm using verbal stimuli (digits). The results demonstrated a significant advantage to right VF-left hemisphere presentation that was associated with the memory comparison stage of the task, but not with the perceptual encoding and response stages. These data are more consistent with a relative efficiency model of hemispheric specialization than with a functional localization model. © 1980.
Published Version (Please cite this version)
This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.
My research focuses primarily on the cognitive neuroscience of aging: the investigation of age-related changes in perception, attention, and memory, using both behavioral measures and neuroimaging techniques, including positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and diffusion tensor imaging (DTI).
The behavioral measures have focused on reaction time, with the goal of distinguishing age-related changes in specific cognitive abilities from more general effects arising from a slowing in elementary perceptual processes. The cognitive abilities of interest include selective attention as measured in visual search tasks, semantic and episodic memory retrieval, and executive control processes.
The behavioral measures are necessary to define the cognitive abilities of interest, and the neuroimaging techniques help define the functional neuroanatomy of those abilities. The PET and fMRI measures provide information regarding neural activity during cognitive performance. DTI is a recently developed technique that images the structural integrity of white matter. The white matter tracts of the brain provide critical pathways linking the gray matter regions, and thus this work will complement the studies using PET and fMRI that focus on gray matter activation.
A current focus of the research program is the functional connectivity among regions, not only during cognitive task performance but also during rest. These latter measures, referred to as intrinsic functional connectivity, are beginning to show promise as an index of overall brain functional efficiency, which can be assessed without the implementation of a specific cognitive task. From DTI, information can be obtained regarding how anatomical connectivity constrains intrinsic functional connectivity. It will be important to determine the relative influence of white matter pathway integrity, intrinsic functional connectivity, and task-related functional connectivity, as mediators of age-related differences in behavioral measures of cognitive performance.
Ultimately, the research program can help link age-related changes in cognitive performance to changes in the structure and function of specific neural systems. The results also have implications for clinical translation, in terms of the identification of neural biomarkers for the diagnosis of neural pathology and targeting rehabilitation procedures.
Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.