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PL‐04‐01: Cortical connectivity and sensory binding: A neurocognitive approach to the detection and assessment of Alzheimer's disease
Author(s) -
Heindel William
Publication year - 2011
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2011.05.1939
Subject(s) - neuroscience , neurocognitive , sensory system , psychology , neuropathology , perception , cognition , functional connectivity , disease , medicine , pathology
Background: The ability to detect subtle preclinical cognitive changes associated with AD is critical for the effective application of therapeutic strategies. Assessment instruments are also needed to reliably characterize and track changes throughout the course of the disease, and to serve as sensitive measures of therapeutic efficacy in clinical trials. To date, however, the development of effective diagnostic and assessment tests for AD has been strikingly elusive. A potentially fruitful approach is to exploit recent advances in cognitive neuroscience to develop instruments that more directly reflect the unique neuropathology associated with AD. AD has been shown to produce a systematic disruption to projections connecting distinct but functionally related cortical regions. A phenomenon that should be particularly sensitive to the disruption of functional connectivity is sensory binding, or the ability to combine distinct sensory inputs relating to a single object into a coherent, unified representation. Sensory binding is thought to be particularly dependent upon coordinated activity across different cortical regions, and therefore should be a direct neurocognitive probe for assessing functional connectivity in AD. Methods: Findings will be presented from a series of studies assessing the disruption of functional connectivity in AD. Tasks are designed to systematically assess unimodal and multimodal cortical binding at both the perceptual and semantic level: Given that AD is associated with a progressive disruption of corticocortical connections from heteromodal to unimodal association cortices, a comparable gradient of impairment should emerge across levels of cortical binding. Results: AD patients were selectively impaired at binding unimodal and cross-modal information across cortical regions despite intact ability under non-binding conditions. Additional findings suggest that these binding deficits are not due to attentional deficits or dementia generally, but rather are uniquely sensitive to AD pathology.Conclusions: Sensory binding tasks assessing functional connectivity across different levels of cortical processing could lead to a new generation of assessment tools for AD that are specific and sensitive to change across disease severity. The development of these markers could have substantial implications not only for the early detection of AD, but also for the assessment of therapeutic efficacy throughout the course of the disease.