Evidence for a dissociation between perceptual and conceptual priming in Alzheimer’s disease

The status of perceptual priming and word-completion priming in patients with Alzheimer's disease (AD) was examined. Experiment 1 established the reliability of the perceptual priming measure in normal subjects. In Experiment 2, AD patients showed a normal magnitude of perceptual priming. In Experiment 3. a single group of AD patients showed a normal magnitude of perceptual priming and impaired word-completion priming. Further, word-completion prim-ing, but not perceptual priming, was correlated with verbal fluency performance in AD. These results suggest a dissociation between two components of verbal priming. Perceptual priming may reflect the operation of a structural-perceptual memory system mediated by occipital lobe regions relatively spared in AD. Word-completion priming may reflect the operation of a lexical-semantic memory system mediated by temporoparietal lobe regions compromised in AD. The neural architecture of human memory is revealed by dissociations among memory capacities in patients with brain lesions. Some compelling dissociations come from the study of patients who are globally amnesic due to limbic-dience-phalic lesions. Despite severe deficits in recall and recogni-tion of recently encountered information, such patients can show normal repetition priming effects (Cermak, Talbot