Priming is a form of implicit memory, and refers to the fact that the mere processing of an item can facilitate subsequent processing of that same item. Priming effects can occur in the absence of conscious recollection of the prior study episode, and it has, therefore, been suggested that priming and explicit memory are mediated by different memory systems. Evidence from memory disordered patients is critical for this hypothesis, since if it is possible to link the breakdown of explicit memory and priming to damage to different brain regions this would strengthen the independent memory systems hypothesis. However, many difficulties are associated with evaluating priming effects in memory impaired subjects. The priming measures may be less sensitive than explicit memory measures, and the lack of group differences on priming measures may simply reflect low measurement sensitivity. The degree of priming obtained in a given task is related to processing efficiency (i.e. baseline performance), with less efficient processing resulting in greater priming. Therefore, if patients have even mild processing deficits this may mask priming impairments. The proposed project will investigate these issues in normal subjects and alcoholic patients with varying degrees of memory and processing deficits. The project consists of a series of experiments designed to manipulate baseline performance level and sensitivity of the priming measures. In all of the experiments measures of priming, processing efficiency, and explicit memory will be obtained. The subjects will be normal controls and chronic alcoholic patients who differ in the severity of their explicit memory defects, ranging from nonamnesic patients without noticeable memory impairments through """"""""borderline Korsakoff"""""""" patients with only mild memory deficits to severely amnesic patients with Korsakoff's syndrome. Measures of volume loss in specific brain structures will be obtained from MRI. These brain measures will be related to the behavioral indices, using a multiple regression approach, to determine the specific role of each brain region in perceptual/lexical processing, explicit memory, and strength of priming.
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| Ostergaard, A L (1999) Priming deficits in amnesia: now you see them, now you don't. J Int Neuropsychol Soc 5:175-90 |
| Jernigan, T L; Ostergaard, A L; Law, I et al. (1998) Brain activation during word identification and word recognition. Neuroimage 8:93-105 |
| Ostergaard, A L (1998) The effects on priming of word frequency, number of repetitions, and delay depend on the magnitude of priming. Mem Cognit 26:40-60 |
