Word priming and recognition memory are both affected by mesial temporal lobe damage.

Abstract

Amnesic patients with mesial temporal lobe pathology often produce normal priming effects despite severely impaired memory. This is generally interpreted to mean that whereas limbic structures are involved in conscious memory, other structures, comprising a separate memory system, mediate priming effects. Priming and recognition memory measures were correlated with MRI measures of damage to specific brain structures in a sample of 30 subjects. The results provide evidence that both priming and recognition memory may be adversely affected by mesial temporal lobe damage. Furthermore, the results suggest that striatal damage is associated with lexical or perceptual deficits and larger measured priming effects. Thus, co-existing striatal and limbic damage may lead to normal priming performance in some memory-impaired patients. In these instances, normal priming performance may not be mediated by a separate (implicit) memory processing system in the brain.In human memory research, a distinction has been drawn between explicit memory tasks, that is, those tasks requiring conscious recall or recognition of previous experience, and implicit memory tasks, that is, those tasks in which performance is altered as a function of previous experience but which do not require conscious recall of that experience (Graf & Schacter, 1985). Currently, the distinction between explicit and implicit memory is also used to label separate memory systems or separate processes believed to mediate performance on explicit and implicit memory tasks

The effects on priming of word frequency, number of repetitions, and delay depend on the magnitude of priming

“…When the availability of perceptual information was drastically reduced and the magnitude of priming effects greatly increased, a direct relationship between priming and recognition-memory performance was detectable. A similar relationship between priming and recognition memory was reported by Jernigan and Ostergaard (1993) in a mixed group of normal subjects and patients with varying degrees of memory impairments. In this case, the relationship could be observed only after the variability in the priming measure associated with baseline performance level had been removed in a multiple regression analysis.…”

Improved memory functioning and frontal lobe maturation between childhood and adolescence: A structural MRI study

“…It is possible that maturational changes in MTL structures continue into adulthood, are nonmonotonic in nature, and perhaps are in part related to pubertal factors. Speculations that development in the MTL would be specifically related to improved memory performance in this sample were based on adult lesion studies (e.g., Zola-Morgan et al, 1986) and in vivo MRI studies in adults with memory impairment (e.g., Jernigan & Ostergaard, 1993) that suggest that MTL structures play a specific role in encoding. However, evidence from the developmental literature shows that, while children's recognition abilities may already be near peak levels by 8 years of age (for a discussion, see Schneider & Pressley, 1989), their retrieval abilities improve considerably over this age range (7-16 years).…”

Effects of age on tissues and regions of the cerebrum and cerebellum

“…The image-analytic approach is similar to that used in our previous anatomical studies [19,20,22], but represents a significant elaboration of these methods as described previously [21]. Trained anatomists who were blind to subject diagnosis, age, gender or any other identifying information subjected each image dataset to the following image analysis procedures: 1) interactive isolation of intracranial regions from surrounding extracranial tissue, 2) three-dimensional digital filtering of the matrix of pixel values representing brain voxels to reduce inhomogeneity artifact, 3) reslicing of the volume to a standard orientation, 4) tissue segmentation using semi-automated algorithms, and 5) neuroanatomical region-of-interest analysis.…”