Taft, Janna Renee.

Astrogliosis may contribute to the pathogenesis of CNS dysfunction as in Alzheimer's Disease or Sudden Infant Death Syndrome (SIDS). Investigating astrocytic expression in the brain may provide valuable insights into and/or models of CNS disease or injury. This study was designed to test astrocyte expression and distribution in the mature rat and immature rat and cat brain utilizing different fixatives (aldehyde or ethanol), immunocytochemistry (glial fibrillary acidic protein, GFAP, or vimentin), and lesion conditions in the cortex, cerebellum, and brainstem. Findings include a paucity of GFAP positive astrocytes in most regions of the normal rat brainstem, evidence of astrogliosis in lesions, and the most intense, reactive astrocytes in the 7 day post-lesion condition. The results imply that the rat (brainstem) may make a suitable animal model for investigating the role of hypoxia and astrogliosis in neural trauma such as postulated in SIDS.

A prominent deficit in Alzheimer's disease (AD) is a difficulty in recognizing and naming people. Unfamiliar and famous face recognition tasks are sparse in the neuropsychology literature. It was hypothesized that: a deficit in recognition of faces would be found for AD patients, the semantic mismatch condition would result in the longest response latency and least accurate naming, and semantic cues would not facilitate naming for the AD group. Accuracy and reaction time from ten mild AD patients diagnosed by NINCDS-ADRDA criteria and 10 normal controls (matched age, 66--82 years, education & ethnicity) were tested via unfamiliar and famous faces recognition memory tests and famous faces naming tasks with and without semantic interference. Both subject groups were more accurate on the famous face recognition rather than memory for unfamiliar faces, with significant group differences. The Stroop-like face naming task performance was characterized by an increased interference effect, semantic face-name mismatches produced the longest response delays, and less accurate face naming particularly in the AD group. The semantic cues resulted in a decrease in naming accuracy for the AD patients, which may be indicative of their name retrieval deficit. Consistent with existing face-name models, these findings suggest that the deficit in AD is related to semantic naming rather than the perceptual component of face recognition. Furthermore, the ability to correctly name faces even in the presence of interference may prove to be a diagnostic tool that is sensitive to face naming deficits characteristic in cases of brain damage.