Memory Loss with Lesions of Hippocampal Formation

Abstract

In 1888, Sanger-Brown and Schafer¹described an apparent disturbance of memory in monkeys after the partial or total removal of both temporal lobes. Two years later, Bechterew²in a very brief report, described a patient who had shown an extraordinary degree of memory disturbance, as well as considerable apathy for many years; in the region of the gyrus uncinatus and Ammon's horn in each temporal lobe, the cortex and underlying structures were said to be softened. The matter then lay dormant until 1954, when Scoville³described a grave loss of recent memory in 2 patients after resection of the medial parts of both temporal lobes. The ablations extended posteriorly along the medial surfaces for a distance of about 8 cm. from the tips of the temporal lobes, and probably destroyed the anterior two-thirds of the hippocampus and hippocampal gyrus bilaterally, as well as the amygdala. Later, these