Memory for visual patterns was examined in 131 patients with unilateral temporal- or frontal-lobe excisions and 32 normal control subjects. A deficit in short-term memory for matrices of increasing complexity was exhibited by the right frontal-lobe group. Right temporal lobectomy impaired cued recall of visually homogeneous matrices at each of four serial positions. On the delayed recognition of complex visual scenes, right temporal lobectomy decreased identification of changes in figurative detail and spatial composition, whereas right hippocampectomy impaired identification of changes in spatial location. The interplay between verbal and pictorial codes in memory was also investigated using related word-design pairs. Right or left temporal lobectomy affected the number of designs recalled but only the right temporal-lobe group produced designs of poor quality. When cued with the words, the left temporal-lobe group produced fewer designs than the control subjects, demonstrating a reduced ability to retrieve pictorial information through verbal labels.

No description available.

Thesis (Ph. D.)--University of California, San Diego, 2008. / Title from first page of PDF file (viewed September 3, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 128-137).

No description available.

No description available.

No description available.

No description available.

It has been argued that patients with frontal lobe lesions are impaired in temporal context memory and, more generally, in retrieving the source of one's knowledge or ideas. Furthermore, it has been speculated that a failure to retrieve source information may result in an increased susceptibility to distortions of episodic memories in patients with frontal lobe lesions. The precise role of the frontal cortex, however, in source or episodic retrieval is not clear. Does this region of cortex play a primary role or a secondary, executive role in the processing of such memories? Studies of patients with temporal lobe lesions have also shown impairments in episodic memory, including difficulties in the retrieval of source information. An important issue, therefore, is whether these two brain regions make different contributions to the processing of source information and to the retrieval of episodic memories. / In the present experiments, patients with unilateral excisions restricted to frontal cortex or to the anterior temporal lobe were compared on various tasks examining source memory performance and the accurate retrieval of episodic information. The results of these studies failed to support the general contention that patients with frontal cortex excisions have source (or temporal context) memory impairments. Instead, differences between these patients and normal control subjects appeared to be contingent on whether strategic organizational or control processes were necessary for efficient processing of episodic information. The memory of patients with left temporal lobe excisions, on the other hand, was significantly impaired for both content and source information in most tasks. Furthermore, these subjects showed high rates of inaccuracies and distortions of memory. The false memories of this patient group were attributed to a combination of their poor memory for the specific items of the task and their over-reliance on semantic "gist" or on inferential knowledge about the events. Patients with right temporal lobe excisions were generally less severely impaired on the verbal memory tasks compared with those with left-sided lesions, but were impaired in their memory for the contextual aspects of an event.

This thesis investigated the nature of the deficit in story recall associated with temporal-lobe damage in the left hemisphere dominant for speech. The first three experiments examined whether excision of this region (1) slows the rate at which verbal material is processed, (2) reduces working-memory capacity, or (3) interferes with the integration of information across sentences. Left temporal lobectomy does not impair these aspects of the initial processing of stories, since on none of the above variables was the performance of left temporal-lobe groups deficient relative to that of normal control subjects, or patients with unilateral frontal- or right temporal-lobe removals. The fourth experiment examined the effect of left temporal lobectomy on how quickly a passage was forgotten after it had been learned to criterion. Although patients with such an excision took more trials to learn a story than did normal control subjects, only those patients with extensive left hippocampal removal were impaired when recalling this story 20 minutes later. These results highlight the role of the left hippocampus in the long-term maintenance of story information.

Mémoire (M.A.)-- Université du Québec à Chicoutimi, 2002. / En tête du titre : Université du Québec, mémoire présenté comme exigence partielle de la maîtrise en psychologie offerte à l'Université du Québec à Chicoutimi en vertu d'un protocole d'entente avec l'Université du Québec à Trois-Rivières. CaQTU Comprend des réf. bibliogr. : p. 106-116.