Source versus content memory in patients with a unilateral frontal cortex or a temporal lobe excision

Abstract

It has been suggested previously that patients with a frontal lobe lesion might have a specific impairment in the retrieval of the source of information despite adequate memory for facts. Patients with an anterior temporal excision are known to have impairments in memory for facts and the question arises as to whether they are also impaired in source memory. The present study compared memory for facts and their source in patients with a unilateral frontal cortical or an anterior temporal excision in a situation in which both types of information were encoded explicitly. Patients with a unilateral frontal cortex or a temporal lobe excision watched videos of a game show and were instructed to attend to both the trivia facts and their source (the identity of the speaker or the relative time of presentation). Patients with a frontal cortex excision were not impaired on either fact or source memory. This was true even when a subgroup of patients with an excision involving the dorsolateral frontal cortex was examined. In contrast, patients with a left temporal lobe excision were impaired in both fact and identity source memory and right temporal lobe patients were impaired in identity source memory. All patients performed similarly to normal controls in temporal source memory. The present results are consistent with the view that source information is part of an associative network of information about an episode and that the medial temporal region is critical for both source and content memory. Furthermore, if source information is encoded explicitly, the frontal cortex does not appear to be necessary for its retrieval. Instead, it is proposed that the frontal cortex plays a metacognitive role in memory retrieval.

Formation of Long-Term Memory Representation in Human Temporal Cortex Related to Pictorial Paired Associates

“…The anterior temporal activation converges with the results of neuropsychological studies showing permanent retrograde amnesia following anterior temporal cortical damage and with the results of neuroimaging studies on semantic knowledge (Kapur et al, 1992;Damasio et al, 1996;Gorno-Tempini et al, 1998;Cabeza and Nyberg, 2000;Bar et al, 2001;Martin and Chao, 2001;Tsukiura et al, 2002;Thaiss and Petrides, 2003;Ploran et al, 2007). Although the right hippocampal activation during retrieval of newly learned figures followed the rule of the right hemisphere dominance in nonverbal processing (Milner, 1971;Kelley et al, 1998;Wagner et al, 1998b;Gazzaniga, 2005), the anterior temporal region did not.…”

Age-Related Changes in Right Middle Frontal Gyrus Volume Correlate with Altered Episodic Retrieval Activity

“…Although we cannot determine from our current experimental design, prior studies of the specific cognitive processes mediated by distinct nodes of activity, such as left DLPFC, have emphasized the role of left DLPFC during successful context retrieval (Thaiss and Petrides, 2003;Dobbins et al, 2004;Mitchell et al, 2004Mitchell et al, , 2006, and have suggested that this region is involved in mediating cognitive control processes during memory retrieval, such as retrieval search, response selection, and/or postretrieval monitoring (Rajah et al, 2008). Similarly, several studies have reported greater inferior parietal cortex activity during retrieval success (Wagner et al, 2005).…”

Prefrontal Engagement during Source Memory Retrieval Depends on the Prior Encoding Task

“…The impact of encoding task and instruction observed here is consistent with two recent behavioral studies. Thaiss and Petrides (2003), after observing an exception to the typical finding that patients with prefrontal damage perform poorly in source memory tests, argued that the high accuracy of their patients was due to explicit instruction during the encoding phase to try to learn relationships. Glisky, Polster, and Routhieaux (1995) have consistently reported that healthy older adults who perform poorly in neuropsychological tests traditionally thought to tap prefrontal function also have special difficulty with source memory tests.…”