Confabulation: Damage to a specific inferior medial prefrontal system

Abstract

Confabulation, the pathological production of false memories, occurs following a variety of aetiologies involving the frontal lobes, and is frequently held to be underpinned by combined memory and executive deficits. However, the critical frontal regions and specific cognitive deficits involved are unclear. Studies in amnesic patients have associated confabulation with damage to the orbital and ventromedial prefrontal cortex.However neuroimaging studies have associated memory control processes which are assumed to underlie confabulation with the right lateral prefrontal cortex. We used a confabulation battery to investigate the occurrence and localisation of confabulation in an unselected series of 38 patients with focal frontal lesions. 12 patients with posterior lesions and 50 healthy controls were included for comparison. Significantly higher levels of confabulation were found in the Frontal group, confirming previous reports. More detailed grouping according to lesion location within the frontal lobe revealed that patients with orbital, medial and left lateral damage confabulated in response to questions probing personal episodic memory. Patients with orbital, medial and right lateral damage confabulated in response to questions probing orientation to time. Performance-led analysis revealed that all patients who produced a total number of confabulations outside the normal range had a lesion affecting either the orbital region or inferior portion of the anterior cingulate. These data provide striking evidence that the critical deficit for confabulation has its anatomical location in the inferior medial frontal lobe. Performance on tests of memory and executive functioning showed considerable variability. Although a degree of memory impairment does seem necessary, performance on traditional 3 executive tests is less helpful in explaining confabulation.

Evidence of an amnesia-like cued-recall memory impairment in nondementing idiopathic Parkinson's disease

“…Like PD patients, patients with frontal lesions are not amnesic; however, they do exhibit deficits on tests of free recall Turner, Cipolotti, Yousry, & Shallice, 2007;Wheeler, Stuss, & Tulving, 1995) and source recall, particularly when the tests depend heavily on the use of memory strategies as applies when multiple learning trials are used (Duarte, Ranganath, & Knight, 2005;Janowsky, Shimamura, & Squire, 1989a;Janowsky, Shimamura, Kritchevsky, & Squire, 1989b). On the other hand, when the demands on effortful executive control processes are reduced by the provision of category cues at test and/or strategic instruction, recall performance has been shown to be less affected ; and item recognition memory is relatively normal (Janowsky et al, 1989a;Parkin, Bindschaedler, Harsent, & Metzler, 1996;Schacter, Curran, Galluccio, Milberg, & Bates, 1996;Shimamura, Jurica, Mangels, & Gershberg, 1995).…”

Confabulation: What is associated with its rise and fall? A study in brain injury

“…Moreover, more recent neuroimaging and evoked potential investigations have particularly pinpointed damage within the ventro-medial and/or orbito-frontal brain regions (Schnider, 2003;Gilboa et al, 2006;Toosy et al, 2008;Turner, Cipolotti, Yousry, & Shallice, 2008;Gilboa & Verfaellie, 2010;Nahum, Bouzerda-Wahlen, Guggisberg, Ptak, & Schnider, 2012;Hebscher, Barkan-Abramski, Goldsmith, Aharon-Peretz, & Gilboa, 2015;Schnider et al, 2013;Manuel, David, Bikson, & Schnider, 2014).…”

Confabulation: A Beginner’s Guide for legal professionals

“…This issue is particularly salient when confabulation is suspected or confirmed to be present [39]. People, including legal professionals and jurors, are more likely to believe a memory is true if the person appears confident in that memory.…”