Absence of Priming Coupled with Substantially Preserved Recognition in Lorazepam-Induced Amnesia

Abstract

Two experiments are reported on priming when subjects are in an amnesic state induced by lorazepam. The primed tasks were completion of word-stems and generation of words from specified categories. In both experiments, lorazepam subjects showed no evidence of priming; whereas control subjects showed substantial priming. Recognition by the amnesic subjects of items produced in the priming tests, although impaired, was well above the chance level. These findings contrast with those obtained with organic amnesic subjects, for whom priming is typically normal but recognition is grossly impaired. The theoretical implications of this double dissociation between priming and recognition are discussed.

Is benzodiazepine-induced amnesia due to deactivation of the left prefrontal cortex?

“…We established that automatic processing had occurred, but found no significant impairment due to midazolam. This is the pattern of results typically seen after benzodiazepine treatment and is in accord with results reported in the literature (Brown et al 1989;Ghoneim and Mewaldt 1990;Curran 1991;Joyce and File 1995). Encoding into explicit memory (E-A) activated the left prefrontal brain regions, which included many BAs previously reported to be activated during explicit episodic memory encoding (Shallice et al 1994;Tulving et al 1994a;Fletcher et al 1995).…”

“…Benzodiazepines are widely known to cause anterograde amnesia by impairing explicit (conscious) acquisition into long-term episodic memory (Ghoneim and Mewaldt 1990;Curran 1991;File et al 1998), whereas automatic processing during incidental encoding is unaffected (Brown et al 1989;Joyce and File 1995). The question underlying the present study is whether the pattern of benzodiazepine impairment of explicit memory results from a relatively greater impact of the drug in brain areas associated with encoding into explicit memory than in other brain areas.…”

Scopolamine but Not Lorazepam Modulates Face Repetition Priming A Psychopharmacological fMRI Study

“…Both drugs also impaired the behavioral index of repetition priming, suggesting that GABAergic and cholinergic systems modulate neuronal plasticity necessary for priming in this paradigm. The behavioral impairments with lorazepam were consistent with prior studies using picture-fragment completion, word-fragment completion, or wordstem completion tasks Vidailhet et al 1994;Vidailhet et al 1999;Danion et al 1992;Brown et al 1989). Behavioral impairments of repetition priming with scopolamine, on the other hand, were not in line with the majority of prior studies (Knopman 1991;Danion et al 1990;Schifano and Curran 1994), and we suggested that these differences could be caused by a lower active dose used in these previous studies (see Thiel et al 2001 for discussion).…”

“…Our finding that lorazepam did not impair priming in a face recognition paradigm seems in contrast with most previous studies investigating the pharmacological modulation of repetition priming. Thus, lorazepam has been consistently shown to reduce behavioral indices of priming in several paradigms, including picture-fragment completion, word-fragment completion, and word-stem completion tasks Vidailhet et al 1994;Vidailhet et al 1999;Danion et al 1992;Brown et al 1989). We were able to replicate lorazepam's impairments on word-stem completion priming (Thiel et al 2001) but were not able to find attenuated priming when using a face priming paradigm in the same volunteers.…”

Influence of Benzodiazepines on Auditory Perception

“…The main effects of BZDs are well known; they include a sedative, an anxiolytic, a muscle relaxant, and an anticonvulsivant action. As regards their side effects, besides habituation (Woods et al, 1987), BZDs have been shown to have a detrimental influence on certain cognitive or perceptual abilities, such as memory (Clarke et al, 1970;Brown et al, 1982Brown et al, , 1989Knopman, 1991;Sellal et al, 1992) and attention (Johnson et al, 1995;Carter et al, 1998). However, none of these studies have involved the auditory sensory modality.…”