Abstract
An important question in memory research is how best to characterize the role of the medial temporal lobes (MTLs) in memory. The relational processing theory proposes that some portion of the MTLs are critically involved in binding together different elements of a memory trace (Eichenbaum, 1999; Winocur & Kinsbourne, 1978). One limitation of this theory is that it does not specify whether MTL structures are needed for working memory (WM) tasks that require the retention of configural or “bound” items. Previous research has shown that feature binding and location-location binding are critically involved in visual WM (Luck & Vogel, 1997; Jiang, Olson, & Chun, 2000). Much of the existing literature would suggest that the MTL is not necessary for binding in WM because amnesic patients are thought to have intact verbal and visual STM. However prior studies have not examined amnesic performance on STM tasks that require binding.
Here we test MTL amnesics and age-matched controls on two WM tasks for singular or bound information. Subjects were required to remember either three sequentially presented objects, locations, or object-location conjunctions. After a delay of either 1 s or 8 s, recognition performance was assessed. Results show that amnesic patients have intact object STM and location STM but impaired memory for object-location conjunctions. These findings extend the relational processing theory by showing that the MTLs are critical for mnemonic binding even at short delays.