Medial Prefrontal Theta Oscillations Track the Time Course of Interference during Selective Memory Retrieval

Abstract

Memory retrieval is often challenged by other irrelevant competing memories that cause interference. This phenomenon is typically studied with the retrieval practice paradigm in which a category cue (e.g., Fruits) is presented together with an item-specific cue (e.g., Or::). Presentation of the category cue usually induces interference by reactivating competing memories (e.g., Banana, Apple, etc.), which is thought to be solved by means of inhibition, leading to retrieval-induced forgetting of these competing memories. Previous studies associated interference with an increase in medial prefrontal theta band (4-8 Hz) oscillations, but these studies could not disentangle the interference from the inhibition processes. We here used a retrieval practice procedure in which the category cue was presented before the item-specific cue to disentangle the interference from the inhibition signal. Furthermore, a competitive retrieval condition was contrasted with a noncompetitive condition. At a behavioral level, retrieval-induced forgetting was found in the competitive but not in the noncompetitive condition. At a neural level, presentation of the category cue elicited higher levels of theta power in the competitive condition, when compared with the noncompetitive retrieval condition. Importantly, this difference was localized to the ACC, which has been associated with the detection and mediation of interference. Additionally, theta power decreased upon presentation of the item-specific cue, and this difference was related to later forgetting. Our results therefore disentangle, for the first time, interference and inhibition in episodic memory retrieval and suggest that theta oscillations track the fine-grained temporal dynamics of interference during competitive memory retrieval.

Interference resolution in face perception and name retrieval

“…According to these results, simply being exposed to the stimuli without the need of an active effort to retrieve information does not yield forgetting of unpractised but related items. This comes in line with previous research showing the same pattern of results (Anderson et al, 2000;Ferreira, Marful, Staudigl, Bajo, & Hanslmayr, 2014;Hanslmayr, Staudigl, Aslan, & Bäuml, 2010).…”

“…Soriano, Jiménez, Román, & Bajo, 2009), as well as by several electrophysiological (e.g. Ferreira, Marful, Staudigl, Bajo, & Hanslmayr, 2014; …”

Increases in theta CSD power and coherence during a calibrated stop-signal task: implications for goal-conflict processing and the Behavioural Inhibition System

“…Firstly, the involvement of the MF region suggests that the activity may be part of the conflict resolution and inhibitory functions of the BIS. Specifically, magnetoencephalogram research has linked medial prefrontal theta to interference resolution and inhibition during episodic memory retrieval (Ferreira, Marful, Staudigl, Bajo, & Hanslmayr, 2014). Specifically, during memory recall, the hippocampus (acting as the core of the BIS) is thought to reduce the effects of interference by eliminating competing memories to enable the individual to recall only the correct memory (Gray & McNaughton, 2000).…”

Dopamine Modulates Delta-Gamma Phase-Amplitude Coupling in the Prefrontal Cortex of Behaving Rats

“…Theta oscillations are also present in other cortical regions, including the PFC. Importantly, the amplitude of theta oscillations in the PFC and its coupling with hippocampal theta has been related with spatial memory in rodents (Jones and Wilson, 2005; O'Neill et al, 2013) and humans (Canolty et al, 2006; Ferreira et al, 2014; Kaplan et al, 2014). Gamma oscillations (>20 Hz) have been implicated in episodic memory in humans (Nyhus and Curran, 2010), as well as memory encoding and retrieval in the hippocampus of rodents (Colgin and Moser, 2010).…”