scholarly journals Alpha-band oscillations track the retrieval of precise spatial representations from long-term memory

2018 ◽  
Author(s):  
David W. Sutterer ◽  
Joshua J. Foster ◽  
John T. Serences ◽  
Edward K. Vogel ◽  
Edward Awh

AbstractA hallmark of episodic memory is the phenomenon of mentally re-experiencing the details of past events, and a well-established concept is that the neuronal activity that mediates encoding is reinstated at retrieval. Evidence for reinstatement has come from multiple modalities, including functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG). These EEG studies have shed light on the time-course of reinstatement, but have been limited to distinguishing between a few categories and/or limited measures of memory strength. The goal of this work was to investigate whether recently developed experimental and technical approaches, namely an inverted encoding model applied to alpha oscillatory power in conjunction with sensitive tests of memory retrieval in a continuous space, can track and reconstruct memory retrieval of specific spatial locations. In Experiment 1, we establish that an inverted encoding model applied to multivariate alpha topography can track retrieval of precise spatial memories. In Experiment 2, we demonstrate that the pattern of multivariate alpha activity at study is similar to the pattern observed during retrieval. Finally, we observe that these encoding models predict memory retrieval behavior, including the accuracy and latency of recall. These findings highlight the broad potential for using encoding models to characterize long-term memory retrieval.

2019 ◽  
Vol 122 (2) ◽  
pp. 539-551 ◽  
Author(s):  
David W. Sutterer ◽  
Joshua J. Foster ◽  
John T. Serences ◽  
Edward K. Vogel ◽  
Edward Awh

A hallmark of episodic memory is the phenomenon of mentally reexperiencing the details of past events, and a well-established concept is that the neuronal activity that mediates encoding is reinstated at retrieval. Evidence for reinstatement has come from multiple modalities, including functional magnetic resonance imaging and electroencephalography (EEG). These EEG studies have shed light on the time course of reinstatement but have been limited to distinguishing between a few categories. The goal of this work was to use recently developed experimental and technical approaches, namely continuous report tasks and inverted encoding models, to determine which frequencies of oscillatory brain activity support the retrieval of precise spatial memories. In experiment 1, we establish that an inverted encoding model applied to multivariate alpha topography tracks the retrieval of precise spatial memories. In experiment 2, we demonstrate that the frequencies and patterns of multivariate activity at study are similar to the frequencies and patterns observed during retrieval. These findings highlight the broad potential for using encoding models to characterize long-term memory retrieval. NEW & NOTEWORTHY Previous EEG work has shown that category-level information observed during encoding is recapitulated during memory retrieval, but studies with this time-resolved method have not demonstrated the reinstatement of feature-specific patterns of neural activity during retrieval. Here we show that EEG alpha-band activity tracks the retrieval of spatial representations from long-term memory. Moreover, we find considerable overlap between the frequencies and patterns of activity that track spatial memories during initial study and at retrieval.


2016 ◽  
Vol 33 (S1) ◽  
pp. S412-S412
Author(s):  
V. Giannouli

IntroductionThere is a hypothesis in cognitive psychology that long-term memory retrieval is improved by intermediate testing than by restudying the information. The effect of testing has been investigated with the use of a variety of stimuli. However, almost all testing effect studies to date have used purely verbal materials such as word pairs, facts and prose passages.ObjectiveHere byzantine music symbol–word pairs were used as to-be-learned materials to demonstrate the generalisability of the testing effect to symbol learning in participants with and without depressive symptoms.MethodFifty healthy (24 women, M age = 26.20, SD = 5.64) and forty volunteers with high depressive symptomatology (20 women, M age = 27.00, SD = 1.04) were examined. The participants did not have a music education. The examination material was completely new for them: 16 byzantine music notation stimuli, paired with a verbal label (the ancient Greek name of the symbol). Half of the participants underwent intermediate testing and the others restudied the information in a balanced design.ResultsResults indicated that there were no statistically significant differences in final memory test performance after a retention interval of 5 minutes for both groups of participants with low and high level depressive symptomatology (P > 0.005). After a retention interval of a week, tested pairs were retained better than repeatedly studied pairs for high and low depressive symptomatology groups (P < 0.005).ConclusionsThis research suggests that the effect of testing time on later memory retrieval can also be obtained in byzantine symbol learning.Disclosure of interestThe authors have not supplied their declaration of competing interest.


2020 ◽  
pp. 311-332
Author(s):  
Nicole Hakim ◽  
Edward Awh ◽  
Edward K. Vogel

Visual working memory allows us to maintain information in mind for use in ongoing cognition. Research on visual working memory often characterizes it within the context of its interaction with long-term memory (LTM). These embedded-processes models describe memory representations as existing in three potential states: inactivated LTM, including all representations stored in LTM; activated LTM, latent representations that can quickly be brought into an active state due to contextual priming or recency; and the focus of attention, an active but sharply limited state in which only a small number of items can be represented simultaneously. This chapter extends the embedded-processes framework of working memory. It proposes that working memory should be defined operationally based on neural activity. By defining working memory in this way, the important theoretical distinction between working memory and LTM is maintained, while still acknowledging that they operate together. It is additionally proposed that active working memory should be further subdivided into at least two subcomponent processes that index item-based storage and currently prioritized spatial locations. This fractionation of working memory is based on recent research that has found that the maintenance of information distinctly relies on item-based representations as well as prioritization of spatial locations. It is hoped that this updated framework of the definition of working memory within the embedded-processes model provides further traction for understanding how we maintain information in mind.


2020 ◽  
Vol 10 (12) ◽  
pp. 937
Author(s):  
Soyiba Jawed ◽  
Hafeez Ullah Amin ◽  
Aamir Saeed Malik ◽  
Ibrahima Faye

The hemispherical encoding retrieval asymmetry (HERA) model, established in 1991, suggests that the involvement of the right prefrontal cortex (PFC) in the encoding process is less than that of the left PFC. The HERA model was previously validated for episodic memory in subjects with brain traumas or injuries. In this study, a revised HERA model is used to investigate long-term memory retrieval from newly learned video-based content for healthy individuals using electroencephalography. The model was tested for long-term memory retrieval in two retrieval sessions: (1) recent long-term memory (recorded 30 min after learning) and (2) remote long-term memory (recorded two months after learning). The results show that long-term memory retrieval in healthy individuals for the frontal region (theta and delta band) satisfies the revised HERA asymmetry model.


2021 ◽  
Vol 33 (1) ◽  
pp. 119-128
Author(s):  
Anna Castiglione ◽  
Adam R. Aron

Quickly preventing the retrieval of (inappropriate) long-term memories might recruit a similar control mechanism as rapid action-stopping. A very specific characteristic of rapid action-stopping is “global motor suppression”: When a single response is rapidly stopped, there is a broad skeletomotor suppression. This is shown by the technique of TMS placed over a task-irrelevant part of the primary motor cortex (M1) to measure motor-evoked potentials. Here, we used this same TMS method to test if rapidly preventing long-term memory retrieval also shows this broad skeletomotor suppression effect. Twenty human participants underwent a Think/No-Think task. In the first phase, they learned word pairs. In the second phase, they received the left-hand word as a cue and had to either retrieve the associated right-hand word (“Think”) or stop retrieval (“No-Think”). At the end of each trial, they reported whether they had experienced an intrusion of the associated memory. Behaviorally, on No-Think trials, they reported fewer intrusions than Think trials, and the reporting of intrusions decreased with practice. Physiologically, we observed that the motor-evoked potential, measured from the hand (which was irrelevant to the task), was reduced on No-Think trials in the time frame of 300–500 msec, especially on trials where they did report an intrusion. This unexpected result contradicted our preregistered prediction that we would find such a decrease on No-Think trials where the intrusion was not reported. These data suggest that one form of executive control over (inappropriate) long-term memory retrieval is a rapid and broad stop, akin to action-stopping, that is triggered by the intrusion itself.


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