Theta Oscillations Reflect the Dynamics of Interference in Episodic Memory Retrieval

Humans remember less and less of what was encoded as more and more time passes. Selective retrieval can interrupt such time-dependent forgetting, enhancing recall not only of the retrieved but also of the nonretrieved information. The recall enhancement has been attributed to context retrieval and the idea that selective retrieval reactivates the retrieved item's temporal context during study, which can facilitate recall of other items that had a similar context at study. However, it is unclear whether context retrieval induces a transient discontinuity in the stream of temporal context only, or a more permanent updating of context that would entail a lasting interruption of time-dependent forgetting. In three experiments, we analyzed time-dependent forgetting of encoded information right after study and after time-lagged selective retrieval. Selective retrieval boosted recall of the nonretrieved information up to the levels observed directly after study. Intriguingly, it also created a restart of time-dependent forgetting that made forgetting after retrieval indistinguishable from forgetting after study and thus induced a reset of the recall process. The results suggest that selective retrieval can revive forgotten memories and cause lasting recall enhancement, effects likely mediated by context retrieval and a permanent updating of temporal context.

Seemingly effortless tasks, such as recognizing faces and retrieving names, become harder as we age. Such difficulties may be due to the competition generated in memory by irrelevant information that comes to mind when trying to recall a specific face or name. It is unknown, however, whether age-related struggles in retrieving these representations stem from an inability to detect competition in the first place, or from being unable to suppress competing information once interference is detected. To investigate this, we used the retrieval practice paradigm, shown to elicit memory interference, while recording electrophysiological activity in young and older adults. In two experiments, young participants showed Retrieval-Induced Forgetting (RIF), reflecting the suppression of competing information, whereas older adults did not. Neurally, mid-frontal theta power (~4–8 Hz) during the first retrieval cycle, a proxy for interference detection, increased in young compared to older adults, indicating older adults were less capable of detecting interference. Moreover, while theta power was reduced across practice cycles in younger adults, a measure of interference resolution, older adults did not show such a reduction. Thus, in contrast with younger adults, the lack of an early interference detection signal rendered older adults unable to recruit memory selection mechanisms, eliminating RIF.

An attempt to retrieve an item from memory can result in negative effect on future retrieval of other related-but-unwanted items, and such negative consequence of selective retrieval is called ‘Retrieval Induced Forgetting’ (Anderson, Bjork, & Bjork, 1994). The majority of research on retrieval-induced forgetting has employed word recall task to demonstrate the suppression of non-retrieved items on semantic level. The current study suggests that selective retrieval during mental imagery can invoke deterioration of perceptual representation itself. The participants engaged in mental imagery task in which they retrieved the shape of previously studied line-drawing pictures in mind. The category name and the fragmented lines of each picture were presented as retrieval cues. Experiment 1 measured recall accuracy for the picture names to determine whether mental imagery task can invoke retrieval-induced forgetting in verbal dimension. The result showed that recall accuracy for non-retrieved items in retrieved categories (Rp-) was significantly worse than that for non-retrieved categories (Nrp). Experiment 2 employed perceptual identification task in which participant adjusted the level of occluding noise until they were able to identify the original pictures. Noise level for correct identification was lower for Rp- items than Nrp items when measured with the identical pictures presented at the study phase but not with mirror-reversed pictures. This result confirms the decline in identification performance for Rp- items was mainly due to perceptual suppression than to semantic suppression. Experiment 3 employed recognition between a pair of different pictures that have the same name and meaning. The result showed that recognition time for Rp- items was slower than Nrp items. These results suggest that selective retrieval of specific representation during mental imagery can induce forgetting of semantically related-but-unwanted representations in perceptual dimension.

Selective retrieval of a specific target memory often leads to the forgetting of related but irrelevant memories. Current cognitive theory states that such retrieval-induced forgetting arises due to inhibition of competing memory traces. To date, however, direct neural evidence for this claim has not been forthcoming. Studies on selective attention suggest that cortical inhibition is mediated by increased brain oscillatory activity in the alpha/beta frequency band. The present study, testing 18 human subjects, investigated whether these mechanisms can be generalized to selective memory retrieval in which competing memories interfere with the retrieval of a target memory. Our experiment was designed so that each cue used to search memory was associated with a target memory and a competitor memory stored in separate brain hemispheres. Retrieval-induced forgetting was observed in a condition in which the competitor memory interfered with target retrieval. Increased oscillatory alpha/beta power was observed over the hemisphere housing the sensory representation of the competitor memory trace and predicted the amount of retrieval-induced forgetting in the subsequent memory test. These results provide the first direct evidence for inhibition of competing memories during episodic memory retrieval and suggest that competitive retrieval is governed by inhibitory mechanisms similar to those employed in selective attention.

Decision letter for "The Effects of External Cue Overlap and Internal Goals on Selective Memory Retrieval as Revealed by Electroencephalographic (EEG) Neural Pattern Reinstatement"

Review for "The Effects of External Cue Overlap and Internal Goals on Selective Memory Retrieval as Revealed by Electroencephalographic (EEG) Neural Pattern Reinstatement"

Selective retrieval practice of category exemplars often impairs the recall of related items, a phenomenon known as retrieval-induced forgetting (RIF). In Experiment 1 the role of item typicality (high, low) and presentation format of category exemplars (random, grouped) were analysed, while in Experiment 2 two encoding strategies (inter and intracategory) to modulate RIF were tested. Exemplar typicality was the critical factor underlying RIF. Competition during retrieval practice rendered RIF in the typical exemplars, but RIF did not appear when the exemplars were low typicality. The greater impairment of strong exemplars is in line with the inhibitory account of RIF and the notion of interference dependence. Inhibition appeared with random and grouped presentations suggesting that presentation format of the exemplars is not a critical factor in modulating RIF in a category-cued recall task. Distinctive processing instructions using sentences that connected items from different categories (intercategory strategy) and integration instructions by using size to organise the exemplars within categories (intracategory strategy) easily avoided competition and the need of inhibition processes in recall.

TDCS over the right inferior frontal gyrus disrupts control of interference in memory: A retrieval-induced forgetting study

Enhancement of selective attention and memory retrieval after blockade of alpha 2 adrenoceptors

Neuroarchitecture uses neuroscientific tools to better understand architectural design and its impact on human perception and subjective experience. The form or shape of the built environment is fundamental to architectural design, but not many studies have shown the impact of different forms on the inhabitants’ emotions. This study investigated the neurophysiological correlates of different interior forms on the perceivers’ affective state and the accompanying brain activity. To understand the impact of naturalistic three-dimensional (3D) architectural forms, it is essential to perceive forms from different perspectives. We computed clusters of form features extracted from pictures of residential interiors and constructed exemplary 3D room models based on and representing different formal clusters. To investigate human brain activity during 3D perception of architectural spaces, we used a mobile brain/body imaging (MoBI) approach recording the electroencephalogram (EEG) of participants while they naturally walk through different interior forms in virtual reality (VR). The results revealed a strong impact of curvature geometries on activity in the anterior cingulate cortex (ACC). Theta band activity in ACC correlated with specific feature types (rs (14) = 0.525, p = 0.037) and geometry (rs (14) = −0.579, p = 0.019), providing evidence for a role of this structure in processing architectural features beyond their emotional impact. The posterior cingulate cortex and the occipital lobe were involved in the perception of different room perspectives during the stroll through the rooms. This study sheds new light on the use of mobile EEG and VR in architectural studies and provides the opportunity to study human brain dynamics in participants that actively explore and realistically experience architectural spaces.

This paper introduces a high-performance vehicle detection algorithm for a parking management system based on wireless sensor technology. The parking lot is represented as a wireless sensor network cluster modeled as an m n grid in a rectangle of size l x h. A wireless sensor node is deployed in each grid and one gateway is set for the cluster. The status of each parking space is detected by a sensor node and the result is reported to the gateway. To reduce the false positive rate caused by various sources of interference, we developed a high-performance vehicle detection algorithm to filter out the noises from the passing-by cars and the environment. The performance of the algorithm is verified through extensive simulation. The three scenarios of low, medium and high interference levels are simulated. Results suggest that our proposed vehicle detection algorithm can effectively detect the status of parking lot with zero false positive rate at the low and medium interference levels, and 3.3% at high interference level.

When motor sequences are stored in memory in a categorised manner, selective retrieval of some sequences can induce forgetting of the non-retrieved sequences. We show that such retrieval-induced forgetting (RIF) occurs not only in cued recall but also in a test assessing memory indirectly by providing novel test cues without involving recall of items. Participants learned several sequential finger movements (SFMs), each consisting of the movement of two fingers of either the left or the right hand. Subsequently, they performed retrieval practice on half of the sequences of one hand. A final task then required participants to enter letter dyads. A subset of these dyads corresponded to the previously learned sequences. RIF was present in the response times during the entering of the dyads. The finding of RIF in the slowed-down execution of motor programmes overlapping with initially trained motor sequences suggests that inhibition resolved interference between procedural representations of the acquired motor sequences of one hand during retrieval practice.

Giving Birth and Returning to Work: The Impact of Work–Family Conflict on Women's Health After Childbirth

When things look wrong: Theta activity in rule violation

Collective narcissism—a phenomenon in which individuals show excessively high regard for their own group—is ubiquitous in studies of small groups. We examined how Americans from the 50 U.S. states (N = 2,898) remembered U.S. history by asking them, “In terms of percentage, what do you think was your home state’s contribution to the history of the United States?” The mean state estimates ranged from 9% (Iowa) to 41% (Virginia), with the total contribution for all states equaling 907%, indicating strong collective narcissism. In comparison, ratings provided by nonresidents for states were much lower (but still high). Surprisingly, asking people questions about U.S. history before they made their judgment did not lower estimates. We argue that this ethnocentric bias is due to ego protection, selective memory retrieval processes involving the availability heuristic, and poor statistical reasoning. This study shows that biases that influence individual remembering also influence collective remembering.