Neural Correlates Of Familiarity Research Articles

The late positive event-related potential component is time locked to the decision in recognition memory tasks

Two event-related potential (ERP) components are commonly observed in recognition memory tasks: the Frontal Negativity (FN400) and the Late Positive Component (LPC). These components are widely interpreted as neural correlates of familiarity and recollection, respectively. However, the interpretation of LPC effects is complicated by inconsistent results regarding the timing of ERP amplitude differences. There are also mixed findings regarding how LPC amplitudes covary with decision confidence. Critically, LPC effects have almost always been measured using fixed time windows relative to memory probe stimulus onset, yet it has not been determined whether LPC effects are time locked to the stimulus or the recognition memory decision. To investigate this, we analysed a large (n = 132) existing dataset recorded during recognition memory tasks with old/new decisions followed by post-decisional confidence ratings. We used ERP deconvolution to disentangle contributions to LPC effects (defined as differences between hits and correct rejections) that were time locked to either the stimulus or the vocal old/new response. We identified a left-lateralised parietal LPC effect that was time locked to the vocal response rather than probe stimulus onset. We also isolated a response-locked, midline parietal ERP correlate of confidence that influenced measures of LPC amplitudes at left parietal electrodes. Our findings demonstrate that, contrary to widespread assumptions, the LPC effect is time locked to the recognition memory decision and is best measured using response-locked ERPs. By extension, differences in response time distributions across conditions of interest may lead to substantial measurement biases when analysing stimulus-locked ERPs. Our findings highlight important confounding factors that further complicate the interpretation of existing stimulus-locked LPC effects as neural correlates of recollection. We recommend that future studies adopt our analytic approach to better isolate LPC effects and their sensitivity to manipulations in recognition memory tasks.

Relationships between age, fMRI correlates of familiarity and familiarity-based memory performance under single and dual task conditions

Using fMRI, we investigated the effects of age and divided attention on the neural correlates of familiarity and their relationship with memory performance. At study, word pairs were visually presented to young and older participants under the requirement to make a relational judgment on each pair. Participants were then scanned while undertaking an associative recognition test under single and dual (auditory tone detection) task conditions. The test items comprised studied, rearranged (words from different studied pairs) and new word pairs. fMRI familiarity effects were operationalized as greater activity elicited by studied pairs incorrectly identified as ‘rearranged’ than by correctly rejected new pairs. The reverse contrast was employed to identify ‘novelty’ effects. Behavioral familiarity estimates were equivalent across age groups and task conditions. Robust fMRI familiarity effects were identified in several regions, including medial and superior lateral parietal cortex, dorsal medial and left lateral prefrontal cortex, and bilateral caudate. fMRI novelty effects were identified in the anterior medial temporal lobe. Both familiarity and novelty effects were largely age-invariant and did not vary, or varied minimally, according to task condition. In addition, the familiarity effects correlated positively with a behavioral estimate of familiarity strength irrespective of age. These findings extend a previous report from our laboratory, and converge with prior behavioral reports, in demonstrating that the factors of age and divided attention have little impact on behavioral and neural estimates of familiarity.

Unitization could facilitate item recognition but inhibit verbatim recognition for picture stimuli: behavioral and event-related potential study.

It is widely accepted that unitization can promote familiarity-based associative recognition, but the effect of unitization on item recognition remains unclear. The goals of this study were to elaborate on how unitization affected item recognition and the neural correlates of familiarity and recollection for item recognition. In study, the participants were asked to learn related and unrelated picture pairs, and in test, they were required to distinguish single old pictures form new pictures. In experiment 1, we used R/K/N paradigm to estimate the contribution of familiarity and recollection to item recognition, the results showed that unitization could improve item recognition through increasing recollection selectively. In experiment 2, we used ERP old/new effects to estimate the neural correlates of familiarity and recollection, the results showed that unitization could improve item recognition through a selective reduction in LPC effect. Inspired by DRM paradigm, in experiment 3, we divided the new pictures into semantically related lure pictures and semantically unrelated new pictures to explore the effects of unitization on item recognition and verbatim recognition (the ability to distinguish old pictures from lure pictures). The behavioral results showed that unitization could improve item recognition, but it damaged verbatim recognition. The ERP results revealed that there were larger LPC effects in the unrelated condition than in the related condition, regardless of item or verbatim recognition. In summary, we believed that unitization could indeed improve item recognition, but it damaged verbatim recognition.

Unitization does not impede overall item recognition performance: Behavioral and event-related potential study.

It is widely accepted that unitization can promote familiarity-based associative recognition, but the role of unitization in recognition of individual component elements which originate from compound words remains unclear. The goals of this study were to elaborate on how unitization affects item recognition and further examine the effect of unitization on the extent to which familiarity and recollection contribute to item recognition. During the study phase, participants were asked to learn 48 compound words and 48 unrelated word pairs, and during the test phase, they were instructed to distinguish old from new words. We disassociated the contribution of familiarity and recollection to recognition with remember/know paradigm in experiment 1 and with ERPs old/new effects in experiment 2. The results showed that the overall item recognition was equivalent between the two retrieval conditions. Disassociation the contribution of familiarity and recollection, we found that there was higher recollection-based item recognition performance for compound-old words than for unrelated-old words in experiment 1. In contrast, in experiment 2, the magnitude of later parietal old/new effect related to recollection was larger for the former than for the latter, indicating that equivalent levels of memory retrieval were achieved through "less" neural correlates of familiarity and recollection. By synthesizing the results of experiment 1 and 2, we believed unitization did not impede overall item recognition performance.

Neural Correlates of Familiarity in Music Listening: A Systematic Review and a Neuroimaging Meta-Analysis.

Familiarity in music has been reported as an important factor modulating emotional and hedonic responses in the brain. Familiarity and repetition may increase the liking of a piece of music, thus inducing positive emotions. Neuroimaging studies have focused on identifying the brain regions involved in the processing of familiar and unfamiliar musical stimuli. However, the use of different modalities and experimental designs has led to discrepant results and it is not clear which areas of the brain are most reliably engaged when listening to familiar and unfamiliar musical excerpts. In the present study, we conducted a systematic review from three databases (Medline, PsychoINFO, and Embase) using the keywords (recognition OR familiar OR familiarity OR exposure effect OR repetition) AND (music OR song) AND (brain OR brains OR neuroimaging OR functional Magnetic Resonance Imaging OR Position Emission Tomography OR Electroencephalography OR Event Related Potential OR Magnetoencephalography). Of the 704 titles identified, 23 neuroimaging studies met our inclusion criteria for the systematic review. After removing studies providing insufficient information or contrasts, 11 studies (involving 212 participants) qualified for the meta-analysis using the activation likelihood estimation (ALE) approach. Our results did not find significant peak activations consistently across included studies. Using a less conservative approach (p < 0.001, uncorrected for multiple comparisons) we found that the left superior frontal gyrus, the ventral lateral (VL) nucleus of the left thalamus, and the left medial surface of the superior frontal gyrus had the highest likelihood of being activated by familiar music. On the other hand, the left insula, and the right anterior cingulate cortex had the highest likelihood of being activated by unfamiliar music. We had expected limbic structures as top clusters when listening to familiar music. But, instead, music familiarity had a motor pattern of activation. This could reflect an audio-motor synchronization to the rhythm which is more engaging for familiar tunes, and/or a sing-along response in one's mind, anticipating melodic, harmonic progressions, rhythms, timbres, and lyric events in the familiar songs. These data provide evidence for the need for larger neuroimaging studies to understand the neural correlates of music familiarity.

Independent contributions of fMRI familiarity and novelty effects to recognition memory and their stability across the adult lifespan

The impact of age on the neural correlates of familiarity-driven recognition memory has received relatively little attention. Here, the relationships between age, the neural correlates of familiarity, and memory performance were investigated using an associative recognition test in young, middle-aged and older participants. Test items comprised studied, rearranged (items studied on different trials) and new word pairs. fMRI ‘familiarity effects’ were operationalized as greater activity for studied test pairs incorrectly identified as ‘rearranged’ than for correctly rejected new pairs. The reverse contrast was employed to identify ‘novelty’ effects. Estimates of familiarity strength were slightly but significantly lower for the older relative to the younger group. With the exception of one region in dorsal medial prefrontal cortex, fMRI familiarity effects (which were identified in medial and lateral parietal cortex, dorsal medial and left lateral prefrontal cortex, and bilateral caudate among other regions) did not differ significantly with age. Age-invariant ‘novelty effects’ were identified in the anterior hippocampus and the perirhinal cortex. When entered into the same regression model, familiarity and novelty effects independently predicted familiarity strength across participants, suggesting that the two classes of memory effect reflect functionally distinct mnemonic processes. It is concluded that the neural correlates of familiarity-based memory judgments, and their relationship with familiarity strength, are largely stable across much of the healthy adult lifespan.

Unitization improves source memory in older adults: An event-related potential study

Aging-related decline in episodic memory, particularly in associative memory, is attributed to an impaired recollection of the specific details of a study episode. Fortunately, familiarity is relatively preserved in older adults. Previous studies have indicated that unitization is a specialized form of learning that increases the contribution of familiarity to associative retrieval. Here we examined whether older adults’ associative memory could be improved when employing an encoding strategy that encouraged unitization. Young and older adults encoded items and background colors either in a unitized condition (i.e., by imagining the color as an internal feature of the item) or in a non-unitized condition (i.e., by imagining the color as a contextual feature of the item). The participants then performed a source recognition test. The effects of unitization on the neural correlates of familiarity were measured by event-related potentials (ERPs). The age differences in source memory performance were lower in the unitized condition than in the non-unitized condition. The older adults only demonstrated neural correlates of familiarity-based source recognition in the unitized condition. These findings suggest that a unitized encoding strategy could improve source memory performance in older adults by enhancing the involvement of familiarity in source recognition.

The posterior parietal cortex: Comparing remember/know and source memory tests of recollection and familiarity

Numerous neuroimaging studies have shown a dissociation within the left posterior parietal cortex (PPC) between recollection and familiarity, with dorsal regions routinely active during familiarity and ventral regions active during recollection. The two most common methods for separating the neural correlates of these retrieval states are the remember/know paradigm and tests probing source memory. While relatively converging results have been found using these methods, the literature is lacking an adequate and direct comparison of the two procedures. We directly compared these two methodologies and found differences in both the magnitude and extent of activation within the left PPC. During familiarity, dorsal PPC regions were more strongly activated by the source test, while the remember/know test led to stronger recollection-related activations within the ventral regions of the PPC. This modulation of PPC activity is particularly important because it suggests that the neural correlates of familiarity and recollection depend on how they are operationalized. Previous assumptions that remember/know and source memory tests are functionally equivalent should therefore be re-evaluated. Additionally, any theories attempting to explain the functional role of the PPC during memory retrieval must take these differences into account.

Neural correlates of familiarity and conceptual fluency are dissociable at encoding

Familiarity and conceptual fluency belong to explicit and implicit memory respectively. Since familiarity and conceptual fluency co-occur at certain circumstances and share some similarities, it is difficult to distinguish them. By using ERPs, in present study, we sought to differentiate the Dm effects, the differential neural activities due to later memory performances, of familiarity and conceptual fluency at encoding. We used ancient pictographic characters as stimuli, which were categorized as high or low meaningfulness based on the subjective ratings. In Experiment 1, conceptual fluency was observed to be induced exclusively by the repetition of relative meaningful items. In Experiment 2, Dm effects of familiarity and conceptual fluency were observed, respectively. In addition, the distribution of conceptual fluency Dm effects was found to be more posterior than that of familiarity Dm effects. These findings provide the dissociation of familiarity and conceptual fluency at encoding and further support the distinction between explicit and implicit memory.

Neural correlates of familiarity and conceptual fluency in a recognition test with ancient pictographic characters

Familiarity and conceptual priming refer to distinct memory expressions and are subtypes of explicit memory and implicit memory, respectively. Given that the neural events that produce conceptual priming may in some cases promote familiarity, distinguishing between neural signals of these two types of memory may further our understanding of recognition memory mechanisms. Although FN400 event-related potentials observed during recognition tests have often been ascribed to familiarity, much evidence suggests that they should instead be ascribed to conceptual fluency. To help resolve this controversy, we studied potentials elicited by unrecognizable ancient Chinese characters. These stimuli were categorized as high or low in meaningfulness based on subjective ratings. Conceptual priming was produced exclusively by repetition of characters high in meaningfulness. During a recognition test in which recollection was discouraged, FN400 old–new effects were observed, and amplitudes of the FN400 potentials varied inversely with familiarity confidence. However, these effects were absent for old items given low meaningfulness ratings. For both high and low meaningfulness, late positive (LPC) potentials were found in old–new comparisons, and LPC amplitudes were greater when higher familiarity confidence was registered during the recognition test. These findings linked familiarity and conceptual fluency with different brain potentials – LPC and FN400, respectively – and provide additional evidence that explicit memory and implicit memory have distinct neural substrates.

Differential effects of aging on the neural correlates of recollection and familiarity

The present experiment aimed to investigate age differences in the neural correlates of familiarity and recollection, while keeping performance similar across age groups by varying task difficulty. Twenty young and 20 older adults performed an episodic memory task in an event-related functional magnetic resonance imaging (fMRI) design. At encoding, participants were presented with pictures, either once or twice. Then, they performed a recognition task, with a Remember/Know paradigm. A similar performance was observed for the two groups in the Easy condition for recollection and in the Hard condition for familiarity. Imaging data revealed the classic recollection-related and familiarity-related networks, common to young and older groups. In addition, we observed that some activity related to recollection (left frontal, left temporal, left parietal cortices and left parahippocampus) and familiarity (bilateral anterior cingulate, right frontal gyrus and left superior temporal gyrus) was reduced in older compared to young adults. However, for recollection processes only, older adults additionally recruited the right precuneus, possibly to successfully compensate for their difficulties, as suggested by a positive correlation between recollection and precuneus activity.

Neurophysiological evidence for a recollection impairment in amnesia patients that leaves familiarity intact

In several previous behavioral studies, we have identified a group of amnestic patients that, behaviorally, appear to exhibit severe deficits in recollection with relative preservation of familiarity-based recognition. However, these studies have relied exclusively on behavioral measures, rather than direct measures of physiology. Event-related potentials (ERPs) have been used to identify putative neural correlates of familiarity- and recollection-based recognition memory, but little work has been done to determine the extent to which these ERP correlates are spared in patients with relatively specific memory disorders. ERP studies of recognition in healthy subjects have indicated that recollection and familiarity are related to a parietal old-new effect characterized as a late positive component (LPC) and an earlier mid-frontal old-new effect referred to as an ‘FN400’, respectively. Here, we sought to determine the extent to which the putative ERP correlates of recollection and familiarity are intact or impaired in these patients. We recorded ERPs in three amnestic patients and six age matched controls while they made item recognition and source recognition judgments. The current patients were able to discriminate between old and new items fairly well, but showed nearly chance-level performance at source recognition. Moreover, whereas control subjects exhibited ERP correlates of memory that have been linked to recollection and familiarity, the patients only exhibited the mid-frontal FN400 ERP effect related to familiarity-based recognition. The results show that recollection can be severely impaired in amnesia even when familiarity-related processing is relatively spared, and they also provide further evidence that ERPs can be used to distinguish between neural correlates of familiarity and recollection.

Effects of retention interval on recognition memory: Electrophysiological and behavioural evidence

Event Abstract Back to Event Effects of retention interval on recognition memory: Electrophysiological and behavioural evidence Dimitris Tsivilis1*, W El-Deredy1, N. Williams2 and J. J. Downes2 1 School of Psychological Sciences, University of Manchester, United Kingdom 2 School of Psychology, University of Liverpool, United Kingdom According to dual-process theories, recognition memory is supported by two independent processes, recollection which is associated with retrieval of episodic details- and familiarity- an item-specific, non-episodic form of memory. Event-related potential (ERP) studies have linked familiarity to a mid-frontal negative going old/new effect, also known as the FN400, whereas a later onsetting (around 500 ms) parietal, positive going effect has been associated with recollection. However, these investigations have involved short retention intervals mostly in the range of a few minutes between study and test. As a result, little is known about either the memory processes that support recognition memory at longer intervals or their neural correlates. In the first experiment, we contrasted ERPs elicited during retrieval by two different sets of object pictures studied at delays of 4 weeks (remote) and 5 min (recent) prior to a recognition memory test. As expected, recognition responses showed greater accuracy and reduced latency for recent relative to remote memories. Electrophysiological analysis showed that whereas both recent and remote memories elicited the FN400, only recent memories modulated the later old/new parietal effect. A separate behavioural study using a variant of the Remember/Know procedure, found that whereas recent memories were based on both recollection and familiarity, remote memories were supported almost exclusively by familiarity, thus confirming the electrophysiological findings. Taken together the two studies provide further support for the notion that the FN400 and the late-parietal effects are the neural correlates of familiarity and recollection, respectively. Importantly, they also suggest that longer retention intervals affect not only the quantity of retrieved memories but also their quality with successful recognition of remote stimuli lacking episodic content. These are also in line with theories of remote memory which propose a gradual, time-dependant transformation of episodic to semantic memories. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Memory & Learning Citation: Tsivilis D, El-Deredy W, Williams N and Downes JJ (2008). Effects of retention interval on recognition memory: Electrophysiological and behavioural evidence. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.304 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Dec 2008; Published Online: 10 Dec 2008. * Correspondence: Dimitris Tsivilis, School of Psychological Sciences, University of Manchester, Manchester, United Kingdom, Dimitris.Tsivilis@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Dimitris Tsivilis W El-Deredy N. Williams J. J Downes Google Dimitris Tsivilis W El-Deredy N. Williams J. J Downes Google Scholar Dimitris Tsivilis W El-Deredy N. Williams J. J Downes PubMed Dimitris Tsivilis W El-Deredy N. Williams J. J Downes Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Dissociating recollection from familiarity: Electrophysiological evidence that familiarity for faces is associated with a posterior old/new effect

In recognition memory research, a tension exists between dual-process and single-process models of episodic retrieval. Dual-process models propose that ‘familiarity’ assessment and the ‘recollection’ of contextual information are independent processes, while single-process models claim that one common process supports retrieval. Event-related potentials (ERPs) have been used to show dissociations between the mid frontal and the left parietal ERP old/new effects, which have been associated with familiarity and recollection, respectively. While much ERP evidence favours dual-process theory, Yovel and Paller [Yovel, G., Paller, K.A., 2004. The neural basis of the butcher-on-the-bus phenomenon: when a face seems familiar but is not remembered. NeuroImage 21, 789–800] used faces as retrieval cues to demonstrate that posterior old/new effects index both familiarity and recollection, a finding consistent with single-process models. Here we present evidence supporting Yovel and Paller’s claim that a posterior old/new effect indexes familiarity for faces, along with a novel finding that recollection is associated with an anterior old/new effect. Importantly, and in contrast to Yovel and Paller, the old/new effects associated with familiarity and recollection were topographically dissociable, consistent with a dual-process view of recognition memory. The neural correlates of familiarity and recollection identified here for faces appear to be different from those typically observed, suggesting that the ERP old/new effects associated with episodic recognition are not the same under all circumstances.