Recognition Memory Performance Research Articles

Effects of the Glycine Transporter-1 Inhibitor Iclepertin (BI 425809) on Sensory Processing, Neural Network Function, and Cognition in Animal Models Related to Schizophrenia.

N-methyl-D-aspartate (NMDA) receptor hypofunction leading to neural network dysfunction is thought to play an important role in the pathophysiology of cognitive impairment associated with schizophrenia (CIAS). Increasing extracellular concentrations of the NMDA receptor co-agonist glycine through inhibition of glycine transporter-1 (GlyT1) has the potential to treat CIAS by improving cortical network function through enhanced glutamatergic signaling. Indeed, the novel GlyT1 inhibitor iclepertin (BI 425809) improved cognition in a recent clinical study in patients with schizophrenia. The present study tested the ability of iclepertin to reverse deficits in auditory sensory processing and cortical network function induced by the uncompetetive NMDA receptor antagonist, MK-801, using electroencephalography (EEG) to measure auditory event-related potentials (AERPs) and 40 Hz auditory steady-state response (ASSR). In addition, improvements in memory performance with iclepertin were evaluated using the T-maze spontaneous alternation test in MK-801-treated mice and the social recognition test in naïve rats. Iclepertin reversed MK-801-induced deficits in the AERP readouts N1 amplitude and N1 gating, as well as reversing deficits in 40 Hz ASSR power and intertrial coherence. Additionally, iclepertin significantly attenuated an MK-801-induced increase in basal gamma power. Furthermore, iclepertin reversed MK-801-induced working memory deficits in mice and improved social recognition memory performance in rats. Overall, this study demonstrates that inhibition of GlyT1 is sufficient to attenuate MK-801-induced deficits in translatable EEG parameters relevant to schizophrenia. Moreover, iclepertin showed memory-enhancing effects in rodent cognition tasks, further demonstrating the potential for GlyT1 inhibition to treat CIAS. SIGNIFICANCE STATEMENT: Despite the significant patient burden caused by cognitive impairment associated with schizophrenia, there are currently no approved pharmacotherapies. In this preclinical study, the novel glycine transporter inhibitor iclepertin (BI 425809) reversed sensory processing deficits and neural network dysfunction evoked by inhibition of N-methyl-D-aspartate receptors and enhanced working memory performance and social recognition in rodents. These findings support previous clinical evidence for the procognitive effects of iclepertin.

Interferon beta attenuates recognition memory impairment and improves brain glucose uptake in a rat model of Alzheimer's disease: Involvement of mitochondrial biogenesis and PI3K pathway

Interferon beta (IFNβ) is a cytokine with anti-apoptotic and anti-inflammatory properties, and its beneficial effects on Alzheimer's disease (AD) have been recently shown. The alterations in cerebral glucose uptake are closely linked to memory deficit and AD progression. The current study was designed to determine if IFNβ can improve recognition memory and brain glucose uptake in a rat model of AD. The lentiviruses expressing mutant human amyloid precursor protein were injected bilaterally to the rat hippocampus. From day 23 after virus injection, rats were intranasally treated with recombinant IFNβ protein (68,000 IU/rat) every other day until day 50. Recognition memory performance was evaluated by novel object recognition test on days 46–49. The 18F-2- fluoro-deoxy-d-glucose positron emission tomography (18F-FDG-PET) was used to determine changes in brain glucose metabolism on day 50. The expression of the PI3K/Akt pathway components, neurotrophins and mitochondrial biogenesis factors were also measured by qPCR in the hippocampus. Our results showed that IFNβ treatment improves recognition memory performance in parallel with increased glucose uptake and neuronal survival in the hippocampus of the AD rats. The neuroprotective effect of IFNβ could be attributed, at least partly, to activation of PI3K-Akt-mTOR signaling pathway, increased expression of NGF, and mitochondrial biogenesis. Taken together, our findings suggest the therapeutic potential of IFNβ for AD.

The dissociating of reward feedback on familiarity and recollection processing: evidence from event-related potential.

Although previous studies have explored the effect of reward feedback on recognition memory, electrophysiological evidence for reward-enhanced memory and its underlying processing mechanisms remains unclear. This study adopts reward-learning and recognition memory tasks. Participants were asked to learn the reward values of two-color images (each color image had either reward or nonreward feedback) in the reward-learning task, and then tested their recognition memory performance with reward and nonreward feedback items. Results demonstrated that the recognition memory performance of rewarded items was better than that of nonrewarded items. During the reward-learning period, nonreward feedback elicited larger feedback-related negativity (FRN) and P300 amplitudes compared with reward feedback. The findings indicated that participants mainly engaged in prediction error processing in the early stage, followed by comparing and context update of the learned items. During the recognition memory period, reward items elicited larger FN400 amplitude and smaller LPC amplitude compared with nonreward items. This suggests that reward item retrieval has deeper memory traces and can identify items faster, relying mainly on familiarity processing. Conversely, nonreward, as a general or inhibitory item, requires more detail and cognitive resources, that is, relies on recollection processing. These findings indicated that participants had different process patterns between reward and nonreward items during recognition retrieval.

Scene memory and hippocampal volume in middle-aged women with early hormone loss

The present study explored whether early midlife bilateral salpingo-oophorectomy (BSO), a female-specific risk factor for dementia, is associated with reduced medial temporal lobe structure and function. Younger middle-aged women with the BRCA1/2 mutation and a BSO prior to spontaneous menopause (SM) were recruited. We determined the performance of women with BSO not taking estradiol-based hormone therapy (n = 18) on a task measuring object and scene recognition and quantified medial temporal lobe subregion volumes using manually segmented high-resolution T2-weighted MRI scans. Comparisons were made to those with BSO taking estradiol-based hormone therapy (n = 20), age-matched premenopausal controls (n = 28), and older women in SM not taking hormone therapy matched for duration of hormone deprivation (n = 17). Reduced hippocampal integrity specific to the BSO group not taking hormone therapy was observed, reflected by significantly smaller dentate gyrus/CA2/CA3 volumes and lower scene recognition memory performance. These findings show that hippocampal subfield volume may be useful for identifying early midlife changes in women at elevated risk for dementia.

Investigation of the optimal dose for experimental lipopolysaccharide-induced recognition memory impairment: behavioral and histological studies.

Lipopolysaccharide (LPS) administration is one of the most commonly used methods for inducing inflammation in animal models. Several animal studies have investigated the effects of acute and chronic peripheral administration of LPS on cognitive impairment. However, no previous study has compared the effects of different doses of chronically administered LPS on recognition memory performance. Here, we aimed to investigate the optimal dose of chronically administered LPS for the induction of recognition memory impairment in mice. LPS at different doses (0.25, 0.50 and 0.75 mg/kg) was administered to SWR/J mice daily for 7 days. On day 9, the open field, novel object recognition and novel arm discrimination behavioral tests were performed. Additionally, prefrontal cortical histological examination was conducted. Compared with the control group, mice injected with 0.75 mg/kg LPS notably showed no object preference (familiar vs. novel), a reduction in the discrimination index, and spatial recognition impairment. Administration of the 0.25 and 0.50 mg/kg doses of LPS showed a preference for the novel object compared with the familiar object, had no significant impact on the discrimination index, and caused spatial recognition impairment. These behavioral results are in line with the histological examination of the prefrontal cortex, which revealed that the 0.75 mg/kg dose produced the most histological damage. Our findings suggest that for chronic peripheral administration of LPS, 0.75 mg/kg is the optimal dose for inducing neuroinflammation-associated recognition memory deficits.

Attentional Features of Mindfulness are Better Predictors of Face Recognition than Empathy and Compassion-Based Constructs.

Recent research has employed measures of either empathy, compassion or mindfulness and linked better face recognition memory to higher scores of identification with all humanity and mindfulness but not empathy or compassion. Additionally, empathy, compassion and mindfulness have been suggested as concepts that intertwine, but research has not yet examined how their respective personality questionnaires map onto latent concepts. We employed these measures together to explore their factor structure and, using structural equation modelling, we investigated if the suggested latent variables predict recognition memory performance for face and non-face stimuli. Attentional notions of mindfulness described a latent factor that predicted face recognition. All self-compassion facets and the non-react mindfulness facet described a latent factor, which predicted false alarms in face recognition. Finally, empathy and compassion-based notions described one latent factor, which did not predict recognition performance. None of the latent variables predicted performance in either object or voice recognition. Collectively, findings indicate attention-based mindfulness to benefit face recognition, prompting further research into the potential of mindfulness to support the face recognition process.

Recognition memory is impacted in atypical “non‐amnestic” Alzheimer’s disease

AbstractBackgroundMemory encoding and retrieval deficits have increasingly been identified in atypical phenotypes of AD, including posterior cortical atrophy (PCA) and logopenic variant primary progressive aphasia (lvPPA), despite traditional assumptions that memory is spared in these groups. There is a critical need to better understand relationships between these encoding deficits and recognition memory performance. Here we aim to build on the current literature by investigating recognition memory performance across the atypical AD syndromic spectrum.MethodThirty‐seven amyloid‐positive patients with atypical syndromes of AD (14 PCA, 9 lvPPA, and 14 amnestic dysexecutive) were administered the California Verbal Learning Test (CVLT‐II‐SF). Recognition memory performance (d’) and Total Learning were calculated. Independent samples t‐tests were conducted to test the hypothesis that amnestic dysexecutive patients would show greater d’ impairment compared to non‐amnestic (PCA, lvPPA) groups. Bivariate correlations were conducted to determine if Total Learning was related to d’ performance. Whole‐cortex general linear models, thresholded at p<0.01, were conducted to determine where cortical atrophy was related to d’ and Total Learning across all participants.ResultRecognition memory was poor across both groups but trended toward worse in the amnestic dysexecutive group (mean d’=1.3) compared to the non‐amnestic group (mean d’=1.9; t=1.8, p=0.08). Total Learning was related to d’ in the non‐amnestic group (r=0.72, p=0.0002), but not in the amnestic dysexecutive group (p<0.7). In the full sample, cortical atrophy was related to Total Learning in a strongly left‐lateralized pattern in the medial parietal and lateral temporoparietal cortices, while atrophy in left>right anterior medial temporal cortices was related to d’.ConclusionRecognition memory is not spared in atypical phenotypes of AD traditionally thought to be “non‐amnestic,” such as PCA and lvPPA. In these groups, individuals who showed stronger learning did not show storage decay, while those who struggled to learn showed poor discriminability. In the amnestic dysexecutive group, recognition discriminability was impaired regardless of learning ability, suggesting clearer storage loss. Convergent evidence from this and our prior work (Wolk & Dickerson et al., 2011) shows that when encoding or storage is impaired in atypical or typical AD, it is due to neurodegeneration in common circuits subserving these memory processes.

Effect of Alzheimer’s pathology on the functional architecture of memory networks during rest and task states in aging

AbstractBackgroundIntrinsic brain networks are relatively consistently organized between rest and task states in young individuals. We performed this study in order to determine whether the same is true in aging, and whether measures of AD pathology affect this relationship.MethodWe used task‐based (mnemonic discrimination task with object and scene stimuli) and rest fMRI to measure functional connectivity (FC) in an anterior temporal (AT) and posteromedial (PM) network in older (OA; N=49, 74±5 years, 31F) and younger adults (YA; N=24, 27±4 years, 9F). We calculated the correlation between rest and task FC states by conducting a Pearson’s correlation between the rest and task FC matrices for each participant. We used PiB‐PET to measure global Aβ (using threshold of 1.065 to classify OA as PiB+/‐) and FTP‐PET to measure tau within an AT and PM composite ROI in OA. We also measured recognition memory performance during the mnemonic discrimination task requiring discrimination of repeated stimuli from lures.ResultResting state and task FC in the ATPM network were less correlated in older compared to younger adults. In addition, less correlated rest vs. task FC was associated with higher levels of FTP in ATPM networks in PiB+ older adults. Finally, less correlated rest vs. task FC was associated with worse recognition performance (among all participants and OA alone) during the object trials.ConclusionThese findings link AD pathology to disruption of the functional architecture of intrinsic brain networks during rest and memory task states in OA. They also suggest that memory decline in some older adults may be influenced by the extent of change in functional architecture between rest and task demands. Overall, dynamic FC changes from rest to task may provide a novel mechanism in which aging impacts cognition.

Transcranial Magnetic Stimulation Trains at 1 Hz Frequency of the Right Posterior Parietal Cortex Facilitate Recognition Memory

Neuroimaging, neuropsychological, and brain stimulation studies have led to contrasting findings regarding the potential roles of the lateral parietal lobe in episodic memory. Studies using brain stimulation methods reported in the literature do not offer unequivocal findings on the interactions with stimulation location (left vs. right hemisphere) or timing of the stimulation (encoding vs. retrieval). To address these issues, active and sham 1 Hz repetitive transcranial magnetic stimulation (rTMS) trains of 600 stimuli were applied over the right or left posterior parietal cortex (PPC) before the encoding or before the retrieval phase of a recognition memory task of unknown faces in a group of 40 healthy subjects. Active rTMS over the right but not the left PPC significantly improved non-verbal recognition memory performance without any significant modulation of speed of response when applied before the retrieval phase. In contrast, rTMS over the right or the left PPC before the encoding phase did not modulate memory performance. Our results support the hypothesis that the PPC plays a role in episodic memory retrieval that appears to be dependent on both the hemispheric lateralization and the timing of the stimulation (encoding vs. retrieval).

Voluntary alcohol binge-drinking in adolescent C57Bl6 mice induces delayed appearance of behavioural defects in both males and females.

Adolescence is a developmental period characterized by significant changes in brain architecture and behaviour. The immaturity of the adolescent brain is associated with heightened vulnerability to exogenous agents, including alcohol. Alcohol is the most consumed drug among teenagers, and binge‐drinking during adolescence is a major public health concern. Studies have suggested that adolescent alcohol exposure may interfere with the maturation of frontal brain regions and lead to long‐lasting behavioural consequences. In this study, by using a slightly modified version of the Drinking in the Dark paradigm, adolescent C57Bl6 mice reach high blood alcohol concentration after voluntary binge‐drinking. In order to assess short‐ and long‐term consequences of adolescent alcohol exposure (AAE), a battery of behavioural tests was performed during late adolescence and during adulthood. We showed that AAE had no short‐term effect on young mice behaviour but rather increased anxiety‐ and depressive‐like behaviours, as well as alcohol consumption during adulthood. Moreover, alcohol binge‐drinking during adolescence dramatically decreased recognition memory performances and behavioural flexibility in both adult males and females. Furthermore, we showed that voluntary consumption of alcohol during adolescence did not trigger any major activation of the innate immune system in the prefrontal cortex. Together, our data suggest that voluntary alcohol binge‐drinking in adolescent mice induces a delayed appearance of behavioural impairments in adulthood.

THE ROLE OF FACIAL ATTRACTIVENESS AND GENDER ON CHANGE DETECTION AND RECOGNITION MEMORY

This study aimed to investigate the effect of automatic attentional bias on change detection and recognition memory performance. In this context, attractive faces, which have priority in attention selection, were used as stimuli. The data of 110 participants were analyzed (54 females, 56 males, Mage = 20.87 ± 1.80). As a result, there was a significant effect of attractiveness [F(2.73, 295.16) = 37.33, p < .001, ƞp2 = .26] and model gender [F(1, 108) = 6.47, p < .05, ƞp2 = .06] on change detection performance. Accordingly, the fastest performance is when only the target was an attractive female; the slowest performance was observed when only the distractors were attractive female. On the other hand, the data of 94 participants (46 females, 48 males, Mage = 21.05 ± 1.95) were analyzed for the recognition memory. Accordingly, low memory performance was generally observed. Memory sensitivity was significantly lower for attractive faces (-.31) than average-looking ones (.59). Besides, bias to respond “old” for attractive faces were higher than average-looking faces for both model genders. Therefore, the findings suggest that the decision criterion was more liberal for attractive faces (for females -.06, for males -.46) than average faces (for females .15, for males .33). On the other hand, there was no significant effect of the participant gender on both attention and memory tasks (p > .05). The study is the first known change detection and recognition memory study to examine participant gender, model gender, and attractiveness together. The limitations of the study and suggestions for future studies are handled in the discussion section.

Dim light in the evening causes coordinated realignment of circadian rhythms, sleep, and short-term memory

Light provides the primary signal for entraining circadian rhythms to the day/night cycle. In addition to rods and cones, the retina contains a small population of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). Concerns have been raised that exposure to dim artificial lighting in the evening (DLE) may perturb circadian rhythms and sleep patterns, and OPN4 is presumed to mediate these effects. Here, we examine the effects of 4-h, 20-lux DLE on circadian physiology and behavior in mice and the role of OPN4 in these responses. We show that 2 wk of DLE induces a phase delay of ∼2 to 3 h in mice, comparable to that reported in humans. DLE-induced phase shifts are unaffected in Opn4-/- mice, indicating that rods and cones are capable of driving these responses in the absence of melanopsin. DLE delays molecular clock rhythms in the heart, liver, adrenal gland, and dorsal hippocampus. It also reverses short-term recognition memory performance, which is associated with changes in preceding sleep history. In addition, DLE modifies patterns of hypothalamic and cortical cFos signals, a molecular correlate of recent neuronal activity. Together, our data show that DLE causes coordinated realignment of circadian rhythms, sleep patterns, and short-term memory process in mice. These effects are particularly relevant as DLE conditions-due to artificial light exposure-are experienced by the majority of the populace on a daily basis.

Haptic recognition memory and lateralisation for verbal and nonverbal shapes

ABSTRACT Laterality effects generally refer to an advantage for verbal processing in the left hemisphere and for non-verbal processing in the right hemisphere, and are often demonstrated in memory tasks in vision and audition. In contrast, their role in haptic memory is less understood. In this study, we examined haptic recognition memory and laterality for letters and nonsense shapes. We used both upper and lower case letters, with the latter designed as more complex in shape. Participants performed a recognition memory task with the left and right hand separately. Recognition memory performance (capacity and bias-free d') was higher and response times were faster for upper case letters than for lower case letters and nonsense shapes. The right hand performed best for upper case letters when it performed the task after the left hand. This right hand/left hemisphere advantage appeared for upper case letters, but not lower case letters, which also had a lower memory capacity, probably due to their more complex spatial shape. These findings suggest that verbal laterality effects in haptic memory are not very prominent, which may be due to the haptic verbal stimuli being processed mainly as spatial objects without reaching robust verbal coding into memory.

Greater dependence on working memory and restricted familiarity in orangutans compared with rhesus monkeys.

The prefrontal cortex is larger than would be predicted by body size or visual cortex volume in great apes compared with monkeys. Because prefrontal cortex is critical for working memory, we hypothesized that recognition memory tests would engage working memory in orangutans more robustly than in rhesus monkeys. In contrast to working memory, the familiarity response that results from repetition of an image is less cognitively taxing and has been associated with nonfrontal brain regions. Across three experiments, we observed a striking species difference in the control of behavior by these two types of memory. First, we found that recognition memory performance in orangutans was controlled by working memory under conditions in which this memory system plays little role in rhesus monkeys. Second, we found that unlike the case in monkeys, familiarity was not involved in recognition memory performance in orangutans, shown by differences with monkeys across three different measures. Memory in orangutans was not improved by use of novel images, was always impaired by a concurrent cognitive load, and orangutans did not accurately identify images seen minutes ago. These results are surprising and puzzling, but do support the view that prefrontal expansion in great apes favored working memory. At least in orangutans, increased dependence on working memory may come at a cost in terms of the availability of familiarity.

Adaptation and initial validation of the Arabic version of the Word Memory Test (WMTARB)

Background The feigning of cognitive impairment is common in neuropsychological assessments, especially in a medicolegal setting. The Word Memory Test (WMT) is a forced-choice recognition memory performance validity test (PVT) which is widely used to detect noncredible performance. Though translated to several languages, this was not done for one of the most common languages, Arabic. The aim of the current study was to evaluate the convergent validity of the Arabic adaptation of the WMT (WMTARB) among Israeli Arabic speakers. Methods We adapted the WMT to Arabic using the back-translation method and in accordance with relevant guidelines. We then randomly assigned healthy Arabic speaking adults (N = 63) to either a simulation or honest control condition. The participants then performed neuropsychological tests which included the WMTARB and the Test of Memory Malingering (TOMM), a well-validated nonverbal PVT. Results The WMTARB had high split-half reliability and its measures were significantly correlated with that of the TOMM (p < .001). High concordance was found in classification of participants using the WMTARB and TOMM (specificity = 94.29% and sensitivity = 100% using the conventional TOMM trial 2 cutoff as gold standard). As expected, simulators' accuracy on the WMTARB was significantly lower than that of honest controls. None of the demographic variables significantly correlated with WMTARB measures. Conclusion The WMTARB shows initial evidence of reliability and validity, emphasizing its potential use in the large population of Arabic speakers and universality in detecting noncredible performance. The findings, however, are preliminary and mandate validation in clinical settings.

The Effects of Mindfulness-Based Stress Reduction on Negative Self-Representations in Social Anxiety Disorder-A Randomized Wait-List Controlled Trial.

This study examines the impact of mindfulness-based stress reduction (MBSR) vs. wait list (WL) on the self-reference effect involving negative adjectives in individuals with social anxiety disorder (SAD). Eighty-five participants with SAD were randomly assigned to 12 weeks of MBSR or WL and completed an incidental SRE task that assessed treatment-related negative self-representations. Self-related negative adjectives were worse remembered in MBSR than in WL, and other-related negative adjectives were better remembered in MBSR than in WL. No differences emerged between the levels of self- and other-related processing for adjectives in MBSR. Moreover, the MBSR-related decreases in the difference in recognition memory performance between self and other conditions, that is, the treatment-related equilibrium, could predict the MBSR-related decreases in social anxiety symptoms. The selfless functioning and self-other control that can provide reasonable interpretations for these findings were discussed.

How well imageability, concreteness, perceptual strength, and action strength predict recognition memory, lexical decision, and reading aloud performance

ABSTRACT We examined how well imageability, concreteness, perceptual strength, and action strength predicted recognition memory, lexical decision, and reading aloud performance. We used our imageability estimates [Cortese, M. J., & Fugett, A. (2004). Imageability ratings for 3,000 monosyllabic words. Behavior Methods and Research, Instrumentation, & Computers, 36(3), 384–387. https://doi.org/10.3758/BF03195585; Schock, J., Cortese, M. J., & Khanna, M. M. (2012a). Imageability ratings for 3,000 disyllabic words. Behavior Research Methods, 44(2), 374–379. https://doi.org/10.3758/s13428-011-0162-0], concreteness norms of Brysbaert and colleagues [Brysbaert, M., Warriner, A. B., & Kuperman, V. (2014). Concreteness ratings for 40 thousand generally known English lemmas. Behavior Research Methods, 46(3), 904–911. https://doi.org/10.3758/s13428-013-0403-5], and perceptual and action strength ratings of Lynott and colleagues [Lynott, D., Connell, L., Brysbaert, M., Brand, J., & Carney, J. (2020). The lancaster sensorimotor norms: Multidimensional measures of perceptual and action strength for 40,000 English words. Behavior Research Methods, 52(3), 1271–1291. https://doi.org/10.3758/s13428-019-01316-z]. Our results indicate imageability is the best predictor, but methodological differences between ratings studies may contribute to the results. Surprisingly, action strength was negatively (albeit weakly) related to recognition memory. Analyses of item zRTs from the English lexicon project indicate these variables were not strong predictors of reading aloud or lexical decision performance. However, there is a small, consistent positive relationship between concreteness and zRTs (i.e., a facilitative abstractness effect). We believe researchers should either employ or control for imageability rather than concreteness, perceptual strength, or action strength when conducting recognition memory experiments. In addition, image-based codes generated at encoding strengthen memory traces but do not provide major inputs into reading aloud and lexical decision processes. Also, the facilitative abstractness effect on lexical decision and reading aloud zRTs may reflect more robust lexical representations for abstract words than concrete words, and that these two constructs are distinct.

Recognition Receiver Operating Characteristic Curves: The Complex Influence of Input Statistics, Memory, and Decision-making.

Receiver operating characteristic (ROC) analysis is the standard tool for studying recognition memory. In particular, the curvilinearity and the y-offset of recognition ROC curves have been interpreted as indicative of either memory strength (single-process models) or different memory processes (dual-process model). The distinction between familiarity and recollection has been widely studied in cognitive neuroscience in a variety of conditions, including lesions of different brain regions. We develop a computational model that explicitly shows how performance in recognition memory is affected by a complex and, as yet, underappreciated interplay of various factors, such as stimulus statistics, memory processing, and decision-making. We demonstrate that (1) the factors in the model affect recognition ROC curves in unexpected ways, (2) fitting R and F parameters according to the dual-process model is not particularly useful for understanding the underlying processes, and (3) the variability of recognition ROC curves and the controversies they have caused might be due to the uncontrolled variability in the contributing factors. Although our model is abstract, its functional components can be mapped onto brain regions, which are involved in corresponding functions. This enables us to reproduce and interpret in a coherent framework the diverse effects on recognition memory that have been reported in patients with frontal and hippocampal lesions. To conclude, our work highlights the importance of the rich interplay of a variety of factors in driving recognition memory performance, which has to be taken into account when interpreting recognition ROC curves.

Hungarian Structural Focus: Accessibility to Focused Elements and Their Alternatives in Working Memory and Delayed Recognition Memory.

The present work investigates the memory accessibility of linguistically focused elements and the representation of the alternatives for these elements (i.e., their possible replacements) in Working Memory (WM) and in delayed recognition memory in the case of the Hungarian pre-verbal focus construction (preVf). In two probe recognition experiments we presented preVf and corresponding focusless neutral sentences embedded in five-sentence stories. Stories were followed by the presentation of sentence probes in one of three conditions: (i) the probe was identical to the original sentence in the story, (ii) the focused word (i.e., target) was replaced by a semantically related word and (iii) the target word was replaced by a semantically unrelated but contextually suitable word. In Experiment 1, probes were presented immediately after the stories measuring WM performance, while in Experiment 2, blocks of six stories were presented and sentences were probed with a 2-minute delay measuring delayed recognition memory performance. Results revealed an advantage of the focused element in immediate but not in delayed retrieval. We found no effect of sentence type on the recognition of the two different probe types in WM performance. However, results pertaining to the memory accessibility of focus alternatives in delayed retrieval showed an interference effect resulting in a lower memory performance. We conclude that this effect is indirect evidence for the enhanced activation of focus alternatives. The present work is novel in two respects. First, no study has been conducted on the memory representation of focused elements and their alternatives in the case of the structurally marked Hungarian pre-verbal focus construction. Second, to our knowledge, this is the first study that investigates the focus representation accounts for WM and delayed recognition memory using the same stimuli and same measured variables. Since both experiments used exactly the same stimulus set, and they only differed in terms of the timing of recognition probes, the principle of ceteris paribus fully applied with respect to how we addressed our research question regarding the two different memory systems.

The presence of semantic content in a visual recognition memory task reduces the severity of neglect

Patients with right hemisphere damage often show a lateral bias when asked to report the left side of mental images held in visual working memory (i.e. representational neglect). The neural basis of representational neglect is not well understood. One hypothesis suggests that it reflects a deficit in attentional-exploratory mechanisms, i.e. an inability to direct attention to the left side of the image. Another proposition states that intact visual working memory (VWM) is necessary for correctly creating a mental image. Here we examined two components of VWM in patients with unilateral spatial neglect (USN): memory for identity, and memory for spatial position. We manipulated the strength of memory representations by presenting two distinct categories of objects, in separate blocks. These were familiar namable objects (fruits, etc.), and unfamiliar abstract objects. The former category elicits stronger working-memory traces, thanks to preexisting visual and semantic representations in long-term memory. We hypothesized that if USN patients show a lateralized deficit in VWM, it should be more pronounced for abstract objects, due to their weaker working-memory traces. Importantly, to isolate a spatially lateralized deficit in memory from a failure to fully perceive the object-arrays, we ensured that all included patients perceived every item during the encoding phase. We used a working-memory task: participants viewed object arrays and had to memorize items' identities and spatial positions. Then, single objects were presented requiring ‘old/new’ recognition, and retrieval of ‘old’ items’ original positions. Our results show a lateral bias in patients’ recognition-memory performance. Remarkably, it was threefold milder for namable objects compared to abstract objects. We conclude that VWM lateralized deficit is substantial in USN patients and could play a role in representational neglect.