Recollection and familiarity in schizophrenia:An ERP investigation using face recognition exclusion tasks

Recent studies suggest that the recollection deficit observed in schizophrenia may not be a unitary phenomenon but could depend on the information to retrieve. Here we investigated whether the nature of the perceptual information affects recollection and familiarity in schizophrenia. ERP old/new effects were explored in 20 patients with schizophrenia and 20 healthy controls during unfamiliar face exclusion tasks, with either intrinsic (expression) or extrinsic (background) information either changing or remaining the same between study and test. Schizophrenia patients rejected old faces as distractors in a greater extent than healthy controls. The FN400 old/new effect (300-500ms) was found in both groups. It was sensitive to facial expression change for healthy controls but not schizophrenia patients. In addition, the parietal old/new effect was lower for correctly excluded faces for patients, but not for controls. This points to the conclusion that schizophrenia patients discriminate between target and non-target faces on the basis of the memory strength signal corresponding to the study-test mismatch rather than the recollection of the critical information, as observed in healthy controls. This functioning can be useful when study-test perceptual mismatch must be detected but, in return, can lead to the over-exclusion of old stimuli.

Unitization of internal and external features contributes to associative recognition for faces: Evidence from modulations of the FN400

Associative recognition requires discriminating between old items and conjunction lures constructed by recombining elements from two different study items. This task can be solved not only by recollection but also by familiarity if the to-be-remembered stimuli are perceived as a unitized representation. In two event-related potential (ERP) studies, we provide evidence for the integration of internal and external facial features by showing that the early frontal old-new effect (considered a correlate of familiarity) is modulated by the specific combination of facial features. Participants studied faces consisting of internal features (eyes, eyebrows, nose, and mouth) paired with external features (hair, head shape, and ears). During the testing phase, intact, recombined, and new faces were presented. Recombined faces consisted of internal and external features taken from two different studied faces. The results showed that at the frontal sites, during the time window from 300 to 500 ms, ERPs to intact faces were more positive than those to new and recombined faces; the latter two did not differ from one another. The late parietal effect was observed only after a more extended study phase in Experiment 2. We take the modulation of the early frontal old-new effect as evidence for the contribution of familiarity to associative recognition for combinations of internal and external facial features.

Format change and semantic relatedness effects on the ERP correlates of recognition: old pairs, new pairs, different stories

In this event-related potential (ERP) study, we investigated the effects of format change and semantic relatedness in a recognition task using pairs composed of a word and a line drawing. The semantic relatedness of the pairs (related: rabbit-carrot; unrelated: duck-artichoke) influenced their associative properties and corresponding distinctiveness, while format change refers to the switching of an item from the verbal form to the line drawing form between study and recognition (e.g., the word "egg" is associated with a drawing of a hen at study, and a line drawing of an egg is associated with the word "hen" at test). Study-test format change thus prevents visual matching while maintaining conceptual matching. While the N300 potential was only modulated by the semantic relatedness of the pair, both factors modulated recognition performance and corresponding ERP old/new effects with larger mid-frontal N400 old/new effect (300-500 ms) and larger parietal old/new effect (500-800 ms) in the same compared to the different-format condition, as well as for related compared to unrelated pairs. Furthermore, the semantic relatedness of correctly recognized old pairs modulated the anterior N400 while it modulated the posterior N400 for correctly rejected pairs. These results suggest that semantic relatedness and familiarity related to the amount of change between study and test present distinct ERP signatures in the N400 window. They suggest also that the distinctiveness and the ease of the retrieval of the pair could be determining for the parietal old/new effect.

The Interaction Between Memory Trace and Memory Judgment in Age-Related Decline

BACKGROUND/STUDY CONTEXT

Associative memory deficit and executive functioning deficit are two alternative--but nonexclusive--accounts of the episodic memory deficit observed in aging. The first explain the episodic memory decline generally observed in aging by an associative memory deficit (memory decline per se), whereas the second explains it by an executive functioning deficit. This distinction could be critical in early discrimination between healthy aging and very mild Alzheimer's-type dementia.

METHODS

Memory performance was measured in older adults (n = 20) and paired younger participants (n = 20), whereas the facial expression and auditory context (spoken voice) associated with the face were manipulated between study and test. Recollection and familiarity were estimated using a remember/know judgment, and source memory performance was obtained depending on the information to retrieve.

RESULTS

Although no between-group difference was observed for correctly recognized old faces, older participants made more false alarms than younger ones, thus revealing lower discriminability (d'). Facial expression change decreased recognition for all participants, whereas auditory context change decreased recognition only for younger participants. Remember/know judgments revealed age-related deficits in both recollection and familiarity, the relative decrease in familiarity reported by older adults was particularly large in the expression change conditions, and a disadvantage in source memory performance was particularly pronounced when the task was to retrieve auditory context associated with the face at study.

CONCLUSIONS

The present findings show that age-related associative memory differences occur with familiarity as well as recollection and are observed in situations that do not necessarily require conscious retrieval. This age-related decline is more prominent for multimodal (face-auditory context) than for intraitem (face-expression) associations. The value of exploring both memory trace and memory judgment was discussed, and potential applications for the development of neuropsychological tools for memory assessment in aging were highlighted.

Perceptually or conceptually driven recognition: on the specificities of the memory deficit in schizophrenia

This study explored the effects of exemplar changes on visual object recognition in patients with schizophrenia and paired control subjects. The experimental design was derived from the process-dissociation procedure (PDP: Jacoby, 1991). The objects presented at test could be the same exemplar as at study (physically identical picture), a different exemplar of the same object category, or a new, non-studied object. In the inclusion task, participants had to generalize their recognition to the conceptual level by accepting both different and identical exemplars as old. In the exclusion task, on the other hand, they had to accept only the same exemplars of the studied objects as old. Overall, performance was better on the inclusion task than on the exclusion task; schizophrenia patients performed worse than controls on the inclusion task but not the exclusion task, misrecognizing different exemplars more often than healthy controls. The present findings reveal that both recollection and familiarity are impaired in patients with schizophrenia, who present a relational, conceptually driven memory deficit. This deficit does not allow them to recognize an object as a member of a specific category independently of perceptual variations. This retrieval mode influences their subjective awareness of items׳ familiarity, and should be considered as a target for remediation.

Face recognition in schizophrenia: do individual and average ROCs tell the same story?

INTRODUCTION

Many studies have shown that recollection process is impaired in patients with schizophrenia, whereas familiarity is generally spared. However, in these studies, the Receiver Operating Characteristic (ROC) presented is average ROC likely to mask individual differences.

METHODS

In the present study using a face-recognition task, we computed the individual ROC of patients with schizophrenia and control participants. Each group was divided into two subgroups on the basis of the type of recognition processes implemented: recognition based on familiarity only and recognition based on familiarity and recollection.

RESULTS

The recognition performance of the schizophrenia patients was below that of the control participants only when recognition was based solely on familiarity. For the familiarity-alone patients, the score obtained on the Scale for the Assessment of Positive Symptoms (SAPS) was correlated with the variance of the old-face familiarity. For the familiarity-recollection patients, the score obtained on the Scale for the Assessment of Negative Symptoms (SANS) was correlated with the decision criterion and with the old-face recollection probability.

CONCLUSIONS

These results show that one cannot ascribe the impaired recognition observed in patients with schizophrenia to a recollection deficit alone. These results show that individual ROC can be used to distinguish between subtypes of schizophrenia and could serve as a basis for setting up specific cognitive remediation therapy for individuals with schizophrenia.

Effect of semantic coherence on episodic memory processes in schizophrenia

Schizophrenia is associated with severe episodic retrieval impairment. The aim of this study was to investigate the possibility that schizophrenia patients could improve their familiarity and/or recollection processes by manipulating the semantic coherence of to-be-learned stimuli and using deep encoding. Twelve schizophrenia patients and 12 healthy controls of comparable age, gender, and educational level undertook an associative recognition memory task. The stimuli consisted of pairs of words that were either related or unrelated to a given semantic category. The process dissociation procedure was used to calculate the estimates of familiarity and recollection processes. Both groups showed enhanced memory performances for semantically related words. However, in healthy controls, semantic relatedness led to enhanced recollection, while in schizophrenia patients, it induced enhanced familiarity. The familiarity estimates for related words were comparable in both groups, indicating that familiarity could be used as a compensatory mechanism in schizophrenia patients.