Anterior medial temporal lobe activation during encoding of words: FMRI methods to optimize sensitivity

The existence of a rostrocaudal gradient of medial temporal lobe (MTL) activation during memory encoding has historically received support from positron emission tomography studies, but less so from functional MRI (FMRI) studies. More recently, FMRI studies have demonstrated that characteristics of the stimuli can affect the location of activation seen in the MTL when those stimuli are encoded. The current study tested the hypothesis that MTL activation during memory encoding is related to the modality of stimulus presentation. Subjects encoded auditorily or visually presented words in an FMRI novelty paradigm. Imaging and analysis parameters were optimized to minimize susceptibility artifact in the anterior MTL. Greater activation was observed in the anterior than posterior MTL for both modalities of stimulus presentation. The results indicate that anterior MTL activation occurred during encoding, independent of stimulus modality and provide support for the hypothesis that verbal-semantic memory processing occurs in anterior MTL. The authors suggest that technical factors are critical for observing the rostrocaudal gradient in MTL memory activation.     

The effect of encoding time on retention by infants and young children

Using a Visual Recognition Memory (VRM) procedure, we examined the effect of encoding time on retention by 1- and 4-year olds. Irrespective of age, shorter familiarization time reduced retention, and longer familiarization time prolonged retention. The amount of familiarization that yielded retention after a given delay decreased as a function of age.     

Effects of positive and negative delusional ideation on memory

We investigated the relationship between levels of delusional ideation (whether positive or negative delusions) and the activation and distortion of memory by using pairs of positive and negative adjectives describing personality traits where those adjectives had similar meanings. We presented one of each pair of adjectives in the learning phase. Immediately after the learning phase in Experiment 1, we asked whether each adjective had been presented. Participants with high (positive or negative) delusional ideation were more likely to indicate that they had learned adjectives that they had not actually learned. This finding suggested that non-learned positive (or negative) adjectives that were associated with learned negative (or positive) adjectives were more likely to be activated in participants prone to positive (or negative) delusional ideation. However, in Experiment 2, two forced-choice tests were conducted immediately after the learning phase. In this context, participants, regardless of their proneness to delusional ideation, could almost always correctly distinguish what had and had not been presented, suggesting that the activation of learned items was still stronger than that for non-learned items in the immediate test. As time passed, the proportion of false alarms for positive or negative adjectives was higher in the two forced-choice tests among those with high proneness to (positive or negative) delusional ideation, suggesting that participants with delusional ideation were increasingly likely to depend on internal conditions for retrieval over time. Nous avons examiné la relation entre les niveaux d'idéation illusoire (qu'elle soit positive ou négative) et l'activation et la distorsion de la mémoire, en utilisant des paires d'adjectifs positifs et négatifs à significations similaires décrivant des traits de personnalité. Nous avons présenté un membre de chaque paire d'adjectifs lors d'une phase d'apprentissage. Dans une première expérience, immédiatement après la phase d'apprentissage, nous avons demandé si chaque adjectif avait été présenté. Les participants ayant un niveau d'idéation illusoire (positive ou négative) élevé étaient plus susceptibles d'indiquer qu'ils avaient appris les adjectifs qu'ils n'avaient pas appris. Ce résultat suggérait que les adjectifs positifs (ou négatifs) non appris qui étaient associés à des adjectifs négatifs (ou positifs) appris étaient plus susceptibles d'être activés chez les participants portés à l'idéation illusoire positive (ou négative). Dans une deuxième expérience, deux tests à choix forcés ont été menés immédiatement après la phase d'apprentissage. Dans ce contexte, les participants, indépendamment de leur tendance à l'idéation illusoire, pouvaient presque toujours distinguer correctement ce qui avait été présenté de ce qui n'avait pas été présenté, suggérant que l'activation des items appris était encore plus forte que celle des items non appris dans le test immédiat. Avec le temps, la proportion de fausses alarmes pour les adjectifs positifs ou négatifs était plus élevée dans les deux tests à choix forcés chez les participants portés à l'idéation illusoire (positive ou négative), ce qui suggère que les participants avec idéation illusoire étaient de plus en plus susceptibles de dépendre de leurs conditions internes lors du rappel à mesure que le temps passait. En este estudio se investigó la relación entre los niveles de ideación delusional (tanto delusiones positivas como negativas) y la activación y distorsión de la memoria a través del uso de pares de adjetivos positivos y negativos que describen rasgos de personalidad. Estos pares de adjetivos tenían significados similares. En la fase de aprendizaje se presentó un miembro de cada par de adjetivos. Inmediatamente después de la fase de aprendizaje se realizó el primer experimento, en el cual se preguntó al participanten si es que se le habían presentado cada uno de los adjetivos. Los participantes con elevada ideación delusiva (positiva o negativa) reportaran con una mayor probabilidad haber aprendido adjetivos que en realidad no se les había presentado. Este hallazgo sugiere que adjetivos positivos (o negativos) no aprendidos que estaban asociados con adjetivos negativos (o positivos) aprendidos, tenían una mayor probabilidad de ser activados en participantes propensos a una ideación delusiva positiva (o negativa). En el segundo experimento se llevaron a cabo inmediatamente después de la fase de aprendizaje dos pruebas de decisión forzada. En este contexto se pudo observar que los participantes a pesar de su tendencia hacia una ideación delusional, lograron distinguir en la mayoría de los casos correctamente entre los adjetivos que les fueron presentado y lo que no. Esto sugiere que la activación de los items aprendidos fue mucho más intensa que la de los items no aprendidos en el test. Sin embargo se pudo observar en los participantes de las dos pruebas de decisión forzada que con el paso del tiempo el porcentaje de falso reconocimiento de adjetivos positivos y negativos fue más elevado entre aquellas personas con una alta tendencia hacia una ideación delusional (positiva o negativa). Esto sugiere que en participantes con ideación delusional el reconocimiento de información a lo largo del tiempo probablemente es muy dependiente de condiciones internas.     

Children’s eyewitness memory: A comparison of two interviewing strategies as realized by forensic professionals

A critical issue for developmental psychology is how to obtain accurate and complete eyewitness memory reports from preschoolers without offering suggestions that might result in false allegations. We examined effects of two interviewing strategies (police/verbal interviews and clinician/prop-assisted interviews) on young children’s reports about a medical examination. A total of 58 4-year-olds participated in the study, which conformed to a 2 (Interview Type) × 2 (Number of Interviews) factorial design. Analyses revealed that interviewers spent less time off topic and asked more free recall questions in the police/verbal interviews than in the clinician/prop-assisted interviews. Compared with police/verbal interviews, clinician/prop-assisted interviews resulted in significantly more correct rejections and commission errors in children’s memory reports. However, on a final free recall test, error rates were comparable across conditions. Higher child verbal intelligence predicted memory accuracy in police/verbal interviews, and greater parental attachment anxiety predicted children being asked a higher number of misleading questions. The study provides new insights into interview techniques that promote preschoolers’ accurate eyewitness reports.     

Modeling and estimating recall processing capacity: Sensitivity and diagnostic utility in application to mild cognitive impairment

We investigate the potential for using latency-based measures of retrieval processing capacity to assess changes in performance specific to individuals with mild cognitive impairment (MCI), a reliable precursor state to Alzheimer’s Disease. Use of these capacity measures is motivated in part by exploration of the effects of atrophy on a computational model of a basic hippocampal circuit. We use this model to suggest that capacity may be a more sensitive indicator of the underlying atrophy than speed of processing, and test this hypothesis by adapting a standard behavioral measure of memory (the free and cued selective reminding test, FCSRT) to allow for the collection of cued recall latencies. Participants were drawn from five groups: college-aged, middle-aged, healthy elderly, those with a diagnosis of MCI, and a sample of MCI control participants. The measure of capacity is shown to offer increased classificatory sensitivity relative to the standard behavioral measures, and is also shown to be the behavioral measure that correlated most strongly with hippocampal volume.     

From Mecca with tolerance: religion,social recategorisation and social capital

Does participation in mass religious rituals promote intergroup conflict or does it promote intergroup tolerance? We assess these claims by examining the effects of the annual pilgrimage to Mecca (the hajj) on sociopolitical views of Muslims in Russia’s North Caucasus. Participant observation during the hajj and a quasi-experimental focus group study of pilgrims and non-pilgrims produced paradoxical findings. While the hajj strengthened their ingroup pride as Muslims, the pilgrims came through as more outgroup-tolerant and prosocial than the non-pilgrims. We develop a synthetic theoretical solution: in high-identity-value, high-diversity common group settings social recategorisation and social capital become transitive – that is, inclusive views and social capital effects within an ingroup extend to outgroups. This means that intergroup conflict could be reduced by not only maximising contact across conflicting groups, but also by bringing together as many subgroups as possible within each conflicting group in settings where their common identity is positively affirmed in a non-discriminatory fashion.     

A cross-modal weapon focus effect: The influence of a weapon's presence on memory for auditory information

To examine whether a weapon's presence impairs witnesses' memory for auditory information (as it impairs memory for visual information), we conducted two experiments in which undergraduates watched one version of a videotape depicting a male target who held either a weapon or a neutral object and conversed with a female character. The semantic content of his remarks was either easy or difficult to comprehend. The weapon's presence did not affect voice identification accuracy or memory for the target's vocal characteristics (e.g., pitch, loudness, speech rate) but did worsen memory for semantic content in the Difficult Comprehension condition. Our results can be explained by multiple resource models of attention, which propose separate resource “pools” for different sensory modalities.     

Memory of pain and affect associated with migraine and non-migraine headaches

The main aims of this study were to assess memory of pain and pain-related affect in headache sufferers and to compare the pain memories of individuals who suffer from migraines and those who experience non-migraine headaches. A total of 313 women participated in the study, 86 of whom had a diagnosis of migraine headache. The women rated their state anxiety about having a headache, the intensity and unpleasantness of headache pain, and their emotions while actually experiencing a headache. Either three or six months later, the participants were asked to recall their state anxiety, the intensity and unpleasantness of pain, and the emotions they had felt. Regardless of the length of recall delay or migraine diagnosis, participants accurately remembered both pain intensity and unpleasantness. Together, recalled anxiety, experienced pain and recalled positive affect were the most important predictors of memories for headache, accounting for 41% and 37% of the total variance in recalled pain intensity and unpleasantness, respectively. However, participants overestimated recalled positive and negative affect. The effect of recalled affect on memory of headache, together with the overestimation of recalled affect, suggests that although memory of headache is accurate, it is influenced by distorted memories of affect.