Recognition memory for emotional and neutral faces: an event-related potential study

This study examined emotional influences on the hypothesized event-related potential (ERP) correlates of familiarity and recollection (Experiment 1) and the states of awareness (Experiment 2) accompanying recognition memory for faces differing in facial affect. Participants made gender judgments to positive, negative, and neutral faces at study and were in the test phase instructed to discriminate between studied and nonstudied faces. Whereas old-new discrimination was unaffected by facial expression, negative faces were recollected to a greater extent than both positive and neutral faces as reflected in the parietal ERP old-new effect and in the proportion of remember judgments. Moreover, emotion-specific modulations were observed in frontally recorded ERPs elicited by correctly rejected new faces that concurred with a more liberal response criterion for emotional as compared to neutral faces. Taken together, the results are consistent with the view that processes promoting recollection are facilitated for negative events and that emotion may affect recognition performance by influencing criterion setting mediated by the prefrontal cortex.     

Posttrial d-cycloserine enhances the emotional memory of an incentive downshift event

The present research was designed to determine whether an incentive downshift event induces an emotional memory that can be modulated by d-cycloserine (DCS), a partial agonist at the glycine site of N-methyl-d-aspartate receptor (NMDAR). DCS has been reported to have memory-enhancing properties in other training situations. Experiments 1 and 2 involved a consummatory successive negative contrast (cSNC) situation in which animals are exposed to an incentive downshift involving sucrose solutions of different concentrations. DCS administration (30 mg/kg, ip) immediately after the first 32-to-4% sucrose downshift trial (Experiment 1) retarded recovery of consummatory behavior, but immediately after the first 32-to-6% sucrose downshift trial (Experiment 2) did not affect recovery. There was no evidence that DCS affected consummatory behavior in the absence of an incentive downshift in a manner analogous to a conditioned taste aversion (Experiment 3). These results suggest that activation of NMDARs via the glycine modulatory site enhances the emotional memory triggered by exposure to an incentive downshift event.     

Language processing abnormalities in adolescents with psychotic-like experiences: an event related potential study

Language impairments are a well established finding in patients with schizophrenia and in individuals at-risk for psychosis. A growing body of research has revealed shared risk factors between individuals with psychotic-like experiences (PLEs) from the general population and patients with schizophrenia. In particular, adolescents with PLEs have been shown to be at an increased risk for later psychosis. However, to date there has been little information published on electrophysiological correlates of language comprehension in this at-risk group. A 64 channel EEG recorded electrical activity while 37 (16 At-Risk; 21 Controls) participants completed the British Picture Vocabulary Scale (BPVS-II) receptive vocabulary task. The P300 component was examined as a function of language comprehension. The at-risk group were impaired behaviourally on receptive language and were characterised by a reduction in P300 amplitude relative to the control group. The results of this study reveal electrophysiological evidence for receptive language deficits in adolescents with PLEs, suggesting that the earliest neurobiological changes underlying psychosis may be apparent in the adolescent period.     

Enhancement of declarative memory by emotional arousal and visual memory function in Alzheimer's disease

The specific effects of visual and verbal memory on the ability of emotional arousal to enhance declarative memory were examined by using multiple linear regression analysis on data from a sample of 56 patients with probable Alzheimer's disease (AD). The enhancing effect of emotion on memory was evaluated by an illustrated story paradigm, and the visual and verbal memory by a standard memory test. In AD, memory enhancement by emotion was significantly correlated with visual memory but not with verbal memory, regardless of age, sex, educational attainment, and severity of dementia, suggesting a close association between memory enhancement by emotion and visual memory.     

Acute effects of nicotine administration during prospective memory, an event related fMRI study

We previously demonstrated that stimulating neuronal nicotinic acetylcholine receptors modulates prospective memory (PM), the ability to remember and implement a prior intention. Here we used fMRI to explore the neuronal correlates of acute nicotinic (1 mg) modulation during PM, employing a double blind, valence-matched placebo-controlled design, and a solely event-related analysis. Eight healthy adults completed on two occasions (1 week washout) a simple attentional task containing infrequent PM trials. PM activated bilateral parietal, prefrontal (BA10) and anterior cingulate, and deactivated genual cingulate and medial prefrontal regions. Further, acute nicotine administration decreased activity within a largely overlapping right parietal region. This data validates a purely event-related approach to exploring PM, and suggests procholinergic modulation of PM by parietal rather than BA10/frontal regions.     

False memory and level of processing effect: an event-related potential study

Event-related potentials (ERPs) were used to determine the effects of level of processing on true and false memory, using the Deese-Roediger-McDermott (DRM) paradigm. In the DRM paradigm, lists of words highly associated to a single nonpresented word (the 'critical lure') are studied and, in a subsequent memory test, critical lures are often falsely remembered. Lists with three critical lures per list were auditorily presented here to participants who studied them with either a shallow (saying whether the word contained the letter 'o') or a deep (creating a mental image of the word) processing task. Visual presentation modality was used on a final recognition test. True recognition of studied words was significantly higher after deep encoding, whereas false recognition of nonpresented critical lures was similar in both experimental groups. At the ERP level, true and false recognition showed similar patterns: no FN400 effect was found, whereas comparable left parietal and late right frontal old/new effects were found for true and false recognition in both experimental conditions. Items studied under shallow encoding conditions elicited more positive ERP than items studied under deep encoding conditions at a 1000-1500 ms interval. These ERP results suggest that true and false recognition share some common underlying processes. Differential effects of level of processing on true and false memory were found only at the behavioral level but not at the ERP level.     

The influence of self-awareness on emotional memory formation: an fMRI study

Evidence from functional neuroimaging studies of emotional perception shows that when attention is focused on external features of emotional stimuli (external perceptual orienting—EPO), the amygdala is primarily engaged, but when attention is turned inwards towards one’s own emotional state (interoceptive self-orienting—ISO), regions of the salience network, such as the anterior insula (AI) and the dorsal anterior cingulate cortex (dACC), also play a major role. Yet, it is unknown if ISO boosts the contributions of AI and dACC not only to emotional ‘perception’ but also to emotional ‘memory’. To investigate this issue, participants were scanned with functional magnetic resonance imaging (fMRI) while viewing emotional and neutral pictures under ISO or EPO, and memory was tested several days later. The study yielded three main findings: (i) emotion boosted perception-related activity in the amygdala during both ISO and EPO and in the right AI exclusively during ISO; (ii) emotion augmented activity predicting subsequent memory in AI and dACC during ISO but not during EPO and (iii) high confidence memory was associated with increased amygdala–dACC connectivity, selectively for ISO encoding. These findings show, for the first time, that ISO promotes emotional memory formation via regions associated with interoceptive awareness of emotional experience, such as AI and dACC.     

Chronic effects of social drinking in a card-sorting task: an event related potential study.

OBJECTIVE: The Wisconsin Card Sorting Task (WCST) is one of the most widely used neuropsychological tests of frontal lobe function, which is thought to be affected by regular alcohol use. The present study used a computer-adapted version of the WCST to assess the effects of chronic alcohol consumption on the brain. METHODS: Participants (N=59) sorted cards according to an initially unknown sorting rule, which referred to shape, number, or color. The correctness of the chosen sorting rule was indicated by a feedback stimulus. This correct sorting rule had to be followed for a number of stimuli, and when it changed participants had to find out which rule had to be followed next. A distinction was made between early (correct sorting rule is unknown) and late trials (correct sorting rule is known and applied). To measure brain activity related during the task event related potentials (ERPs) were recorded to the target and feedback stimulus in light (N=14), moderate (N=16) and heavy (N=19) social drinkers and excessive alcohol users (N=10). RESULTS: No differences in number of series completed or the reaction time in each trial, were found between the four groups. In contrast, a mid-frontal N1 component in reaction to the feedback stimuli did reveal differences between the four groups. In the light and moderate drinkers, on early feedback trials the N1 was larger relative to late feedback trials, but this effect was absent in the heavy social drinkers and excessive drinkers. CONCLUSIONS: The reduced N1 effect with increasing alcohol intake could reflect abnormal allocation of attention or impaired conflict monitoring, possibly based on activity in the anterior cingulate cortex. SIGNIFICANCE: Heavy social drinking and excessive drinking leads to changes in the mid-frontal N1 during feedback trials of the WCST.     

缺血性白质脑病患者事件相关电位研究

目的探讨缺血性白质脑病患者认知障碍、情感障碍的特点及规律,及对事件相关电位进行研究。方法收集缺血性白质脑病患者480例和正常对照86例,分别应用MMSE和Hamilton焦虑量表和24项版本抑郁量表进行测评,并进行事件相关电位P300、N400检测。结果缺血性白质脑病不同分级认知障碍、情感障碍差异有统计学意义,随着脑白质损害加重、分级增高,认知障碍和情感障碍加重,事件相关电位P300和N400潜伏期明显延长,波幅明显降低。结论缺血性白质脑病可造成患者严重认知、情感障碍,事件相关电位P300、N400可作为早期诊断缺血性白质脑病认知障碍的客观指标。     

Cognition in epilepsy: a multichannel event related potential (P300) study

Auditory event-related potentials (AERP) were elicited in 68 epileptic patients and 30 age-matched controls. Epileptic patients had significantly prolonged N2 and P300 (P3) latencies compared with controls. Seven patients were above the range of 3 standard deviations from the control mean values. Amongst epileptics, patients with temporal lobe epilepsy had significantly prolonged P3 latencies compared to patients with idiopathic generalized epilepsy. Patients with abnormal EEGs had significantly prolonged P3 latencies compared to those with normal EEGs. Patients on anticonvulsant monotherapy had shorter P3 latencies, compared to patients taking a combination of two or more anticonvulsants. Patients on shorter duration of treatment had less prolonged P3 latencies compared to those on longer anticonvulsant treatment.     

Visual processing in the inferior temporal cortex: An intracranial event related potential study

ObjectiveTo investigate visual processing over the inferior temporal cortex (ITC) by recording intracranial event-related potentials (IERPs), and correlating the results with those of electrocortical stimulation mapping (ESM).MethodsIERPs to word, non-word, and non-letter visual stimuli were recorded over the ITC in 6 patients with intractable epilepsy. Two patients underwent ESM of the same contacts.ResultsIERPs were observed at 18 electrodes in 4 out of 6 patients. Nine electrodes showed early IERPs (peak latency ? 200 ms) over the posterior and middle ITC and 7 of them showed a following late ERP component, “early + late IERPs”. Nine electrodes showed late IERPs (peak latency > 200 ms) over the middle and anterior ITC. Among four electrodes showing language or visual phenomena by ESM, one electrode showed a short latency IERP, another electrode showed a late IERP, and the remaining two electrodes showed no IERPs.ConclusionsOur findings further support that the visual recognition occurred sequentially from posterior to anterior ITC. Dissociation of IERPs and ESM may be explained by the methodological difference.SignificanceIERP study disclosed that visual recognition occurred sequentially from posterior to anterior ITC.     

精神分裂症患者事件相关电位P300的对照研究

目的:探讨精神分裂症患者听觉诱发电位P300的特征及病程对P300的影响。方法:对68例精神分裂症患者(研究组)和30名正常对照(正常对照组)进行事件相关电位P300的检测,并分析比较不同病程对P300的影响。结果:研究组Fz、Cz、FC1的P300潜伏期较对照组明显延迟(t分别=2.67,3.48,3.36;P均<0.01);Fz、Cz、FC1、FC2的波幅较对照组显著降低(t分别=5.97,2.54,4.57,3.80;P均<0.01)。对研究组中病程<6个月组和病程>5年组的患者比较发现,病程>5年组的患者Fz、Cz潜伏期延迟(t=9.23,7.63;P均<0.01),波幅降低(t=11.97,6.66;P均<0.01)。结论:精神分裂症患者认知功能受损,病程越长,受损越重。     

Influence of emotional content and context on memory in mild Alzheimer's disease

Healthy subjects remember emotional stimuli better than neutral, as well as stimuli embedded in an emotional context. This better memory of emotional messages is linked to an amygdalo-hippocampal cooperation taking place in a larger fronto-temporal network particularly sensitive to pathological aging. Amygdala is mainly involved in gist memory of emotional messages. Whether emotional content or context enhances memory in mild Alzheimer's disease (AD) patients is still debated. The aim of the present study is to examine the influence of emotional content and emotional context on the memory in mild AD, and whether this influence is linked to amygdala volume. Fifteen patients affected by mild AD and 15 age-matched controls were submitted to series of negative, positive, and neutral pictures. Each series was embedded in an emotional or neutral sound context. At the end of each series, participants had to freely recall pictures, and answer questions about each picture. Amygdala volumes were measured on patient 3D-MRI scans. In the present study, emotional content significantly favored memory of gist but not of details in healthy elderly and in AD patients. Patients' amygdala volume was positively correlated to emotional content memory effect, implying a reduced memory benefit from emotional content when amygdala was atrophied. A positive context enhanced memory of pictures in healthy elderly, but not in AD, corroborating early fronto-temporal dysfunction and early working memory limitation in this disease.     

Differential effects of emotional content on event-related potentials in word recognition memory

The aim of this study was to delineate the influence of the emotional content of stimuli to be remembered on the recognition performance of normal subjects by means of the event-related potential (ERP) technique. When words are presented repeatedly, brain responses to repeated and recognized items are characterized by a more positive waveform, referred to as "old/new effect". Words judged for their emotional connotation ("negative", "positive" and "neutral") were presented successively on a video monitor to subjects, who had the task to indicate whether a given word occurred for the first ("new") or second ("old") time within the list by pressing one of two buttons. For each word category, the ERPs of the old words were more positive compared to those of the new items from about 250 ms after stimulus. The old/new effect was significantly enhanced for the negative and positive items compared to the neutral stimuli between 450 and 650 ms after stimulus pointing to a significant influence of the emotional content of words on verbal memory processes. This paradigm appears to be feasible to investigate interactions of emotion and cognition in psychiatric patients.     

Knowing which and knowing what: a potential mouse model for age-related human declarative memory decline

The present study was built on the original report of Eichenbaum et al. [Eichenbaum, H., Fagan, A., Mathews, P. & Cohen, N.J. (1988), Behav. Neurosci., 102, 3531-3542] on the contrasting effects of fornix lesion in different versions of an odour-guided discrimination task in rats, and attempted to extend this into a mouse model for the preferential loss of declarative memory seen in human senescence. Each of the two experiments reported here consisted of a two-stage paradigm, with an initial learning phase followed by a test phase. The information acquired in the first stage was identical in both experiments, i.e. the valence or reward contingency associated with six (three positive and three negative) arms of a radial maze. The only parameter which was varied between Experiment A and B, and also between the two successive stages within each experiment, was the way of presenting the arms to the mice, i.e. either in pairs (simultaneous discriminations) or one at a time (successive go : no-go discrimination). Performance in the first stage demonstrated that our aged mice were impaired in learning concurrent simultaneous discriminations but not successive go/no-go discrimination, thereby resembling that reported in rats with hippocampal damage. Most importantly, our present set of data supports the conclusion that two forms of memory expression for the same piece of acquired experience can be assessed in the same subjects by manipulating the way of presenting two arms that were previously experienced separately. These two forms of memory expressions are differentially affected in aged mice, thereby demonstrating the highly selective and specific deleterious effect of ageing.     

The effect of different negative emotional context on involuntary attention: an ERP study

Event-related brain potentials (ERPs) were used to examine the different negative emotional contexts on involuntary attention, induced by a task-irrelevant sound, in an auditory-visual distraction paradigm. The emotional contexts comprised sad, fearful and neutral, and the irrelevant auditory stimuli consisted of repetitive standard sounds (80%) and environmental novel sounds (20%). The present results revealed that there were apparently different mismatch negativity (MMN) and Novelty-P3 components among these emotional contexts. Specifically, the amplitude of MMN showed no significant difference, indicating that the early stage of involuntary attention was not affected by the emotional context. Then, the amplitude of Novelty-P3, indicating the involuntary orienting of attention to novel sounds, attenuated greatest in the sad context. This pattern of results was more likely due to the competition for attention resources between affective processing and the novel sounds. That is to say, sad inhibit the involuntary attention to some extent, whereas perceiving fear cues facilitated novelty detection.     

Selective impairment of declarative memory following stimulation of dentate gyrus granule cells: a naloxone-sensitive effect

Albino rats received 10 s of sub-seizure electrical stimulation applied to the dentate gyrus granule cells immediately after acquisition of information on trial 1 of a 2-trial radial maze spatial memory task. Granule cell stimulation selectively reduced the probability of accessing information held in declarative memory (‘knowing that’ a particular maze location contains food) while leaving procedural memory intact (‘knowing how’ to search for food in the maze). This specific memory impairment was prevented by pretreatment with the opiate antagonist naloxone. Naloxone also improved memory performance when given to non-stimulated subjects.     

Age-related alterations in simple declarative memory and the effect of negative stimulus valence

Healthy aging has been shown to modulate the neural circuitry underlying simple declarative memory; however, the functional impact of negative stimulus valence on these changes has not been fully investigated. Using BOLD fMRI, we explored the effects of aging on behavioral performance, neural activity, and functional coupling during the encoding and retrieval of novel aversive and neutral scenes. Behaviorally, there was a main effect of valence with better recognition performance for aversive greater than neutral stimuli in both age groups. There was also a main effect of age with better recognition performance in younger participants compared to older participants. At the imaging level, there was a main effect of valence with increased activity in the medial-temporal lobe (amygdala and hippocampus) during both encoding and retrieval of aversive relative to neutral stimuli. There was also a main effect of age with older participants showing decreased engagement of medial-temporal lobe structures and increased engagement of prefrontal structures during both encoding and retrieval sessions. Interestingly, older participants presented with relatively decreased amygdalar-hippocampal coupling and increased amygdalar-prefrontal coupling when compared to younger participants. Furthermore, older participants showed increased activation in prefrontal cortices and decreased activation in the amygdala when contrasting the retrieval of aversive and neutral scenes. These results suggest that although normal aging is associated with a decline in declarative memory with alterations in the neural activity and connectivity of brain regions underlying simple declarative memory, memory for aversive stimuli is relatively better preserved than for neutral stimuli, possibly through greater compensatory prefrontal cortical activity.     

The effect of trance on memory content.

In a Yucatecan crisis cult of short duration, the millenary expectations are remembered long after the dissolution of the cult. So is Satan who, it is felt, tempted the congregation. The cultural innovations instituted during the cult, however, are almost immediately forgotten. The differential recall is shown to be related to the quality of the trance behavior during the cult and to the threatening versus neutral content of the memory material.     

Auditory sensory memory in 2-year-old children: an event-related potential study

Auditory sensory memory is assumed to play an important role in cognitive development, but little is known about it in young children. The aim of this study was to estimate the duration of auditory sensory memory in 2-year-old children. We recorded the mismatch negativity in response to tone stimuli presented with different interstimulus intervals. Our findings suggest that in 2-year-old children the memory representation of the standard tone remains in the sensory memory store for at least 1 s but for less than 2 s. Recording the mismatch negativity with stimuli presented at various interstimulus intervals seems to be a useful method for studying the relationship between auditory sensory memory and normal and disturbed cognitive development.