Emotional memory modulation in schizophrenia: an overview

Emotional memory for facial expressions in schizophrenia spectrum disorders: The role of encoding method

Memory is better for emotional rather than neutral events or materials (emotional enhancement of memory; EEM). Evidence suggests that this memory benefit remains intact in schizophrenia, but conflicting findings present the need for further research to understand how and when this process occurs. Here, we examine whether different encoding methods for learning emotional faces may result in different EEM patterns in those with schizophrenia spectrum disorders (SSD). A patient group (n = 28) and healthy comparisons (n = 29) encoded faces in two conditions that manipulated attentional focus to promote direct (emotion judgements) or indirect (sex discrimination) processing of emotional content. Based on literature in schizophrenia showing selective emotion perception deficits on tasks of direct processing but relatively intact emotion perception on indirect processing tasks, we hypothesized that patients would show greater EEM effects when faces were encoded indirectly. This hypothesis was not supported, and the patient group instead showed a similar intact EEM for angry and fearful faces to healthy comparisons in both encoding conditions. Further, using the Remember/Know paradigm, we demonstrated that the EEM in SSD appears selective to recollection-based memory, which helps to explain inconsistencies in past literature that has not differentiated between recognition domains. These findings have important implications for improving emotional memory and functional outcomes in SSD; future research should establish how the EEM for facial expressions may relate to social functioning.

Functional connectivity abnormalities of the long-axis hippocampal subregions in schizophrenia during episodic memory

Past evidence suggests that hippocampal subregions, namely the anterior and posterior parts, may be engaged in distinct networks underlying the memory functions which may be altered in patients with schizophrenia. However, of the very few studies that have investigated the hippocampal longitudinal axis subdivisions functional connectivity in patients with schizophrenia, the majority was based on resting-state data, and yet, none aimed to examine these during an episodic memory task. A total of 41 patients with schizophrenia and 45 healthy controls were recruited for a magnetic resonance imaging protocol in which they performed an explicit memory task. Seed-based functional connectivity analysis was employed to assess connectivity abnormalities between hippocampal subregions and voxel-wise connectivity targets in patients with schizophrenia. We observed a significantly reduced connectivity between the posterior hippocampus and regions from the default mode network, but increased connectivity with the primary visual cortex, in patients with schizophrenia compared to healthy subjects. Increased connectivity between the anterior hippocampus and anterior temporal regions also characterized patients with schizophrenia. In the current study, we provided evidence and support for studying hippocampal subdivisions along the longitudinal axis in schizophrenia. Our results suggest that the abnormalities in hippocampal subregions functional connectivity reflect deficits in episodic memory that may be implicated in the pathophysiology of schizophrenia.

Painful Life Events in Psychiatric Disorders: A Quantitative and Qualitative Analysis

We reported in a previous study the painful events experienced in the past in subjects with schizophrenia or major depression, in comparison to controls, and related them to the experimental pain sensitivity, anxiety, and the diagnosis. We present here the detailed analysis of these past painful events, with the aim of determining whether schizophrenic, depressive and control groups are qualitatively (type of painful events experienced, emotional or sensory components associated with pain) and quantitatively (duration, severity, and intensity) comparable concerning their past painful experiences. The questionnaire used relies on memory and feelings and will provide an indication about the way pain is experienced and memorized in daily life. The reported history of pain was not the same in the three groups. Depressed subjects differed from the others by the number of reported painful events. Painful events of everyday life, such as trauma without fracture and wounds, were the most highly reported painful events for all groups. Surprisingly, the daily pain events are associated to affective component of pain perception. Other kinds of event were differently reported between the groups. Experience of pain appears to be memorized and reported differently depending on the psychiatric disorder and type of event. The characteristics of each individual, their previous experience, contribute to the expression of psychiatric disorders, including in the field of pain. Past pain experience should be taken into account when attending someone for pain.

Nonsocial and social cognition in schizophrenia: current evidence and future directions

Cognitive impairment in schizophrenia involves a broad array of nonsocial and social cognitive domains. It is a core feature of the illness, and one with substantial implications for treatment and prognosis. Our understanding of the causes, consequences and interventions for cognitive impairment in schizophrenia has grown substantially in recent years. Here we review a range of topics, including: a) the types of nonsocial cognitive, social cognitive, and perceptual deficits in schizophrenia; b) how deficits in schizophrenia are similar or different from those in other disorders; c) cognitive impairments in the prodromal period and over the lifespan in schizophrenia; d) neuroimaging of the neural substrates of nonsocial and social cognition, and e) relationships of nonsocial and social cognition to functional outcome. The paper also reviews the considerable efforts that have been directed to improve cognitive impairments in schizophrenia through novel psychopharmacology, cognitive remediation, social cognitive training, and alternative approaches. In the final section, we consider areas that are emerging and have the potential to provide future insights, including the interface of motivation and cognition, the influence of childhood adversity, metacognition, the role of neuroinflammation, computational modelling, the application of remote digital technology, and novel methods to evaluate brain network organization. The study of cognitive impairment has provided a way to approach, examine and comprehend a wide range of features of schizophrenia, and it may ultimately affect how we define and diagnose this complex disorder.

Fear extinction disruption in a developmental rodent model of schizophrenia correlates with an impairment in basolateral amygdala-medial prefrontal cortex plasticity

Schizophrenia patients typically exhibit prominent negative symptoms associated with deficits in extinction recall and decreased ventromedial prefrontal cortex activity (vmPFC, analogous to medial PFC infralimbic segment in rodents). mPFC activity modulates the activity of basolateral amygdala (BLA) and this connectivity is related to extinction. mPFC and BLA activity has been shown to be altered in the methylazoxymethanol acetate (MAM) developmental disruption model of schizophrenia. However, it is unknown if there are alterations in extinction processes in this model. Therefore, we investigated extinction and the role of mPFC-BLA balance in MAM rats. Male offspring of pregnant rats treated with Saline or MAM (20 mg/kg; i.p.) on gestational day 17 were used in fear conditioning (contextual/tone) and electrophysiological experiments (mPFC-BLA plasticity). No difference was observed in conditioning, extinction, and test sessions in contextual fear conditioning. However, MAM-treated rats demonstrated impairment in extinction learning and recall in tone fear conditioning. Furthermore, high frequency stimulation (HFS) of the BLA decreased spike probability in the mPFC of saline-treated rats but not in MAM rats. NMDA antagonist microinjected into the BLA disrupted extinction learning and recall in control rats, resulting in a similar deficit as that observed in MAM-treated rats. These data demonstrate extinction impairment in the MAM model that is analogous to that observed in schizophrenia patients, that was probably due to disruption in the regulation of mPFC activity by glutamatergic neurotransmission in the BLA.

Emotional effect on cognitive control in implicit memory tasks in patients with schizophrenia

The aim of this study was to reveal a potential effect of emotion on cognitive control in the implicit memory task with emotionally neutral and unpleasant words in healthy controls and patients with schizophrenia using a 3.0 T functional MRI (fMRI). A total of 15 patients with schizophrenia and 15 healthy controls underwent the fMRI. fMRI data were obtained while the participants performed the implicit memory tasks with emotionally neutral and unpleasant words. During the implicit memory retrieval with emotionally neutral words, the predominant activation areas observed in patients in contrast to healthy controls included the precuneus, superior parietal gyrus, and dorsolateral prefrontal cortex (dlPFC). In the implicit memory retrieval with unpleasant words, patients with schizophrenia showed dominant activities in the superior and middle temporal gyri, fusiform gyrus, supramarginal gyrus, postcentral gyrus, occipital gyrus, lingual gyrus, parahippocampal gyrus, amygdala, and insula as well as precuneus, superior parietal gyrus, and dlPFC. Blood-oxygen-level-dependent signal changes in the dlPFC were correlated positively with the scores of the negative symptoms under the PANSS during implicit memory retrieval with unpleasant words in patients with schizophrenia. These findings would be useful to understand the neural mechanisms related to general impairment of cognitive and emotional functions commonly observed in schizophrenia.

Associations between trait anhedonia and emotional memory deficits in females with schizophrenia versus major depression

Individuals with schizophrenia (SZ) and individuals with major depressive disorder (MDD) demonstrate impaired emotional memory and decreased enjoyment of pleasant experiences (e.g., anhedonia). However, it is unclear whether these impairments reflect similar or different processes in the two diagnostic groups. This study compared emotional memory performance in three groups of females - controls, MDD, and SZ. Given that physical and social trait anhedonia has been shown to differentiate course of illness and emotional functioning within each disorder, the present study also examined whether trait anhedonia related to emotional memory differently in the groups. Participants viewed emotional and neutral images and twenty-four hours later completed an incidental recognition test. SZ participants demonstrated a trend for the worst memory performance. Across all groups, high intensity and negative images were remembered most accurately, while groups were not differentially influenced by the valence of the stimuli. Physical anhedonia was predictive of reduced memory for negative stimuli across all diagnostic groups. Group specific findings indicated that higher levels of social anhedonia were predictive of poorer memory, but only in the SZ group. Effects remained significant when controlling for depressive symptoms. Results are considered in light of the differing role of anhedonia in SZ and MDD.

Implicit emotion perception in schizophrenia

Explicit but not implicit facial emotion perception has been shown to be impaired in schizophrenia. In this study, we used newly developed technology in social neuroscience to examine implicit emotion processing. It has been shown that when people look at faces, they automatically infer social traits, and these trait judgments rely heavily on facial features and subtle emotion expressions even with neutral faces. Eighty-one individuals with schizophrenia or schizoaffective disorder and 62 control subjects completed a computer task with 30 well-characterized neutral faces. They rated each face on 10 trait judgments: attractive, mean, trustworthy, intelligent, dominant, fun, sociable, aggressive, emotionally stable and weird. The degree to which trait ratings were predicted by objectively-measured subtle emotion expressions served as a measure of implicit emotion processing. Explicit emotion recognition was also examined. Trait ratings were significantly predicted by subtle facial emotional expressions in controls and patients. However, impairment in the implicit emotion perception of fear, happiness, anger and surprise was found in patients. Moreover, these deficits were associated with poorer everyday problem-solving skills and were relatively independent of explicit emotion recognition. Implicit emotion processing is impaired in patients with schizophrenia or schizoaffective disorder. Deficits in implicit and explicit emotion perception independently contribute to the patients' poor daily life skills. More research is needed to fully understand the role of implicit and explicit processes in the functional deficits of patients, in order to develop targeted and useful remediation interventions.

The relationship between insight and autobiographical memory for emotional events in schizophrenia

The relation of episodic and semantic memory for emotional- (positive, negative) and neutral-valenced autobiographical events to illness insight was examined in individuals with schizophrenia. Reduced recall of episodic details for negative events was significantly associated with impaired awareness of having a past mental disorder and its social consequences. Deficits in episodic memory for negative autobiographical events may underlie impaired insight in schizophrenia.

Preserved emotional memory modulation in first episode psychosis

Although patients with schizophrenia have severe memory impairments and emotional deficits, studies investigating emotional memory modulation (EMM) in schizophrenia show contradictory results, possibly due to methodological differences and small group size. We investigated whether impaired EMM is already present in First Episode Psychosis (FEP) and whether impairments in EMM are task or stimulus dependent. Forty-five FEP and thirty-seven Healthy Control (HC) male participants matched for age performed visual and verbal short-term (immediate recall) and long-term (after 24h recognition) memory tasks with neutral, negative and positive stimuli. On all tasks overall memory performance for FEP was significantly below that of HC. Although EMM varied by task and type of stimulus, none of the tasks showed a difference in EMM between FEP and HC. There were no differences between FEP and HC in the way emotion modulates different memory domains. This could mean that EMM is spared in the early course of schizophrenia.

Impairment in emotional modulation of attention and memory in schizophrenia

Emotion plays a critical role in cognition and goal-directed behavior via complex interconnections between the emotional and motivational systems. It has been hypothesized that the impairment in goal-directed behavior widely noted in schizophrenia may result from defects in the interaction between the neural (ventral) emotional system and (rostral) cortical processes. The present study examined the impact of emotion on attention and memory in schizophrenia. Twenty-five individuals with schizophrenia related psychosis and 25 healthy control subjects were administered a computerized task in which they were asked to search for target images during a Rapid Serial Visual Presentation of pictures. Target stimuli were either positive or negative, or neutral images presented at either 200ms or 700ms lag. Additionally, a visual hedonic task was used to assess differences between the schizophrenia group and controls on ratings of valence and arousal from the picture stimuli. Compared to controls, individuals with schizophrenia detected fewer emotional images under both the 200ms and 700ms lag conditions. Multivariate analyses showed that the schizophrenia group also detected fewer positive images under the 700ms lag condition and fewer negative images under the 200ms lag condition. Individuals with schizophrenia reported higher pleasantness and unpleasantness ratings than controls in response to neutral stimuli, while controls reported higher arousal ratings for neutral and positive stimuli compared to the schizophrenia group. These results highlight dysfunction in the neural modulation of emotion, attention, and cortical processing in schizophrenia, adding to the growing but mixed body of literature on emotion processing in the disorder.

Normal brain activation in schizophrenia patients during associative emotional learning

Emotional deficits are among the core features of schizophrenia and both associative emotional learning and the related ability to verbalize emotions can be reduced. We investigated whether schizophrenia patients demonstrated impaired function of limbic and prefrontal areas during associative emotional learning. Patients and controls filled out an alexithymia questionnaire and performed an associative emotional learning task with positive, negative and neutral picture-word pairs during fMRI scanning. After scanning, they indicated for each pair whether they remembered it. We conducted standard GLM analysis and Independent Component Analysis (ICA). Both the GLM results and task-related ICA components were compared between groups. The alexithymia questionnaire indicated more cognitive-emotional processing difficulties in patients than controls, but equal experienced intensity of affective states. Patients remembered less picture-word pairs, irrespective of valence. GLM analysis showed significant visual, temporal, amygdalar/hippocampal, and prefrontal activation in all subjects. ICA identified a network of brain areas similar to GLM, mainly in response to negative stimuli. Neither analysis showed differences between patients and controls during learning. Although in previous studies schizophrenia patients showed abnormalities in both memory and emotion processing, neural circuits involved in cross-modal associative emotional learning may remain intact to a certain degree, which may have potential consequences for treatment.