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Autobiographical-episodic memory is considered to be the most complex of the five long-term memory systems. It is autonoetic, which means, self-reflective, relies on emotional colorization, and needs the features of place and time; it allows mental time traveling. Compared to the other four long-term memory systems-procedural memory, priming, perceptual, and semantic memory-it develops the latest in phylogeny and ontogeny, and is the most vulnerable of the five systems, being easily impaired by brain damage and psychiatric disorders. Furthermore, it is characterized by its fragility and proneness to distortion due to environmental influences and subsequent information. On the brain level, a distinction has to be made between memory encoding and consolidating, memory storage, and memory retrieval. For encoding, structures of the limbic system, with the hippocampus in its center, are crucial, for storage of widespread cortical networks, and for retrieval again a distributed recollection network, in which the prefrontal cortex plays a crucial role, is engaged. Brain damage and psychiatric diseases can lead to what is called "focal retrograde amnesia." In this context, the clinical picture of dissociative or functional or psychogenic amnesia is central, as it may result in autobiographical-emotional amnesia of the total past with the consequence of an impairment of the self as well. The social environment therefore can have a major impact on the brain and on autobiographical-episodic memory processing. This article is categorized under: Psychology > Memory

The psychiatric disease of dissociative amnesia is described and illustrated with case reports. It is emphasized that dissociative amnesia has a stress or trauma-related etiology and that affected individuals, contrary to the still dominant clinical belief, are frequently more severely and enduringly affected. That means, most of them show severe retrograde amnesia for their biography, usually accompanied by changes in their personality and sometimes also by alterations in other cognitive and emotive domains. As many patients show the phenomenon of “la belle indifference”, their motivation for therapy or treatment of their amnesia is reduced. Patients also seem to a high degree to possess immature, unstable personality features. Nevertheless, a number of quite divergent, though largely not evidence-based, therapeutic approaches exist and are described. They are divided into (a) psychopharmacological and somatic treatments, (b) psychotherapeutic interventions, and (c) neuropsychological rehabilitation. Furthermore, detailed treatment strategies are provided.

Violence is a ubiquitous phenomenon, which has been part of the experience of humanity since its inception. Violence has classically been viewed as being associated with being male. In general population, men are reported to commit violent acts significantly more frequently than women. As the interdisciplinary research data point to, violence is a complex phenomenon that could be approached from different perspectives, such as social, economic, political, religious, biological, and genetic. We hereby provide a review of the neurobiological mechanisms underlying the gender distinctions in violence and aggression in both general and psychiatric population.

Environmentally induced stress may lead to a phenomenon termed ‘mnestic block syndrome’. The memory changes primarily affect the patient's autobiography by either blocking the retrieval of old memories, or by impairing the formation of new memories. We studied patients with either form of amnesia neuropsychologically and with functional imaging methods. We obtained a right temporo-frontal hypometabolism in patients with psychogenic amnesia, restricted to their autobiography. We conclude that environmentally induced brain changes are due to the action of stress hormones leading to a block of memory-related information flow in the brain which can persist over decades.

We herein present a 51-year-old single female inpatient with treatment-resistant recurrent depressive disorder. Her most recent depressive episode has been severe and followed a chronic course, lasting for longer than 2 years. During the exacerbation of the patient's suicidal thoughts and plans, we repeatedly and independently observed vegetative and behavioural changes of the therapy-accompanying dog of the patient. Our findings suggest a role for dog-assisted therapy for augmenting treatment as well as for enhancing and developing novel adjunctive strategies for risk assessment in patients with chronic depression and suicidality. Possible social-biological mechanisms and underpinnings are discussed, by drawing on the available literature and comparative psychology. Collaboration with animal behaviourists and animal welfare scientists, in order to improve behavioural and physiological data interpretation and humaneness of dog-assisted therapy, is emphasised as a crucial component of future research.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) – is the most common genetic source of vascular dementia in adults, being caused by a mutation in NOTCH3 gene. Spontaneous de novo mutations may occur, but their frequency is largely unknown. Ischemic strokes and cognitive impairments are the most frequent manifestations, but seizures affect up to 10% of the patients. Herein, we describe a 47-year-old male scholar with a genetically confirmed diagnosis of CADASIL (Arg133Cys mutation in the NOTCH3 gene) and a seemingly negative family history of CADASIL illness, who was investigated with a comprehensive neuropsychological testing battery and neuroimaging methods. The patient demonstrated on one hand severe and accelerated deteriorations in multiple cognitive domains such as concentration, long-term memory (including the episodic-autobiographical memory domain), problem solving, cognitive flexibility and planning, affect recognition, discrimination and matching, and social cognition (theory of mind). Some of these impairments were even captured by abbreviated instruments for investigating suspicion of dementia. On the other hand the patient still possessed high crystallized (verbal) intelligence and a capacity to put forth a façade of well-preserved intellectual functioning. Although no definite conclusions can be drawn from a single case study, our findings point to the presence of additional cognitive changes in CADASIL in middle adulthood, in particular to impairments in the episodic-autobiographical memory domain and social information processing (e.g., social cognition). Whether these identified impairments are related to the patient’s specific phenotype or to an ascertainment bias (e.g., a paucity of studies investigating these cognitive functions) requires elucidation by larger scale research.

Remembering the past is a core feature of human beings, enabling them to maintain a sense of wholeness and identity and preparing them for the demands of the future. Forgetting operates in a dynamic neural connection with remembering, allowing the elimination of unnecessary or irrelevant information overload and decreasing interference. Stress and traumatic experiences could affect this connection, resulting in memory disturbances, such as functional amnesia. An overview of clinical, epidemiological, neuropsychological, and neurobiological aspects of functional amnesia is presented, by preponderantly resorting to own data from patients with functional amnesia. Patients were investigated medically, neuropsychologically, and neuroradiologically. A detailed report of a new case is included to illustrate the challenges posed by making an accurate differential diagnosis of functional amnesia, a condition that may encroach on the boundaries between psychiatry and neurology. Several mechanisms may play a role in “forgetting” in functional amnesia, such as retrieval impairments, consolidating defects, motivated forgetting, deficits in binding and reassembling details of the past, deficits in establishing a first person autonoetic connection with personal events, and loss of information. In a substantial number of patients, we observed a synchronization abnormality between a frontal lobe system, important for autonoetic consciousness, and a temporo-amygdalar system, important for evaluation and emotions, which provides empirical support for an underlying mechanism of dissociation (a failure of integration between cognition and emotion). This observation suggests a mnestic blockade in functional amnesia that is triggered by psychological or environmental stress and is underpinned by a stress hormone mediated synchronization abnormality during retrieval between processing of affect-laden events and fact-processing.

Memory and time have multifaceted links. Along the time axis, memory is divided into short- and long-term memory. Another popular time-dependent distinction is between new and old memories and anterograde and retrograde memory impairments, respectively. Time-embedment characterizes the processing of mnemonic information, which encompasses the stages of registration, encoding, consolidation, and storage. Along the content axis, memory is partitioned into five long-term memory systems (procedural, priming, perceptual, semantic, and episodic), which are regarded to build up on each other from both a phylogenetic and ontogenetic perspective. These memory systems are accompanied by different niveaus of self and levels of consciousness. Among these long-term memory systems, the episodic memory system holds a special connection with time, which we aim to detail. In 2005, Tulving defined the episodic memory system as the conjunction of subjective time, autonoetic consciousness, and the experiencing self. Drawing on this last definition of the episodic memory, which lays an emphasis on the linkage to the self, Markowitsch has subsequently promoted the use of the construct “episodic-autobiographical” memory system. The episodic-autobiographical memory system features mental time travelling, an essential property that enables one individual to flexibly travel in subjective time in his/her past and, in addition, to flexibly project him/herself in the future. This property provides a “glue” for the self, supporting a coherent view of one's own person. According to Tulving and Markowitsch, it is unlikely that non-human animals possess the capacity for mental time travelling and the ability to “look into future” (“proscopy”). Furthermore, Tulving and Markowitsch had proposed that the ability for mental time travelling is dependent on age and intellect. Subsequent studies have confirmed that mental time travelling is one of the last features of the episodic- autobiographical memory system that achieves full functionality in humans and is the first one to be afflicted by old age, amnesia or neurodegenerative dementias (e.g., Alzheimer's dementia). At the brain level, the emergence of the capacity for mental time travelling is accompanied by ample structural and functional reorganization of elements of the brain networks supporting episodic-autobiographical memory, autonoetic consciousness, and self-referential processing. In human beings, damage to certain brain regions may alter the sense and consciousness of time in quite different ways. Herein, we have the goal to review changes in time perception and consciousness of time, which accompany different forms of amnesia. Patients with anterograde amnesia manifest an inability to consciously acquire new information for long-term storage and as a consequence are often “stuck in time”. ‘Chronotaraxis’ may accompany certain forms of preponderantly anterograde amnesia, as we aim to exemplify by drawing upon own cases, which were investigated medically, neuropsychologically, and with neuroimaging methods. Patients with retrograde amnesia manifest an inability to consciously retrieve already stored old mnemonic information, usually from the episodic-autobiographical memory domain. They lack the capacity to “ecphorize” old memories. Interestingly, the memory impairments are very similar in the patients with focal traumatic brain injuries and in those with psychogenic forms of amnesia: The patients are unable to engage in mental time traveling into their past. In addition, they show an impaired ability to imagine future personal events, being as a consequence trapped in a “noetic existence”. In psychogenic amnesia with pronounced retrograde memory impairments, we found (via functional neuroimaging) evidence of defective synchronization during retrieval between processing of affectively loaded personal events (that is presumed to preponderantly engage the right hemisphere) and fact-based processing (that is considered to preferentially recruit the left hemisphere). These data are relevant in the light of studies pointing to a right hemisphere bias for higher forms of consciousness. We conjecture that this synchronization abnormality not only leads to a memory blockade, but also to shrinkage of mental time traveling and loss of autonoetic consciousness in psychogenic or functional amnesic conditions.

Introduction Dissociative amnesia is triggered by psychological stress or trauma. Its hallmark is a severe (usually retrograde) memory impairment within episodic-autobiographical domain, occurring without evidence of significant brain damage on conventional structural brain imaging. Objectives This work’s objectives are establishing greater recognition of possible relations between memory performance and social cognition in patients with dissociative amnesia. Aims We review data on social cognition (affective and cognitive theory of mind, simulation, empathy, social judgment, moral judgment) from our own patients with dissociative amnesia. Methods Patients were investigated medically, psychiatrically and with neuropsychological and neuroimaging methods. Results Patients with dissociative amnesia show variable degrees of impairments of components of social cognition, based on their comorbid conditions (e.g. concurrent clinical or subclinical depression), types of memory impairments (e.g. extent of retrograde amnesia, presence of autobiographical semantic deficits), pattern of brain metabolic changes, personality characteristics, neuropsychological profile (performance on executive functions or emotional processing) and testing paradigms. Conclusions The impairment in dissociative amnesia seems to go beyond the conscious mnemonic deficit, encompassing various aspects of social information processing. Knowledge about the pattern of metabolic and micro-structural brain changes in patients with dissociative amnesia as well as a fine-grained analysis of the neural correlates of various aspects of social cognition might provide an understanding of when and how episodic-autobiographical memory contributes to social cognition. As several studies emphasized, some structures involved in mnemonic processing may also play a role in social perception, cognition and behavioural regulation, including future-minded choice behaviour.

Introduction Co-occurring impairments of episodic-autobiographical memory and theory of mind were described in several psychiatric and neuropsychiatric disorders. Despite sophisticated elaborations in theoretical domains, the relationship between episodic-autobiographical memory and social cognition remains unelucidated. Objectives This work’s objectives are establishing greater recognition of the possible contribution of episodic - autobiographical memory to social cognition, by resorting to data from developmental amnesia (a condition with onset in early childhood, caused by relatively selective bilateral damage to hippocampi). Aims We describe a young adult with amnesia with neurodevelopmental mechanisms. Methods The patient was investigated medically, psychiatrically, with extensive neuropsychological methods and with neuroimaging. Results Neuroimaging revealed grossly reduced hippocampi volumes bilaterally. There was no evidence of pathology in the underlying parahippocampal region or other areas. Performance on tasks that tapped on various aspects of social cognition was non-uniform, ranging from within normal limits to moderate impairment. Conclusions According to our knowledge, this is among the first case reports about a comprehensive evaluation of social information processing in a patient with amnesia with neurodevelopmental mechanisms. This patient showed impairments in performance in some laboratory tasks for social cognition, but not in others. This suggests that various components of social cognition may have different neural correlates; their unraveling may aid understanding of when and how episodicautobiographical memory contributes to social cognition. This study also emphasizes the need to employ various tasks to assess social cognition in patients with amnesia, which go beyond traditional laboratory paradigms.

Dissociative memory disturbances characterize dissociative disorders (such as dissociative amnesia, dissociative fugue, dissociative identity disorder, Ganser syndrome) and certain anxiety disorders (post-traumatic stress disorder). Across various cultures, they are recognized to be precipitated by psychological stress. In immigrant populations, stressful experiences arising during migration and acculturation could lead to somatic and psychiatric symptoms (including dissociative ones). A delayed onset of these symptoms - that at times occurs - may reflect a kindling sensitization or an incubation effect.ObjectivesWe review four patients who developed Dissociative Disorders (Dissociative Amnesia and Ganser Syndrome) on a background of stresses related to immigration.MethodsPatients were investigated medically, psychiatrically and neuropsychologically and in part neuroradiologically.ResultsPatients were adult males with Eastern or Central European background and no known previous psychiatric or medical illnesses. They immigrated to Germany or Canada and encountered several difficulties in the process of migration or adaptation to the new country. All developed severe psychiatric dissociative symptoms after objectively minor stresses, which occurred several years after their immigration to the new country of residence. Despite adequate treatment, their symptoms followed a chronic course. The patients’ neuropsychological profiles shared similarities, such as executive functioning deficits (e.g. limited cognitive flexibility) and impairments of emotional processing in addition to severe autobiographical amnesia.ConclusionsWe propose that stresses related to immigration and acculturation could trigger dissociative memory disorders in immigrants via a dysregulation of the hormonal stress responses, which is mediated by individual characteristics (cognitive flexibility, emotional processing abilities, language competence and cultural affiliations).