Autobiographical memory and the self in a case of transient epileptic amnesia

Embodiment in episodic memory through premotor-hippocampal coupling

Episodic memory (EM) allows us to remember and relive past events and experiences and has been linked to cortical-hippocampal reinstatement of encoding activity. While EM is fundamental to establish a sense of self across time, this claim and its link to the sense of agency (SoA), based on bodily signals, has not been tested experimentally. Using real-time sensorimotor stimulation, immersive virtual reality, and fMRI we manipulated the SoA and report stronger hippocampal reinstatement for scenes encoded under preserved SoA, reflecting recall performance in a recognition task. We link SoA to EM showing that hippocampal reinstatement is coupled with reinstatement in premotor cortex, a key SoA region. We extend these findings in a severe amnesic patient whose memory lacked the normal dependency on the SoA. Premotor-hippocampal coupling in EM describes how a key aspect of the bodily self at encoding is neurally reinstated during the retrieval of past episodes, enabling a sense of self across time.

Understanding the relationship between self and memory through the IAM task

In this article we present a review of research on the IAM Task, whereby memories are cued by self-images in the form of "I am … " statements, such as I am a grandfather, I am a Bob Dylan fan, I am from Darlington, I am a Psychologist. Such cues are particularly successful at accessing memories associated with the formation of specific aspects of the self. We describe the conceptual and historical context for the development of our task and review findings from other researchers who have used the same basic design. We present aggregate data and examples from across several experiments, examining how these patterns change in psychological distress and dysfunction. We also discuss research on "I will be" statements and how these have been adopted to examine self-related future cognitions. We conclude that the working self operates to organise memory retrieval and make accessible episodic and semantic material for self-relevant periods across the lifespan. Moreover, accessibility of self-images can be modulated by retrieval of autobiographical memories, highlighting Conway's bidirectional relationship between memory and the self. We provide suggestions for future research and for the first time provide a standardised version of our IAM Task for use by researchers.

Present and future selves in Parkinson's disease

The study of the self in neuropsychological patients raises not only theoretical questions on the relationships between the self, autobiographical memory (AM), and episodic future thinking but also clinical issues for patients' daily life and care. We addressed this issue in Parkinson's disease patients for whom AM and future thinking impairments have been documented. All patients and controls generated and dated up past and future self-images and provided associated past and future events. Our findings suggest a subtle pattern of preservation/impairment of different dimensions (quantitative and qualitative) of self-images, which rely partially on the episodic quality of past and future events.

Late-recovery from "permanent" vegetative state in the context of severe traumatic brain injury: A case report exploring objective and subjective aspects of recovery and rehabilitation

This article provides a detailed outline of the recovery of a young male patient during his emergence from a vegetative state (VS) 19 months after suffering a severe traumatic brain injury. Several similar cases have been documented, but these tend not to consider the subjective experience of the patient or family; our aim was therefore to provide a detailed account that emphasises our neuropsychological exploration of the impact of the injury on this person, and looks at the experience of his mother along the timeline from his accident to the end of a successful period in rehabilitation. Clinical details are presented including standardised and non-standard assessments, neuropsychological interventions, as well as reflections from the patient himself. Moreover, qualitative data from an interview with his mother is used to illustrate the emotional impact on family of such a vacillating diagnostic status and prognosis for the future. We conclude that late-emergence from VS is increasingly documented and further cases must be published to better understand this phenomenon. The present case illustrates the emotional impact this situation can have on a patient and his or her family, and gives an important insight into a patient's view of his or her life and identity following such an event.

Autobiographical memory and the self in a single-case of chronic unilateral spatial neglect

Unilateral spatial neglect (USN) is mainly defined as a condition affecting perception and the mental representation of the environment. However, nothing is known about its impact on the ability to mentally represent one's past and on personal identity. We addressed these questions in a case of chronic USN, DR, a 59-year-old right-handed woman, who underwent a variety of measures exploring the self and autobiographical memory (AM). DR showed preserved self-images and her AM performance was only preserved when memories were prompted by her own self-images and not by self-unrelated cues. Our findings are discussed in light of the interconnection between the self and AM.

Neuropsychological deficits in temporal lobe epilepsy: A comprehensive review

Temporal lobe epilepsy (TLE) is the most prevalent form of complex partial seizures with temporal lobe origin of electrical abnormality. Studies have shown that recurrent seizures affect all aspects of cognitive functioning, including memory, language, praxis, executive functions, and social judgment, among several others. In this article, we will review these cognitive impairments along with their neuropathological correlates in a comprehensive manner. We will see that neuropsychological deficits are prevalent in TLE. Much of the effort has been laid on memory due to the notion that temporal lobe brain structures involved in TLE play a central role in consolidating information into memory. It seems that damage to the mesial structure of the temporal lobe, particularly the amygdale and hippocampus, has the main role in these memory difficulties and the neurobiological plausibility of the role of the temporal lobe in different aspects of memory. Here, we will cover the sub-domains of working memory and episodic memory deficits. This is we will further proceed to evaluate the evidences of executive function deficits in TLE and will see that set-shifting among other EFs is specifically affected in TLE as is social cognition. Finally, critical components of language related deficits are also found in the form of word-finding difficulties. To conclude, TLE affects several of cognitive function domains, but the etiopathogenesis of all these dysfunctions remain elusive. Further well-designed studies are needed for a better understanding of these disorders.

Sameness and the self: philosophical and psychological considerations

In this paper I examine the concept of cross-temporal personal identity (diachronicity). This particular form of identity has vexed theorists for centuries-e.g., how can a person maintain a belief in the sameness of self over time in the face of continual psychological and physical change? I first discuss various forms of the sameness relation and the criteria that justify their application. I then examine philosophical and psychological treatments of personal diachronicity (for example, Locke's psychological connectedness theory; the role of episodic memory) and find each lacking on logical grounds, empirical grounds or both. I conclude that to achieve a successful resolution of the issue of the self as a temporal continuant we need to draw a sharp distinction between the feeling of the sameness of one's self and the evidence marshaled in support of that feeling.

Novel forms of forgetting in temporal lobe epilepsy

Transient Epileptic Amnesia (TEA) is a recently defined subtype of temporal lobe epilepsy, principally affecting people in middle age with a male predominance. Its key manifestation is the occurrence of recurring episodes of transient amnesia, usually lasting less than an hour and often occurring on waking. One-third of patients have exclusively amnestic attacks, while in two-thirds, at least some attacks are accompanied by other manifestations of epilepsy, especially olfactory hallucinations. Several lines of evidence point to a seizure focus in the medial temporal lobes. Transient Epileptic Amnesia is accompanied by a striking loss of autobiographical memories in two-thirds of sufferers, accelerated loss of memories which had been acquired successfully in around one half, and topographical amnesia in around one-third. This paper reviews the findings of the TIME project (The Impairment of Memory in Epilepsy - http://sites.pcmd.ac.uk/time/tea.php) in relation to TEA, accelerated long-term forgetting, and remote memory impairment.

[Syndrome of transient epileptic amnesia and epileptic amnesic syndrome: the same entity?]

A chronic subjective cognitive impairment can be symptomatic of temporal lobe epilepsy (TLE); it is thereby frequently reversible with the use of antiepileptic monotherapy. In this field, two distinct syndromes have been described: the Epileptic Amnesic Syndrome (EAS) and the Syndrome of Transient Epileptic Amnesia. Their diagnostic criteria have much in common but identification of STEA is based only on transient amnesic attacks. On the contrary, EAS takes into account subtle temporal lobe seizures. Here, we report a case where chronic cognitive disturbances were combined with very limited temporal lobe seizures while amnesic attacks were lacking. Antiepileptic drug treatment led to normalization of cognitive function. The criteria of STEA were not applicable because of the lack of transient amnesia in the patients' medical history. Considering brief episodes of flashbacks and abdominal pain as possibly seizure-related, the criteria of EAS were more operative: they allowed proper investigation to confirm TLE in our patient.

Déjà experiences in temporal lobe epilepsy

Historically, déjà vu has been linked to seizure activity in temporal lobe epilepsy, and clinical reports suggest that many patients experience the phenomenon as a manifestation of simple partial seizures. We review studies on déjà vu in epilepsy with reference to recent advances in the understanding of déjà vu from a cognitive and neuropsychological standpoint. We propose a decoupled familiarity hypothesis, whereby déjà vu is produced by an erroneous feeling of familiarity which is not in keeping with current cognitive processing. Our hypothesis converges on a parahippocampal dysfunction as the locus of déjà vu experiences. However, several other temporal lobe structures feature in reports of déjà vu in epilepsy. We suggest that some of the inconsistency in the literature derives from a poor classification of the various types of déjà experiences. We propose déjà vu/déjà vécu as one way of understanding déjà experiences more fully. This distinction is based on current models of memory function, where déjà vu is caused by erroneous familiarity and déjà vécu by erroneous recollection. Priorities for future research and clinical issues are discussed.