La projection vers le futur : neuropsychologie, neuro-imagerie et psychopathologie

Abstract

Although memory is thought to be past-oriented, it is also profoundly future-oriented, allowing both re-experiencing of past life events and pre-experiencing of future events. This tendency to project into the future implies, as does episodic memory, a sufficient degree of self-awareness, an awareness that subsequently allows for a sense of continuity and individual identity in the long term. Therefore, future self-projection, also called “episodic future thinking”, constitutes an ability that is favorable to individual development, both in the adaptive capacities that it allows and in the individual future objectives that it creates in the long term. This continuity over time is assumed to be stable, regardless of the environmental, developmental, and social changes that occur around the subject throughout life. Moreover, future projection corresponds to a deeply introspective activity, as it is focused on internal processes and thoughts centered on past and future oneself. Numerous studies have shown that future projection involves the use of a particular neural network corresponding to the “default network”, i.e., a set of cerebral structures activated when the brain is at passive rest. A rest that is perhaps not a rest at all, since this time could be devoted to mental activities of introspection, notably within the framework of future simulations in relation to oneself and one's past. The episodic basis of future projection as well as the involvement of this default network makes it sensitive to any alteration of memory or psychological functioning, the impossibility of memorizing or recalling past events having a strong impact on the capacity to imagine the future. Examples include Alzheimer's disease, where hippocampal and therefore memory damage is associated with a strong alteration in the ability to estimate the remaining future time, or post-traumatic stress disorder, where traumatic exposure and the resulting symptoms lead to a feeling of a “foreshortened” future. This work proposes to revisit this demonstrated link between episodic memory and future projection, through the observation of a simultaneous impairment of mnesic and projective capacities, firstly in the field of clinical neuropsychology, secondly in the context of psychiatric and neurological pathologies. Beyond its episodic characteristic, recent literature now demonstrates the fundamentally identity-based foundation of future projection. Imagining and projecting oneself into the future would allow one to build a stable long-term individual identity, marked by the creation of healthy future goals appropriate to one's past and future life history. Moreover, it has been demonstrated today that the ability to project into the future has a real influence on the therapeutic work carried out in various psychiatric pathologies, such as addictive behaviors or post-traumatic stress disorder. We propose to return to this identity segment of future projection at greater length, a literature borrowing both from its episodic and phenomenological characteristics. Finally, we consider the development of a recent literature demonstrating a possible “double-edged” effect of future projection: behind the individual and identity fulfillment promoted by future projection may lie significant future anxiety, resulting from pervasive and maladaptive projection. It is possible that future projection requires a balancing effect, whose individual benefits and risks depend strongly on the associated identity and psychological context.