Rethinking the Reserve with a Translational Approach: Novel Ideas on the Construct and the Interventions

Abstract

The concept of brain, cognitive, and neural reserves has been introduced to account for the apparent discrepancies between neurological damage and clinical manifestations. However, these ideas are yet theoretical suggestions that are not completely assimilated in the clinical routine. The mechanisms of the reserves have been extensively studied in the neurodegenerative pathologies, first of all the Alzheimer's disease. Both human and animal studies addressed this topic by following two parallel pathways. Specific aim of the present review is to attempt to combine the suggestions derived from the two different research fields to deepen the knowledge about reserves. In fact, the achievement of a comprehensive theoretical framework on reserve mechanisms is an essential step to propose well-timed interventions tailored on the clinical characteristics of patients. The present review highlights the importance of addressing three main aspects: the definition of reserve proxy measures, the interaction between reserve level and therapeutic interventions, and the specific time-window of reserve efficacy.

Consensus Paper. Cerebellar Reserve: From Cerebellar Physiology to Cerebellar Disorders

“…This property can result in clinical tolerance to pathology and reversibility after its removal. The notion of reserve was initially proposed to account for differences in susceptibility of the cerebral cortex to aging or pathological damage [5][6][7][8][9]. In this regard, reserve is defined as a moderator between pathology and outcome [5].…”

“…In contrast, cognitive reserve relates to functional activity, such as utilizing "pre-existing cognitive approaches" or "enlisting compensatory approaches" [5]. Since these functional activities depend on the integrity of brain networks, it has been proposed that neural reserve is a consequence of "the efficacy of neural circuitry and the ability to process information" [8], and that these mechanisms contribute to compensation for aging or dementia-related processes [5][6][7][8][9]. In our consideration of cerebellar reserve, we draw attention to this classical meaning of resilience to impairment, and we also highlight the notion of reversibility [10] (Table 1).…”

Testing for the Myth of Cognitive Reserve: Are the Static and Dynamic Cognitive Reserve Indexes a Representation of Different Reserve Warehouses?

“…In accordance with these observations, the idea has been developed that an enriched brain, that is a brain that modified its neuronal structure as a consequence of complex environmental stimulations, better tolerates the neuronal damage [1][2]. This view assumes the development of cerebral reserves (the brain reserve-BR, the cognitive reserve-CR and finally, the neural reserve-NR) allowing a higher efficiency of the brain networks as well as a more tuned engagement of different neural pathways despite the cerebral damage [5].…”

“…In the last thirty years the scientific literature has been increasingly interested in the mechanisms underlying brain and cognitive reserve [1][2]. In fact, several animal and human studies showed the beneficial effects of stimulant life experiences on the structure and functionality of the brain [2][3][4].…”

“…Briefly, the BR refers to the brain structure (the quantity of neurons, synapses, and dendrites) supposing that subjects with larger brain cope better with the neurological damage than those with smaller brains [1][2]. The CR refers to the efficiency of cognitive functions assuming that individuals with higher level of CR are able both to use more efficiently the pre-existent cognitive processes and they are, also, able enlisting the alternative cognitive functions to withstand brain damages [1][2].…”