(Not) building on what you know : understanding the impact of stress and major stress mediators on our ability to successfully use prior knowledge

Abstract

Learning and memory constitute critical processes that enable us to behave adaptively and respond adequately to our surroundings. The latter is dependent on our ability to utilize prior knowledge, to form schemas, i.e. specific knowledge structures that can act as scaffolds and aid learning of schema-related information, or for the purpose of generalizing across new but related situations. Both, schema-based learning and memory generalization have been shown to rely on specific brain structures, such as the ventromedial prefrontal cortex as well as the hippocampus. These structures are highly sensitive to stress and major stress mediators such as cortisol and noradrenaline. However, how our ability to utilize prior knowledge is impacted by stress and these stress mediators is not yet clear. To this end, we conducted three studies to investigate the impact of acute stress, as well as of the stress mediators cortisol and noradrenaline on the performance and neural underpinnings of the use of prior knowledge in schema-based learning and memory generalization. Results showed that stress or increased cortisol levels led to an inability to use prior knowledge to aid learning and hampered with the neural ensemble involved in schema-detection and learning, while increased noradrenergic arousal led to impaired memory generalization specifically in women. Hence, the current work is the first to show an impact of stress and specific stress mediators on our ability to use prior knowledge in different contexts and settings. Results have important implications for educational purposes and are also of clinical relevance as many stress-related mental disorders prominently feature impaired memory processes.