The Trier Social Stress Test: principles and practice

Researchers interested in the neurobiology of the acute stress response in humans require a valid and reliable acute stressor that can be used under experimental conditions. The Trier Social Stress Test (TSST) provides such a testing platform. It induces stress by requiring participants to make an interview-style presentation, followed by a surprise mental arithmetic test, in front of an interview panel who do not provide feedback or encouragement. In this review, we outline the methodology of the TSST, and discuss key findings under conditions of health and stress-related disorder. The TSST has unveiled differences in males and females, as well as different age groups, in their neurobiological response to acute stress. The TSST has also deepened our understanding of how genotype may moderate the cognitive neurobiology of acute stress, and exciting new inroads have been made in understanding epigenetic contributions to the biological regulation of the acute stress response using the TSST. A number of innovative adaptations have been developed which allow for the TSST to be used in group settings, with children, in combination with brain imaging, and with virtual committees. Future applications may incorporate the emerging links between the gut microbiome and the stress response. Future research should also maximise use of behavioural data generated by the TSST. Alternative acute stress paradigms may have utility over the TSST in certain situations, such as those that require repeat testing. Nonetheless, we expect that the TSST remains the gold standard for examining the cognitive neurobiology of acute stress in humans.

Restoring phronesis and practice: marketing's forgotten p's

Purpose – The purpose of this paper is to examine the evolution of marketing’s philosophical conversation over the past 120 years, focusing on the emergent meaning of the notion that marketing should become more “scientific”. Design/methodology/approach – This paper focuses on the US academic marketing literature, primarily journal articles and books published in the first half of the 20th century. Findings – The Aristotelian distinction between techné, epistemé and phronesis provides a rich basis for framing philosophical discussion in marketing, and should supplant the art-science debate and Anderson’s distinction between science1 and science2. Prior to 1959, the marketing journals provided a forum for phronesis, though this diminished as the academic marketing community largely abandoned the inductive, contextual approach in favour of a deductive, “scientific” methodology. The Ford Foundation played an important role in effecting this change. Practical implications – The paper highlights the importance of forums where practitioners can reflect on the ethical and social implications of their practices and then work to enhance these practices for the greater social good. Social implications – Questions the value of distinctions between marketing theorists and practitioners and the consequential focus of marketing journals. Originality/value – Advances the concept of phronesis in the marketing literature and distinguishes it from epistemé, which has dominated academic marketing discourse over the past 60 years.

Growing up in a bubble: using germ-free animals to assess the influence of the gut microbiota on brain and behavior

There is a growing recognition of the importance of the commensal intestinal microbiota in the development and later function of the central nervous system. Research using germ-free mice (mice raised without any exposure to microorganisms) has provided some of the most persuasive evidence for a role of these bacteria in gut-brain signalling. Key findings show that the microbiota is necessary for normal stress responsivity, anxiety-like behaviors, sociability, and cognition. Furthermore, the microbiota maintains central nervous system homeostasis by regulating immune function and blood brain barrier integrity. Studies have also found that the gut microbiota influences neurotransmitter, synaptic, and neurotrophic signalling systems and neurogenesis. The principle advantage of the germ-free mouse model is in proof-of-principle studies and that a complete microbiota or defined consortiums of bacteria can be introduced at various developmental time points. However, a germ-free upbringing can induce permanent neurodevelopmental deficits that may deem the model unsuitable for specific scientific queries that do not involve early-life microbial deficiency. As such, alternatives and complementary strategies to the germ-free model are warranted and include antibiotic treatment to create microbiota-deficient animals at distinct time points across the lifespan. Increasing our understanding of the impact of the gut microbiota on brain and behavior has the potential to inform novel management strategies for stress-related gastrointestinal and neuropsychiatric disorders.