Letter from the Guest Editor:

Darragh Devine, Associate Professor
Behavioural Neuroscience Program
Department of Psychology

Effects of Stress on Behavior and Biology

Evolutionary success is based upon the ability of species to fit into their ecological niches.  However, those environments are constantly in flux.  Some changes are physical, such as seasonal temperature variations, and some are emotional, such as shifts in social hierarchies within a group.  Whatever the source, environmental fluctuations can present significant stressful challenges to the well-being of organisms, and their ability to adapt is fundamental for both individual and species survival.

Coping with stress is generally achieved by modifying the organism’s behavioral and physiological activities during the stress exposure.  For example, an organism may adjust its behaviors to avoid the presence of an aversive stimulus, or it may mount a hormonal response to counter the adverse effects of the stressor.  However, these coping responses can be expensive to maintain, and the toll of severe or prolonged stress exposure can be extremely detrimental to emotional and physical well-being.  Toxins and other physical stressors can overwhelm the organisms’ capacity to cope, causing serious or even life-threatening biological damage.  Emotional stress can bring about debilitating cognitive and emotional disturbances.  Furthermore, the ability to cope with particular stressors varies from species to species, and even from individual to individual within a species.  Accordingly, research on species and individual responses to stress is critical, if we are to further understand the impact of environmental challenges on health.

In this issue of the Journal of Undergraduate Research, five outstanding young scholars report on the impact of environmental stress in species ranging from fish to man.  One study raises an alarming concern that specific chemical pollutants may impair the reproductive success of fish.  Another study describes the role of a particular neurotransmitter in fear and anxiety responses when animals are presented with the challenge of an unfamiliar environment.  A third identifies that individual differences in innate stress responsiveness underlie vulnerability for self-injurious behavior, a devastating disorder that is common in autism and developmental disabilities.  Two papers examine the role of social interactions in health and well-being.  One characterizes the impact of social defeat stress on behavioral despair, a model of major depression in rodents.  The other documents the positive impact of social support on patients’ perception of their own treatments for Parkinson’s disease.

This broad range of investigations of physical and emotional challenges illustrates the ubiquitous nature of stress in daily life, and the profound impact that it can have on health.  Inter-individual variability in disease resistance or vulnerability is apparent throughout these investigations, and these differences hint at the important interactions between genetic endowment, past history, and current environments in determining physical and emotional well-being.