Loneliness typically refers to the feelings of distress and dysphoria resulting from a discrepancy between a person's desired and achieved levels of social relations, and there is now considerable evidence that loneliness is a risk factor for poor psychological and physical health. Loneliness has traditionally been conceptualized as a uniquely human phenomenon. However, over millions of years of evolution, efficient and manifold neural, hormonal, and molecular mechanisms have evolved for promoting companionship and mutual protection/assistance and for organizing adaptive responses when there is a significant discrepancy between the preferred and realized levels of social connection. We review evidence suggesting that loneliness is not a uniquely human phenomenon, but, instead, as a scientific construct, it represents a generally adaptive predisposition that can be found across phylogeny. Central to this argument is the premise that the brain is the key organ of social connections and processes. Comparative studies and animal models, particularly when integrated with human studies, have much to contribute to the understanding of loneliness and its underlying principles, mechanisms, consequences, and potential treatments.
Human responses to brief psychological stressors are characterized by changes and large individual differences in autonomic, neuroendocrine, and immune function. The authors examined the effects of brief psychological stressors on cardiovascular, neuroendocrine, and cellular immune response in 22 older women to investigate the common effects of stress across systems. They also used interindividual variation in heart rate reactivity, cardiac sympathetic reactivity (as indexed by preejection period reactivity in their reactivity paradigm), and cardiac vagal reactivity (as indexed by respiratory sinus arrhythmia reactivity) to explore the heterogeneity in human responses to brief psychological stressors. The results revealed that brief psychological stressors heightened cardiac activation, elevated plasma catecholamine concentrations, and affected the cellular immune response. It was also found that individuals characterized by high, relative to low, cardiac sympathetic reactivity showed higher stress-related changes in adrenocorticotropic hormone and cortisol plasma levels but comparable changes in epinephrine and norepinephrine concentrations. These data suggest that the effects of psychological stressors on cardiovascular and cellular immune response are governed by coordinated regulatory mechanism(s) and that going beyond the simple notion of heart rate reactivity to examine neural substrates may shed light on the interrelationships among and the regulatory mechanisms for the autonomic, endocrine, and immune responses to stressors.
ABSTRACT Guidelines are proposed for the collection, analysis, and description of electromyographic (EMG) data. The guidelines cover technological issues in EMG recording, social aspects of EMG experimentation, and limits to inferences that can be drawn in EMG research. An atlas is proposed for facial EMG electrode placements, and standard EMG terminology is suggested.
The 1990s were declared by Congress to be the "decade of the brain." This declaration is important to all psychologists, not only neuroscientists, because with this declaration come expectations of the cognitive and behavioral sciences generally and because the brain does not exist in isolation but rather is a fundamental component of developing and aging individuals who themselves are mere actors in the larger theater of life. This article examines the importance of a multilevel, integrative approach to the study of mental and behavioral phenomena in the decade of the brain, reviews how this approach highlights the synergistic relationship between theoretical and clinically relevant research, and illustrates how this approach can foster the transition from microtheories to general psychological theories.
We present evidence from a 5-year longitudinal study for the prospective associations between loneliness and depressive symptoms in a population-based, ethnically diverse sample of 229 men and women who were 50-68 years old at study onset. Cross-lagged panel models were used in which the criterion variables were loneliness and depressive symptoms, considered simultaneously. We used variations on this model to evaluate the possible effects of gender, ethnicity, education, physical functioning, medications, social network size, neuroticism, stressful life events, perceived stress, and social support on the observed associations between loneliness and depressive symptoms. Cross-lagged analyses indicated that loneliness predicted subsequent changes in depressive symptomatology, but not vice versa, and that this temporal association was not attributable to demographic variables, objective social isolation, dispositional negativity, stress, or social support. The importance of distinguishing between loneliness and depressive symptoms and the implications for loneliness and depressive symptomatology in older adults are discussed.
Most studies of social relationships in later life focus on the amount of social contact, not on individuals' perceptions of social isolation. However, loneliness is likely to be an important aspect of aging. A major limiting factor in studying loneliness has been the lack of a measure suitable for large-scale social surveys. This article describes a short loneliness scale developed specifically for use on a telephone survey. The scale has three items and a simplified set of response categories but appears to measure overall loneliness quite well. The authors also document the relationship between loneliness and several commonly used measures of objective social isolation. As expected, they find that objective and subjective isolation are related. However, the relationship is relatively modest, indicating that the quantitative and qualitative aspects of social relationships are distinct. This result suggests the importance of studying both dimensions of social relationships in the aging process.
Thoracic impedance is modulated by events within the respiratory cycle, which represents a source of “noise” in impedance cardiography. Respiration itself, however, is a physiological rhythm of interest to psychophysiologists. We report here methods and validation for deriving impedance pneumographic measures of respiration from impedance cardiography signals, based on standard tetrapolar band electrodes. We recorded the change in impedance (Δ Z ), the first derivative of the change in impedance ( dZ/dt ), output from a strain‐gauge respirometer, and criterion spirometry from eight healthy adults during rest, paced breathing, abdominal breathing, thoracic breathing, and a mental arithmetic task. Transfer function analyses revealed that a Δ Z d signal (derived by integration of the dZ/dt signal) provided the best estimate of the criterion spirometric measure for all parameters (coherence, phase, and gain), accounting for almost 90% of the variance in respiratory waveform morphology. The results document the potential utility of impedance pneumography, as derived from standard impedance cardiography signals.
