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Biomedical subjects

J T Cacioppo

Publications and source records attributed to J T Cacioppo.

At least 19 recordsLinked to original sources
PubMed1996

Brain imaging and cognitive neuroscience. Toward strong inference in attributing function to structure.

Cognitive neuroscience has emerged from the neurosciences and cognitive psychology as a scientific discipline that aims at the determination of "how brain function gives rise to mental activity" (S. M. Kosslyn & L. M. Shin, 1992, p. 146). While research in cognitive neuroscience combines many levels of neuroscientific and psychological analyses, modern imaging techniques that monitor brain activity during behavioral or cognitive operations have significantly contributed to the emergence of this discipline. The conclusions deduced from these studies are inherently localizationistic in nature; in other words, they describe cognitive functions as being localized in focal brain regions (brain activity in a defined brain region, phi, is involved in specific cognitive function, psi). A broad discussion about the virtues and limitations of such conclusions may help avoid the emergence of a mentalistic localizationism (i.e., the attribution of mentalistic concepts such as happiness, morality, or consciousness to brain structure) and illustrates the importance of a convergence with information generated by different research strategies (such as, for example, evidence generated by studies in which the effects of experimental manipulations of local neuronal processes on cognitive functions are assessed). Progress in capitalizing on brain-imaging studies to investigate questions of the form "brain structure or event phi is associated with cognitive function psi" may be impeded because of the way in which inferences are typically formulated in the brain imaging literature. A conceptual framework to advance the interpretation of data describing the relationships between cognitive phenomena and brain structure activity is provided.

Animals↗
PubMed1996

The relationship between social support and physiological processes: a review with emphasis on underlying mechanisms and implications for health.

In this review, the authors examine the evidence linking social support to physiological processes and characterize the potential mechanisms responsible for these covariations. A review of 81 studies revealed that social support was reliably related to beneficial effects on aspects of the cardiovascular, endocrine, and immune systems. An analysis of potential mechanisms underlying these associations revealed that (a) potential health-related behaviors do not appear to be responsible for these associations; (b) stress-buffering effects operate in some studies; (c) familial sources of support may be important; and (d) emotional support appears to be at least 1 important dimension of social support. Recommendations and directions for future research include the importance of conceptualizing social support as a multidimensional construct, examination of potential mechanisms across levels of analyses, and attention to the physiological process of interest.

Blood Pressure↗
PubMed1996

Quantity-based interference and symbolic representations in chimpanzees (Pan troglodytes).

Five chimpanzees with training in counting and numerical skills selected between 2 arrays of different amounts of candy or 2 Arabic numerals. A reversed reinforcement contingency was in effect, in which the selected array was removed and the subject received the nonselected candies (or the number of candies represented by the nonselected Arabic numeral). Animals were unable to maximize reward by selecting the smaller array when candies were used as array elements. When Arabic numerals were substituted for the candy arrays, all animals showed an immediate shift to a more optimal response strategy of selecting the smaller numeral, thereby receiving the larger reward. Results suggest that a response disposition to the high-incentive candy stimuli introduced a powerful interference effect on performance, which was effectively overridden by the use of symbolic representations.

Animals↗
PubMed1995

Bioelectrical echoes from evaluative categorization: II. A late positive brain potential that varies as a function of attitude registration rather than attitude report.

We report evidence of both correspondence and independence between participants' attitude report and a late positive potential (LPP) of the event-related potential. Attitude reports and LPPs to positive, neutral, and negative stimuli that were preceded by positive stimuli were recorded while participants either reported accurately their attitudes or misreported neutral or negative attitudes. Evaluatively inconsistent, in contrast to consistent, stimuli evoked a larger LPP regardless of whether participants reported accurately or misreported their attitudes. These results were replicated in a second study in which attitude reports and LPPs to negative, neutral, and positive stimuli that were preceded by negative stimuli were recorded. Findings suggest that the LPP evoked during evaluative judgments reflects attitude categorization rather than attitude report processes and can potentially assess attitudes that people are unwilling to report.

Adult↗
PubMed1995

Individual differences in cardiac sympathetic control predict endocrine and immune responses to acute psychological stress.

Potential mechanisms coordinating individual differences in cardiovascular reactivity and endocrine and immune responses to acute psychological stress were examined. Twenty-three young, healthy women performed a mental arithmetic challenge while measures of cardiovascular, endocrine, and immune function were assessed. Results revealed that the acute stressor was associated with changes in the cardiovascular, endocrine, and immune systems. More important analyses revealed that individual differences in cardiovascular reactivity predicted stress-induced cortisol changes. Furthermore, cardiac sympathetic control, as indexed by preejection period, was specifically related to changes in natural killer cell activity. These results suggest that distinct physiological pathways are activated in response to acute psychological stress.

Adolescent↗
PubMed1995

Appraisal support predicts age-related differences in cardiovascular function in women.

The influence of appraisal support on age-related differences in cardiovascular function was examined. Resting assessments of heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), respiratory sinus arrhythmia (RSA), and preejection period were obtained from 45 young and 20 elderly women. Consistent with prior research, results revealed that the elderly women had higher blood pressure and lower RSA than the young women. More important, appraisal support predicted age-related differences in SBP and DBP: Age predicted elevated blood pressure for women low in appraisal support, whereas age was unrelated to blood pressure for women high in appraisal support. These preliminary data suggest that appraisal support may be an important predictor of long-term physiological function and health.

Adolescent↗
PubMed1995

The metrics of cardiac chronotropism: biometric perspectives.

The selection of heart period versus heart rate as a chronotropic metric has been considered from quantitative and statistical perspectives, which have not yielded a universal preference for either metric. In the present paper, we discuss biometric considerations that bear on the selection of the optimal chronotropic metric. Biometric evidence reveals that the transfer functions relating autonomic nerve traffic to chronotropic effects on the heart are more nearly linear for heart period than for heart rate. This confers considerable advantage on heart period as a chronotropic metric and can facilitate the study of psychophysiological relationships. We further show that heart period offers greater flexibility, because heart period data can be evaluated in cardiac time units (beats) or in real-time units (s), whereas heart rate data can only be analyzed in real time. These considerations suggest clear advantages to heart period as a chronotropic metric.

Animals↗
PubMed1995

Delay in seeking a cancer diagnosis: delay stages and psychophysiological comparison processes.

Two analyses of patient delay in seeking a medical diagnosis are considered. In the first, a model of delay is presented. Specifically, delay is comprised of four stages (appraisal, illness, behavioural and scheduling delay intervals), each governed by a conceptually distinct set of decisional and appraisal processes beginning with the initial day that an unexplained symptom is detected to the day the individual appears before a physician. The second analysis is a social psychological one of the attributions individuals draw when relating their symptoms to their expectations and knowledge about physiological bodily processes. The eight principles of Psychophysiological Comparison Theory (PCT) provide the basis for clarifying the psychological processes of symptom interpretation and appraisal. Two studies were conducted with women seeking diagnostic evaluations for prevalent cancers: breast or gynaecological tumours. Regarding the delay model, results indicated that the delay intervals were independent (i.e. uncorrelated). Also, appraisal delay constituted the majority (at least 60 per cent) of the total delay. In the test of PCT, support was found across measures of symptoms, the context in which the symptoms arose, and the inferences people made about the symptoms.

Adolescent↗
PubMed1995

The dissociation of catecholamine and hypothalamic-pituitary-adrenal responses to daily stressors using dexamethasone.

The hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) systems are implicated in the human stress response. One characterization of these systems is that they are nonspecific in their response, but differ in activation threshold and time course. Additionally, they have been found to be affected commonly by strong metabolic stressors and infusions of CRH, and a hypothesis has been developed primarily from animal research that CRH stimulates both the HPA and SAM systems. To determine whether CRH was significantly involved in tonic as well as psychological stress-induced catecholamine levels in man, we infused 24 normal male undergraduate students with either saline (n = 12) or dexamethasone (DEX; n = 12) and evaluated their subsequent plasma levels of ACTH, cortisol, epinephrine (EPI), and not epinephrine (NEPI). DEX produced a dramatic decrease in ACTH and cortisol levels, but no significant changes in EPI or NEPI occurred over a 4-h sampling interval. After the administration of math and speech stressors in a controlled laboratory setting, DEX inhibited the ACTH and cortisol release that was noted in the saline group, but stress-induced increases in EPI and NEPI were comparable in both groups. Thus, our study suggests that there is a difference in the neural pathways for tonic and stress-induced stimulation of the SAM and HPA systems.

Adrenocorticotropic Hormone↗
PubMed1994

Bioelectrical echoes from evaluative categorizations: I. A late positive brain potential that varies as a function of trait negativity and extremity.

Attitudes can be conceptualized in terms of the elementary operations of evaluative categorization and response selection-execution. This article describes a component of the event-related potential that is associated with the first of these operations. Ss were exposed to sequences of 6 traits and performed a dichotomous evaluative categorization task. Evaluative inconsistency was varied by embedding very positive, moderately positive, moderately negative, and very negative traits in sequences containing predominantly very positive traits. Highly and moderately evaluatively inconsistent traits, compared with mildly inconsistent or consistent traits, evoked a larger amplitude late positive potential (LPP) that was maximal over centroparietal regions. Furthermore, extremely evaluatively inconsistent traits evoked a larger amplitude LPP than moderately evaluatively inconsistent traits even though both sets of traits were judged to be negative.

Affect↗
PubMed1994

Construals of preillness relationship quality predict cardiovascular response in family caregivers of Alzheimer's disease victims.

The authors examined the relationships between family caregivers' construal of their preillness affection for and cohesiveness with an Alzheimer's disease (AD) patient and subsequent cardiovascular functioning. Scale validation demonstrated the psychometric properties. In a study conducted 2 years later, 31 family caregivers of AD victims performed stress-inducing tasks while cardiovascular activity was monitored. Path analyses revealed that caregivers relatively high in preillness affection for the AD patient were characterized by lower heart rate reactivity and resting diastolic blood pressure. In contrast, caregivers relatively high in preillness cohesion were characterized by higher resting systolic and diastolic blood pressure. These results suggest that caregivers' social relationships may play an important, although not always beneficial, role in cardiovascular regulation and health.

Affect↗
PubMed1994

Autonomic space and psychophysiological response.

Contemporary findings reveal that autonomic control of dually innervated target organs cannot adequately be viewed as a continuum extending from parasympathetic to sympathetic dominance. Rather, a two-dimensional autonomic space, bounded by sympathetic and parasympathetic axes, is the minimal representation necessary to characterize the multiple modes of autonomic control. We have previously considered the theoretical implications of this view and have developed quantitative conceptual models of the formal properties of autonomic space and its translation into target organ effects. In the present paper, we further develop this perspective by an empirical instantiation of the quantitative autonomic space model for the control of cardiac chronotropy in the rat. We show that this model (a) provides a more comprehensive characterization of cardiac response than simple measures of end-organ state, (b) permits a parsing of the multiple transformations underlying psychophysiological responses, (c) illuminates and subsumes psychophysiological principles, such as the Law of Initial Values, (d) reveals an interpretive advantage of expressing cardiac chronotropy in heart period rather than heart rate, and (e) has fundamental implications for the direction and interpretation of a broad range of psychophysiological studies.

Animals↗
PubMed1994

Social neuroscience: autonomic, neuroendocrine, and immune responses to stress.

The immune system is influenced by central nervous system processes that are shaped by social and psychological factors. Considerations of social factors, intrapersonal process, and autonomic psychophysiology therefore may contribute to a fuller understanding of both immune and brain function. Research reviewed here (a) examines the socioemotional factors that contribute to, or moderate, responses to brief and chronic stressors, (b) determines whether or not stable individual differences in heart rate reactivity predict neuroendocrine and immune responses to a brief psychological stressor and to an influenza virus vaccine, and (c) investigates the autonomic origins of individual differences in low and high heart rate reactivity and their relationship to neuroendocrine and immune responses to chronic and acute stressors. Among our findings are: (a) acute psychological stressors activate the sympathetic adrenomedullary system across individuals and affect immune function; and (b) individuals characterized by high sympathetic cardiac reactivity to acute psychological stressors also show a relative activation of the hypothalamic pituitary adrenocortical system and altered immune function.

Arousal↗
PubMed1994

Origins of baseline variance and the Law of Initial Values.

The Law of Initial Value (LIV) asserts that the magnitude of a phasic psychophysiological response is dependent on the initial baseline level. Although results in accord with the LIV are often observed, exceptions are frequent, especially for between-subjects analyses. A general assumption in studies of the LIV is that a given baseline difference is equivalent regardless of its functional origin. The present study examined the relationships between basal heart period variance, arising from alternate sources, and the magnitude of the chronotropic response to a speech stressor. Results reveal that baseline differences due to orthostatic manipulations, which are known to be largely of autonomic origin, yielded larger LIV effects than did individual differences in basal heart period, which include a significant nonautonomic component. The minimal LIV-like effects of baseline differences associated with non-autonomic factors, relative to variations in autonomic control, may contribute to the inconsistent appearance of between-subjects LIV effects.

Adolescent↗
PubMed1994

The effects of an acute psychological stressor on cardiovascular, endocrine, and cellular immune response: a prospective study of individuals high and low in heart rate reactivity.

High and low reactors were preselected on the basis of their heart rate reactivity to a speech stressor in a prescreening session. In the main study, subjects were exposed to a mental arithmetic plus noise stressor. Cardiovascular activity was recorded during baseline and stressor, and blood was drawn prior to and following the stressor for endocrine and immune assays. Results revealed that the stressor decreased the blastogenic response to concanavalin A and increased natural killer cell numbers and cytotoxicity, absolute numbers of CD8+ T-lymphocytes, norepinephrine and epinephrine levels, heart rate, and blood pressure responses. In addition, cortisol and natural killer cell cytotoxicity responses to the stressor differentiated individuals high versus low in heart rate reactivity. These results suggest that the interactions among the autonomic nervous system, endocrine system, and immune system are not only amenable to psychophysiological analysis but that such analyses may play an important role in illuminating underlying mechanisms.

Adolescent↗
PubMed1994

Autonomic cardiac control. I. Estimation and validation from pharmacological blockades.

Pharmacological blockades have been used to estimate the relative contributions of the autonomic branches to cardiac chronotropic control. Systematic biases in these estimates, however, can arise from both methodological and physiological factors. Selective blockades can be interpreted by two inferential models, and a single blockade condition can yield estimates of autonomic control for both autonomic branches. The residual autonomic control of the heart after blockade of a single division provides an index of the functional contribution of the unblocked branch. In contrast, the change in chronotropic state of the heart after blockade of the same division reflects the subtractive loss of that branch and thus provides an index of the normal contribution of the blocked branch. We demonstrate that the systematic biases that can arise in blockade studies introduce distortions of the subtractive and residual estimates that are of equal magnitude but opposite sign. Consequently, the discrepancy between the subtractive- and residual-model estimates provides a measure of bias in blockade studies and permits the derivation of validity indices that can facilitate interpretations of blockade data.

Adrenergic Antagonists↗
PubMed1994

Autonomic cardiac control. II. Noninvasive indices and basal response as revealed by autonomic blockades.

Heart period, systolic time intervals, low and high frequency heart period variability, blood pressure, and respiration were measured in female subjects under three drug conditions (saline, atropine sulfate, metoprolol) while sitting and standing on three consecutive days. Following preinfusion baseline recordings, saline, metoprolol (14 mg), or atropine sulfate (2 mg) was infused for 15 min (by using a double-blind procedure). Recordings were taken during a postinfusion baseline and in response to an orthostatic stressor (standing versus sitting postures). At the end of the metoprolol session, atropine sulfate was infused and responses were monitored during the postinfusion (i.e., double blockade) baseline and during orthostatic stressor. Analyses of the blockade data revealed that the preejection period (PEP) reflected sympathetic but not vagal influences on the heart, and high frequency (HF, 0.12-0.40 Hz) heart rate variability (respiratory sinus arrhythmia) reflected vagal but not sympathetic influences on the heart. No other measure provided a specific index of the tonic sympathetic or vagal activation of the heart. Postinfusion PEP under saline predicted individual differences in postinfusion cardiac sympathetic activation, whereas postinfusion heart period (but not HF variability) under saline predicted individual differences in postinfusion cardiac vagal activation.

Adult↗