Our research at the BSL is concerned with individual differences in stress reactivity in relation to emotion states, and health. The focus is on central nervous system function in relation to behavior and responses of the cardiovascular, and endocrine systems. Physical and psychological stress arises when the well being of the body is threatened by a physically or emotionally distressing event, such as dynamic exercise or work on a challenging psychomotor or cognitive task, such as mental arithmetic. Motivated behavior includes states of activation to achieve a goal or avoid an unpleasant outcome along with positive and negative affective processes, the brain states that accompany them, and the physiological consequences.

Challenges such as these can cause significant cardiovascular and endocrine systems leading to significant changes from the resting state. We measure cardiovascular function using noninvasive blood pressure monitors and impedance cardiography. The impedance technique allows reliable, noninvasive measurements of cardiac output and peripheral vascular resistance. Taken together with blood pressure, these permit an unusually complete view of the cardiovascular adjustments to various stressors in persons having cardiovascular risk profiles. We have recently developed an ambulatory impedance monitor for studies outside the laboratory. Emotion states can be reported on by the volunteer or their physiological counterparts can be tested using physiological monitoring. A recent addition to our methodology is the startle reflex and the emotion modulated startle paradigm. Three projects are being conducted.

The first concerns acute effects of caffeine on the cardiovascular and endocrine systems in relation to risk for hypertension. A moderate dose of caffeine (equivalent to 2-3 cups of coffee) raises blood pressure and increases stress hormone output. These responses are present when the person is at rest and also during behavioral and mental stress. The blood pressure response to caffeine is greater in persons at high risk for hypertension than in low risk individuals. The effects of caffeine have been documented most clearly in men. We have recently begun to examine its effects in women. Notably, in postmenopausal women, caffeine may raise blood pressure more than in premenopausal women. We are currently testing these two groups for the effects of acute caffeine intake in the laboratory and in daily life. There is a special emphasis in this project to compare postmenopausal women receiving hormone replacements to those who are not.

The second major project is dedicated to examining behavioral, emotional, and physiological responses in young adults with a family history of alcohol or other substance abuse. The work is based on a theory of substance abuse risk that implicates mild disorders of central nervous system processes that aid in regulation of affect, behavior, and physiology. The project involves an extensive psychiatric evaluation of each volunteer along with a careful documentation of the histories of first degree relatives. Our study calls for testing the volunteers for their subjective emotional responses to standard laboratory challenges and to document their cardiovascular, endocrine, and subjective responses to these situations. In addition we are studying specific cognitive task challenges and their behavioral effects in persons at high and at low risk.

A third project is devoted to the study of the effects of the stress hormone, cortisol on emotion states and cognitive processes, especially memory. Cortisol has large numbers of receptors in the frontal cortex, temporal lobes, and septal and amygdaloid nuclei. These all have the potential to alter the way in which subjects perceive the environment and how they process information. This work involves manipulating cortisol levels either through natural stress responses or by administering the substance directly. There is evidence that cortisol can either enhance or impair memory depending on the conditions of testing and the memory process under study.

Behavioral Sciences Laboratory
V.A. Medical Center, 151-A
921 N.E. 13th Street
Oklahoma City, OK 73104
(405) 270-0501, Ext. 3124