Tony Buchanan | Saint Louis University (original) (raw)

Papers by Tony Buchanan

Psychoneuroendocrinology, 1999

Prior studies have reported cortisol secretion to be primarily influenced by negative affect, but... more Prior studies have reported cortisol secretion to be primarily influenced by negative affect, but less is known about cortisol activity during states of activation involving increased positive affect and decreased negative affect. On separate days, 30 healthy young men experienced: an activating and humorous video; a speech stressor; and a resting control period. Cortisol was measured in saliva before and after each 30-min mood induction. Positive affect (activation) was increased similarly by both the video and the speech compared to rest (pB.0001). Negative affect increased during the speech and decreased during the video (pB.001). Cortisol increased only during the speech (pB .0001). Following the video, however, cortisol was decreased significantly (pB .0001). Rest day cortisol revealed no differences across periods (p\ .1). These results suggest that the hypothalamic-pituitaryadrenocortical axis is a dynamic system influenced by changes in negative affect irrespective of the experience of generalized activation. : S 0 3 0 6 -4 5 3 0 ( 9 8 ) 0 0 0 7 8 -X

Frontiers in behavioral neuroscience, 2014

Stress clearly influences decision making, but the effects are complex. This review focuses on th... more Stress clearly influences decision making, but the effects are complex. This review focuses on the potential for stress to promote prosocial decisions, serving others at a temporary cost to the self. Recent work has shown altruistic responses under stress, particularly when the target's need is salient. We discuss potential mechanisms for these effects, including emotional contagion and offspring care mechanisms. These neurobiological mechanisms may promote prosocial-even heroic-action, particularly when an observer knows the appropriate response and can respond to a target in need. The effects of stress on behavior are not only negative, they can be adaptive and altruistic under conditions that promote survival and well-being at the individual and group level.

Pharmacology Biochemistry and Behavior, 2001

Exogenous cortisol's modulation of the acoustic startle reflex (ASR) was tested alone and dur... more Exogenous cortisol's modulation of the acoustic startle reflex (ASR) was tested alone and during exposure to affectively valenced photographs in healthy men and women. During nonmodulated startle, oral hydrocortisone had a biphasic dose effect, with 5 mg increasing and 20 mg decreasing, eyeblink reflex magnitude compared to placebo. During emotion modulation, 20 mg of hydrocortisone reduced reflex magnitude without affecting

Psychological Bulletin, 2007

Long-term memories are influenced by the emotion experienced during learning as well as by the em... more Long-term memories are influenced by the emotion experienced during learning as well as by the emotion experienced during memory retrieval. The present article reviews the literature addressing the effects of emotion on retrieval, focusing on the cognitive and neurological mechanisms that have been revealed. The reviewed research suggests that the amygdala, in combination with the hippocampus and prefrontal cortex, plays an important role in the retrieval of memories for emotional events. The neural regions necessary for online emotional processing also influence emotional memory retrieval, perhaps through the reexperience of emotion during the retrieval process.

Memory tends to be better for emotionally arousing information than for neutral information. Evid... more Memory tends to be better for emotionally arousing information than for neutral information. Evidence from animal studies indicates that corticosteroids may be necessary for this memory enhancement to occur. We extend these findings to human memory performance. Following administration of cortisol (20 mg) or placebo, participants were exposed to pictures varying in emotional arousal. Incidental memory for the pictures was assessed one week later. We show that elevated cortisol levels during memory encoding enhances the long-term recall performance of emotionally arousing pictures relative to neutral pictures. These results extend previous work on corticosteroid enhancement of memory and suggest that high cortisol levels during arousing events result in enhanced memory in humans.

Cognition & emotion, Jan 7, 2015

Cognitive control and emotional control share many similarities, but the specific relationship be... more Cognitive control and emotional control share many similarities, but the specific relationship between these processes is not well understood. This study explored the relationship between three types of cognitive control (working memory updating, response inhibition and set-shifting) and two emotional regulation strategies (expressive suppression and cognitive reappraisal). Corrugator electromyography, behaviour and self-reports of affect were measured as indices of emotion regulation. Results indicate that working memory updating predicted negative affect reduction during reappraisal and during expressive suppression. This study specifically shows that the working memory component of cognitive control is associated with negative affect reduction. Response inhibition and set-shifting were not specifically related to negative affect reduction, but these variables did predict aspects of emotional behaviour and regulation. These results suggest a general role for cognitive control in s...

Communicative & integrative biology, 2010

We recently reported data related to emotions collected in conjunction with a museum exhibit on e... more We recently reported data related to emotions collected in conjunction with a museum exhibit on emotion (Goose Bumps!-The Science of Fear).1 In this addendum, we present additional data collected as part of that study. We collected two commonly measured indices of emotional arousal, salivary cortisol and α-amylase, before and after participants had gone through a realistic fear challenge course as part of the exhibit. We found that α-amylase, but not cortisol, showed a highly specific increase only for those participants who endorsed both emotional arousal and negative valence. By contrast, the fear-inducing course resulted in high arousal but positive valence in some participants; in these, no increased α-amylase was measured. We conclude that salivary α-amylase is a promising biomarker for fearful experiences, and suggest that it is important to pay attention to positively valenced arousal that may be induced by fearful stimuli in a laboratory setting.

Learning & memory (Cold Spring Harbor, N.Y.)

The medial temporal lobe is known to play a role in the processing of olfaction and memory. The s... more The medial temporal lobe is known to play a role in the processing of olfaction and memory. The specific contribution of the human amygdala to memory for odors has not been addressed, however. The role of this region in memory for odors was assessed in patients with unilateral amygdala damage due to temporal lobectomy (n = 20; 11 left, 9 right), one patient with selective bilateral amygdala damage, and in 20 age-matched normal controls. Fifteen odors were presented, followed 1 h later by an odor-name matching test and an odor-odor recognition test. Signal detection analyses showed that both unilateral groups were impaired in their memory for matching odors with names, these patients were not significantly impaired on odor-odor recognition. Bilateral amygdala damage resulted in severe impairment in both odor-name matching as well as in odor-odor recognition memory. Importantly, none of the patients were impaired on an auditory verbal learning task, suggesting that these findings refl...

Psychology and Aging, 2014

Although past research has suggested a link between chronic stress and both physical and mental w... more Although past research has suggested a link between chronic stress and both physical and mental well-being in older adults, less is known about the degree to which neuroendocrine markers of stress are associated with higher-order cognitive processes such as decision-making. In a sample of healthy older adults (55-85 years), we tested the degree to which variation in the diurnal cortisol rhythm, an index of hypothalamic-adrenal-pituitary axis dynamics, was related to differences in risky decision-making. We found that diurnal cortisol fall predicted performance on the Cups Task, a risky decision-making task that independently tests risk-taking to achieve gains and risk-taking to avoid losses. For potential gains, we found that greater risk-taking was associated with lower diurnal cortisol fall, independent of age or sex of the participant. For risks to avoid potential losses, we found that lower diurnal fall was associated with suboptimal decision-making for men only. Compared with males with more typical diurnal fall, those who displayed lower diurnal fall made more risky choices and demonstrated lower sensitivity to the expected value of the risky choice. We integrate these results with the extant literature on the effects of stress on decision-making and cognitive aging.

Psychoneuroendocrinology, 2010

The ability to produce appropriate physiological and psychological responses to stressful situati... more The ability to produce appropriate physiological and psychological responses to stressful situations depends on accurate recognition and appraisal of such situations. Such ability is also important for proper emotion regulation. A number of studies have suggested that the medial prefrontal cortex (mPFC) plays a significant role in emotion regulation, as well as in the control of physiological endpoints of emotion regulation such as the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). Further, recent work has suggested that men and women may differ in these mechanisms of neural control of emotion regulation. Here, we examined the role of the human mPFC in self-report, ANS, and HPA stress reactivity by testing a group of participants with damage to this region (9 women and 9 men), a brain damaged comparison group (6 women and 6 men), and healthy comparison participants (27 women and 27 men) on an orthostatic challenge and the Trier Social Stress Test (TSST). The mPFC participants showed heightened self-reported stress in response to the TSST. In women, mPFC damage led to an increased cortisol response to the TSST. By contrast, in men, greater volume of mPFC damage was correlated with a decreased cortisol response. Finally, men with mPFC damage showed altered autonomic control of the heart (higher heart rate and lower high frequency heart rate variability) during an orthostatic challenge. These findings support the idea that the mPFC is involved in the regulation of physiological and psychological responses to stress and that this regulation may differ between men and women.

Cognitive Brain Research, 1999

The relationship between activity within the human auditory cortices and the duration of heard to... more The relationship between activity within the human auditory cortices and the duration of heard tones was investigated by measuring the hemodynamic response with functional magnetic resonance imaging. We demonstrate that there is no significant influence of stimulus duration as used here on the intensity and spatial extent of the hemodynamic response in the auditory cortices. We found however, that the time course of the hemodynamic response to the repeated stimulus presentation exhibited a characteristic decline after the first stimulus exposure during the activation period. The possible reasons for this time course are currently unknown, however, several factors may be involved, including top-down mechanisms andror the interplay of tissue perfusion and oxygen consumption. q

Cognitive Brain Research, 2000

This study examined the neural areas involved in the recognition of both emotional prosody and ph... more This study examined the neural areas involved in the recognition of both emotional prosody and phonemic components of words Ž . expressed in spoken language using echo-planar, functional magnetic resonance imaging fMRI . Ten right-handed males were asked to Ž . discriminate words based on either expressed emotional tone angry, happy, sad, or neutral or phonemic characteristics, specifically, Ž . initial consonant sound bower, dower, power, or tower . Significant bilateral activity was observed in the detection of both emotional and verbal aspects of language when compared to baseline activity. We found that the detection of emotion compared with verbal detection resulted in significant activity in the right inferior frontal lobe. Conversely, the detection of verbal stimuli compared with the detection of emotion activated left inferior frontal lobe regions most significantly. Specific analysis of the anterior auditory cortex revealed increased right hemisphere activity during the detection of emotion compared to activity during verbal detection. These findings illustrate bilateral involvement in the detection of emotion in language while concomitantly showing significantly lateralized activity in both emotional and verbal detection, in both the temporal and frontal lobes. q

Social Neuroscience, 2012

Physiological resonance between individuals is considered fundamental to the biological capacity ... more Physiological resonance between individuals is considered fundamental to the biological capacity for empathy. Observers of pain and distress commonly exhibit increases in reported distress, autonomic arousal, facial mimicry, and overlapping neural activity. An important, unstudied question is whether physiological stress can also resonate. Physiological stress is operationalized as activation of the hypothalamic pituitary adrenocortical (HPA) and sympatho-adrenomedullary (SAM) axes. People often report an aversive state resulting from the stress of another, but this could be conveyed through resonating arousal or distress, without activating the physiological stress response. Physiological stress is particularly important to examine since it commonly occurs chronically, with known negative effects on health. Salivary cortisol and salivary alpha-amylase (sAA) were measured in both speakers and observers during a modified Trier Social Stress Test (TSST) to assess activation of the HPA and SAM axes (respectively). Cortisol (but not sAA) responses resonated between speakers and observers. The cortisol response of observers increased with trait empathy and was not related to the speaker's subjective fear or distress. This study provides a novel method for examining physiological resonance, and indicates that we can indeed catch another's physiological stress, suggesting a specific health risk for those in the social network of stressed individuals.

Psychophysiology, 1996

We investigated gender differences in cardiovascular and pain responses to the cold pressor (CP) ... more We investigated gender differences in cardiovascular and pain responses to the cold pressor (CP) test in persons with positive (PH1) or negative parental history (PH2) for hypertension. Previous work has suggested an attenuated sensitivity to painful stimulation in hypertensive men and more recently in men with parental disposition for hypertension. It is not known whether this hypoalgesic effect is present in PH1 women. In this study, we evaluated differences in pain perception between men and women with PH1 or PH2 using an assessment method to measure current as well as delayed pain. Participants rated their pain every 15 s during a 90-s hand CP (0±48C) and a 90-s post-CP rest period. Systolic and diastolic blood pressures (SBP, DBP) and heart rate (HR) were measured before, during, and after the CP. PH1 and PH2 groups did not differ in age, height, weight, education, resting SBP, DBP, or HR. PH1 men showed greater DBP responses to the CP than PH2 men, while female groups did not differ in cardiovascular responses to the CP. Although pain ratings during the CP did not differ between groups, post-CP reported pain receded faster in the PH1 men than in the PH2 men. PH1 women, on the other hand, tended to report greater pain than PH2 women. These ®ndings question the generalizability of the hypoalgesic effects in hypertension-prone women. q 1999 International Association for the Study of Pain. Published by Elsevier Science B.V.

PLoS ONE, 2010

Background: How do we recognize emotions from other people? One possibility is that our own emoti... more Background: How do we recognize emotions from other people? One possibility is that our own emotional experiences guide us in the online recognition of emotion in others. A distinct but related possibility is that emotion experience helps us to learn how to recognize emotions in childhood.

Physiology & Behavior, 2011

Major depressive disorder (MDD) is associated with alterations in stress physiology. Severe melan... more Major depressive disorder (MDD) is associated with alterations in stress physiology. Severe melancholic depression is characterized by hypercortisolism, but community dwelling mildly depressed individuals and those with remitted MDD have shown reduced or normal reactivity to stress. There are also pronounced sex differences both in the incidence of MDD and in stress reactivity. To explore the relationships among depression history, sex differences, and stress, we examined stress reactivity in people with and without a history of MDD. Twenty-two participants with remitted MDD (12 men and 10 women) and 36 never depressed comparison participants (22 men and 14 women) participated in the study. Cortisol and alpha-amylase (sAA) were sampled from saliva before, 10 min after, and 30 min after the Trier Social Stress Test (TSST). Participants filled out the Positive Affect Negative Affect Schedule (PANAS) before and after they underwent the TSST. Women with remitted MDD showed reduced cortisol response to the TSST compared with the never MDD women, while men with remitted MDD showed comparable cortisol reactivity to the never depressed men. The groups did not differ on sAA reactivity to stress. The remitted MDD group (overall and men and women separately) reported greater negative affect both before and after stress compared to the never depressed group. Women from both groups reported greater post-stress negative affect than men. In contrast, men from both groups reported higher positive affect before and after stress than women. Given that the sex difference findings were not dependent on depression history, self-reported affective differences in response to stress may predate depressive symptoms and contribute to sex differences in depression incidence.

Neuron, 2006

Food preferences are acquired through experience and can exert strong influence on choice behavio... more Food preferences are acquired through experience and can exert strong influence on choice behavior. In order to choose which food to consume, it is necessary to maintain a predictive representation of the subjective value of the associated food stimulus. Here, we explore the neural mechanisms by which such predictive representations are learned through classical conditioning. Human subjects were scanned using fMRI while learning associations between arbitrary visual stimuli and subsequent delivery of one of five different food flavors. Using a temporal difference algorithm to model learning, we found predictive responses in the ventral midbrain and a part of ventral striatum (ventral putamen) that were related directly to subjects' actual behavioral preferences. These brain structures demonstrated divergent response profiles, with the ventral midbrain showing a linear response profile with preference, and the ventral striatum a bivalent response. These results provide insight into the neural mechanisms underlying human preference behavior.

Neurobiology of Learning and Memory, 2008

In some situations, memory is enhanced by stressful experience, while in others, it is impaired. ... more In some situations, memory is enhanced by stressful experience, while in others, it is impaired. The specific components of the stress-response that may result in these differing effects remain unclear, and the current study sought to address this knowledge gap. Forty healthy participants (20 women, 20 men) were exposed to emotionally arousing and neutral pictures. Twenty-four hours later, 20 participants underwent a social stressor (speech and math tests), and 20 underwent a control reading task, both followed by a delayed recall task. Cortisol responders to the stress condition (5 men and 1 woman) showed reduced memory retrieval for both neutral and emotionally arousing pictures. Men and women in the stress condition who did not produce a cortisol response showed increased retrieval of unpleasant pictures compared to controls. The results provide further evidence that cortisol is a primary effector in the stress-induced memory retrieval deficit. At the same time, stress can enhance memory retrieval performance, especially for emotional stimuli, when the cortisol response is absent.

Nature Neuroscience, 2005

Neurobiological studies demonstrate the amygdala's role in emotional memory, and psychological st... more Neurobiological studies demonstrate the amygdala's role in emotional memory, and psychological studies suggest a particular pattern: enhanced memory for the gist but not the details of complex stimuli. We hypothesized that these two findings are related. Whereas normal (n 5 52) and brain-damaged (n 5 22) controls showed the expected enhancement of gist memory when the encoding context was emotional, persons with unilateral damage to the medial temporal lobe including the amygdala (n 5 16) did not show this pattern. Furthermore, amygdala volume showed a significant positive correlation with gist memory but not with overall memory. A further study in four subjects with selective medial temporal damage sparing the amygdala, and one with selective damage confined to the amygdala, confirmed the specificity of this effect to the amygdala. The data support a model whereby the amygdala focuses processing resources on gist, possibly accounting for features of traumatic memories and eyewitness testimony in real life.