Adriaan Tuiten

Testosterone shifts the balance between sensitivity for punishment and reward in healthy young women

Animal research has demonstrated reductions in punishment sensitivity and enhanced reward dependency after testosterone administration. In humans, elevated levels of testosterone have been associated with violent and antisocial behavior. Interestingly, extreme forms of violent and antisocial behavior can be observed in the psychopath. Moreover, it has been argued that reduced punishment sensitivity and heightened reward dependency are crucially involved in the etiology and maintenance of psychopathy. A task that has been proven to be capable of simulating punishment-reward contingencies is the IOWA gambling task. Decisions to choose from decks of cards become motivated by punishment and reward schedules inherent in the task. Importantly, clinical and subclinical psychopaths demonstrate a risky, disadvantageous pattern of decision-making in the task, indicating motivational imbalance (insensitivity for punishment and enhanced reward dependency). Here, in a double-blind placebo-controlled crossover design (n = 12), whether a single administration of testosterone would shift the motivational balance between the sensitivity for punishment and reward towards this tendency to choose disadvantageously was investigated. As hypothesized, subjects showed a more disadvantageous pattern of decision-making after testosterone compared to placebo administration. These findings not only provide the first direct evidence for the effects of testosterone on punishment-reward contingencies in humans, but they also give further insights into the hypothetical link between testosterone and psychopathy.

Correlations among Salivary Testosterone, Mood, and Selective Attention to Threat in Humans

An experiment was designed to investigate the relation among salivary testosterone, mood, and selective attention to threat. The participant group consisted of 32 nonclinical subjects (16 men and 16 women). Individuals completed the Profile Of Mood States (POMS) and performed a pictorial emotional Stroop task measuring selective attention to angry faces. Anticipating a time lag between testosterone (as measured in saliva) and cognitive emotional behavior, multiple time-coursed saliva samples were taken preceding the assessment of questionnaire and task for every subject. In both sexes, salivary testosterone was significantly related to mood (i.e., anger and tension) and selective attention to angry faces when saliva samples were taken 6 h before questionnaire and task assessment. Research on the relation between testosterone and human behavior might benefit by taking into account time lags between the behavioral manifestations and the continuously changing levels of testosterone.

Attentional biases for angry faces: Relationships to trait anger and anxiety

In two experiments selective attention to angry faces was investigated in relation to trait anger and anxiety. A pictorial emotional Stroop task comparing colour-naming latencies for neutral and angry faces was employed. In Experiment 1 using an unmasked task, individuals scoring high on trait anger showed an attentional bias for angry faces. In Experiment 2, unmasked and masked versions of the task were used. Individuals were selected on low and high trait anxiety, but there was no indication of a relation between attentional bias scores and anxiety. When individuals were subsequently reallocated to groups on the basis of trait anger scores, the high anger group showed an attentional bias for angry faces in the unmasked and the masked task. Results are discussed in relation to recent neurobiological findings from our laboratory, as reflecting an evolutionary-evolved, content-specific response to the facial expression of anger.

Does Carbohydrate-rich, Protein-poor Food Prevent a Deterioration of Mood and Cognitive Performance of Stress-prone Subjects when Subjected to a Stressful Task?

This study investigates whether in stress-prone subjects, carbohydrate-rich, protein-poor food (CR/PP) prevents a deterioration of mood and performance under uncontrollable laboratory stress conditions. The assumption was that in stress-prone subjects there is a higher risk of serotonin deficiency in the brain and that carbohydrates may prevent a functional shortage of central serotonin during acute stress, due to their potentiating effect on brain tryptophan. Twenty-four subjects with a high stress-proneness (HS) and 24 subjects with a low stress-proneness (LS) participated in an uncontrollable stress situation under both a CR/PP and a protein-rich, carbohydrate-poor (PR/CP) diet condition. The plasma ratio of tryptophan to the other large neutral amino acids (LNAA) (ratio Tryptophan/ summation operatorLNAA) was determined as a measure indicating the dietary effect on brain tryptophan and serotonin levels. Significant increases were found in the ratio tryptophan/ summation operatorLNAA during the CR/PP diet compared with the PR/CP diet. Experimental stress had significant effects on pulse rate, skin conductance, cortisol and mood in all subjects. During the CR/PP diet only the HS subjects did not show the stress-induced rise in depression, decline in vigour and cortisol elevation that they showed after the PR/CP diet. With respect to cognitive performance, significant dietary effects were found on reaction time. It is suggested that CR/PP food in HS subjects may increase personal control, probably under the influence of higher levels of brain tryptophan and serotonin.

A single administration of testosterone induces cardiac accelerative responses to angry faces in healthy young women.

Recently, it was demonstrated how individuals with high levels of testosterone selectively attend toward angry faces. It was argued that this suggests that high levels of testosterone are associated with an aggressive, dominating personality style. In this study, the authors used a double-blind, placebo-controlled design to examine whether exogenous testosterone would induce cardiac acceleration in response to angry faces. Participants (healthy young women) were exposed to neutral, happy, or angry faces. Administration of a single dosage of testosterone (0.5 mg) induced an accelerative cardiac response to angry faces. It is argued that this effect is due to the encouragement of dominance behavior and the inclination toward aggression. Possible mechanisms behind testosterone-driven changes in behavior are discussed with relevance to steroid-responsive networks in the limbic system that drive and control motivational and physiological aspects of social behavior.

Conscious and preconscious selective attention to social threat: different neuroendocrine response patterns

This study was designed to investigate the relationship between selective attention to social threat and neuroendocrine activity. Selective attention to social threat was measured using a supraliminal (unmasked) and a subliminal (masked) version of a pictorial emotional Stroop task, comparing color-naming latencies of neutral and angry faces. Neuroendocrine activity was assessed as (pre-task to post-task) increases in salivary cortisol and testosterone. Forty subjects were randomly assigned to the unmasked or masked version of the task. Analyses for the unmasked task revealed that post-task cortisol levels were significantly increased in subjects showing selective attention to angry faces. Results for the masked task indicated that post-task cortisol and testosterone levels were significantly increased in subjects showing preconscious selective attention to angry faces. The difference in neuroendocrine activity between tasks is suggested to depend on cortical (i.e. prefrontal) control in the unmasked task. Thus, psychological affective regulatory processes were involved in the unmasked task, whereas the neuroendocrine response patterns in the masked task indicates a biologically prepared mechanism.

Effects of testosterone administration on selective aspects of object-location memory in healthy young women

Previous work has indicated that object-location memory is sensitive to sex differences as well as variations in the menstrual cycle. The goal of the present study was to further examine the hormonal basis of human spatial memory by assessing the effects of a single dose of exogenous testosterone in healthy young women on three recall conditions: positional reconstruction; object-to-position-assignment; and the combined condition in which subjects both have to reconstruct the precise locations and to link the different objects to the correct places. In the latter condition, delayed recall (3 min delay) improved with testosterone. Although the effects were only small and need further substantiation, they support the idea that testosterone may have an activational effect on selective aspects of cognitive functioning.

BASELINE SALIVARY CORTISOL LEVELS AND PRECONSCIOUS SELECTIVE ATTENTION FOR THREAT: A Pilot Study

This study was conducted to examine the relationship between baseline salivary cortisol (CORT) levels and selective attention for displays of angry faces. Selective attention was investigated using a pictorial emotional Stroop task, comparing colournaming-speed of angry and neutral faces. The task was assessed in supraliminal (unmasked) and subliminal (masked) conditions to 28 non-clinical subjects (14 male and 14 female). Repeated measures analysis of variance revealed a significant interaction between median split CORT levels (low vs. high) and masked face valence (angry vs. neutral). The latter effect was mainly due to significant facilitation in the high CORT subject-group; these subjects seemed to allocate their attention away from the masked angry face. A relation between baseline CORT levels and fast withdrawal behavior is suggested.

Effects of food on cortisol and mood in vulnerable subjects under controllable and uncontrollable stress

The aim of this study was to investigate whether in stress-prone subjects, carbohydrate-rich, protein-poor food (CR/PP) diminished depressive mood and a cortisol response under controllable as well as uncontrollable laboratory stress. Twenty-two subjects with high stress proneness (HS) and 23 subjects with low stress proneness (LS) participated in a controllable- and uncontrollable-stress experiment during either a CR/PP or protein-rich, carbohydrate-poor (PR/CP) diet. Both controllable and uncontrollable laboratory stress significantly increased pulse rate and skin conductance in HS and LS subjects, whereas uncontrollable stress increased feelings of depression, anger, tension, and fatigue and decreased feelings of vigor. Only in HS subjects, a cortisol response and feelings of depression became lower under the CR/PP diet condition, irrespective of the controllability of the laboratory stressor, suggesting an increased ability to cope with stress. Because the CR/PP diet compared with the PR/CP diet previously has been found to cause a 42% increase in plasma tryptophan/SigmaLNAA, seen as an indirect measure of increases in brain serotonin levels, the present results suggest that an enhanced serotonin function in HS subjects may be involved.

Sex differences and menstrual cycle effects in human spatial memory

A typical test of spatial memory requires subjects to relocate a number of objects in their original, previously studied positions. It has been argued that this test includes multiple separate processing components (Postma, A., De Haan, E.H.F., 1996. Quarterly Journal of Experimental Psychology 48A (1), 178-199; Postma, A., Izendoorn, R., De Haan, E.H.F., 1998. Brain and Cognition 36, 334-345). One has to encode the precise positions occupied, assign the various objects to the correct (relative) locations, and achieve an integration of both types of spatial information. The present study examined the presence of sex differences and the role of hormonal factors for these selective components of spatial memory. A computerised, immediate (working) memory version of the test was used, comparing 23 males and 34 females on three experimental conditions: positions only, object-to-position-assignment, and the combined condition, requiring integration of the other two components. In line with previous research (Postma et al., 1998) males showed a selective advantage for fine-grained, metric positional reconstruction (i.e. positions-only). Interestingly, a within-subjects comparison in the females only revealed a menstrual cycle effect for exactly the same dimension of spatial memory. In the nonmenstrual phase, females were better than during menstruation. This clearly implies a role for sex hormones in spatial memory, even though a subsequent analysis of testosterone samples in saliva did not reveal a significant correlation with measures of spatial memory in both males and females.