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Biomedical subjects

Jack van Honk

Publications and source records attributed to Jack van Honk.

At least 37 records · Page 2Linked to original sources
PubMed2005

The cerebellum on the rise in human emotion.

For decennia the cerebellum has largely been excluded from scientific enquiry beyond motor function. However, the intimate afferent and efferent connections to the midbrain and limbic system provide for the neuroanatomical foundation of cerebellar involvement in emotion and emotional disorders. Moreover, an increasing body of empirical evidence indicates that the cerebellum may be involved in emotion regulation. Both functional and structural abnormalities of the cerebellum have been demonstrated in emotional disorders, including depression and schizophrenia. Research shows that the functional repertoire of the cerebellum is broader than previously thought and its involvement in emotion is noteworthy.

Adult↗
PubMed2005

Administration of testosterone increases functional connectivity in a cortico-cortical depression circuit.

Increasing evidence suggests that the steroid hormone testosterone (T) enhances libido and decreases depression. Even a single administration of T (0.5 mg sublingually) in healthy young women is sufficient to enhance physiological sexual responsiveness. Such physiological evidence is not yet available for the link between T and depression. Recent research has revealed that lowered functional connectivity in a specific cortico-cortical pathway may be a sensitive physiological index for depression. This pathway, comprised of the left prefrontal and right parietal cortex, has been named a cortical depression circuit. In the present study, a single dose of T was administered to healthy young women to investigate the effects on the functional connectivity in this cortico-cortical depression circuit. It was hypothesized that administration of T would lead to an increase of functional connectivity. In a double-blind placebo-controlled, crossover design, fourteen healthy females received (sublingually) a single dose of 0.5 mg T or placebo in a randomly assigned fashion. Three hours after drug administration the functional coupling between the left prefrontal and right parietal cortex was established by measuring the interhemispheric electroencephalogram (EEG) coherence for the different frequency bands. Compared to placebo, T administration significantly increased the functional connectivity in the sigma (1-3 Hz) frequency range between the left prefrontal and right parietal cortex. Reductions in interhemispheric coherence in the sigma frequency range have been observed in clinically depressed patients. Thus the present findings may provide a first insight into the neurobiological mechanism by which T decreases depression. The fact that only a single dose of T was able to induce the effect in healthy female subjects suggests that the mechanism is highly sensitive. A feasible application of T treatment in the struggle against depression is discussed.

Adult↗
PubMed2005

A framework for targeting alternative brain regions with repetitive transcranial magnetic stimulation in the treatment of depression.

It has been argued that clinical depression is accompanied by reductions in cortical excitability of the left prefrontal cortex (PFC). In support of this, repetitive transcranial magnetic stimulation (rTMS), which is a method of enhancing cortical excitability, has shown antidepressant efficacy when applied over the left PFC, although the overall therapeutic effects remain inconclusive. The cerebral pathophysiology of depression is, however, not limited to dysfunctions in the PFC, thus, targeting alternative brain regions with rTMS may provide new therapeutic windows in the treatment of depression. Evidence from electroencephalography and lesion studies suggests that not only is the left PFC involved in depression but also the parietal cortex and cerebellum. Furthermore, rTMS over the parietal cortex and the cerebellum has been found to improve mood and emotional functioning, at least in healthy volunteers. We have integrated these findings in an rTMS-oriented theoretical framework for the neurobiology of low mood and depression. To establish the possible therapeutic efficacy of this model, whereby, for example, the application of slow rTMS over the right parietal cortex and fast rTMS over the cerebellum may be beneficial in different subtypes of depression, clinical rTMS studies that target the parietal cortex and cerebellum are warranted.

Brain↗
PubMed2004

Extending the global workspace theory to emotion: phenomenality without access.

Recent accounts on the global workspace theory suggest that consciousness involves transient formations of functional connections in thalamo-cortico-cortical networks. The level of connectivity in these networks is argued to determine the state of consciousness. Emotions are suggested to play a role in shaping consciousness, but their involvement in the global workspace theory remains elusive. In the present study, the role of emotion in the neural workspace theory of consciousness was scrutinized by investigating, whether unconscious (masked) and conscious (unmasked) display of emotional compared to neutral facial expressions would differentially modulate EEG coherence. EEG coherence was measured by means of computing an average EEG coherence value between the frontal, parietal, and midline scalp sites. Objective awareness checks evidenced that conscious identification of the masked facial expressions was precluded. Analyses revealed reductions in EEG coherence in the lower frequency range for the masked as compared to unmasked neutral facial expressions. Crucially, a decline in EEG coherence was not observed for the emotional facial expressions. In other words, the level of EEG coherence did apparently vary as a function of awareness, but not when emotion was involved. The current finding suggests that EEG coherence is modulated by unconscious emotional processes, which extends common views on the global workspace architecture of consciousness.

Adult↗
PubMed2004

Functionally dissociated aspects in anterior and posterior electrocortical processing of facial threat.

The angry facial expression is an important socially threatening stimulus argued to have evolved to regulate social hierarchies. In the present study, event-related potentials (ERP) were used to investigate the involvement and temporal dynamics of the frontal and parietal regions in the processing of angry facial expressions. Angry, happy and neutral faces were shown to eighteen healthy right-handed volunteers in a passive viewing task. Stimulus-locked ERPs were recorded from the frontal and parietal scalp sites. The P200, N300 and early contingent negativity variation (eCNV) components of the electric brain potentials were investigated. Analyses revealed statistical significant reductions in P200 amplitudes for the angry facial expression on both frontal and parietal electrode sites. Furthermore, apart from being strongly associated with the anterior P200, the N300 showed to be more negative for the angry facial expression in the anterior regions also. Finally, the eCNV was more pronounced over the parietal sites for the angry facial expressions. The present study demonstrated specific electrocortical correlates underlying the processing of angry facial expressions in the anterior and posterior brain sectors. The P200 is argued to indicate valence tagging by a fast and early detection mechanism. The lowered N300 with an anterior distribution for the angry facial expressions indicates more elaborate evaluation of stimulus relevance. The fact that the P200 and the N300 are highly correlated suggests that they reflect different stages of the same anterior evaluation mechanism. The more pronounced posterior eCNV suggests sustained attention to socially threatening information.

Adult↗
PubMed2004

Anterior asymetrical alpha activity predicts Iowa gambling performance: distinctly but reversed.

Animal research indicates that the prefrontal cortex (PFC) plays a crucial role in decision making. In concordance, deficits in decision making have been observed in human patients with damage to the PFC. Contemporary accounts of decision making suggest that emotion guides the process of decision making by ways of providing for reward-punishment contingencies. A task capable of assessing the influence of reward and punishment on decision making is the Iowa gambling task. In this task decisions become motivated by inherent punishment and reward schedules. Insensitivity for punishment together with a strong reward dependency results in risk taking, which is in the gambling task the disadvantageous strategy. Interestingly, the processing of punishment and reward is argued to be lateralized over the right and left PFC, respectively. Here we investigated whether more relative left compared to right-sided frontal brain activity (left-sided dominance) quantified as reduced alpha (8-12 Hz) activity in the electroencephalogram (EEG) would lead to a more risky, disadvantageous pattern of decision making. Contrary to what was expected, relatively more right compared to left frontal brain activity was strongly associated with the disadvantageous strategy. The results are discussed in terms of recent theoretical accounts which argue that the functional interpretation of baseline frontal alpha activity depends on the mental operation involved and does not necessarily imply inactivity.

Adolescent↗
PubMed2004

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.

Administration, Sublingual↗
PubMed2004

Sex differences for selective forms of spatial memory.

In the present study, a systematic comparison of sex differences for several tests of spatial memory was conducted. Clear evidence for more accurate male performance was obtained for precise metric positional information in a wayfinding task and in an object location memory task. In contrast, no sex difference characterized topological information processing (object-to-position assignment). Together, these findings provide further insight in the specificity of sex differences in spatial memory and in the functional architecture of spatial memory. Implications for the relevant evolutionary basis are discussed.

Adult↗
PubMed2004

A single administration of testosterone improves visuospatial ability in young women.

Previous research has documented correlations between endogenous testosterone levels and visuospatial cognitive function. Some causal relations have also been established in treatment designs in which testosterone was administered to elderly subjects for a number of weeks. Particularly, one study reported a selective effect of a single administration of testosterone on some aspects of spatial memory in 15 women. The present study tested the hypothesis whether a single administration of 0.5 mg of sublingual testosterone would improve visuospatial ability in healthy young women on a test that has consistently been associated with male superiority. Twenty-six women participated in a double-blind placebo-controlled cross-over trial of single administration of testosterone and placebo. Subjects were tested in the same phase of the menstrual-cycle. Four to five hours after both administrations, subjects completed a standardized measure of visuospatial ability (3-D Mental Rotations Test). Visuospatial ability improved significantly after testosterone administration compared to placebo, after controlling for learning effects due to repeated testing. Testosterone is suggested to be causally related to visuospatial ability in young women.

Adult↗
PubMed2004

Emotional stroop performance for masked angry faces: it's BAS, not BIS.

Theoretical models concerning selective attention to emotional stimuli predict heightened vigilance to angry faces in people with heightened trait anxiety or greater activity of the Behavioral Inhibition System (BIS). Recent evidence from electroencephalographic lateralization and affect studies and from studies assessing attentional biases to angry faces suggest, however, that heightened anger and activity of the Behavioral Activation System (BAS) should predict vigilant responding to angry faces. Social anxiety should predict avoidance of angry faces. Results from a masked emotional Stroop task verified these hypotheses, but an unmasked emotional Stroop provided no reliable relations. This dissociation confirms earlier claims that masked emotional Stroop performance is impervious to conscious control over the cognitive-emotional processes, as measured by the Stroop task.

Affect↗
PubMed2003

Low cortisol levels and the balance between punishment sensitivity and reward dependency.

The neuro-endocrinological basis of psychopathy, a disorder characterized by lack of fear, is relatively unknown. However, low levels of cortisol may result in fearlessness and have been observed in individuals with psychopathic tendencies. Low fear models state that psychopaths are not motivated to avoid punishment, especially when reward is pending. In agreement, disadvantageous decision making on the IOWA gambling task in psychopaths and psychopathic analogous, indicates low punishment sensitivity and high reward dependency. Here, it was investigated whether low basal cortisol levels predicted the balance between punishment sensitivity and reward dependency in the same manner. As hypothesized, the most disadvantageous pattern of decision making was found in the subjects with the lowest cortisol levels. These findings suggest that low levels of cortisol may set the balance between the sensitivity for punishment and reward dependency towards a pre-disposition for psychopathy.

Adult↗
PubMed2003

Reductions in phenomenological, physiological and attentional indices of depressive mood after 2 Hz rTMS over the right parietal cortex in healthy human subjects.

Research into emotion and emotional disorders by repetitive transcranial magnetic stimulation (rTMS) has largely been restricted to the prefrontal regions. There is, however, also evidence for the parietal cortex being implicated in emotional (dys-)functioning. Here we used rTMS to investigate a role of the right parietal cortex in depression. In a placebo-controlled design, 2 Hz rTMS at 90% of the individual motor threshold (MT) was applied over the right parietal cortex of eight healthy subjects for 20 min continuously. Effects on mood, autonomic activity and motivated attention were investigated. Significant reductions in depressive mood were observed immediately following and 30 min after stimulation. Moreover, these findings were objectified by a concurring pattern of autonomically mediated changes in the attentional processing of angry facial expressions. These data suggest a role for the right parietal cortex in affective brain circuits regulating phenomenological, physiological and attentional aspects of depressive functioning.

Adult↗
PubMed2003

High frequency repetitive transcranial magnetic over the medial cerebellum induces a shift in the prefrontal electroencephalography gamma spectrum: a pilot study in humans.

In the present study the anatomical projections from the medial cerebellum to the prefrontal cortex (PFC) were investigated in healthy human subjects, using high frequency repetitive transcranial magnetic (rTMS) stimulation and electroencephalography (EEG). Medial cerebellar rTMS, compared to placebo induced a significant shift in anterior asymmetry, from left to right dominance in the fast (30-50 Hz) EEG spectrum, whereas occipital and lateral cerebellum stimulation did not show such an effect. Moreover elevations in mood and alertness were reported again after medial cerebellar stimulation only. Taken together, these data confirm and further specify the assumed cerebellar modulation of PFC activity and affect.

Adult↗
PubMed2003

Reductions in CI amplitude after repetitive transcranial magnetic stimulation (rTMS) over the striate cortex.

Slow repetitive transcranial magnetic stimulation (rTMS) is a method capable of transiently inhibiting cortical excitability and disrupting information processing in the visual system. This method can be used to topographically map the functional contribution of different cortical brain areas in visual processing. An early electrophysiological component, the CI is argued to reflect early visual processing. In addition, source-localization studies have provided evidence for the assumption that the striate cortex is the underlying neural generator of CI. In the present placebo-controlled, crossover study, slow rTMS was applied in order to further investigate the relationship between the striate cortex and the CI component. Based on the inhibitory effects of slow rTMS, a reduction in CI amplitude and an increase in latency were expected. Compared to placebo stimulation, slow rTMS over the striate cortex resulted in significant decreases of the CI amplitude, but did not affect latency. The present study provides causal evidence for the involvement of the striate cortex in generating the CI component.

Adolescent↗
PubMed2002

1 hz rTMS over the right prefrontal cortex reduces vigilant attention to unmasked but not to masked fearful faces.

BACKGROUND: Recent repetitive transcranial magnetic stimulation (rTMS) research in healthy subjects suggests that the emotions anger and anxiety are lateralized in the prefrontal cortex. Low-frequency rTMS over the right prefrontal cortex (PFC) shifts the anterior asymmetry in brain activation to the left hemisphere and reduces anxiety. The same rTMS technique results in enhanced anger-related emotional processing, observed as elevations in attention for angry faces. The current study used low-frequency rTMS over the right PFC and indexed selective attention to fearful faces, hypothesizing a reduction in attention for fearful faces, i.e., a reversal of the latter effect. METHODS: In a placebo-controlled design, 1 Hz rTMS at 130% of the individual motor threshold (MT) was applied continuously over the right PFC of eight healthy subjects for 20 minutes. Effects on motivated attention were investigated by means of an emotional Stroop task, indexing selective attention to masked and unmasked fearful faces. RESULTS: Vigilant attention for masked and unmasked fearful faces was observed after placebo stimulation. As hypothesized, rTMS reduced the vigilant emotional response to the fearful face, but only in the unmasked task. CONCLUSIONS: These data provide further support for the lateralization of the emotions anger and anxiety in the prefrontal cortex. In addition, the absence of an effect for masked fearful faces suggests that changes in emotional processing after a single session of rTMS predominantly involve the cortical affective pathways.

Adult↗
PubMed2002

Defective somatic markers in sub-clinical psychopathy.

Damasio's somatic marker hypothesis is argued to be specifically applicable to psychopathy, though evidence has been meager until now. The principal evidence for the somatic marker hypothesis is based on findings in patients with orbitofrontal lesions, showing absent punishment learning on the Iowa gambling task. Interestingly, neuroimaging studies indicate orbitofrontal dysfunction in psychopathy also. Here we investigated the somatic marker hypothesis in subjects selected on low and high psychopathic behavioral characteristics from the outer extreme ranges of a large subject pool (n = 525). The low psychopathic subject group (n = 16) showed intact punishment learning, suggesting somatic markers came to guide their decisions in the course of the game. In contrast, such punishment learning was not observed in the high psychopathic subject group (n = 16), who mimicked the gambling behavior of orbitofrontal patients. These findings provide further evidence for the hypothesized link between psychopathy and orbitofrontal dysfunction.

Adult↗