Derik Hermann

Gender differences in the processing of standardized emotional visual stimuli in humans: a functional magnetic resonance imaging study.

Pictures from the International Affective Picture System were used in a functional magnetic resonance imaging study to assess gender differences in brain activation in ten male and ten female volunteers. The affectively positive, negative and neutral pictures were presented for 750 ms in a single event design and were carefully matched for arousal, valence and stimulus content. Men and women showed no significant difference in valence, arousal, skin conductance response and startle modulation. Only in men was amygdala activation observed in the pleasant condition. Furthermore, men showed a stronger brain activity for positive visual stimuli than women in the frontal lobe (inferior and medial frontal gyrus). In women, stronger brain activation for affectively negative pictures was observed in the anterior and medial cingulate gyrus. These results indicate that it is crucial to take gender differences into account when emotional paradigms are used in functional brain imaging.

Correlation of Stable Elevations in Striatal μ-Opioid Receptor Availability in Detoxified Alcoholic Patients With Alcohol Craving: A Positron Emission Tomography Study Using Carbon 11–Labeled Carfentanil

Main Outcome Measures: After 1 to 3 weeks of abstinence, the availability of μ-opiate receptors in the ventral striatum, including the nucleus accumbens, was significantly elevated in alcoholic patients compared with healthy controls and remained elevated when 12 alcoholic patients had these levels measured 5 weeks later (P .05 corrected for multiple testing). Higher availability of μ-opiate receptors in this brain area correlated significantly with the intensity of alcohol craving as assessed by the OCDS.

Alcohol-associated stimuli activate the ventral striatum in abstinent alcoholics.

Summary. Alcohol-associated cues may act as conditioned stimuli that activate the brain reward system and motivate alcohol intake in alcoholics. Alcohol-associated visual stimuli were presented during functional magnetic resonance imaging. An activation of the ventral putamen was observed in alcoholics but not in control subjects. Patients with a strong activation of the ventral putamen relapsed during the next three months. This observation supports the hypothesis that alcohol use affects areas involved in brain reward circuits and that their stimulus-induced activation may be associated with an increased risk for relapse.

Initial, habitual and compulsive alcohol use is characterized by a shift of cue processing from ventral to dorsal striatum

AIMS During the development of drug addiction, initial hedonic effects decrease when substance use becomes habitual and ultimately compulsive. Animal research suggests that these changes are represented by a transition from prefrontal cortical control to subcortical striatal control and within the striatum from ventral to dorsal domains of the striatum, but only limited evidence exists in humans. In this study we address this hypothesis in the context of alcohol dependence. DESIGN, SETTING AND PARTICIPANTS Non-abstinent heavy social drinkers (n = 21, 5.0 ± 1.5 drinks/day, 13 of them were alcohol-dependent according to DSM-IV) and light social drinkers (n = 10, 0.4 ± 0.4 drinks/day) were examined. MEASUREMENTS We used a cue-reactivity functional magnetic resonance imaging (fMRI) design during which pictures of alcoholic beverages and neutral control stimuli were presented. FINDINGS In the dorsal striatum heavy drinkers showed significant higher activations compared to light drinkers, whereas light social drinkers showed higher cue-induced fMRI activations in the ventral striatum and in prefrontal areas compared to heavy social drinkers [region of interest analyses, P < 0.05 false discovery rate (FDR)-corrected]. Correspondingly, ventral striatal activation in heavy drinkers correlated negatively with obsessive-compulsive craving, and furthermore we found a positive association between cue-induced activation in the dorsal striatum and obsessive-compulsive craving in all participants. CONCLUSIONS In line with our hypothesis we found higher cue-induced activation of the ventral striatum in social compared to heavy drinkers, and higher dorsal striatal activation in heavy drinkers. Increased prefrontal activation may indicate that social drinkers activate cortical control when viewing alcohol cues, which may prevent the development of heavy drinking or alcohol dependence. Our results suggest differentiating treatment research depending on whether alcohol use is hedonic or compulsive.

Development of alcohol-associated cues and cue-induced brain activation in alcoholics

The objective of this study was to develop new standardized alcohol-associated cues and assess their effects on brain activation with functional magnetic resonance imaging (fMRI). Pictures of alcoholic and neutral beverages and affectively neutral pictures were presented to 44 abstinent alcoholics and 37 age-matched healthy control subjects. We assessed the skin conductance response, and the elicited arousal and valence. Alcoholics and control subjects did not differ in arousal, valence or skin conductance response evoked by alcohol-associated and affectively neutral stimuli, while nonalcoholic beverages were rated as more unpleasant and arousing by alcoholics compared with control subjects. In the fMRI pilot study, alcohol and abstract pictures were presented to six abstinent alcoholics and induced a significant activation of brain areas associated with visual emotional processes such as the fusiform gyrus, parts of the brain reward system (basal ganglia and orbitofrontal gyrus) and further brain regions in the frontal and parietal cortices associated with the attention network. These observations suggest that standardized pictures of alcoholic beverages can be used to assess brain circuits involved in the processing and evaluation of alcohol cues.

Dorsolateral Prefrontal Cortex N-Acetylaspartate/Total Creatine (NAA/tCr) Loss in Male Recreational Cannabis Users

BACKGROUND Cannabinoids present neurotoxic and neuroprotective properties in in vitro studies, inconsistent alterations in human neuroimaging studies, neuropsychological deficits, and an increased risk for psychotic episodes. METHODS Proton magnetic resonance spectroscopy ((1)H-MRS), neuropsychological testing, and hair analysis for cannabinoids was performed in 13 male nontreatment-seeking recreational cannabis users and 13 male control subjects. RESULTS A significantly diminished N-acetylaspartate/total creatine (NAA/tCr) ratio in the dorsolateral prefrontal cortex (DLPFC) was observed in cannabis users (p = .0003). The NAA/tCr in the putamen/globus pallidum region correlated significantly with cannabidiol (R(2) = .66, p = .004). Results of the Wisconsin Card Sorting test, Trail making Test, and D2 test for attention were influenced by cannabinoids. CONCLUSIONS Chronic recreational cannabis use is associated with an indication of diminished neuronal and axonal integrity in the DLPFC in this study. As chronic cannabis use is a risk factor for psychosis, these results are interesting because diminished NAA/tCr ratios in the DLPFC and neuropsychological deficits were also reported in schizophrenia. The strong positive correlation of NAA/tCr and cannabidiol in the putamen/globus pallidum is in line with neuroprotective properties of cannabidiol, which were also observed in in vitro model studies of Parkinsons disease.

Translational magnetic resonance spectroscopy reveals excessive central glutamate levels during alcohol withdrawal in humans and rats.

BACKGROUND In alcoholism, excessive glutamatergic neurotransmission has long been implicated in the acute withdrawal syndrome and as a key signal for dependence-related neuroplasticity. Our understanding of this pathophysiological mechanism originates largely from animal studies, but human data are needed for translation into successful medication development. METHODS We measured brain glutamate levels during detoxification in alcohol-dependent patients (n = 47) and in healthy control subjects (n = 57) as well as in a rat model of alcoholism by state-of-the-art ¹H-magnetic magnetic resonance spectroscopy at 3 and 9.4 T, respectively. RESULTS We found significantly increased glutamate levels during acute alcohol withdrawal in corresponding prefrontocortical regions of treatment-seeking alcoholic patients and alcohol-dependent rats versus respective control subjects. The augmented spectroscopic glutamate signal is likely related to increased glutamatergic neurotransmission because, enabled by the high field strength of the animal scanner, we detected a profoundly elevated glutamate/glutamine ratio in alcohol-dependent rats during acute withdrawal. All dependence-induced metabolic alterations normalize within a few weeks of abstinence in both humans and rats. CONCLUSIONS Our data provide first-time direct support from humans for the glutamate hypothesis of alcoholism, demonstrate the comparability of human and animal magnetic resonance spectroscopy responses, and identify the glutamate/glutamine ratio as potential biomarker for monitoring disease progression.

Effects of Cue-Exposure Treatment on Neural Cue Reactivity in Alcohol Dependence: A Randomized Trial

BACKGROUND In alcohol-dependent patients, alcohol-associated cues elicit brain activation in mesocorticolimbic networks involved in relapse mechanisms. Cue-exposure based extinction training (CET) has been shown to be efficacious in the treatment of alcoholism; however, it has remained unexplored whether CET mediates its therapeutic effects via changes of activity in mesolimbic networks in response to alcohol cues. In this study, we assessed CET treatment effects on cue-induced responses using functional magnetic resonance imaging (fMRI). METHODS In a randomized controlled trial, abstinent alcohol-dependent patients were randomly assigned to a CET group (n = 15) or a control group (n = 15). All patients underwent an extended detoxification treatment comprising medically supervised detoxification, health education, and supportive therapy. The CET patients additionally received nine CET sessions over 3 weeks, exposing the patient to his/her preferred alcoholic beverage. Cue-induced fMRI activation to alcohol cues was measured at pretreatment and posttreatment. RESULTS Compared with pretreatment, fMRI cue-reactivity reduction was greater in the CET relative to the control group, especially in the anterior cingulate gyrus and the insula, as well as limbic and frontal regions. Before treatment, increased cue-induced fMRI activation was found in limbic and reward-related brain regions and in visual areas. After treatment, the CET group showed less activation than the control group in the left ventral striatum. CONCLUSIONS The study provides first evidence that an exposure-based psychotherapeutic intervention in the treatment of alcoholism impacts on brain areas relevant for addiction memory and attentional focus to alcohol-associated cues and affects mesocorticolimbic reward pathways suggested to be pathophysiologically involved in addiction.

Diminished gray matter in the hippocampus of cannabis users: possible protective effects of cannabidiol.

BACKGROUND Chronic cannabis use has been associated with memory deficits and a volume reduction of the hippocampus, but none of the studies accounted for different effects of tetrahydrocannabinol (THC) and cannabidiol (CBD). METHODS Using a voxel based morphometry approach optimized for small subcortical structures (DARTEL) gray matter (GM) concentration and volume of the hippocampus were measured in 11 chronic recreational cannabis users and 13 healthy controls, and correlated with THC and CBD from hair analyses. GM volume was calculated by modulating VBM using Jacobian determinants derived from the spatial normalization. RESULTS Cannabis users showed lower GM volume located in a cluster of the right anterior hippocampus (P(uncorr)=0.002; effect size Cohens d=1.34). In a regression analysis an inverse correlation of the ratio THC/CBD with the volume of the right hippocampus (P(uncorr) p<0.001, Cohens d=3.43) was observed. Furthermore Cannabidiol correlated positively with GM concentration (unmodulated VBM data), but not with GM volume (modulated VBM) in the bilateral hippocampus (P=0.03 after correction for hippocampal volume; left hippocampus Cohens d=4.37 and right hippocampus 4.65). CONCLUSIONS Lower volume in the right hippocampus in chronic cannabis users was corroborated. Higher THC and lower CBD was associated with this volume reduction indicating neurotoxic effects of THC and neuroprotective effects of CBD. This confirms existing preclinical and clinical results. As a possible mechanism the influence of cannabinoids on hippocampal neurogenesis is suggested.

Effects of acute psychological stress on adhesion molecules, interleukins and sex hormones: implications for coronary heart disease.

Abstract Rationale. Subjects with high levels of daily stress suffer from an increased risk of coronary heart disease. Increased concentrations of the intercellular adhesion molecule-1 (ICAM-1) contribute to atherosclerosis. Cell adhesion molecules may be activated by psychological stress exposure, depending on their interaction with the interleukin network, sex hormones and cortisol secretion. Objectives. To assess effects of acute psychological stress on the interaction between cell adhesion molecules, interleukins, sex hormones and cortisol in healthy male subjects. Methods. Cell adhesion molecules, interleukin-1 beta (IL-1β), IL-2, IL-6, sex hormones and cortisol levels of 18 healthy male physicians were measured before and after an academic oral presentation and on a control day. Results. The oral presentation was perceived as a stressful event and was accompanied by a significant increase in cortisol secretion in all volunteers. Soluble ICAM-1 and IL-1β also increased in all subjects after psychological stress exposure. The stress-associated increase in IL-2 concentrations approached statistical significance and correlated negatively with luteinizing hormone plasma levels. Estradiol concentrations correlated positively with IL-6 levels. Conclusions. Subjective ratings and the increase in cortisol plasma concentrations support the validity of the chosen stress model. Acute stress exposure was followed by an increase in IL-1β, IL-2 and soluble ICAM-1 plasma concentrations, which can contribute to coronary heart disease and immunological disorders.