Anxiety and cerebral cortical metabolism in normal persons

Health-Related Quality of Life: Longitudinal Analysis From the Time of Breast Biopsy Into the Post-treatment Period

Background: The physical, psychological, social, and spiritual quality of life (QoL) may be affected by breast cancer diagnosis and treatment, with mixed findings for psychological quality of life and cognitive ability performance. The present study aimed to evaluate QoL in women over 1 year from biopsy for a breast abnormality. Methods: Self-reported measures of physical, psychological, social, and spiritual QoL were obtained after biopsy results but prior to treatment initiation (baseline), 4 and 12 months later. CogState computerized neuropsychological screening battery also provided an evaluation of psychological QoL. Three groups of women including those with benign biopsy results, those with malignancy treated with chemotherapy, and those with malignancy not treated with chemotherapy were compared at 4 and 12 months after adjusting for baseline to isolate the effects of treatment. Additional covariates included are age, level of education, and income. Results: Benign biopsy results group included 72 women, whereas malignancy was found in 87 women of whom 33 were treated with chemotherapy and 54 without chemotherapy. At the time of diagnosis, women with cancer had worse psychological and social QoL but better spiritual QoL than those with benign biopsy results. Only CogState monitoring accuracy was worse for women with cancer compared with the controls at the time of biopsy results. After adjusting for QoL at baseline, women treated for cancer had worse physical and social QoL at 4 and 12 months later. Psychological well-being was worse for women with cancer at 4th month but improved at 1 year. No differences in cognition were found at 4 and 12 months when adjusted for baseline cognition and covariates. Discussion: Breast cancer is a traumatic life event for women, affecting psychological and social QoL domains, yet increasing spiritual QoL. Later, cancer treatment worsens physical, psychological, and social QoL compared with those without cancer. Conclusions: These findings suggest that interventions to improve psychological QoL may be especially important at the time of cancer diagnosis, while interventions to improve physical well-being are the most needed during and following cancer treatment. Support to improve social QoL is needed from the time of diagnosis into post-treatment survivorship.

Neural basis of anxiolytic effects of cannabidiol (CBD) in generalized social anxiety disorder: a preliminary report

Animal and human studies indicate that cannabidiol (CBD), a major constituent of cannabis, has anxiolytic properties. However, no study to date has investigated the effects of this compound on human pathological anxiety and its underlying brain mechanisms. The aim of the present study was to investigate this in patients with generalized social anxiety disorder (SAD) using functional neuroimaging. Regional cerebral blood flow (rCBF) at rest was measured twice using (99m)Tc-ECD SPECT in 10 treatment-naïve patients with SAD. In the first session, subjects were given an oral dose of CBD (400 mg) or placebo, in a double-blind procedure. In the second session, the same procedure was performed using the drug that had not been administered in the previous session. Within-subject between-condition rCBF comparisons were performed using statistical parametric mapping. Relative to placebo, CBD was associated with significantly decreased subjective anxiety (p < 0.001), reduced ECD uptake in the left parahippocampal gyrus, hippocampus, and inferior temporal gyrus (p < 0.001, uncorrected), and increased ECD uptake in the right posterior cingulate gyrus (p < 0.001, uncorrected). These results suggest that CBD reduces anxiety in SAD and that this is related to its effects on activity in limbic and paralimbic brain areas.

Normoglycemic plasma glucose levels affect F-18 FDG uptake in the brain

OBJECTIVE

The aim of this study was to investigate whether normoglycemic glucose concentrations interfere with cerebral F-18 FDG uptake.

METHODS

The analysis was based on 2 sets of paired PET scans in 94 patients who were in complete metabolic remission after the successful completion of treatment for lymphoma. For these 188 PET scans, 2 subgroups were defined according to the plasma glucose level at the time of scanning. Group 1 contained the PET images that were associated with the lower of both normoglycemic plasma glucose levels, whereas group 2 contained the PET images that were associated with the higher of both plasma glucose levels. SUVs (standard uptake values) in the cerebellum between both groups were compared using paired sample T test. Subsequently, SUVs were normalized to a standard glucose concentration and normalized SUVs were again compared. Further, we calculated the coefficient of variation of SUVs in group 1 and 2 both before and after the normalization step.

RESULTS

Mean plasma glucose level was 86 mg/dL (SD of 9 mg/dL) in group 1 and 97 mg/dL (SD of 10 mg/dL) in group 2. Mean SUV was 3.8 (SD of 1.1) for group 1 and 3.5 (SD of 1.1) for group 2. Mean SUV in group 1 was slightly but statistically significantly higher than the mean SUV in group 2 (p < 0.01). Mean normalized SUV was 3.6 (SD of 1.1) in group 1 and 3.7 (SD of 1.3) in group 2. A paired comparison between normalized SUVs in both groups indicated that there was no statistically significant difference (p < 0.31). The coefficient of variation for the SUVs in group 1 and 2 before normalization was 29 and 30%, respectively. The coefficient of variation for the normalized SUVs in group 1 and 2 was 30 and 34%, respectively.

CONCLUSIONS

Our results indicated that plasma glucose levels that are within the normoglycemic range have a small but systematic effect on F-18 FDG uptake in the brain (following an inverse relationship). Normalizing plasma glucose levels to a standard glucose concentration successfully reduced the intra-subject variability of SUV measures. Inter-subject variability, however, remained high suggesting that other factors have an influence as well.

Anxiety, respiration, and cerebral blood flow: implications for functional brain imaging

Brain functional imaging methods, such as fMRI, are sensitive to changes in cerebral blood flow (CBF) that are normally associated with changes in regional neural activation. However, other endogenous and exogenous factors can alter CBF independently of brain neural activity, thus complicating the interpretation of functional imaging data. The presence of an anxiety disorder, as well as change in state anxiety, is often accompanied by respiratory alterations that affect arterial CO(2) tensions and produce significant changes in CBF that are independent of task-related neural activation. Therefore, the effects of trait and state anxiety need to be given close consideration in interpreting functional imaging findings. In this paper, we review the dependence of most brain functional imaging methods on localized changes in CBF and the potentially confounding effects of anxiety-related alterations of respiration on interpreting patterns of functional activation. Approaches for addressing these effects are discussed.

The worried mind: autonomic and prefrontal activation during worrying

To study the psychophysiological correlates of worrying, the authors recorded heart rate, respiratory sinus arrhythmia (RSA), skin conductance level, and alpha electroencephalographic asymmetry in healthy males during baseline, relaxation, worry induction, and anticipation of an impromptu speech task. Compared with baseline, relaxation, and anticipation, worrying was associated with greater heart rate and lower RSA. Worrying was further characterized by higher skin conductance levels compared with baseline but lower levels than during anticipation. Finally, worrying was associated with relatively greater left frontal activity compared with anticipation. Trait public speaking anxiety was positively correlated with left frontal activity during worrying. These results support the notion that worrying is a unique emotional state that is different from fearful anticipation.

Effects of cannabidiol (CBD) on regional cerebral blood flow

Animal and human studies have suggested that cannabidiol (CBD) may possess anxiolytic properties, but how these effects are mediated centrally is unknown. The aim of the present study was to investigate this using functional neuroimaging. Regional cerebral blood flow (rCBF) was measured at rest using (99m)Tc-ECD SPECT in 10 healthy male volunteers, randomly divided into two groups of five subjects. Each subject was studied on two occasions, 1 week apart. In the first session, subjects were given an oral dose of CBD (400 mg) or placebo, in a double-blind procedure. SPECT images were acquired 90 min after drug ingestion. The Visual Analogue Mood Scale was applied to assess subjective states. In the second session, the same procedure was performed using the drug that had not been administered in the previous session. Within-subject between-condition rCBF comparisons were performed using statistical parametric mapping (SPM). CBD significantly decreased subjective anxiety and increased mental sedation, while placebo did not induce significant changes. Assessment of brain regions where anxiolytic effects of CBD were predicted a priori revealed two voxel clusters of significantly decreased ECD uptake in the CBD relative to the placebo condition (p<0.001, uncorrected for multiple comparisons). These included a medial temporal cluster encompassing the left amygdala-hippocampal complex, extending into the hypothalamus, and a second cluster in the left posterior cingulate gyrus. There was also a cluster of greater activity with CBD than placebo in the left parahippocampal gyrus (p<0.001). These results suggest that CBD has anxiolytic properties, and that these effects are mediated by an action on limbic and paralimbic brain areas.

Mood state and cerebral metabolism in persons with age-associated memory impairment

People undergoing medical procedures sometimes experience feelings that may influence the results. In this study, we explore the relationship between changes in mood state self-ratings and cerebral glucose metabolism during positron emission tomography (PET) in persons with age-associated memory impairment (mean age 59.4 +/- 9.8 years). Brain regions of interest involved in both mood and memory were examined. Mood ratings of increased boredom correlated significantly with mesial temporal and parietal asymmetry and decreased parietal metabolism. Mood ratings of increased fatigue correlated with basal ganglia asymmetry and the right basal ganglia and left mesial temporal metabolism. These findings suggest that subjective mood state changes during PET may influence metabolism in brain regions implicated in emotion and memory function in people with age-related memory complaints.

Cerebral glucose utilization is reduced in second test session

Cerebral glucose utilization was higher during the first positron emission tomography (PET) session than during the second session, as assayed using the PET [18F]fluorodeoxyglucose method in male human volunteers. This difference was due largely to data from subjects with low-trait anxiety, since subjects with high anxiety showed similar metabolism in both PET sessions. High-anxiety subjects showed greater right/ left ratios of cerebral metabolism than low-anxiety subjects, particularly during the second PET session. These findings suggest that the level of anxiety may be an important variable to consider in PET studies using multiple sessions.

Cerebral vasodilation and vasoconstriction associated with acute anxiety

A randomized, between-groups, repeated measures design was used to evaluate changes in cerebral blood flow (CBF), rating scales, and physiologic indices under resting conditions, during 5% CO2 inhalation in combination with epinephrine or saline infusions, in generalized anxiety disorder patients and controls. Subjects were divided into those with decreased anxiety and mild and more severe anxiety increase. The first group was found to have most pronounced CBF increase during CO2 inhalation, with the second group showing less marked increase, and the last group the least increase. In animals, sympathetic activation limits hypercapnic cerebral vasodilation. Thus, the restricted hypercapnic cerebral vasodilation during severe anxiety may be mediated through cervical sympathetic fibers, which innervate cerebral vessels.

Activation PET scanning in pretreatment evaluation of patients with cerebral tumours or vascular lesions in or close to the sensorimotor cortex

Treatment of tumours and vascular lesions in or close to eloquent cortex may inflict neurological deficits. Intra-operative mapping procedures have been used for many decades in efforts to minimize neurological sequelae. The possibility for non-invasive pre-operative brain mapping has emerged with the advent of positron emission tomography (PET). In this paper we report on 11 patients with a tumour or vascular lesion in or close to the sensorimotor (10 patients) or visual cortex (one patient). The patients were subjected to activation PET scanning by means of vibrotactile or visual stimulation. The results show that in most of the patients the important relation between the lesion and the sensorimotor cortex could be determined. The patient with a lesion in the occipital lobe had involvement of the entire visual cortex as judged by comparison with activated areas on the nonlesion side.

Mood effects on limbic blood flow correlate with emotional self-rating: a PET study with oxygen-15 labeled water

Positron emission tomography was used to study the effects of experimentally controlled mood states on cerebral blood flow (CBF), measured with the quantitative equilibrium infusion method and 15O-labeled water. Twenty-seven brain regions in each hemisphere were assessed in 16 normal subjects. CBF and heart rate were measured during happy and sad mood induction, and during two nonemotional control conditions: sex differentiation and resting baseline. Valence-specific effects of mood on CBF were obtained for subcortical, but not for frontal-temporal or control regions. CBF increased in left amygdala and decreased in right amygdala during sad mood relative to the averaged control conditions. These changes correlated with shifts toward negative affect. Correlations were opposite for subcortical (negative affect associated with lower left hemispheric CBF) compared with frontal-temporal cortical regions. Results support limbic involvement in regulating emotional states and suggest some reciprocity between subcortical and frontal-temporal regulation of emotional experience.

Differential effects of mood on cortical cerebral blood flow: a 133xenon clearance study

Studies of healthy and clinical populations have suggested valence-specific cortical and subcortical neural systems regulating emotions. In a study of 12 normal volunteers, the 133xenon clearance method for measuring regional cerebral blood flow (CBF) was used to study the effects of experimentally controlled mood states on regional brain activity within superficial cortex. CBF was measured with 254 detectors and bolus infusion during a happy mood induction task, a sad mood induction task, a sex differentiation task, and a resting baseline condition. CBF increased during sad and decreased during happy mood induction, relative to the activated (sex differentiation) and the nonactivated (resting) nonemotional control conditions. Increased CBF during sad mood induction was correlated with greater negative mood changes. Conversely, increased CBF was associated with a stronger subjective experience of positive affect during happy mood induction. This suggests that cortical arousal may serve to intensify the conscious experience of emotion. Heart rate accelerated during happy and sad mood induction and during sex differentiation relative to a pretask baseline condition. Some regional specificity of effects was also observed. The occipital temporal region showed higher overall CBF during sad mood induction than during happy mood induction. The only region that showed specific lateralized changes in CBF which differentiated sad from happy states was the frontal pole, with left CBF being higher during sad and lower during happy mood induction relative to right CBF. For sad mood induction, there were significant regional differences among correlations between CBF and self-ratings. These were attributable to higher negative correlations (i.e., higher CBF correlates with negative self-rating) in midtemporal, occipital temporal, and postcentral regions. These correlations did not vary across the 15 regions for happy mood induction. For sad mood induction, heart rate correlated positively with CBF increase and with negative affect. Correlations were opposite for happy mood induction. The results suggest high cortical and autonomic arousal during negative/sad mood and low cortical and high autonomic arousal during positive/happy mood. They underscore the value of integrating emotional experience with physiologic measures in neuroimaging activation studies.

Abnormal regional CBF response in left hemisphere of dysphasic children during a language task

This study used xenon 133 inhalation and single-photon computed tomography to measure regional cerebral blood flow during a quiet resting condition, a simple auditory task, and an auditory phonemic discrimination task in 3 age-matched groups of children suffering from developmental language disabilities: expressive dysphasia, expressive-receptive dysphasia, and attention-deficit hyperactivity disorder. An absence of left hemisphere activation was observed in the expressive-receptive group during the phonemic discrimination task as compared to both expressive and attention-deficit hyperactivity disorder children, together with an absence of left inferior parietal region activation in dysphasics as compared to hyperactive children. These results favor the hypothesis of an abnormal lateralization for language in dysphasic children and point toward possible different pathologic localizations in the different clinical subtypes of dysphasia.

Anxiety, emotion and cerebral blood flow

Regional cerebral blood flow was measured by the xenon inhalation technique using a DSPECT system, during neutral and emotional auditory stimulations. Subjects were 10 high and 10 low trait anxiety, right-handed females. State anxiety was retrospectively assessed. Results indicated a lower rCBF in the high trait or state anxiety subjects who presented also a global rCBF asymmetry in the right > left direction. Additionally, the emotional content of the stimuli interacted significantly with the side of the brain in the thalamic area.

Different mental imagery abilities result in different regional cerebral blood flow activation patterns during cognitive tasks

Using regional cerebral blood flow (rCBF) imaging, two populations having high and low imagery abilities were compared at rest and while performing two cognitive tasks: silent verb conjugation and mental imagery. The imagery task produced an rCBF increase in the left visual association and left frontal cortices in both groups. Differences between high and low imagers were observed on global and regional flow responses to cognitive tasks: low imagers showed a whole cortex CBF increase during both tasks; high imagers showed a right dominance in the visual association cortex in all conditions, and in the parietal association cortex at rest.

Glucose metabolism in psychiatric disorders: how can we facilitate comparisons among studies?

Positron emission tomography (PET) offers a possibility to study brain function and its relationship to psychiatric disorders. Clinical studies have demonstrated that several psychiatric diseases are coupled with changes in brain glucose metabolism. Schizophrenia seems to involve a lower metabolism in wide areas of the brain--both cortical and subcortical structures. Depression probably involves dysfunction of the metabolism in dorsolateral prefrontal cortex. Obsessive compulsive disorder, panic disorder, anorexia nervosa and the experience of anxiety may involve increased metabolic rates. The results from the different studies do not allow quantitative comparisons or detailed analyses because of large differences in experimental and clinical methodology. The term Good Clinical PET Practice (GCPP) is suggested to encourage standardization in clinical investigations. GCPP includes standardization of both experimental factors (lumped constant, arterialization, purity of tracer, regions of interest, relative rates) and clinical factors (state of the subject, wakefulness, anxiety, gender, course of the disease) in PET performance.

Regional brain glucose metabolism: correlations to biochemical measures and anxiety in patients with schizophrenia

Regional brain glucose metabolism in 20 patients with schizophrenia (DSM-III) was investigated by positron emission tomography (PET) with uniformly labeled 11C-glucose as the tracer. Monoamine metabolites were analyzed in cerebrospinal fluid (CSF) and serum, and prolactin was analyzed in serum. Intensity of anxiety was rated directly after the PET study. Ten healthy volunteers served as controls. In the patients, weak positive and negative relationships were found between homovanillic acid in CSF and prolactin in serum, respectively, and regional metabolic rates. In all subjects, positive correlations were found between the level of anxiety and the regional glucose metabolism. In the controls, positive correlations were found between anxiety and the frontal/parietal ratios of the left hemisphere, whereas anxiety scores of the patients correlated negatively to relative metabolic rates of the right medial frontal cortex and the left thalamus. These observations may indicate alterations in the neuronal systems participating in the initiation of anxiety and arousal in schizophrenia.

Anxiety levels in dreams: relation to localized cerebral glucose metabolic rate

Ten normal male subjects were injected with D-[18F]deoxyglucose during REM sleep, and 32-45 min later they were aroused and reported their dreams as well as free associations to these dreams. Nonparametric correlations between the anxiety scores derived from the typescripts of these verbal reports by the Gottschalk-Gleser content analysis method and localized cerebral glucose metabolic rates obtained from PET scans revealed significant positive correlations in lateral parietal and medial frontal cortex and negative correlations in adjacent white matter.