The effect of anxiety and hostility in silent mentation on localized cerebral glucose metabolism

Frontal lobe regulation of blood glucose levels: support for the limited capacity model in hostile violence-prone men

Hostile men have reliably displayed an exaggerated sympathetic stress response across multiple experimental settings, with cardiovascular reactivity for blood pressure and heart rate concurrent with lateralized right frontal lobe stress (Trajanoski et al., in Diabetes Care 19(12):1412-1415, 1996; see Heilman et al., in J Neurol Neurosurg Psychiatry 38(1):69-72, 1975). The current experiment examined frontal lobe regulatory control of glucose in high and low hostile men with concurrent left frontal lobe (Control Oral Word Association Test [verbal]) or right frontal lobe (Ruff Figural Fluency Test [nonverbal]) stress. A significant interaction was found for Group × Condition, F (1,22) = 4.16, p ≤ .05 with glucose levels (mg/dl) of high hostile men significantly elevated as a function of the right frontal stressor (M = 101.37, SD = 13.75) when compared to the verbal stressor (M = 95.79, SD = 11.20). Glucose levels in the low hostile group remained stable for both types of stress. High hostile men made significantly more errors on the right frontal but not the left frontal stressor (M = 17.18, SD = 19.88) when compared to the low hostile men (M = 5.81, SD = 4.33). These findings support our existing frontal capacity model of hostility (Iribarren et al., in J Am Med Assoc 17(19):2546-2551, 2000; McCrimmon et al., in Physiol Behav 67(1):35-39, 1999; Brunner et al., in Diabetes Care 21(4):585-590, 1998), extending the role of the right frontal lobe to regulatory control over glucose mobilization.

Quantification of Tc-99m-ethyl cysteinate dimer brain single photon emission computed tomography images using statistical probabilistic brain atlas in depressive end-stage renal disease patients: Correlation with disease severity and symptom factors

This study adapted a statistical probabilistic anatomical map of the brain for single photon emission computed tomography images of depressive end-stage renal disease patients. This research aimed to investigate the relationship between symptom clusters, disease severity, and cerebral blood flow. Twenty-seven patients (16 males, 11 females) with stages 4 and 5 end-stage renal disease were enrolled, along with 25 healthy controls. All patients underwent depressive mood assessment and brain single photon emission computed tomography. The statistical probabilistic anatomical map images were used to calculate the brain single photon emission computed tomography counts. Asymmetric index was acquired and Pearson correlation analysis was performed to analyze the correlation between symptom factors, severity, and regional cerebral blood flow. The depression factors of the Hamilton Depression Rating Scale showed a negative correlation with cerebral blood flow in the left amygdale. The insomnia factor showed negative correlations with cerebral blood flow in the left amygdala, right superior frontal gyrus, right middle frontal gyrus, and left middle frontal gyrus. The anxiety factor showed a positive correlation with cerebral glucose metabolism in the cerebellar vermis and a negative correlation with cerebral glucose metabolism in the left globus pallidus, right inferior frontal gyrus, both temporal poles, and left parahippocampus. The overall depression severity (total scores of Hamilton Depression Rating Scale) was negatively correlated with the statistical probabilistic anatomical map results in the left amygdala and right inferior frontal gyrus. In conclusion, our results demonstrated that the disease severity and extent of cerebral blood flow quantified by a probabilistic brain atlas was related to various brain areas in terms of the overall severity and symptom factors in end-stage renal disease patients.

Cerebral glucose metabolism abnormalities in patients with major depressive symptoms in pre-dialytic chronic kidney disease: statistical parametric mapping analysis of F-18-FDG PET, a preliminary study

AIMS

The aim of the present study was to investigate the relationship between depressive symptoms and cerebral glucose metabolism in pre-dialytic chronic kidney disease (PDCKD) patients.

METHODS

Twenty-one patients with stage 5 CKD and 21 healthy volunteers underwent depressive mood assessment and statistical parametric mapping (SPM) using F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET).

RESULTS

Several voxel clusters of significantly decreased cerebral glucose metabolism were found in PDCKD patients. The largest cluster was left prefrontal cortex (Brodmann area [BA] 9). The second largest cluster was also left prefrontal cortex (BA 9). The third largest clusters were right prefrontal cortex (BA 10) and right basolateral prefrontal cortex (BA 46). Other brain areas also showed decreased cerebral glucose metabolism including left anterior cingulate gyrus (BA 32), left premotor cortex (BA 6), left transverse temporal gyrus (BA 41), left superior temporal gyrus (BA 42), right basolateral prefrontal cortex (BA 44), right inferior parietal lobule (BA 39), left middle temporal gyrus (BA 19), and left angular gyrus (BA 39). Hypermetabolized brain areas, however, were not found in PDCKD patients compared to normal controls. For the right orbitofrontal cortex there was a negative correlation of cerebral glucose metabolism with Hamilton Depression Rating Scale (HDRS) in PDCKD patients (BA 11).

CONCLUSION

PDCKD patients with depressive symptoms had decreased cerebral glucose metabolism in several brain areas. For the right orbitofrontal cortex there was a negative correlation with HDRS in PDCKD patients. The present findings provide functional neuroimaging support for abnormal cerebral glucose metabolism in PDCKD patients with depressive symptoms.

Differential effects of infralimbic vs. ventromedial orbital PFC lidocaine infusions in CD-1 mice on defensive responding in the mouse defense test battery and rat exposure test

The ventromedial prefrontal cortex (vmPFC) is extremely sensitive to a variety of stressful situations and threatening events, and has been suggested to be an associative cortical brain system processing the integration of anxiety-related cognitive, affective and motivated behavior in rodents, primates and humans. In addition, recent evidence suggests that (a) anxiety-related affective processing appears to be lateralized to the right hemisphere vmPFC; and (b) there appears to be functional heterogeneity within the rodent vmPFC. The present study evaluated the possibility that distinct sub-areas of the right hemisphere ventral PFC might differentially influence anxiety-like defensive responding in two different predator stress situations following transient inactivation of the ventromedial orbital (vMO) or infralimbic (IL) vmPFC in CD-1 mice. In week 1, IL vmPFC lidocaine infusions reduced anxiety-like defensive responding in mice (enhanced approach and contact) confronted with a hand-held anesthetized rat stimulus in the mouse defense test battery (vMO inactivation exerted minimal effects). In week 2, vMO lidocaine infusions enhanced anxiety-like defensive responding (enhanced avoidance and protected risk assessment) toward a barricaded live rat in the rat exposure test (IL inactivation exerted minimal effects). Although it is unclear whether week 1 mouse defense test battery testing influenced week 2 rat exposure test results, these preliminary data suggest functional differences within the mouse right hemisphere ventral PFC related to cautious evaluation of predator threat. Given the dense unilateral reciprocal connectivity between the IL and vMO subregions of the PFC, both associative ventromedial cortical areas may exert complimentary yet dissociable roles in the processing of threat stimuli. This suggests that while the IL vmPFC may mediate cautious evaluation of threat situations (risk assessment), the vMO PFC may inhibit prepotent avoidance responses to facilitate such IL-mediated adaptive behavioral responses.

The hippocampal formation--orbitomedial prefrontal cortex circuit in the attentional control of active memory

The long held view that the hippocampal formation is not only essential, but also solely responsible for declarative memory in humans (and by analogy non-human primates) has come into question. Based on extensive reciprocal connection patterns between the hippocampal formation and the orbitoventromedial prefrontal cortex in primates and rats, a central role for the hippocampal formation in the attentional control of behavior is emerging. In this paper, evidence is reviewed showing that the hippocampal-orbitomedial prefrontal cortex circuit may be involved in attentional monitoring of the internal sensorium. This attentional monitoring system, in a sense, is the working memory of viscero-emotional processing. The hippocampal formation can thus be viewed as a discrepancy detector with respect to the relative activational status of cognitive/emotional set in the orbitomedial prefrontal cortex. Discrepancies between the current representation of the internal milieu and the "just-prior" representation held "on-line" in orbitomedial prefrontal cortex associative working memory, are signaled from the hippocampus to the prefrontal cortex prospective attentional systems to activate, process, and reconcile internal (past) with external (present) environments, and finally to effectively alter active working emotional "sets" to exert cognitive-emotional control of behavior.

Brain metabolic changes associated with symptom factor improvement in major depressive disorder

BACKGROUND

Symptoms of major depressive disorder (MDD) have been linked to regional brain function through imaging studies of symptom provocation in normal control subjects and baseline studies of subjects with MDD. We examined associations between change in depressive symptom factors and change in regional brain metabolism from before to after treatment of MDD.

METHODS

Thirty-nine outpatients with MDD underwent 18F-fluorodeoxyglucose positron emission tomography scanning before and after treatment with either paroxetine or interpersonal psychotherapy. Associations were determined between changes in regional brain metabolism and changes in four Hamilton Depression Rating Scale factors (anxiety/somatization [ANX], psychomotor retardation [PR], cognitive disturbance [COGN], and sleep disturbance) and two corresponding Profile of Mood States subscales (tension [TENS] and fatigue [FATIG]).

RESULTS

Improvement in ANX, PR, TENS, and FATIG factors was associated with decreasing ventral frontal lobe metabolism. Improvement in ANX and TENS was also associated with decreasing ventral anterior cingulate gyrus (AC) and anterior insula activity, whereas improvement in PR was associated with increasing dorsal AC activity. COGN improvement was associated with increasing dorsolateral prefrontal cortex metabolism.

CONCLUSIONS

Brain regions that show significant relationships with symptom provocation in normal control subjects have similar relationships with MDD symptoms as they improve with treatment.

Source localization of EEG activity during hypnotically induced anxiety and relaxation

The engagement of different brain regions which implement subjectively experienced emotional states in normals is not completely clarified. Emotional states can conveniently be induced by hypnosis-based suggestions. We studied brain electric activity during hypnotically induced anxiety and relaxation in 11 right-handed normals (5 males, 6 females, mean age 26.5+/-7.6 years). After induction of light hypnosis, anxiety and then relaxation was suggested using a standardized text (reverse sequence in half of the subjects). Nineteen-channel, eyes-closed EEG (20 artifact-free s/subject) was analyzed (source localization using FFT approximation and low resolution electromagnetic tomography, LORETA). Global tests revealed the strongest difference (P<0.005) between EEG source gravity center locations during the two emotional states in the excitatory beta-2 EEG frequency band (18.5-21 Hz). Post hoc tests showed that the sources were located more right during anxiety than during relaxation (P=0.01). LORETA specified that anxiety showed maximally stronger activity than relaxation in right Brodmann area 10, and relaxation showed maximally stronger activity than anxiety in left Brodmann area 22. Clearly, the two induced emotional states were associated with activity of different neural populations. Our results agree with reports on brain activity shifted to the right (especially fronto-temporal) during negative compared with positive emotions, and support the role of beta-2 EEG frequency in emotional states.

Neural correlates of maternal separation in rhesus monkeys

BACKGROUND

The neurobiological basis of stress and anxiety in primates remains poorly understood. In this study, we examined the neural response to a naturalistic social stressor: maternal separation. We used rhesus monkeys as an animal model because of their close phylogenetic affinity with humans.

METHODS

Six juvenile rhesus monkeys received [(18)F]-fluorodeoxyglucose positron emission tomography scans following 1) a period together with their mothers and again after separation from their mothers 2) with or 3) without visual contact. Image subtraction revealed brain regions that exhibited altered activity during separation. In addition, plasma cortisol concentrations obtained following each condition were tested for correlations with regional brain activity.

RESULTS

Maternal separation activated the right dorsolateral prefrontal cortex and the right ventral temporal/occipital lobe. There was also decreased activity in left dorsolateral prefrontal cortex associated with separation stress. Correlational analyses demonstrated these activated and deactivated regions to be positively and negatively correlated with cortisol, respectively. Additionally, correlational analyses revealed cortisol-related activation in brainstem areas previously implicated in stress and anxiety.

CONCLUSIONS

In juvenile rhesus monkeys, the stress of maternal separation is associated with activation in the right dorsolateral prefrontal cortex and ventral temporal/occipital lobes and decreased activity in the left dorsolateral prefrontal cortex.

Medial prefrontal transection enhances social interaction. I: behavioral studies

Behavioral effects of a medial prefrontal cortex (MPFC) transection were assessed in animal tests of anxiety. Social investigation and plus-maze open arm exploration increased in MPFC damaged animals relative to sham ones. MPFC lesions prevented D-amphetamine (2 mg/kg, i.p.) induced social investigation decrease and exaggerated general locomotion increase. Diazepam (1 mg/kg, i.p.) and MPFC synergistically increased open arm exploration on a second (repeated) plus-maze trial. These results suggest that the MPFC would be implicated in a generalized mechanism of warning enabling emission of appropriate responses to anxiogenic stimuli. Although, this lesion did not modify motor activity itself, the pattern of the motor activation induced by amphetamine was altered. The role of the MPFC areas in the behavioral response associated with fear is discussed.

The postconcussion syndrome after mild head trauma: is brain damage overdiagnosed? Part 1

Many investigators attribute the postconcussion syndrome following mild closed head injury to permanent brain damage. The evidence supporting this conclusion is reviewed, including the force necessary to cause permanent brain damage; the basis for determining whether the patient was exposed to sufficient force in the accident to permanently damage the brain; the basis for determining whether the patient actually has permanent brain damage (not just brain dysfunction) traceable to the accident; and whether the location and severity of brain damage is sufficient to account for the postconcussion syndrome.

CONCLUSION

the evidence for permanent traumatic brain damage as the cause of the postconcussion syndrome following mild closed head injury is weak.

Cerebral activation, hostility, and cardiovascular control during mental stress

OBJECTIVE

Hostility has been established as a risk factor for the development of coronary artery disease. Putatively pathogenic hemodynamic and neuroendocrine responses to psychological stressors are associated with hostility, but the cerebral effects of hostility and their relationship to these responses are unknown. This pilot study examined cardiovascular and cerebral blood flow responses to stress in subjects with high and low levels of trait hostility.

METHODS

Regional cerebral blood flow was measured by single-photon emission computed tomography (SPECT) during a control condition and in response to mental arithmetic stress.

RESULTS

The stressor was associated with reduced blood flow to the prefrontal cortex, and this reduction was greater in the high hostility subjects.

CONCLUSION

These preliminary findings support the hypothesis that mental arithmetic stress is associated with reduced blood flow to prefrontal cortex, and that trait hostility is associated with a stronger effect.

Regional brain activity during transient self-induced anxiety and anger in healthy adults

BACKGROUND

Several studies have demonstrated that transient self-induced sadness activates anterior paralimbic structures. To further examine the specificity of these findings and the neural substrates involved in anger and anxiety, we studied the neural correlates of the induction of anxiety and anger in healthy adults.

METHODS

We used H2(15)O and positron emission tomography (PET) to measure regional cerebral blood flow (rCBF) in 16 healthy adults during the induction of transient anxiety, anger, and neutral emotions. Subjects achieved differential emotions by recalling prior life events while viewing affect-appropriate faces.

RESULTS

Both the anxiety and anger conditions were associated with increased normalized rCBF in left inferior frontal and left temporal pole regions and decreased rCBF in right posterior temporal/parietal and right superior frontal cortex, compared to the neutral induction. Additionally, compared to neutral induction, anxiety was associated with increased rCBF in the left anterior cingulate and cuneus and decreased rCBF in right medial frontal cortex, while the anger induction was uniquely associated with increased rCBF in right temporal pole and thalamus.

CONCLUSIONS

Self-generated transient states of anxiety and anger are associated with both overlapping and distinct regional brain activity patterns and provide a template for further dissection of specific components of normal and pathologic emotions.

Task-independent effect of time on rCBF

Positron emission tomography was used to identify brain regions that showed general increase or decrease in regional cerebral blood flow (rCBF) across time that was task-independent. Twelve male subjects were scanned eight times: the first and last scans were taken while subjects performed a baseline fixation task and the middle six scans were taken while subjects performed a visuomotor activation task. To determine whether there was a consistency across different studies in the regions that showed this time-related change in rCBF two additional datasets were analyzed. There were similarities across all three studies in the regions that showed a monotonic task-independent change in activity. In all three studies there was a general bilateral decrease in rCBF of occipital and temporal areas across scans that might be related to habituation in the visual domain. Increases in rCBF were found in anterior cingulate, postcentral gyrus, and precentral gyrus across studies. It is likely that these changes reflect motor learning and motor program retrieval. This implies that, unless the experimenter controls for time-dependent changes in brain activity, the interpretation of task-related changes in rCBF may be confounded by these monotonic changes in rCBF. We present analytic strategies to identify experimental effects that are independent of nonspecific time effects, which can be used when it is not possible to control these effects through counterbalancing the experimental design. Nonspecific confounds are particularly relevant in functional MRI studies in which the number of scans acquired per study is much larger.

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.

Neuroanatomical characterization of Fos induction in rat behavioral models of anxiety

Immunohistochemical staining for Fos-like immunoreactivity (Fos-LI) was used to map functional activation in discrete brain regions of rats processed in three empirical models of anxiety: foot shock avoidance responding in a shuttle box, the elevated plus maze, and an air puff-induced ultrasonic vocalization test. The avoidance test and elevated plus maze induced prominent Fos-LI in select brain regions, including the medial prefrontal, cingulate, and ventrolateral orbital cortices, taenia tecta, nucleus accumbens, paraventricular nucleus of the hypothalamus, medial nucleus of the amygdala and lateral septum. Air puff stimuli that produced ultrasonic vocalizations induced Fos-LI to a more limited extent compared to the plus maze and avoidance test, with only the medial prefrontal cortex, medial nucleus of the amygdala, and lateral septum being significantly affected by air-puff. Even though the sensory stimuli and environmental conditions associated with the three anxiety models were markedly different, specific common forebrain regions were affected, i.e. the medial prefrontal cortex, medial amygdala, and lateral septum. It is hypothesized that these regions are components of a circuit in the rat brain related to anxiety or distress. To determine the potential relationship between generalized arousal and the observed induction of Fos-LI in the anxiety models, rats were tested in a non-aversive situation involving marked behavioral activation. Accordingly, after vigorous bar pressing behavior for reinforcement with sweetened condensed milk, induction of Fos-LI was minimal and comparable to that in unhandled control rats. These latter data indicate that the distinctive neuroanatomical patterns of Fos-LI observed in the paradigms related to anxiety were not simply due to generalized behavioral activation. In summary, select common brain regions were identified that express Fos-LI in empirical models of anxiety. These data provide a functional framework to explore neuroanatomical sites of action of psychotherapeutic drugs that influence behavioral responses in these tasks.

The cerebral neurobiology of hope and hopelessness

Hope and hopelessness are useful constructs that have been employed by clinicians in theory making regarding the pathogenesis and course of disease and in the application of various psychological and medical treatments to illness. French (1952) and Frank (1968) viewed hope as a necessary motivating force in influencing an individual to try to overcome inner psychological conflicts and seek to resolve a psychoneurosis. Melges and Bowlby (1969) classified the types of hopelessness in psychopathological processes. Perley et al. (1971), using an objective method for content analysis of small samples of speech (Gottschalk 1974), found that elevated hope scores predicted continuation of psychiatric treatment rather than dropping out. Gottschalk et al. (1967, 1969) found that hope scores derived from verbal samples predicted the duration of survival of patients with terminal cancer receiving irradiation treatment (1969) and predicted relatively favorable outcome in psychotherapy (1967).