A balanced brain asymmetry modulates T cell-mediated events

Right-Sided clinical findings are worse prognostic factor in Multiple Sclerosis patients?

OBJECTIVE

To investigate the importance of the side of clinical findings in predicting the prognosis in multiple sclerosis (MS) patients.

METHODS

In our study we enrolled 361 MS patients. This study as retrospective was performed. On neurological examinations, clinical findings were recorded as right, left and bilateral. We used the Expanded Disability Status Scale (EDSS), Multiple Sclerosis Severity Score (MSSS), Progression Index (PI) for neurological status.

RESULTS

At the first attack, there were differences in the EDSS, PI and MSSS of right-sided findings between remission and attack periods (p=0.057, p=0.008, p=0.017 respectively). In the right-sided clinical findings, the value of PI and MSSS were higher than the others between in remission and attack periods (p=0.002, p=0.045 respectively). At last attack, we found statically differences in EDSS, MSSS values between remission and attack periods in only right-sided clinical findings (p=0.042, p=0.027 respectively). In the first presentation the PI value in bilateral clinical signs was lower (p=0.016).

CONCLUSION

Right-sided clinical findings were poor prognostic factors in all stages of MS, whereas bilateral findings were not poor prognostic factor in the early-stage MS.

The effects of pessimism on cell-mediated immunity in rats

We used a recently developed ambiguous-cue interpretation (ACI) paradigm to investigate whether 'optimism' and 'pessimism' as behavioural traits may be interrelated with immune functions in rodents. To this aim, in a series of ACI tests (cognitive bias screening, CBS), we identified rats that displayed 'pessimistic' and 'optimistic' traits. We found significant differences in immune biomarkers between 'optimistic' and 'pessimistic' animals. Moreover 'pessimism' was associated with significantly lower relative weight of the spleen and thymus, significantly decreased proliferative activity of splenocytes. Pessimism was associated with an increased production of interleukin-(IL)1β and IL-4, activin A, l-selectin, interferon (IFN)-γ and some chemokines and receptors for advanced glycation endproducts. The findings indicate an inflammatory profile in "pessimistic" animals.

Abnormal cortical asymmetry as a target for neuromodulation in neuropsychiatric disorders: A narrative review and concept proposal

Recent advances in knowledge relating to the organization of neural circuitry in the human brain have increased understanding of disorders involving brain circuit asymmetry. These asymmetries, which can be measured and identified utilizing EEG and LORETA analysis techniques, may be a factor in mental disorders. New treatments involving non-invasive brain stimulation (NIBS), including trans-cranial magnetic stimulation, direct current stimulation and vagal nerve stimulation, have emerged in recent years. We propose that EEG identification of circuit asymmetry geometries can direct non-invasive brain stimulation more specifically for treatments of mental disorders. We describe as a narrative review new NIBS therapies that have been developed and delivered, and suggest that they are proving effective in certain patient groups. A brief narrative of influence of classical and operant conditioning of neurofeedback on EEG coherence, phase, abnormalities and Loreta's significance is provided. We also discuss the role of Heart rate variability and biofeedback in influencing EEG co-relates. Clinical evidence is at an early stage, but the basic science evidence and early case studies suggest that this may be a promising new modality for treating mental disorders and merits further research.

Emotion and Affective Style: Hemispheric Substrates

Research on cerebral asymmetry and the experience and expression of emotion is reviewed. The studies described use electrophysiological procedures to make inferences about patterns of regional cortical activation. Such procedures have sufficient temporal resolution to be used in the study of brief emotional experiences denoted by spontaneous facial expressions. In adults and infants, the experimental arousal of positive, approach-related emotions is associated with selective activation of the left frontal region, while arousal of negative, withdrawal-related emotions is associated with selective activation of the right frontal region. Individual differences in baseline measures of frontal asymmetry are associated with dispositional mood, affective reactivity, temperament, and immune function. These studies suggest that neural systems mediating approach- and withdrawal-related emotion and action are, in part, represented in the left and right frontal regions, respectively, and that individual differences in the activation levels of these systems are associated with a coherent nomological network of associations which constitute a person's affective style.

Immunological functioning in Alzheimer's disease: differential effects of relative left versus right temporoparietal dysfunction

The cerebral hemispheres are differentially involved in regulating immunological functioning and the neuropathology associated with Alzheimer's disease (AD) is asymmetrical. Thus, subgroups of AD patients may exhibit different patterns of immunological dysfunction. We explored this possibility in a group of AD patients and found that patients with low white blood cell counts and low lymphocyte numbers exhibited better performance on tests of right temporoparietal functioning. Also, a significant positive relationship exists between lymph numbers and performance on a test of left temporoparietal functioning. Thus, some AD patients have greater immunological dysfunction based on relative left versus right temporoparietal functioning.

Left-sided brain injury associated with more hospital-acquired infections during inpatient rehabilitation

OBJECTIVE

To test the hypothesis that a left-dominant brain immune network (LD-BIN) might affect the occurrence of infection during inpatient rehabilitation of stroke and traumatic brain injury (TBI).

DESIGN

A retrospective analysis was performed on electronic medical records between January 2009 and December 2010. All patients with left- or right-sided stroke or TBI were included into the study. The LD-BIN hypothesis was tested by comparing HAI rates depending on whether patients had left- or right-sided brain lesions.

SETTING

A large inpatient rehabilitation hospital.

PARTICIPANTS

Among the patients (N=2236) with stroke or TBI who had either a left- or right-sided brain lesion, 163 patients were identified with HAIs.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE

Frequency of HAIs.

RESULTS

In the 163 patients identified with HAIs with a diagnosis of stroke or TBI, chi-square analysis revealed a significantly higher proportion of HAIs among patients with left-sided (n=98; 60.1%) relative to right-sided (n=65; 39.9%) brain injuries (χ(2)=6.68, P<.01). These effects could not be attributed to either clinical or demographic factors.

CONCLUSIONS

Our findings are consistent with the hypothesis that an LD-BIN may mediate vulnerability to infection during rehabilitation of patients with stroke or TBI. Further translational research investigating novel means of managing patients based on brain lesion location, and modulating the LD-BIN via behavioral and physiologic interventions, may result in neuroscience-based methods to improve infection resistance in brain-injured patients.

Relationship between neural activity and immunity in patients with undifferentiated somatoform disorder

It has been suggested that somatoform disorders are related to both the brain and the immune system, and that immune functions may be influenced by cerebral asymmetry. However, few studies have examined the relationship between brain activity and immune function in somatoform disorders. Thirty-two patients with non-medicated undifferentiated somatoform disorder were enrolled in this study. Blastogenic responses to phytohemagglutinin (PHA) were used to measure immunity. Regional cerebral perfusion was measured by 99m-Tc-ethyl cysteinate dimer single photon emission computed tomography (SPECT). Significant hypoperfusion was found at the left inferior parietal lobule and the left supramarginal gyrus in the more immune-suppressed (MIS) subgroup compared with the less immune-suppressed (LIS) subgroup. However, no regions of significant hyperperfusion were found in the MIS subgroup compared with the LIS subgroup. Decreased cerebral blood flow in the left inferior parietal lobule and the left supramarginal gyrus in the patient group was also significantly associated with reduced blastogenic responses to PHA regardless of sex and age. These results suggest that the left inferior parietal lobule and the left supramarginal gyrus might play an immunomodulating role in patients with undifferentiated somatoform disorder. In addition, these results suggest the role of cerebral asymmetry in altered immunity in the patients.

EEG source analysis of chronic fatigue syndrome

Sixty-one dextral, unmedicated women with chronic fatigue syndrome (CFS) diagnosed according to the Fukuda criteria (1994) and referred for investigation by rheumatologists and internists were studied with quantitative EEG (43 channels) at rest with eyes open and during verbal and spatial cognitive activation. The EEGs from the patients were compared with recordings from 80 dextral healthy female controls. Only those subjects who could provide 20 1-s artefact-free segments of EEG were admitted into the study. The analysis consisted of the identification of the spatial patterns in the EEGs that maximally differentiated the two groups and the estimation of the cortical source distributions underlying these patterns. Spatial patterns were analyzed in the alpha (8-13Hz) and beta (14-20Hz) bands and the source distributions were estimated using the Borgiotti-Kaplan BEAMFORMER algorithm. The results indicate that the spatial patterns identified were effective in separating the two groups, providing a minimum correct retrospective classification rate of 72% in both frequency bands while the subjects were at rest to a maximum of 83% in the alpha band during the verbal cognitive condition. Underlying cortical source distributions showed significant differences between the two groups in both frequency bands and in all cognitive conditions. Lateralized cortical differences were evident between the two groups in the both frequency bands during both the verbal and spatial cognitive conditions. During these active cognitive conditions, the CFS group showed significantly greater source-current activity than the controls in the left frontal-temporal-parietal regions of the cortex.

Relationships between intestinal parasitosis and handedness

The aim of the study was to investigate if there is a possible relation between intestinal parasitosis and handedness in patients with suspected intestinal parasitosis. Hand preference was assessed on the Edinburgh Handedness Inventory. Stool samples were examined microscopically for the presence of parasite. In the present study right-handers had many more helminth infections and left-handers had many more protozoon infections. Lower rate of helminth infections in the present study, and higher asthma incidences in the left-handed population in literature, may be associated with different immune machinery in left-handed people than in right-handed ones.

What's left in asymmetry?

Left-right patterning is a fascinating problem of morphogenesis, linking evolutionary and cellular signaling mechanisms across many levels of organization. In the past 15 years, enormous progress has been made in elucidating the molecular details of this process in embryos of several model species. While many outside the field seem to believe that the fundamental aspects of this pathway are now solved, workers on asymmetry are faced with considerable uncertainties over the details of specific mechanisms, a lack of conceptual unity of mechanisms across phyla, and important questions that are not being pursued in any of the popular model systems. Here, we suggest that data from clinical syndromes, cryptic asymmetries, and bilateral gynandromorphs, while not figuring prominently in the mainstream work on LR asymmetry, point to crucial and fundamental gaps of knowledge about asymmetry. We identify 12 big questions that provide exciting opportunities for fundamental new advances in this field.

Asymmetric brain function, affective style, and psychopathology: The role of early experience and plasticity

A model of asymmetric contributions to the control of different subcomponents of approach- and withdrawal-related emotion and psychopathology is presented. Two major forms of positive affect are distinguished. An approach-related form arises prior to goal attainment, and another form follows goal attainment. The former is hypothesized to be associated with activation of the left prefrontal cortex. Individual differences in patterns of prefrontal activation are stable over time. Hypoactivation in this region is proposed to result in approach-related deficits and increase an individual's vulnerability to depression. Data in support of these proposals are presented. The issue of plasticity is then considered from several perspectives. Contextual factors are superimposed upon tonic individual differences and modulate the magnitude of asymmetry. Pharmacological challenges also alter patterns of frontal asymmetry. A diverse array of evidence was then reviewed that lends support to the notion that these patterns of asymmetry may be importantly influenced by early environmental factors that result in enduring changes in brain function and structure.

The stressed prefrontal cortex. Left? Right!

The prefrontal cortex (PFC) plays an important role in the integration of cognitive and affective behavior and regulating autonomic and neuroendocrine functions. This region of the brain, which may be considered analogous to the RAM memory of a computer, is important for translating stressful experience into adaptive behavior. The PFC responds to stress and modulates the response to stress through regulation of the hypothalamic paraventricular nucleus (PVN) which, in turn, controls sympathoadrenal and hypothalamic-pituitary-adrenal (HPA) activity. Interestingly, the latter convey the signals that link the CNS with the immune system. The present review highlights findings that contribute to elucidate the involvement of the PFC in the control of behavioral and neuroendocrine responses to chronic stress. It also considers the implications of these regulatory links for disorders of the nervous and immune systems.

On the mechanisms and putative pathways involving neuroimmune interactions

Bidirectional interdependence between the immune system and the CNS involves the intervention of common cofactors. Cytokines are endogenous to the brain, endocrine and immune systems. These shared ligands are used as a chemical language for communication. Such interaction suggests an immunoregulatory role for the brain, and a sensory function for the immune system. Interplay between the immune, nervous and endocrine systems is associated with effects of stress on immunity. Cytokines are thus capable of modulating responses in the CNS, while neuropeptides can exert their effects over cellular groups in the immune system. One way is controlled by the HPA axis, a coordinator of neuroimmune interactions that is essential to unravel in order to elucidate vital communications in a manner that this crosstalk remains a cornerstone in perpetuating a stance of homeostasis.

Evolution of hemispheric specialisation of antagonistic systems of management of the body's energy resources

Excellent and rich reviews of lateralised behaviour in animals have recently been published indexing renewed interest in biological theorising about hemispheric specialisation and yielding rich theory. The present review proposes a new account of the evolution of hemispheric specialisation, a primitive system of "management of the body's energy resources". This model is distinct from traditionally evoked cognitive science categories such as verbal/spatial, analytic/holistic, etc., or the current dominant neuroethological model proposing that the key is approach/avoidance behaviour. Specifically, I show that autonomic, immune, psychomotor, motivational, perceptual, and memory systems are similarly and coherently specialised in the brain hemispheres in rodents and man. This energy resource management model, extended to human neuropsychology, is termed here the "psychic tonus" model of hemispheric specialisation.

Asymmetrical distribution of brain interleukin-6 depends on lateralization in mice

The central nervous system can regulate the peripheral immune system. Moreover, differences between left and right hemispheres (neurochemical brain asymmetries) and behavioral lateralization (functional brain asymmetries) affect immune responses. The molecular basis of brain-immune interactions remains insufficiently understood. Cytokines regulate immune responses, possibly through activation of the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis activities are related to behavioral lateralization and brain asymmetry. Given IL-6 plays a role in asymmetrical brain immunomodulation, one might expect the IL-6 distribution in brain to be asymmetrical and to depend on behavioral lateralization. In order to start to test this hypothesis, male C57BL/6J mice were selected for paw preference and assessed for IL-6 levels in right and left cortex and hippocampus by enzyme linked immunosorbent assay. The results showed asymmetrical distribution of brain IL-6 in left-pawed animals and ambidextrous animals, but not in right-pawed animals, both in cortex and hippocampus. Furthermore, we found a correlation between IL-6 hemispheric distribution and the degree of behavioral lateralization both in cortex and hippocampus. Altogether, these results suggest that brain IL-6 could be a mediator of asymmetrical immunomodulation by the central nervous system.

The level of nitric oxide in the cortex correlates well with brain lateralization

The correlation between nitric oxide (NO) levels in the cortices and brain lateralization was investigated via the paw preference test in which three groups of mice (left-pawed, ambidextrous and right pawed) were selected. Results showed that the right cortices had higher NO levels than the left cortices for both normal and lipopolysaccharide-treated mice. There were significant differences in NO levels in the right/left cortices depending on the behavioral lateralization as expressed by paw preference. Finally, individual levels of NO in the right/left cortices correlated well with individual paw preference scores. The relationship was parabolic. The results suggest a strong relationship between NO asymmetries as well as the direction and the intensity of behavioral lateralization.

Role of cerebral lateralization in control of immune processes in humans

Cerebral lateralization may be important in neural control of immune function. Animal studies have demonstrated differential effects of left and right brain lesions on immune function, but human studies are inconclusive. Here, we show that resections in the language dominant hemisphere of patients with epilepsy reduce lymphocytes, total T cells, and helper T cells. In contrast, resections in the language nondominant hemisphere increased the same cellular elements. T-cell responses to mitogens and microbial antigens were not differentially affected. Left/right arm histamine skin response ratios were altered in patients with left cerebral epileptic focus, and flare skin responses were reduced by left cerebral resections in contrast with an increase after right cerebral resections. The findings demonstrate a differential role of the left and right cerebral hemispheres on immune functions in humans.

An investigation into asymmetrical cortical regulation of salivary S-IgA in conscious man using transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) can activate discrete areas of the cerebral cortex through the intact skull of healthy conscious volunteers. A magnetic coil generates a brief and focused magnetic field that penetrates the skull to activate the specific area of cerebral cortex beneath. This non-invasive procedure is painless, well tolerated by participants and now widely used to explore brain function. We used TMS to investigate asymmetrical cortical regulatory influences on one aspect of immune function: secretion of the antibody immunoglobulin A (S-IgA) into saliva. The right and left temporo-parietal-occipital cortex of 16 healthy, conscious subjects was stimulated on two different occasions, at least 1 week apart. There was an immediate increase in S-IgA concentration following both right and left stimulation. Saliva volume was reduced immediately post-right but not left stimulation. When secretion (microg/min) of S-IgA was calculated (controlling for changing saliva volume) an increase was apparent following left but not right hemisphere stimulation. Furthermore, a significant difference between the relationship between S-IgA concentration and volume of saliva post-left and right stimulation was observed. We conclude that TMS can be used as a tool to investigate cortical regulation of autonomic and immune function in healthy, conscious human subjects and that secretion of saliva and S-IgA is differentially affected by stimulation of the left and right cerebral cortex.

Brain interleukin asymmetries and paw preference in mice

The two sides of the brain are differently involved in the modulation of immune responses as demonstrated by lesion and behavioral approaches. To study the interactions between cerebral cortex cytokines and brain lateralization, three groups of BALB/c mice were selected on the basis of their performance in the paw preference test (left-pawed, ambidextrous and right-pawed) and the levels of interleukin-1beta and interleukin-6 were measured in the two cerebral cortices after an intraperitoneal saline or lipopolysaccharide. Generally, right cortices had higher interleukin-1beta and interleukin-6 levels than left cortices for both saline and lipopolysaccharide-treated mice. A strong correlation between the levels of interleukin-1beta and interleukin-6 in right and left cortices and behavioral lateralization was observed. For the saline-treated mice: in their left cortices, interleukin-1beta levels were higher for ambidextrous mice than for right-pawed mice (P<0.05); in their right cortices, interleukin-6 levels were higher for ambidextrous mice than for right-/left-pawed mice, and right-pawed mice have higher levels of interleukin-6 than left-pawed mice (P<0.01). In their left cortices, interleukin-6 levels are higher for left-pawed mice than for both ambidextrous and right-pawed mice (P<0.01). In their left cortices, interleukin-6 levels are higher for left-pawed mice than for both ambidextrous and right-pawed mice (P<0.01). The quadratic curve equations showed that the levels of interleukin-1beta and interleukin-6 in the right/left cortices had a highly significant correlation with paw preference scores in both normal and lipopolysaccharide-treated mice. In conclusion, the present report demonstrated that the basal levels of interleukin-1beta and interleukin-6 were higher in the right cortex than left cortex in mice. There was a strong correlation between the levels of interleukin-1beta and interleukin-6 and behavioral lateralization, and cytokine asymmetries had a strong correlation with the direction and the intensity of behavioral lateralization.

Relationship between trait anxiety, brain activity and natural killer cell activity in cancer patients: a preliminary PET study

The purpose of this study is to examine the relationship between psychological factors, regional brain activity and natural killer cell activity (NKA). Eight patients with malignant diseases were studied by FDG-PET under a resting condition. NKA and degree of anxiety and depression were measured using Taylor's manifest anxiety scale (MAS) and Zung's self-rating depression scale (SDS). Linear correlation of NKA and psychological measures to the regional brain metabolism in cancer patients was examined using statistical parametric mapping (SPM). Positive linear correlation between NKA and regional metabolic rate ratios was identified in the visual association cortex, anterior cingulate gyrus (CG) and sensorimotor area, and negative correlation was identified in the inferolateral prefrontal cortex (ILPFC), prefrontal cortex (PFC), orbitofrontal cortex (OFC) and anterior temporal cortex. Positive linear correlation to the MAS score was identified in the visual association cortex, anterior CG, primary sensorimotor area and the posterior parietal cortex, and negative correlation was detected in the ILPFC, PFC, OFC and anterior temporal cortex. The NKA and MAS scores positively correlated with each other (p<0.001). The result might serve as supporting data for a hypothesis that psycho-immune interaction is also mediated by the cerebral cortex and limbic system.

Cell-mediated immune hypersensitivity is stronger in the left side of the body than the right in healthy young subjects

More frequent appearance of herpes zoster infection on the left side of the body has been noted. In women, breast cancer occurs more frequently on the left side. It has been suggested that the left neocortex is involved in neuroimmunomodulation via the dopaminergic system. In this study, our purpose was to investigate the possible difference in cell-mediated hypersensitivity between right and left body sides using the tuberculin test with 22 male and 36 female healthy high school students. In the present study, the cell-mediated hypersensitivity was higher in the left side of the body than the right. This difference was slightly more apparent in the girls and may be related to brain asymmetry in neuroimmunomodulation.

Cellular and humoral immunity, mood and exam stress: the influences of self-hypnosis and personality predictors

The effects of self-hypnosis training on immune function and mood were examined in medical students at exam time. Hypnosis involved relaxation and imagery directed at improved immune function and increased energy, alertness and concentration. Hypotheses were made about activated and withdrawn personality differences. Eight high and eight low hypnotically susceptible participants were given 10 sessions of hypnosis, one live and nine tape-recorded, and were compared with control subjects (N=12). CD3, CD4, CD8, CD19 and CD56 NK cells and blood cortisol were assayed. Life-style, activated vs. withdrawn temperament, arousal and anxiety questionnaires were administered. Self-hypnosis buffered the decline found in controls in NK (P<0.002) and CD8 cells (P<0.0.07) and CD8/CD4% (P<0.06) (45-35% order of magnitude differences) while there was an increase in cortisol (P<0.05). The change in NK cell counts correlated positively with changes in both CD8 cells and cortisol. Results were independent of changes in life-style. Energy ratings were higher after hypnosis (P<0.01), and increased calmness with hypnosis correlated with an increase in CD4 counts (P<0.01). The activated temperament, notably the cognitive subscale (speaking and thinking quickly), was predictive of exam levels of T and B lymphocytes (P&z.Lt;0.08-P<0.02), and reaching r=0.72 (P<0.001) in the non-intervention control group. The sizeable influences on cell-mediated immunity achieved by a relatively brief, low cost psychological intervention in the face of a compelling, but routine, stress in young, healthy adults have implications for illness prevention and for patients with compromised immunity.

Importance of immunological and inflammatory processes in the pathogenesis and therapy of Alzheimer's disease

The contribution of autoimmune processes or inflammatory components in the etiology and pathogenesis of Alzheimer's disease (AD) has been suspected for many years. The presence of antigen-presenting, HLA-DR-positive and other immunoregulatory cells, components of complement, inflammatory cytokines and acute phase reactants have been established in tissue of AD neuropathology. Although these data do not confirm the immune response as a primary cause of AD, they indicate involvement of immune processes at least as a secondary or tertiary reaction to the preexisting pathogen and point out its driving-force role in AD pathogenesis. These processes may contribute to systemic immune response. Thus, experimental and clinical studies indicate impairments in both humoral and cellular immunity in an animal model of AD as well as in AD patients. On the other hand, anti-inflammatory drugs applied for the treatment of some chronic inflammatory diseases have been shown to reduce risk of AD in these patients. Therefore, it seems that anti-inflammatory drugs and other substances which can control the activity of immunocompetent cells and the level of endogenous immune response can be valuable in the treatment of AD patients.

Localization of the brain lesion affects the lateralization of T-lymphocyte dependent cutaneous inflammation. Evidence for an immunoregulatory role of the right frontal cortex-putamen region

We have previously demonstrated that brain lesions caused by stroke led to the lateralization of T-cell dependent inflammation. The purpose of this study was to assess the impact of localization of the brain lesion on lateralization of immune responsiveness. The delayed-type hypersensitivity (DTH) reaction was used as an in vivo measure of antigen specific T-lymphocyte reactivity. All stroke patients were examined with computed scan tomography (CT) of the brain to ascertain the localization and extent of the brain lesion. Patients with right-sided brain lesions displayed significantly larger (P = 0.008) DTH responses on the paretic side compared to the contralateral side. Detailed analysis of the localization of the brain lesion revealed that infarcts encompassing frontal lobe-putamen led to significantly larger (P = 0.007) DTH responses on the paretic side compared to the contralateral side. Localization of the brain lesion affects the lateralization of DTH, supporting an asymmetrical modulation of the immune response. In addition, our study points to the frontal cortex-putamen as a putative brain centre regulating the magnitude of immune responses.

Lateralization of T-lymphocyte responses in patients with stroke. Effect of sympathetic dysfunction?

BACKGROUND AND PURPOSE

A number of clinical observations indicate that stroke affects the course of immune-mediated diseases by lateralization of the disease manifestations, such as arthritis. The purpose of this study was to assess the impact of early stroke on lateralization of immune responsiveness.

METHODS

The delayed-type hypersensitivity (DTH) reaction to purified protein derivative was used as an in vivo measure of antigen-specific T-lymphocyte reactivity. Assessment of axon reflex vasodilation was simultaneously used to test for cutaneous sympathetic activity.

RESULTS

There were no significant differences with regard to lateralization of DTH reactivity when all stroke patients were tested. However, patients with minor stroke displayed a significant (P < .001) decrease of DTH reaction on the paretic side compared with the contralateral side. In contrast, patients with major stroke showed a significant increase (P = .022) of DTH reaction on the paretic side. Patients with left hemiparesis had a significantly greater (P = .045) DTH response on the affected side than patients with a right hemiparesis. In addition, only the patients with motor deficit but not with sensory deficit or aphasia displayed side differences in DTH responses. When electrically evoked axon reflexes were studied in relation to DTH reactions, a significant correlation (r = .64; P < .001) was found between side asymmetries of DTH responses and side asymmetries of axon reflexes in an innervated skin area. No similar relation was present in skin areas where cutaneous sympathetic activity had been blocked by regional anesthesia.

CONCLUSIONS

Early stroke lateralizes T-cell-mediated cutaneous inflammation. This effect depends on (1) the localization of the brain lesion, (2) the clinical course of the disease, and (3) the presence of motor deficit and may be mediated by (4) alteration of the cutaneous sympathetic nerve traffic.

Asymmetrical modulation of immune reactivity in left- and right-biased rats after ipsilateral ablation of the prefrontal, parietal and occipital brain neocortex

We report here on the lateralized brain immunomodulation in male Wistar rats, a phenomenon related to the rotational bias of animal and the site of cortical lesion. Rats assigned to left- and right-rotators in a cylindrical Plexiglass rotometer were subjected to the ablation of the ipsilateral prefrontal cortex (PFC), parietal cortex (PC) and occipital cortex (OC) and sensitized with bovine serum albumin (BSA) in complete Freund's adjuvant. Intact and sham-lesioned left-biased animals demonstrated increased Arthus and delayed hypersensitivity skin reactions and antibody production to BSA in comparison with corresponding right-biased animals. PFC ablation decreased humoral and cellular immune responses to BSA in left- but increased in right-biased rats. Lesioning of PC decreased humoral immune reactions in left- but increased in right-rotating animals. OC ablation failed to produce immunological abnormalities. These results suggest that immunopotentiation is associated with the left neocortex, and immunosuppression with the right neocortex. The prefrontal cortex appears to be particularly associated with immune reactions.

Neuroregulation of natural suppressor cell activity

The neuronal control of murine natural suppressor (NS) cell activity was studied in mice following lesion of the arcuate nucleus of the hypothalamus performed by the postnatal treatment with monosodium glutamate (MSG). The suppressor activity was evaluated as the ability of spleen or bone marrow cells (suppressors) to suppress the mitogen-induced lymphocytes proliferation of allogeneic Balb/c spleen cells (indicators). The study was carried out on three different inbred strains of mice (C57BL/6, DBA/2 and CBA). The results demonstrated that, in all strains used, the treatment of mice (12 day-old) with MSG led to a marked reduction of natural suppressor cell activity. This reduction was observed in both spleen and bone marrow, the lymphoid organs in which the NS cell activity is usually present. A reduced NS activity was also present in the bone marrow of MSG-treated adult mice, suggesting a permanent alteration of NS cell activity. These results provide additional support on neuromodulation of immune system.

Neuroendocrine brain asymmetry and physical complaints

It was examined whether there is an association between physical health and alterations of normal brain asymmetry in cerebral control of neuroendocrine activity. In particular, it was studied whether right-handed subjects showing a high amount of physical complaints and recurrent diseases differ in direction and degree of brain asymmetry in cerebral control of cortisol secretion from subjects with only few physical complaints. Lateralized brain activation was achieved by presenting an emotionally aversive film to the subjects' left or right visual hemifield, using a technique for lateralizing visual input that allows prolonged viewing while permitting free ocular scanning. Results revealed a clear association between a high degree of physical complaints and altered brain asymmetry in cerebral control of neuroendocrine activity.

Brain lateralization and immunomodulation

The two sides of the brain may be differently involved in the modulation of immune responses as demonstrated by lesional and behavioral approaches in rodents. Lesions of right or left neocortex induced opposite effects on various immune parameters including mitogen-induced lymphoproliferation, interleukin-2 production, macrophage activation or natural killer cell activity. This animal model, useful to elucidate whereby the brain and the immune system can communicate, appears to be suitable for studying the immune perturbations observed during stroke in humans. Brain asymmetry in modulation of immune reactivity may also be demonstrated in intact animal using a behavioral paradigm. The direction of a lateralized motor behavior ie paw preference in a food reaching task, correlated with an asymmetrical brain organization, was shown to be associated with lymphocyte reactivity, natural killer cell activity and auto-antibody production. The association between paw preference and immune reactivity in mice varies according to the immune parameters tested and is a sex-dependent phenomenon in which genetic background may be involved. The experimental models for investigating asymmetrical brain modulation of the immune system should be useful for studying several physiological, pathological and genetic aspects of neuroimmunomodulation.

Hemispheric asymmetry in the effects of substantia nigra lesioning on lymphocyte reactivity in mice

Asymmetry in brain modulation of the immune system has previously been demonstrated at the neocortex level. In these experiments, the possibility of subcortical immunomodulation was investigated. In mice the substantia nigra was lesioned using the neurotoxin 6-hydroxydopamine. Four and six weeks after left or right lesions of the substantia nigra, spleen lymphocyte mitogenesis was slightly depressed or enhanced respectively as compared to sham operated controls. Differences appeared when comparing left and right lesioned groups. However, natural killer cell activity was unaffected by unilateral lesions of the substantia nigra. These results show that asymmetrical brain modulation may occur at the sub-cortical level and suggest that central dopamine is involved in neuroimmunomodulation.

Asymmetrical effects of cortical ablation on brain monoamines in mice

Neurochemical changes induced by right or left cortical ablation which have previously been described to have immunological effects were investigated in mice. Catecholamine and indolamine levels were determined in the contralateral cortex and in subcortical structures involved in immunoregulation 14 and 60 days after unilateral cortical ablation. Unilateral cortical ablation induced profound and widespread changes in the contralateral cortex but also in subcortical regions of both sides at 14 days after surgery. Lesions of the left neocortex appeared mainly to affect the activity of serotoninergic inputs to the right neocortex, whereas ablations of the right cortex influenced the activity of the catecholaminergic inputs to the left. Sixty days after surgery, modifications in monoamine levels were observed only in the ipsilateral, but not contralateral, subcortical regions, the only exception being that DA turnover in the tuberoinfundibular system remained lowered in both hemispheres after either right or left cortical ablations. Furthermore, some asymmetrical effects of cortical lesions depended on functional brain lateralization as assessed by paw preference. It may be hypothesized that some neurochemical modifications induced by unilateral cortical lesions are, at least partially, responsible for the immunological perturbations observed after cortical ablation.

Brief uncontrollable stress and psychological parameters influence human plasma concentrations of IgM and complement component C3

Thirty-eight men participated in a study of immunological, hormonal, and psychological parameters before and after acute stress situations. A brief but acute stress was repeated daily for 4 days. This exposure caused the plasma levels of IgM and C3 to increase from Basal Day to Experimental Day 4. Significant correlations between endocrine and immunological parameters, and also between psychological measures and immunological parameters, were found. Use of psychological defense was related both to endocrine and immunological changes. The authors concluded that psychological stress may influence immunological functions both indirectly, by hormonal changes, and directly, by nervous regulation during brief but acute stress periods.

Effect of cerebral hemisphere decortication on the cytotoxic activity of natural killer and natural cytotoxic lymphocytes in the mouse

A comparison was made of the effects of left and right cerebral decortication on cytotoxic activity of natural killer and natural cytotoxic lymphocytes in the mouse. Natural killer cytotoxic activity was significantly reduced after right decortication, whereas left decortication led to a less pronounced, though still significant fall. The cytotoxic activity of natural cytotoxic cells, on the other hand, was significantly increased, particularly 15 days after left decortication. These findings mirror the results of previously published personal findings following electrothermocoagulation of the hypothalamus. The suggestion is made that the cortex and the hypothalamus form an integrated system for the control of certain aspects of natural immunity.

Strain-dependent association between immune function and paw preference in mice

The relationship between immune function and the preferred direction of behavioral asymmetry was examined in several mouse strains. Mixed leukocyte reaction, natural killer cell activity, cytotoxic T lymphocyte response and lymphoproliferation in response to mitogens were investigated in animals with left or right paw preference. From the 7 strains and substrains examined, it appeared that differences in immune function between left and right pawed mice, when present, vary in directionality. Thus, in C3H/HeJ and 129/J, left pawed mice had higher immune responses than right pawed mice, whereas in C3H/HeNCr MTV- and BALB/cJ animals, the reverse was found. In C3H/HeNCr MTV+, C57BL/6J and Collin's heterogenous control population for the high/low asymmetry lines, no differences between animals with left or right paw preference were found. The statistical significance of these differences were not uniform for all the immune parameters studied. These data indicate that the association between immune function and preference for using the left versus right paw is a strain-dependent phenomenon and may suggest that the inconsistent evidence for an association between immune deficiency and left-handedness could be due to genetic heterogeneity among subpopulations.

Interactions between non-symmetric mechanical vector forces in the body and the autonomic nervous system: basic requirements for any mechanical technique to engender long-term improvements in autonomic function as well as in the functional efficiency of the respiratory, cardiovascular, and brain systems

There are known anatomical asymmetries in the respiratory, cardiovascular, and nervous system. The coupling mechanisms between each of these systems--lungs-heart, heart-brain, and lungs-brain--are also asymmetrical. There is a growing body of literature indicating that mechanical pressure asymmetrically applied to certain areas of the human body produces changes in the balance of autonomic parameters. These findings implicitly indicate that not only magnitude but also the direction and point of application of the force play a role in its influence upon the autonomic nervous system. Therefore, we suggest that asymmetrical vector forces resulting from the mechanical activity of the lungs, heart and blood moving throughout the circulatory system, will also produce a lateralization effect in autonomic balance. We postulate the existence of negative feedback loops between brain autonomic control and mechanical functions in the body as a fundamental part of the body's homeostatic mechanisms. It follows that any mechanical assist to the respiratory or cardiovascular system will be significantly reduced or even eliminated if these homeostatic mechanisms are not taken into account. Our hypothesis predicts that a long-term improvement in autonomic balance as well as in respiratory, cardiovascular, and brain function can be achieved if mechanical forces are applied to the body with the aim of reducing existing imbalances of mechanical force vectors. This technique implies continually controlling for precise timings resulting from physiological periodical forces as well as factors derived from anatomical and coupling asymmetries in the respiratory, cardiovascular, and nervous systems.

Asymmetric distribution of brain monoamines in left- and right-handed mice

Biogenic amine distributions analyzed in the cerebral neocortex, striatum, anterior hypothalamus, and bulbospinal region, were compared between both hemispheres of left- and right-handed mice. The handedness of mice was determined using a paw preference test. The animals were tested 5 times, once every two weeks, and the biochemical analysis was performed two weeks after the last behavioral evaluation. The results indicated that (1) asymmetrical monoaminergic concentrations exist in the mouse brain. Monoamine contents were found to be higher in the right parietal cortex and anterior hypothalamus than in the left ones; (2) besides the behavioral expression of handedness, left- and right-handed subpopulations of mice differ according to asymmetrical distributions of cortical and bulbospinal NE contents as well as DA turnover of the tuberoinfundibular system.

Immune function in lines of mice selected for high or low degrees of behavioral asymmetry

Cerebral lateralization has been suggested to play a regulatory role in immune function. In this study, several measures of immune function were evaluated in mice selectively bred for either a strong (HI) or weak (LO) degree of behavioral asymmetry (paw preference) and compared to an unselected control population (HET). Both HI and LO animals had fewer spleen cells but higher degrees of [3H]thymidine incorporation into DNA (on a per cell basis) than HET mice. However, only HI mice had lower immune functions compared to HET controls manifest as reduced mixed leukocyte reaction (MLR), cytotoxic T lymphocyte (CTL) activity, and natural killer (NK) cell activity. These findings indicate that although both extremes in the degree of paw preference may be associated with deviations from the norm, a high degree of behavioral lateralization is associated with decreased immune responsiveness in this animal model.

The nucleus basalis is involved in brain modulation of the immune system in rats

Male rats were subjected to bilateral or unilateral excitotoxic lesions of the nucleus basalis magnocellularis (NBM). Three weeks after surgery, mitogen-induced lymphoproliferation and natural killer (NK) cell activity were determined in the spleen. T-cell mitogenesis and NK cell activity were strongly enhanced after bilateral lesions but were not affected after right or left unilateral lesions. B-cell mitogenesis and blood T-cell subset distribution remained unchanged after bilateral or unilateral lesions of the NBM. These results demonstrate that NBM cells are involved in the complex interrelations existing between the central nervous system and the immune system.

Physiological basis for neuroimmunomodulation

A large number of clinical and experimental observations indicate that immune responses may be modulated by the central nervous system (CNS). The immune system (IS) and CNS are known to communicate via the endocrine and the autonomic nervous systems. In this overview, we will focus on the immunomodulating role of neurotransmitters and neuropeptides. Immune cells appear to express membrane antigens similar to those of neural cells. Similarities re-enforce analogies between CNS and IS cells. The concept that the CNS modulates immune functions implies that the immune system feeds back information to the CNS. In fact, interleukins have neuroendocrine functions whether they are produced at the periphery by immune cells or at the CNS level by glial cells. Finally, the possible endocrine functions of lymphocytes are described and it is suggested that a complete regulatory loop between immune and neuro-endocrine systems exists. Studies in neuro-immunomodulation are of great importance from a theoretical point of view, the CNS-IS inter-relationships may not be considered only between the CNS and the periphery but also at the level of the immune micro-environment which may be considered as an immune-neuro-endocrine complex.