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Novel aspect of perinuclear theca assembly revealed by immunolocalization of non-nuclear somatic histones during bovine spermiogenesis.

The perinuclear theca (PT) is an important accessory structure of the sperm head, yet its biogenesis is not well defined. To understand the developmental origins of PT-derived somatic histones during spermiogenesis, we used affinity-purified antibodies against somatic-type histones H3, H2B, H2A, and H4 to probe bovine testicular tissue using three different immunolocalization techniques. While undetectable in elongating spermatid nuclei, immunoperoxidase light microscopy showed all four somatic histones remained associated to the caudal head region of spermatids from steps 11 to 14 of the 14 steps in bovine spermiogenesis. Immunogold electron microscopy confirmed the localization of somatic histones on two nonnuclear structures, namely transient manchette microtubules of step-9 to step-11 spermatids and the developing postacrosomal sheath of step-13 and -14 spermatids. Immunofluorescence demonstrated somatic histone immunoreactivity in the developing postacrosomal sheath, and on anti-beta-tubulin decorated manchette microtubules of step-12 spermatids. Focal antinuclear pore complex labeling on the base of round spermatid nuclei was detected by electron microscopy and immunofluorescence, occurring before the nucleoprotein transition period during spermatid elongation. This indicated that, if nuclear histone export precedes their degradation, this process could only occur in this region, thereby questioning the proposed role of the manchette in nucleocytoplasmic trafficking. Somatic histone immunodetection on the manchette during postacrosomal sheath formation supports a role for the manchette in PT assembly, signifying that some PT components have origins in the distal spermatid cytoplasm. Furthermore, these findings suggest that somatic histones are de novo synthesized in late spermiogenesis for PT assembly.

Animals↗

Continence mechanism of the isolated female urethra: an anatomical study of the intrapelvic somatic nerves.

PURPOSE: A neuroanatomical study was initiated to gain better insight into the continence mechanism of the isolated urethra in women. MATERIALS AND METHODS: We performed a detailed gross and histological neuroanatomical study to identify the intrapelvic somatic pathway from the sacral spinal cord to the female urethral sphincter. Gross anatomical dissection was performed in 5 formalin fixed female adult pelvises by tracing the autonomic nerves from the pelvic plexus and the spinal somatic nerves from S2-S4 to the urethral sphincter. Immunohistochemical staining of urethral step sections with a neuropeptide specific antibody was performed to demonstrate the course of the periurethral somatic nerves in relation to the vaginal wall. RESULTS: Our study demonstrated an intrapelvic somatic pathway derived from the S2, S3 and S4 sacral roots, distinct from the peripheral pudendal nerve, supplying the levator ani and the urethra. The somatic nerves travel beneath the endopelvic fascia in close relation to the inferior vascular pedicle of the bladder and are susceptible to injury during radical pelvic surgery. Mixed autonomic fibers from the pelvic plexus travel along the course of the ureter and are also intimately associated with the vascular pedicle of the bladder. Immunohistochemical staining of urethral step sections demonstrated that the periurethral nerves travel in close relation to the lateral and anterior vaginal wall. CONCLUSIONS: We believe that the identification of intrapelvic somatic pathways to the urethra provides a basis for developing surgical techniques to preserve urethral somatic innervation during radical pelvic surgery in women.

Adult↗

Resource utilization of patients with hypochondriacal health anxiety and somatization.

OBJECTIVES: To examine the resource utilization of patients with high levels of somatization and health-related anxiety. DESIGN: Consecutive patients on randomly chosen days completed a self-report questionnaire assessing somatization and health-related, hypochondriacal anxiety. Their medical care utilization in the year preceding and following completion of the questionnaire was obtained from an automated patient record. The utilization of patients above and below a predetermined threshold on the questionnaire was then compared. PATIENTS AND SETTING: Eight hundred seventy-six patients attending a primary care clinic in a large, urban, teaching hospital. OUTCOME MEASURES: Number of ambulatory physician visits (primary care and specialist), outpatient costs (total, physician services, and laboratory procedures), proportion of patients hospitalized, and proportion of patients receiving emergency care. RESULTS: Patients in the uppermost 14% of the clinic population on somatization and hypochondriacal health anxiety had appreciably and significantly higher utilization in the year preceding and the year following completion of the somatization questionnaire than did the rest of the patients in the clinic. After adjusting for group differences in sociodemographic characteristics and medical comorbidity, significant differences in utilization remained. In the year preceding the assessment of somatization, their adjusted total outpatient costs were $1,312 (95% CI $1154, $1481) versus $954 (95% CI $868, $1057) for the remainder of the patients and the total number of physician visits was 9.21 (95% CI 7.94, 10.40) versus 6.33 (95% CI 5.87, 6.90). In the year following the assessment of somatization, those above the threshold had adjusted total outpatient costs of $1,395 (95% CI $1243, $1586) versus $1,145 (95% CI $1038, $1282), 9.8 total physician visits (95% CI 8.66, 11.07) versus 7.2 (95% CI 6.62, 7.77), and had a 24% (95% CI 19%, 30%) versus 17% (95% CI 14%, 20%) chance of being hospitalized. CONCLUSIONS: Primary care patients who somatize and have high levels of health-related anxiety have considerably higher medical care utilization than nonsomatizers in the year before and after being assessed. This differential persists after adjusting for differences in sociodemographic characteristics and medical morbidity.

Adult↗

Culture and somatization: clinical, epidemiological, and ethnographic perspectives.

OBJECTIVES: The cross-cultural prevalence of somatization and the limitations of current nosology and psychiatric theory for interpreting cultural variations in somatization are reviewed. METHOD: Selective review was conducted of recent research literature and research findings from an epidemiological survey and ethnographic study of help-seeking and health care utilization of a random sample of 2246 residents in a Canadian urban multicultural milieu. RESULTS: Somatization is common in all ethnocultural groups and societies studied to date. However, significant differences in somatization across ethnocultural groups persist even where there is relatively equitable access to health care services. Analysis of illness narratives collected from diverse ethnocultural groups suggests that somatic symptoms are located in multiple systems of meaning that serve diverse psychological and social functions. Depending on circumstances, these symptoms can be seen as an index of disease or disorder, an indication of psychopathology, a symbolic condensation of intrapsychic conflict, a culturally coded expression of distress, a medium for expressing social discontent, and a mechanism through which patients attempt to reposition themselves within their local worlds. CONCLUSION: Major sources of differences in somatization among ethnocultural groups include styles of expressing distress ("idioms of distress"), the ethnomedical belief systems in which these styles are rooted, and each group's relative familiarity with the health care system and pathways to care. Psychological theories of somatization focused on individual characteristics must be expanded to recognize the fundamental social meanings of bodily distress.

Affective Symptoms↗

The distribution of psychiatric and somatic III health: associations with personality and socioeconomic status.

OBJECTIVE: Psychiatric and somatic disorders frequently co-occur in the same individuals. We examined whether this happens because these types of morbidity share risk factors or because they are risk factors for each other. METHODS: Negative binomial regression was used to examine, in a random sample of Dutch adults (N = 7076), cross-sectional associations of sociodemographic and personality variables like income and neuroticism with the presence, over 1 year, of 30 somatic and 13 psychiatric disorders, with the latter diagnosed by structured interview. We examined to what extent the links of these variables with these two morbidity types were independent of each other. RESULTS: This population experienced 5050 somatic and 2438 psychiatric disorders during the preceding year. Subjects reporting more somatic disorders had more psychiatric disorders. Neuroticism, followed closely by low educational attainment, was the strongest correlate of both morbidity types. After adjustment for all other covariates including somatic morbidity, the number of psychiatric diagnoses rose 1.84-fold (95% confidence interval = 1.74-1.94) per standard deviation increase in neuroticism. Likewise, adjusted for all other covariates including psychiatric diagnoses, 1.42 (95% confidence interval = 1.35-1.50) times more somatic disorders were reported per standard deviation increase in neuroticism. CONCLUSIONS: Personal features like neuroticism and low educational attainment are linked with psychiatric and with somatic morbidity. These links are largely independent. Although this study was cross-sectional, the results suggest that these different types of morbidity may have overlapping etiologies. Key words: Comorbidity, multimorbidity coefficient, negative binomial regression, epidemiology, neuroticism, social class.

Adult↗

Somatic complaints disproportionately contribute to Beck Depression Inventory estimates of depression severity in individuals with multiple chemical sensitivity.

A number of individuals with multiple chemical sensitivity (MCS) are also diagnosed with depression. However, there is content overlap in MCS and symptoms of depression with respect to somatic complaints. The Beck Depression Inventory (BDI) was used to document severity of depressive symptomatology in 42 individuals with MCS. The purpose was to determine the extent to which somatic complaints contributed to the total BDI score. Analysis of cognitive-affective and somatic-performance complaints subscale indicated a significantly higher mean item score on somatic-performance items, relative to cognitive-affective items (t = 6.43, P < 0.05). Consequently, the total BDI score classified a greater percentage (43%) of the sample as moderately depressed than did the cognitive-affective subscale score (29%). An item analysis of the BDI revealed that individuals with MCS tended to endorse more somatic-performance items than did a sample of depressed outpatients. Two alternative interpretations are possible: (a) the BDI total score overestimated severity of depressive symptomatology in this sample, and/or (b) individuals with MCS tended to express depressive symptomatology in terms of somatic complaints. It was recommended that until the etiology of MCS is better understood, caution be used when estimating severity of depressive symptomatology in individuals with MCS when measures include somatic items.

Adult↗

Distinctive patterns of medical care utilization in patients who somatize.

BACKGROUND: Somatizing patients have maladaptive and increased rates of medical care utilization. If there were a way of routinely identifying such patients, one that did not require intensive, case-by-case review, they could be targeted for specific interventions to improve their use of medical care. OBJECTIVE: We sought to identify patterns of medical care utilization that would distinguish somatizing and nonsomatizing medical outpatients with acceptable sensitivity and specificity. DESIGN: Subjects completed questionnaires assessing somatization and sociodemographic characteristics. Their medical care utilization was obtained for the 12 months preceding the index visit. We then used multivariable logistic regression and recursive partitioning to identify patients with a provisional diagnosis of somatoform disorder. These exploratory models used various patterns of medical care utilization and sociodemographic characteristics as the independent variables. SUBJECTS: We studied consecutive adults attending 2 primary care practices on randomly chosen days. MEASURES: The provisional diagnosis of a somatoform disorder was assessed with a 15-item self-report questionnaire. The number of primary care visits, specialty visits, mental health visits, emergency visits, and inpatient and outpatient costs were obtained for the 12 months preceding the index visit from our hospital's automated medical records, which also provided a rating of aggregate medical morbidity. Self-reported utilization outside our hospital system was obtained from a subsample of patients. RESULTS: Complete data were obtained on 1440 patients. Somatizing patients had more specialty care than primary care visits, higher outpatient than inpatient costs, and more emergency visits than nonsomatizing patients. A regression model containing 7 measures of utilization and 4 sociodemographic characteristics distinguished somatizing and nonsomatizing patients with a c-statistic = 0.73. Recursive partitioning identified 10 terminal nodes with a very high specificity (99%) but a very low sensitivity (15%). CONCLUSIONS: We identified 7 discrete patterns of medical care utilization that distinguished somatizing and nonsomatizing patients. However, they did so with only modest specificity and sensitivity. This algorithm might be used effectively as the first step in a 2-step screening procedure whose second step would entail more intensive screening or individual, case-by-case review to identify somatizing patients in primary care practice.

Adult↗

The relationship of somatization and depression to experimental pain response in women with temporomandibular disorders.

OBJECTIVE: Patients with temporomandibular pain disorders (TMD) have greater experimental pain perception when compared with pain-free controls. Common psychological features of TMD include somatization and depression. The impact of depression on experimental pain perception has received considerable attention. However, the role of somatization on experimental pain in a chronic pain population has not been explored. METHODS: Fifty-six women with TMD and 59 pain-free controls underwent three experimental pain procedures, including palpation at fixed amounts of pressure, pressure pain thresholds, and an ischemic pain task. Levels of depression and somatization were assessed using the Research Diagnostic Criteria for TMD. Multiple regression analyses were performed to determine the extent to which depression and somatization were associated with experimental pain response. RESULTS: After controlling for characteristic pain intensity and depression, somatization explained a significant proportion of variance in numbers of masticatory sites rated as painful (R2 change = 6.7%, p = .046) with the full model explaining 16.4% of the variance (p = .024). This did not meet an adjusted level of statistical significance (p = .008). After controlling for characteristic pain, only depression added significantly to the model predicting ischemic pain threshold and tolerance. The full models including characteristic pain and depression explained 49% and 20% of the variance in ischemic pain threshold and tolerance, respectively. CONCLUSIONS: These findings suggest that depression and somatization are associated with different measures of experimental pain. Somatization may be related to more attentional and perceptual measures of clinically relevant pain while depression may be related to more behavioral measures of pain.

Adolescent↗

Contrasting Storage Protein Synthesis and Messenger RNA Accumulation during Development of Zygotic and Somatic Embryos of Alfalfa (Medicago sativa L.).

During development on hormone-free media, somatic embryos pass through distinct morphological stages that superficially resemble those of zygotic embryo development (globular, heart, torpedo, cotyledonary stages). Despite these similarities, they differ from zygotic embryos in the extent of cotyledonary development and the patterns of synthesis and quantitative expression of seed-specific storage proteins (7S, 11S, and 2S proteins). Alfin (7S) is the first storage protein synthesized in developing zygotic embryos (stage IV). The 11S (medicagin) and 2S (Low Molecular Weight, LMW) storage proteins are not detectable until the following stage of development (stage V), although all three are present before the completion of embryo enlargement. Likewise, the 7S storage protein is the first to be synthesized in developing somatic embryos (day 5). Medicagin is evident by day 7 and the LMW protein by day 10. In contrast to zygotic embryos, alfin remains the predominant storage protein in somatic embryos throughout development. Not only are the relative amounts of medicagin and the LMW protein reduced in somatic embryos but the LMW protein is accumulated much later than the other proteins. Quantification of the storage protein mRNAs (7S, 11S, and 2S) by northern blot analysis confirms that there are substantial differences in the patterns of message accumulation in zygotic and somatic embryos of alfalfa (Medicago sativa). In zygotic embryos, the 7S, 11S, and 2S storage protein mRNAs are abundant during maturation and, in particular, during the stages of maximum protein synthesis (alfin, stages VI and VII; medicagin, stage VII; LMW, stage VII). In somatic embryos, the predominance of the 7S storage protein is correlated with increased accumulation of its mRNA, whereas the limited synthesis of the 11S storage protein is associated with much lower steady-state levels of its message. The mRNA for the LMW protein is present already by 3 days after transfer to hormone-free media, yet that protein is not evident on stained gels until day 10. Thus, both transcriptional and posttranscriptional events appear to be important in determining the protein complement of these seed tissues. On the basis of storage protein and mRNA accumulation, mature (14 days) somatic embryos most closely resemble stage VI zygotic embryos. The results of the developmental comparison also suggest that the patterns of synthesis of the individual storage proteins (7S, 11S, or 2S) are regulated independently of each other during embryogenesis in alfalfa.

Journal Article↗

Nocturia in relation to somatic health, mental health and pain in adult men and women.

OBJECTIVE: To assess the relationship of nocturia to somatic health, mental health and bodily pain. SUBJECTS AND METHODS: A randomly selected group of men and women aged 20-64 years, living in three small municipalities in northern Sweden, or in the city of Ostersund or in Stockholm, were sent a postal questionnaire containing questions on somatic and mental health, satisfaction with life, pain, nocturnal voiding, work and sick-listing from work. RESULTS: Reports (from 1948 respondents) on poor somatic and mental health and on pain all increased in parallel with increasing frequency of nocturnal voids. In a multiple logistic regression analysis with sex, age, somatic health, mental health and bodily pain as the independent variables, significant independent correlates (odds ratios, confidence intervals) of nocturnal micturition (two or more episodes vs none or one) were: age 45-59 vs 20-44 years, 1.9 (1.3-2.7), > or =60 vs 20-44 years, 3.8 (2.4-6.0); somatic health, poor vs good, 2.3 (1.4-3.7); mental health, poor vs good, 1.9 (1.2-3.0); pain, rather mild vs very mild or none, 1.5 (1.0-2.3); rather severe vs very mild or none, 1.9 (1.1-3.2); and very severe vs very mild or none, 6.0 (2.5-14.0). Gender was deleted by the logistic model. Sick-listing for > or = 60 days during the past year was reported by 4.9%, 10.6%, 5.6% and 38.9% of the men with none, one, two or > or = three nocturnal voids, respectively, and by 10%, 12.4%, 23% and 46.7% (both P < 0.001) of the corresponding women, respectively. Life satisfaction decreased in parallel with increased nocturia. CONCLUSION: The impairment of both somatic and mental health was associated with increased nocturnal voiding. Pain was associated with a substantial increase in nocturia after adjusting for age and somatic and mental health. Sick-leave was more common in association with more nocturnal voids.

Adult↗

Somatic symptoms in headache patients: the influence of headache diagnosis, frequency, and comorbidity.

BACKGROUND: Mood disorders of anxiety and depression are well known to be comorbid with primary headache disorders. Less is known of the comorbidity of other somatic symptoms with headache. METHODS: Headache Clinic patients were screened with the Primary Care Evaluation of Mental Disorders (PRIME-MD), a multidimensional psychiatric screening tool. The prevalence of somatic symptoms was compared by headache diagnosis, frequency of severe headache, and psychiatric diagnosis. Follow-up data were obtained 6 months after consultation. RESULTS: Clinical diagnoses and PRIME-MD data were available for 289 patients. Associated somatic symptoms were more frequent in patients with chronic migraine (mean 5.5, P<.001) and chronic daily headache (CDH) (6.3, P=.008) compared to episodic migraine (4.0); in patients with severe headache >2 days per week compared to 2 days per week had significantly higher somatic counts (P=.01). Six-month follow-up data were available for 140 patients. Associated symptoms decreased both for patients with and without decrease in severe headache frequency (mean reduction of 1.0, P=.01 and 0.8, P=.003, respectively). CONCLUSION: Associated somatic symptoms are more common in patients with chronic migraine and CDH, with more frequent severe headaches, and with associated anxiety or depression. Patients with episodic migraine have similar somatic prevalence as a previously studied primary care population. The spectrum of headache disorders may be characterized as showing increasing somatic prevalence as headaches, particularly severe headaches, become more frequent.

Adult↗

Brain responses to visceral and somatic stimuli in patients with irritable bowel syndrome with and without fibromyalgia.

OBJECTIVE: Symptoms of irritable bowel syndrome (IBS) and fibromyalgia (FM) commonly coexist. We hypothesized that one of the mechanisms underlying this comorbidity is increased activation of brain regions concerned with the processing and modulation of visceral and somatic afferent information, in particular subregions of the anterior cingulate cortex (ACC). METHODS: Regional cerebral blood flow (rCBF) was assessed in age-matched female IBS (n = 10) and IBS + FM (n = 10) subjects using H(2)(15)O positron emission tomography during noxious visceral (rectal) and somatic pressure stimuli. RESULTS: GI symptom severity was significantly higher in the IBS patients compared with the IBS + FM patients (p < 0.05). In addition, IBS + FM patients rated somatic pain as more intense than their abdominal pain (p < 0.05). Whereas the somatic stimulus was less unpleasant than the visceral stimulus for IBS patients without FM, the somatic and visceral stimuli were equally unpleasant in the IBS + FM group. Group differences in regional brain activation were entirely within the middle subregion of the ACC. There was a greater rCBF increase in response to noxious visceral stimuli in IBS patients and to somatic stimuli in IBS + FM patients. CONCLUSION: Chronic stimulus-specific enhancement of ACC responses to sensory stimuli in both syndromes may be associated with cognitive enhancement of either visceral (IBS) or somatic (IBS + FM) sensory input and may play a key pathophysiologic role in these chronic pain syndromes.

Adult↗

Hypothalamic influences on viscero-somatic neurones in the lower thoracic spinal cord of the anaesthetized rat.

1. Single unit electrical activity has been recorded from thirty-four viscero-somatic neurones in the dorsal horn of the lower thoracic spinal cord (T9-T11) of chloralose-anaesthetized rats. All neurones were driven by natural and/or electrical stimulation within their somatic receptive fields and gave excitatory responses to electrical stimulation of the ipsilateral splanchnic nerve. Descending influences on these neurones were tested by electrical and chemical (microinjections of DL-homocysteic acid) stimulation of sites in the rostral hypothalamus. 2. The electrical activity of most viscero-somatic neurones (64%) was inhibited by electrical stimulation at sites throughout the anterior hypothalamus-preoptic region. In any one cell, responses to stimulation of visceral and somatic afferent fibres were inhibited to the same extent and any on-going activity was also depressed. Only one cell was driven by the conditioning stimulus and the electrical activity of the remaining cells (n = 7) was unaffected. 3. At certain hypothalamic sites the effects of electrical conditioning stimulation on the responses of viscero-somatic neurones were compared with those of local microinjection of DL-homocysteic acid. Electrical stimulation at all sites tested (n = 7) led to an inhibition of on-going and evoked neuronal activity. At two hypothalamic sites, both located in the ventral part of the preoptic area, microinjection of DL-homocysteic acid resulted in a complete abolition of the responses to the test stimuli and in a cessation of any on-going activity. Microinjection of DL-homocysteic acid at the remaining five sites had no detectable influences on dorsal horn activity. 4. The results of this study include the first description of input properties of viscero-somatic neurones in the lower thoracic spinal cord of the rat. In addition, these results demonstrate that transmission of visceral and somatic information through these neurones can be modulated by pathways that originate in the anterior hypothalamus-preoptic region of the ventromedial forebrain.

Action Potentials↗

Acute nociceptive somatic stimulus sensitizes neurones in the spinal cord to colonic distension in the rat.

The common co-existence of fibromyalgia and chronic abdominal pain could be due to sensitization of spinal neurones (SNs), as a result of viscero-somatic convergence. The objective of this study is to explore the influence of acute nociceptive somatic stimulation in the form of acid injections, into the ipsilateral somatic receptive field of neurones responsive to colorectal distension (CRD), and the potential role of ionotropic glutamate receptors on sensitization. Action potentials of CRD-sensitive SNs were recorded extracellularly from the lumbar (L(2)-L(5)) spinal cord. Stimulus-response functions (SRFs) to graded CRD (10-80 mmHg, 30 s) were constructed before and 30 min after ipsilateral injection of low pH (4.0, 100 microl) saline into the somatic receptive fields. In some experiments, cervical (C(1)-C(2)) spinalization was performed to eliminate supraspinal influence. The selective NMDA receptor antagonist CGS 19755 and AMPA receptor antagonist NBQX were injected (25 micromol kg(-1), i.v.) to examine their influence on sensitization. Three types of neurones were characterized as short-latency abrupt (SLA, n = 24), short latency sustained (SLS, n = 12), and long-latency (LL, n = 6) to CRD. Ipsilateral injection of low pH (4.0) in the somatic receptive field, but not the contralateral gastrocnemius (GN) or front leg muscles, sensitized responses of these neurones to CRD. Spinalization had no influence on the development of low pH-induced sensitization. Both CGS 19755 and NBQX significantly attenuated the sensitized response to CRD in intact and spinalized animals. Acute nociceptive somatic stimulus sensitizes CRD-sensitive SNs receiving viscero-somatic convergence. The sensitization occurs at the spinal level and is independent of supraspinal influence. Ionotropic glutamate receptors in the spinal cord are involved in sensitization.

Acids↗

How fatigue is related to other somatic symptoms.

AIMS: To assess the relation between fatigue and somatic symptoms in healthy adolescents and adolescents with chronic fatigue syndrome/myalgic encephalopathy (CFS/ME). METHODS: Seventy two adolescents with CFS were compared within a cross-sectional study design with 167 healthy controls. Fatigue and somatic complaints were measured using self-report questionnaires, respectively the subscale subjective fatigue of the Checklist Individual Strength (CIS-20) and the Children's Somatization Inventory. RESULTS: Healthy adolescents reported the same somatic symptoms as adolescents with CFS/ME, but with a lower score of severity. The top 10 somatic complaints were the same: low energy, headache, heaviness in arms/legs, dizziness, sore muscles, hot/cold spells, weakness in body parts, pain in joints, nausea/upset stomach, back pain. There was a clear positive relation between log somatic symptoms and fatigue (linear regression coefficient: 0.041 points log somatic complaints per score point fatigue, 95% CI 0.033 to 0.049) which did not depend on disease status. CONCLUSIONS: Results suggest a continuum with a gradual transition from fatigue with associated symptoms in healthy adolescents to the symptom complex of CFS/ME.

Adolescent↗

Processing of splanchnic and somatic input in thoracic spinal cord of the rat.

To better understand the spinal transmission of visceral afferent information, we conducted neurophysiological studies of single spinal neurons that receive input from the greater splanchnic nerve (GSN). Extracellular single-neuron recordings were made in the thoracic spinal cord of chloralose-anesthetized, paralyzed, and artificially ventilated rats, some of which had undergone acute spinal transection at C1. Neurons were divided into four classes according to their responses to GSN stimulation: one-burst excitatory, two-burst excitatory, biphasic, and inhibited. We then studied the characteristics of the convergent somatic input to each class of neurons using either natural somatic stimuli or electrical stimulation of the iliohypogastric nerve (IHN). Most splanchnic input was mediated by unmyelinated fibers, whereas somatic input was mediated by both unmyelinated and small myelinated fibers. Most of the neurons exhibited somatic receptive fields, and the majority responded to both innocuous and noxious somatic stimuli. However, a small number could be excited only by GSN stimulation. Although a careful analysis of response characteristics indicated that there was a tendency for neurons to exhibit similar responses to electrical stimulation of the GSN and the IHN, we observed many combinations of somatic and visceral responses. We suggest that visceral afferent activity, in addition to being processed via convergent somatovisceral pathways, may be processed by neurons that convey only visceral information or by neurons in which visceral and somatic information is differentially coded.

Afferent Pathways↗

Nonequivalent visual, auditory, and somatic corticotectal influences in cat.

1. The effects of cortical cooling on the responses of cells to visual, somatic, and acoustic stimuli were studied in the cat superior colliculus (SC). When the visual cortex was cooled, the responses of many visual cells of the SC were depressed or eliminated, but the activity of nonvisual cells remained unchanged. This response depression was found in visual cells located in both superficial and deep laminae and was most pronounced in neurons which were binocular and directionally selective. 2. Cooling somatic and/or auditory cortex had no effect on visual SC cells and, with few exceptions, did not alter the activity of somatic or acoustic cells either. 3. The specificity of visual cortex influences on visual responding in the SC was most apparent in multimodal cells. In trimodal cells, the simultaneous cooling of visual, somatic, and auditory cortex eliminated responses to visual stimuli, but did not affect responses to somatic or acoustic stimuli. Visual responses were returned to the precooling level in both unimodal and multimodal cells by cortical rewarming. 4. The present experiments indicate that despite the organizational parallels among visual, somatic, and acoustic cells of the cat SC, the influences they receive from cortex are non-equivalent. Cortical influences appear to play a more critical role in the responses of visual cells than in the responses of somatic and acoustic cells. These observations raise questions about the functional significance of nonvisual corticotectal systems.

Animals↗

Exploring the relations between depression, somatization, dissociation and alexithymia--overlapping or independent constructs?

BACKGROUND: The aim of this study was to extend our knowledge of associations among the constructs of alexithymia, depression, somatization and dissociation. SAMPLING AND METHODS: 924 nonclinical subjects answered questions about depression (21-item Beck Depression Inventory), somatization (13-item somatization part of Symptom Check List-90), dissociation (28-item Dissociative Experiences Scale) and alexithymia (20-item Toronto Alexithymia Scale). In addition, a 12-item General Health Questionnaire (GHQ-12) was administered to detect psychiatric distress among subjects. RESULTS: The results suggested that there was a significant clinical correlation between somatization, dissociation, depression and alexithymia (rho varied from 0.31 to 0.56). The principal component analysis revealed the presence of four components: depression, somatization, dissociation and alexithymia. The use of factor scores diminished the covariance between measures (rho varied from -0.10 to 0.01 between the factor scores). There was almost no correlation between the dissociation factor (rho = 0.06) and alexithymia factor (rho = 0.09) scores and general distress (GHQ-12). CONCLUSIONS: This study suggests that while somatization, dissociation, depression and alexithymia are distinct constructs, they correlate to a considerable extent. The use of factor analysis and factor scores should be considered to diminish covariance between the above constructs. Comparing results between factored and unfactored results may prove illuminating. As a case in point, the results suggest that the part of dissociation that coincides with other constructs (overlaps) is associated with distress, whereas the distinct part of dissociation (no shared covariance) is not associated with distress. The same applies to the alexithymia construct. Longitudinal studies are needed to show whether there is a trait such as a relatively stable dissociation component and also whether a separate state-dependent dissociation component exists that is associated with coincident distress, somatization and depression.

Adolescent↗