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Results for “sensory function”

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PubMed2000

The apical membrane of intestinal brush cells possesses a specialised, but species-specific, composition of glycoconjugates--on-section and in vivo lectin labelling in rats, guinea-pigs and mice.

Brush cells are specialised epithelial cells that are assumed to represent chemoreceptors of the digestive tract. They comprise a small population of the epithelial cells lining the intestine, possess a unique ultrastructure and, in many aspects, resemble the receptor cells of taste buds. To characterise glycoconjugates possibly involved in a sensory function, we investigated brush cells in the small intestine of three species using lectin histochemistry in confocal light and thin-section electron microscopy. Brush cells of rats were selectively labelled by the sialic acid-specific lectin Maackia amurensis agglutinin, those of guinea-pigs by the D-galactose-specific lectin Bandeiraea simplicifolia agglutinin, isolectin B4 and those of mice by the L-fucose-specific lectin Ulex europaeus agglutinin lectin I. Lectin binding sites were consistently located in the glycocalyx of the apical membrane and in that of cytoplasmic vesicles. In vivo lectin labelling revealed that the glycoconjugates of the apical membrane are accessible under physiological conditions, that brush cells do not endocytose and that they probably possess a high membrane turnover rate. The results show that specialisations exist in the composition of glycoconjugates forming the glycocalyx of brush cells in all species investigated. The presence of brush cell-specific glycoconjugates would be in accordance with the current hypothesis of a receptive function of brush cells. Differences in the specific glycosylation patterns among rats, guinea-pigs and mice indicate that species-specific adaptations exist.

Animals↗

PubMed2000

Nitric oxide uncouples gap junctions of supporting Deiters cells from Corti's organ.

Supporting cells of Corti's organ are electrically coupled via gap junctions. They probably serve to maintain the unique cochlear environment that is required for normal sensory function. In this study we used input capacitance measurements under whole-cell voltage-clamp conditions to evaluate the effects of nitric oxide on gap junctional communication between pairs of isolated supporting Deiters cells. We show that the nitric oxide (NO) donor sodium nitroprusside causes the uncoupling of Deiters cells, and that an NO synthase inhibitor blocks the effect. The cGMP analogue 8-bromo-cGMP also uncouples Deiters cells. With either treatment, the input capacitance of pairs of Deiters cells drops to single-cell levels within minutes of application, indicative of electrical uncoupling. We surmise that the NO/cGMP pathway may serve to modulate normal cochlear homeostasis and possibly plays a role in ototoxic mechanisms.

Animals↗

PubMed2004

New morphological data on Cheilospirura hamulosa (Nematoda, Acuarioidea) by means of bright-field and scanning electron microscopy.

This study reports on the morphology and morphometry of the nematode Cheilospirura hamulosa on the basis of bright-field and scanning electron microscopy. Specimens were recovered after necropsies of 28 Brazilian ring-necked pheasants ( Phasianus colchicus) and 30 domestic chickens ( Gallus g. domesticus) from backyard flocks. Measurements relate to the buccal capsule in the males and the distance of the excretory pore from the anterior end in both sexes, while the vulva and ovijector are studied for the first time. The most important taxonomic characters for the diagnosis of this nematode are the four long, longitudinal cordons which are neither anastomosed nor recurrent. They are composed of a groove with margins formed by cuticular specializations that change in appearance and width backward along the body and which run backward from the cephalic region ending near the posterior end as a cuticular depression. According to their morphology, these cordons could probably have nutritional, attachment and/or sensory functions.

Animals↗

PubMed1996

Occurrence of epidermal nerve endings in glabrous and hairy skin of the rat foot after sciatic nerve regeneration.

The occurrence and distribution of intraepidermal nerve endings in hairy and glabrous skin of the rat foot was examined in normal cases and three months after sciatic neurotomy/suture or a crush lesion. The nerve endings were visualized in cryostate sections with antibodies against protein gene product 9.5. Normal glabrous skin exhibited 23.3 endings/mm length. Neurotomy/suture cases had 6.1 endings/mm. In rats with nerve crush injury the occurrence was normal, but the intraepidermal nerve endings tended to be abnormally short and occurred mainly in the basal layer of the epidermis. In sections from hairy skin countings were not possible. Subjective evaluation indicated that the occurrence of dermal and epidermal axon profiles usually was very deficient after neurotomy/suture and essentially normal after crush. Skin samples from the contralateral side of operated animals showed a normal occurrence and distribution of nerve endings. We also noted that cases subjected to neurotomy/suture showed increased numbers of protein gene product 9.5-immunoreactive intraepidermal cells and an abnormally thin epidermis. We suggest that a highly deficient occurrence of intraepidermal nerve endings may be one factor behind the unsatisfactory restitution of the sensory function of the hand typically seen in patients subjected to neurotomy and suture.

Animals↗

PubMed1997

Projections and neurochemical coding of myenteric neurons innervating the mucosa of the guinea pig proximal colon.

Myenteric neurons projecting to the mucosa of the guinea pig proximal colon were identified using the combination of a neuronal tracing method and immunohistochemical techniques. The tracer DiI (1, 1'didodecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) was applied onto the mucosa of a specimen of proximal colon which was then placed in organotypic culture to allow retrograde transport of the dye. After culture, the myenteric plexus was stained with antisera raised against choline acetyltransferase (ChAT) and calbindin (Calb). Of the myenteric neurons labeled with DiI, 99% had smooth cell bodies with Dogiel Type II morphology. Of these neurons, 70% projected in the longitudinal direction and the majority of them (65%) were located anally from the DiI application site, i.e., had ascending projections. Ascending neurons projected over significantly shorter distances than descending ones (3.1+/-0.5 mm vs. 4.6+/-1.2 mm, respectively; P<0.01). Of the labeled myenteric neurons, 98% were ChAT immunoreactive. Of these neurons, 78% were also immunoreactive for Calb and were preferentially ascending neurons. ChAT-immunoreactive but Calb-negative neurons did not have preferential projection. This study revealed the presence of two populations of myenteric neurons projecting to the mucosa of the guinea pig proximal colon. Morphological characteristics and neurochemical coding were suggestive for a putative sensory function for these neurons.

Animals↗

PubMed1998

Remodeling of neural, glial, and tracheal cell populations in the developing manduca wing

This ultrastructural examination of sensory nerves of the Manduca wing has revealed that extensive remodeling occurs among insect sensory neurons and their associated glial cells between pupation and adult emergence. Systematic counts of axons in particular wing nerves throughout adult development have shown that a decrease in axon number per nerve occurs after day 6. The neurons and glial cells that die are believed to be cells present at pupation that have no apparent sensory function but that probably function as guidance scaffolding for neurons and glia that are born after pupation. Despite the loss of several axons from each wing nerve, these nerves continue to grow in diameter during the latter half of adult development as some of the surviving axons increase severalfold in diameter. Each growing wing nerve in turn apparently functions as a scaffold for the proximal to distal growth of adult tracheae. A correspondence exists between adult nerve pathways and adult tracheal pathways, with each trachea maintaining intimate contact with a wing nerve along its entire length.

Journal Article↗

PubMed2001

The spinal nerves innervate putative chemosensory cells in the ventral skin of desert toads, Bufo alvarius.

Toads normally obtain water by absorption across their skin from osmotically dilute sources. When hyperosmotic salt solutions are presented as a hydration source to dehydrated desert toads, they place the ventral skin onto the source but soon afterwards escape to avoid dehydration. The escape behavior coincides with neural excitation of the spinal nerves that innervate putative chemosensory cells in the ventral skin. In the present study, fluorescent dye translocated through the spinal nerves to those receptor cells in the epidermis was photoconverted in the presence of 3, 3'-diaminobenzidine tetrahydrochloride for electron-microscopic observation of the cells and associated nerve terminals. Most of the photoconverted cells were located in the deepest layer of the epidermis, with some being in more intermediate layers. No labeled cell was seen in the outermost layer of living cells. In desert toads, flask cells and Merkel cells are occasionally seen in the epidermis. An association of nerve fibers with these epidermal cells has been reported in some species of the anurans. In the present study, however, the cytological features of the photoconverted cells are neither reminiscent of flask cells nor Merkel cells, but are similar to those of surrounding epithelial cells in each layer of the epidermis. We hypothesize a sensory function for these cells, because they have a close association with nerve fibers and participate in the transepithelial transport of salts that must pass through all cell layers of the skin.

Animals↗

PubMed2000

Pituitary adenylate cyclase-activating polypeptide in intrinsic and extrinsic nerves of the rat pancreas.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is the latest member of the vasoactive intestinal polypeptide (VIP) family of neuropeptides present in nerve fibres in many peripheral organs. Using double immunohistochemistry, with VIP as a marker for intrinsic innervation and calcitonin-gene related peptide (CGRP) as a marker for mainly extrinsic innervation, the distribution and localization of PACAP were studied in the rat pancreas. PACAP was demonstrated in nerve fibres in all compartments of the pancreas and in a subpopulation of intrapancreatic VIP-containing ganglion cells. PACAP and VIP were co-stored in intra- and interlobular nerve fibres innervating acini, blood vessels, and in nerve fibres within the islets of Langerhans. No PACAP immunoreactivity was observed in the islet cells. Another population of PACAP-immunoreactive nerve fibres co-localized with CGRP innervated ducts, blood vessels and acini. PACAP/CGRP-positive nerve fibres were also demonstrated within the islets. Neonatal capsaicin reduced the PACAP-38 concentration by approximately 50%, and accordingly a marked reduction in PACAP/CGRP-immunoreactive nerve fibres in the exocrine and endocrine pancreas was observed. Bilateral subdiaphragmatic vagotomy caused a slight but significant decrease in the PACAP-38 concentration compared with controls. In conclusion, PACAP-immunoreactive nerve fibres in the rat pancreas seem to have dual origin: extrinsic, most probably sensory fibres co-storing CGRP; and intrinsic, constituting a subpopulation of VIP-containing nerve cell bodies and fibres innervating acinar cells and islet cells. Our data provide a morphological basis for the reported effects of PACAP in the pancreas and suggest that PACAP-containing nerves in the rat pancreas may have both efferent and sensory functions.

Animals↗

PubMed2003

Dysphagia evaluation practices: inconsistencies in clinical assessment and instrumental examination decision-making.

The purpose of this study was to determine the nature of swallowing evaluation practices in western Washington, specifically in terms of (a) components of the clinical examination most commonly used, (b) consistency of clinical examination practices across clinicians, and (c) consistency of clinical decision-making (instrumental vs. noninstrumental) given specific patient scenarios. A 21-question survey was sent to 150 speech-language pathologists who provide services to dysphagia patients. Of the 72 (48%) surveys that were returned, 64 provided the data for the study. The results revealed that clinicians who responded to the survey differ somewhat regarding which components they include in a clinical examination of swallowing. There was a high degree of consistency for 11 of the 19 components. Inconsistency across clinicians was revealed in four areas: assessment of sensory function, assessment of the gag reflex, cervical auscultation, and assessment of trial swallows using compensatory techniques. Clinicians agreed in their recommendations on two of the six clinical case scenarios. In general, participating clinicians varied widely in their clinical decision-making. These findings are compared with other studies where variability in clinical practice has raised concerns.

Decision Making↗

PubMed2001

[Relevance of nerve blocks in treating and diagnosing low back pain--is the quality decisive?].

Diagnostic nerve blocks: The popularity of neural blockade as a diagnostic tool in painful conditions, especially in the spine, is due to features like the unspecific character of spinal pain, the irrelevance of radiological findings and the purely subjective character of pain. It is said that apart from specific causes of pain and clear radicular involvement with obvious neurological deficits and corresponding findings of a prolapsed disc in MRI or CT pictures, a diagnosis of the anatomical cause of the pain can only be established if invasive tests are used [5]. These include zygapophyseal joint blocks, sacroiliacal joint blocks, disc stimulation and nerve root blocks. Under controlled conditions, it has been shown that among patients with chronic nonradicular low back pain, some 10-15% have zygapophyseal joint pain [58], some 15-20% have sacroiliacal joint pain [36, 59] and 40% have pain from internal disc disruption [60]. The diagnostic use of neural blockade rests on three premises. First, pathology causing pain is located in an exact peripheral location, and impulses from this site travel via a unique and consistent neural root. Second, injection of local aneasthetic totally abolishes sensory function of intended nerves and does not affect other nerves. Third, relief of pain after local anaesthetic block is attributable solely to block of the target afferent neural pathway. The validity of these assumptions is limited by complexities of anatomy, physiology, and psychology of pain perception and the effect of local anaesthetics on impulse conduction [28]. Facet joints: The prevalence of zygapophyseal joint pain among patients with low back pain seems to be between 15% and 40% [62], but apparently only 7% of patients have pure facet pain [8, 29]. Facet blockade is achieved either by injection of local anaesthetic into the joint space or around the medial branches of the posterior medial rami of the spinal nerves that innervate the joint. There are several problems with intraarticular facet injections, mainly failure to enter the joint capsule and rupture of the capsule during the injection [11]. There is no physiological means to test the adaequacy of medial nerve block, because the lower branches have no cutaneous innervation. Medial ramus blocks (for one joint two nerves have to be infiltrated) are as effective as intraarticular joint blocks [37]. Reproducibility of the test is not high, the specifity is only 65% [61]. For diagnosis of facet pain fluoroscopic control is always necessary as in the other diagnostic blocks. Sacroiliacal joint: Definitely the sacroiliacal joint can be the source of low back pain. Stimulation of the joint by injection in subjects without pain produces pain in the buttock, in the posterior thigh and the knee. There are many clinical tests which confirm the diagnosis, but the interrater reliability is moderate [53]. Intraarticular injection can be achieved in the lower part of the joint with fluoroscopic guidance only, but an accurate intraarticular injection, which is confirmed by contrast medium, even at this place is often difficult. It is not clear whether intraarticular spread is necessary to achieve efficacy. Discography: Two primary syndromes concerning the ventral compartment have been described: anular fissures of the disc and instability of the motion segment. In the syndrome of anular tear, leakage of nucleus pulposus material into the anulus fibrosus is considered to be the source of pain. The studies of Vaharanta [71] and Moneta [41] show a clear and significant correlation between disc pain and grade 3 fissures of the anulus fibrosus. intervertebral discs are difficult to anaesthetize. Intradiskal injections of local anaesthetics may succeed in relieving the patient's pain, but such injections are liable to yield false negative results if the injected agent fails to adequately infiltrate the nerve endings in the outer anulus fibrosus that mediate the patient's pain. In the majority of cases MRI provide adaequate information, but discography may be superior in early stages of anular tear and in clarifying the relation between imaging data and pain [71]. Selective spinal nerve injection: In patients with complicated radiculopathy, the contribution of root inflammation to pain may not be certain, or the level of pathology may be unclear. Diagnostic root blocks are indicated in the following situations: atypical topography of radicular pain, disc prolapses or central spinal stenosis at more than one level and monoradicular pain, lateral spinal stenosis, postnucleotomysyndrome. Injection of individual spinal nerves by paravertebral approach has to be used to elucidate the mechanism and source of pain in this unclear situations. The premise is that needle contact will identify the nerve that produces the patient's characteristic pain and that local anaesthetic delivered to the pathogenic nerve will be uniquely analgesic. Often, this method is used for surgical planning, such as determining the site of foraminotomy. All diagnostic nerve root blocks have to be done under fluoroscopic guidance. Pain relief with blockade of a spinal nerve cannot distinguish between pathology of the proximal nerve in the intervertebral foramen or pain transmitted from distal sites by that nerve. Besides, the tissue injury in the nerve's distribution and neuropathic pain (for instance as a result of root injury) likewise would be relieved by a proximal block of the nerve. Satisfactory needle placement could not be achieved in 10% of patient's at L4, 15% at L5 and 30% at S1 [28]. The positive predictive value of indicated radiculopathy confirmed by surgery ranged between 87-100% [14, 22]. The negative predictive value is poorly studied, because few patients in the negative test group had surgery. Negative predictive values were 27% and 38% of the small number of patients operated on despite a negative test. Only one prospective study was published, which showed a positive predictive value of 95% and an untested negative predictive value [66]. Some studies repeatedly demonstrated that pain relief by nerve root block does not predict success by neuroablative procedures, neither by dorsal rhyzotomy nor by dorsal gangliectomy [46]. Therapeutic nerve blocks - facet joints: Intraarticular injection of steroids offer no greater benefit than injections of normal saline [8, 15] and long lasting success is lacking. In this case, a denervation of the medial branches can be considered. To date three randomized controlled studies of radiofrequency facet denervation have been published. One study [20] reported only modest outcomes and its results remained inconclusive, another study [72] with a double blind controlled design showed some effects in a small selected group of patients (adjusted odds ratio 4.8) 3, 6 and 12 months after treatment, concerning not only reduction of pain but alleviating functional disability also. The third study (34a) showed no effect 3 months after treatment. Discogenic pain: Intradiscal radiofrequency lesions, intradiscal injections of steroids and phenol have been advocated, but there are no well controlled studies. Just recently, intradiscal lesion and denervation of the anulus has been described with promising results, but a randomized controlled study is lacking up to now [31, 55]. Epidural Steroids: Steroids relieve pain by reducing inflammation and by blocking transmission of nociceptive C-fiber input. Koes et al. [33] reviewed the randomized trials of epidural steroids: To date, 15 trials have been performed to evaluate the efficacy, 11 of which showed method scores of 50 points (from 100) ore more. The trials showed inconsistent results of epidural injections. Of the 15 trials, 8 reported positive results and 7 others reported negative results. Consequently the efficacy of epidural steroid injections has not yet been established. The benefits of epidural steroid injections seem to be of short duration only. Future efficacy studies, which are clearly needed, should take into account the apparent methological shortcomings. Furthermore, it is unclear which patients benefit from these injections. In our hands the injection technique can be much improved by fluoroscopic guidance of the needle, with a prone position of the patient, and lateral injection at the relevant level and with a small volume (1-2 ml) and low dose of corticosteroid (20 mg triamcinolone in the case of a monoradicular pain, for example). In the case of epidural adhesions in postoperative radicular pain [50], the study of Heafner showed that the additional effect of hyaloronidase and hypertonic saline to steroids was minimal. In our hands there was no effect in chronic radicular pain 3 months after the injection.

Humans↗

PubMed1990

Effects of nitrous oxide on the somatosensory evoked response in cats.

The effect of nitrous oxide on the activity of the somatosensory system was studied in cats with brain electrodes implanted chronically. The electrodes were implanted in the primary somatosensory cortex, cortical somatosensory radiation, medial lemniscus and midbrain reticular formation. Alterations in the excitability of the primary sensory pathway were assessed by the changes of the input to and output from these brain areas: the response in the medial lemniscus to the stimulation of the skin represented the input to the thalamic relay nucleus and the response recorded in the cortical sensory radiation represented the output from the thalamic relay nucleus. The concentrations of nitrous oxide studied were 50% and 75% in oxygen, and the drug effect was concentration-related. The cortical response to peripheral stimulation was suppressed in amplitude by more than 40% of the control with 75% nitrous oxide, and the response in the cortical radiation was suppressed by 20% of the control with the same dose of nitrous oxide. The response in the cortical radiation to stimulation of the medial lemniscus was suppressed by 20% of the control and the postsynaptic component of the cortical response to the stimulation of the medial lemniscus was suppressed by more than 50% of the control. The multi-unit activity of the brainstem reticular formation was enhanced by nitrous oxide in a dose related manner. The excitability of the thalamic relay nucleus and the primary somatosensory cortex was suppressed by natural slow wave sleep when the reticular multi-unit activity was suppressed, and they were enhanced by paradoxical phase of sleep when the reticular multi-unit activity was enhanced. These findings indicated that the degree of suppression of excitability by nitrous oxide is similar in both the thalamic relay nucleus and sensory cortex, and its action on the brain stem reticular formation is different from that on the primary sensory system. The suppression of sensory functions shown in the present study provides a certain clue to the understanding of the neural basis that though nitrous oxide does not produce deep surgical anesthesia, it does induce potent analgesia and sedation during surgery.

Journal Article↗

PubMed2000

Microsurgical treatment of spontaneous and non-spontaneous spinal epidural haematomas: neurological outcome in relation to aetiology.

BACKGROUND: This retrospective study evaluated the neurological outcome of 26 patients with spontaneous and non-spontaneous spinal epidural haematoma (SEH) who underwent microsurgical clot removal. It was the objective of the present study to investigate whether the aetiology of the SEH has an influence on the neurological outcome. METHODS: The medical records and radiological investigations of 26 patients with SEH were re-examined, and the latency between symptom onset and operation, and the size of the haematoma were determined. Motor and sensory function had been evaluated before surgery and 90 days after discharge. FINDINGS: Fourteen patients with non-spontaneous SEH and 12 patients with spontaneous SEH were identified. After surgery, neurological deficits improved in 9 of the patients with spontaneous (75%) and in 13 of the patients with non-spontaneous SEH (93%). In cases of spontaneous SEH, the median latency between symptom onset and operation was longer (72 hrs vs 7 hrs) and the median extent of the haematoma was larger (3.5 vs 2 spinal segments), than in the non-spontaneous cases. INTERPRETATION: Neurological outcome seems to be related to the aetiology of the SEH. Better outcome was observed in patients with surgically treated non-spontaneous SEH. Two explanations for this finding are worth considering. First, patients with non-spontaneous SEH usually are already under medical surveillance and can undergo medullary decompression more rapidly. Second, the compression of the spinal cord is possibly less severe in non-spontaneous SEH because of their smaller size.

Adolescent↗

PubMed2004

Present situation and future aspects of spinal cord regeneration.

The central nervous system (CNS) has a limited capacity for regeneration after injury. In spinal cord injury (SCI) patients, total loss of all motor and sensory function occurs below the level of injury. Advances in treatment are expected for orthopedic and spinal surgeons. Recently, evidence of axonal regeneration and functional recovery has been reported in animal spinal cord injury models. Our studies on the roles of inhibitory molecules with a comparison between neonatal and adult animals may help serve as therapeutic targets to enhance axonal regeneration for the injured spinal cord. Also, our cell replacement study indicates the possibility of transplanting neural stem cells to supply the cell source for immature oligodendrocytes, which are thought to be essential for both the myelination and trophic support of regenerating axons in the spinal cord. Administration of neurotrophic factors, prevention of inhibitory factors, and stem cell technology have clinical applications in SCI patients. However, spinal cord regeneration involves a multistep process, and several factors have to be controlled after injury. A combination of several treatments could overcome a nonpermissive environment for spinal cord regeneration. Further understanding of the mechanisms and finding optimal targets of spinal cord regeneration are necessary to obtain successful therapies for SCI patients.

Animals↗

PubMed2002

Postnatal development of NR2A and NR2B mRNA expression in rat auditory cortex and thalamus.

Sensory cortex in the rat undergoes rapid postnatal development, especially following the onset of sensory function during so-called "critical periods." To investigate potential mechanisms in the auditory forebrain involving different NMDA receptor subunits, we have used in situ hybridization to determine expression patterns of NR2A and NR2B mRNA at postnatal days 4, 10, 13, 18, 25, and adult. In auditory cortex, NR2A mRNA expression is initially weak but increases rapidly over approximately 2 weeks. NR2B mRNA levels are initially high and remain high. For both subunits, expression tends to be highest in superficial layers of the cortex (except layer 1). Expression is weaker in the auditory thalamus (medial geniculate). Initially, NR2A mRNA expression is very low, whereas NR2B mRNA expression is moderate; both levels increase over approximately 2 weeks. Among medial geniculate subdivisions, NR2A mRNA expression occurs preferentially in the medial division, whereas NR2B mRNA expression is strongest in the ventral division. For auditory cortex and thalamus, NR2A and NR2B mRNA expression peaks about 1 week after the onset of hearing before declining slightly into adulthood. The heterogeneous distribution of NMDAR subunit mRNA throughout development may play a role in auditory forebrain development and function.

Aging↗

PubMed2003

Diagnostic testing in fecal incontinence.

Fecal incontinence is a common problem that disproportionately affects women and the elderly and has a significant impact on the quality of life. Incontinence is often multifactorial. Anorectal manometry, anal endosonography, magnetic resonance imaging, pudendal nerve latency, and electromyography provide morphologic and physiologic assessments of the internal and external anal sphincters, rectal motor and sensory function, rectal compliance, and rectoanal reflexes. This information, in concert, provides clues to the pathophysiology of fecal incontinence and may help to guide medical, surgical, or biofeedback therapy. These tests have also been used to assess the effectiveness of the therapeutic modalities. No data are available on the cost-effectiveness of diagnostic testing in fecal incontinence. Newer techniques, including electrophysiologic testing and morphologic imaging of the anorectum, are being pursued.

Diagnosis, Differential↗

PubMed1985

Preservation of the intercostobrachial nerve during axillary dissection for breast cancer.

Preservation of the intercostobrachial nerve during axillary dissection in 50 patients with stage I breast cancer resulted in a significant improvement in sensory function compared with the standard dissection in which the nerve is routinely sacrificed. No local recurrence was found during the 3 to 5 year follow-up period. This modification is worthwhile in patients with axillas that are clinically negative for cancer.

Afferent Pathways↗

PubMed1995

Gender-, side- and site-dependent variations in human perioral spatial resolution.

Twenty-eight right-handed, young adults participated in a sensory testing experiment to evaluate spatial resolution at 10 positionally matched sites on the right- and left-hand sides of the face. An adaptive psychophysical (i.e. tracking) procedure was used to estimate the threshold spatial separation for perceiving two points of contact at each site. Estimates of the threshold at one site on both sides of the face were also obtained with a method-of-limits procedure similar to that employed for clinical evaluation of patients. In addition, each individual was asked to rate (i) his(her) overall facial sensitivity to touch and (ii) the degree to which he(she) could discern subtle changes in lip, cheek and chin position during speech, chewing and facial expression. Analysis of the estimates of the threshold separation obtained with the tracking procedure revealed a significant effect of gender (p < 0.04) and of site (p < 0.001). Females were more spatially sensitive than males: average threshold separations were 1.55 mm less. Most notably, the threshold increased ninefold with distance posterolaterally from the oral opening. The vermilion of the upper lip was the most spatially sensitive site (population geometric mean = 2.4 mm) and the preauricular skin the least spatially sensitive site (20.9 mm). Significant effects of side and of interactions among gender, side and site were not observed. The estimates obtained with the method-of-limits procedure were very similar to those obtained with the tracking procedure: the latter were 0.67 mm less on the average. Individuals' ratings of overall facial sensitivity to touch were similar for males and females (p > 0.70). Females, however, reported greater ability to discern subtle changes in lip, cheek and chin position than males (p < 0.03). The ratings of this sensory function correlated negatively with the estimates of the threshold separation on the vermilion of the upper lip (p < 0.03).

Adaptation, Physiological↗

PubMed1976

Olfactory stimulation and olfactory bulb removal: effects on territorial aggression in male Syrian golden hamsters.

The Syrian golden hamster exhibits territorial aggression in a laboratory setting, attacking much more when in the home cage than in the cage of another hamster. In expt. 1 it was found that female hamster vaginal discharge (FHVD) greatly inhibits the territorial aggression of males. In expt. 2 it was found that hamster territorial aggression is almost completely eliminated by bilateral olfactory bulbectomy but is unaffected by unilateral olfactory bulbectomy. However, bilateral olfactory bulbectomized (BOB) hamsters fought back normally if attacked first. Blinding increased the territorial aggression of male hamsters. In expt. 3 a peripheral means of impairing olfaction was used. The results suggest that it is the olfactory impairment, rather than the loss of some hypothetical non-sensory functions of the olfactory bulbs, that causes the elimination of territorial aggression after olfactory bulbectomy. Because of the extensive secondary and tertiary olfactory projections to the limbic forebrain and hypothalamus, and because most laboratory mammals are macro-osmatic, the nature and degree of olfactory control should be an important consideration in studies on the neural basis of social behavior.

Aggression↗