Somatosensory research最新文献

{"title":"Vibrotactile masking effects on airpuff-elicited sensations vary with skin region in the human hand.","authors":"J Kekoni,&nbsp;A Pertovaara,&nbsp;H Hämäläinen","doi":"10.3109/07367228709144621","DOIUrl":"https://doi.org/10.3109/07367228709144621","url":null,"abstract":"<p><p>Inhibitory interactions between two tactile signals take place predominantly within mechanoreceptive submodality channels. This finding was utilized in the present study to determine the mechanoreceptive channels contributing to tactile sensations elicited by brief airpuff stimuli applied to the hairy and glabrous skin of the human hand. A reaction time paradigm was used to estimate the sensitivity of four subjects to airpuffs without and during continuous vibration (masker) of low (30 Hz) or high (240 Hz) frequency. The sensitivity to airpuffs (test stimuli) was decreased by a low-frequency masker in the hairy skin and by low- and especially by high-frequency maskers in the glabrous skin. The masking effect was enhanced in both skin areas by increasing the intensity of the masker and by decreasing the intensity of the test stimulus. The results suggest that the mechanisms underlying airpuff-elicited sensations consist of the low-frequency channel in the hairy skin, and of both the low- and high-frequency channels in the glabrous skin.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"5 2","pages":"93-105"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228709144621","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14548452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A quantitative comparison of stimulus-response relationships of vibrissa-activated neurons in subnuclei oralis and interpolaris of the rat's trigeminal sensory complex: receptive field properties and threshold distributions.","authors":"J M Gibson","doi":"10.3109/07367228709144623","DOIUrl":"https://doi.org/10.3109/07367228709144623","url":null,"abstract":"<p><p>Electrical activity of single vibrissa-activated neurons was recorded in pars interpolaris and pars oralis of the nucleus of the trigeminal spinal tract of rats. Stimuli consisted of quantitatively controlled deflections of individual mystacial vibrissae. The evoked spike trains were analyzed as point-process time series with a variety of quantitative procedures. Most second-order trigeminal neurons were directionally sensitive. About one-third of interpolaris neurons and over half of oralis neurons responded to axial push of the hair shaft. About half of the neurons of both oralis and interpolaris had receptive fields that included more than one vibrissa. The upper-quartile receptive field size of neurons of interpolaris was about half that of oralis, although the distributions overlapped. In interpolaris, almost one-fifth of the sample discharged in the absence of an intentionally applied stimulus; in oralis, over one-third of the sample displayed background activity. The ranges of angular displacement thresholds of both samples exceeded three orders of magnitude. The distributions differed quantitatively. They were, nevertheless, similar in shape, and exhibited considerable overlap. The median threshold of oralis neurons was about half that of interpolaris neurons, and about one-fifth that of first-order neurons. About one-fourth of the second-order neurons exhibited a nonmonotonic relationship between pulse displacement and the number of evoked spikes. Neurons of interpolaris tended to be more severely nonmonotonic than those of oralis, and some \"turned off\" at stimulus magnitudes well above threshold. Nevertheless, the number of spikes evoked in either entire sample was a monotonically increasing function of pulse displacement. The range of angular velocity thresholds observed in both second-order samples exceeded three orders of magnitude. As with the angular displacement thresholds, the distributions of angular velocity thresholds were quantitatively different, although their shapes and extremes were similar, and they overlapped extensively. The observed differences of stimulus-response relationships of the neurons in interpolaris and oralis reflect differences in the ways different trigeminal nuclei receive, process, and distribute information to the circuits in which they participate.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"5 2","pages":"135-55"},"PeriodicalIF":0.0,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228709144623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14548561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Somatotopic organization of the second somatosensory area (SII) in the cerebral cortex of the mouse.","authors":"G E Carvell,&nbsp;D J Simons","doi":"10.3109/07367228609144585","DOIUrl":"https://doi.org/10.3109/07367228609144585","url":null,"abstract":"<p><p>The somatotopic organization of the parietal cortex of barbiturate-anesthetized, adult mice was studied using tungsten microelectrodes. A complete representation of the contralateral face and body occupying approximately 4.0-4.5 mm2 was found immediately posterior and lateral to the representation of the face in the first somatosensory area (SI). Within this second somatosensory area (SII), the following findings were made: A relatively large region is devoted to representations of the paws and face, especially the sinus hairs associated with the anterior upper lip and mystacial vibrissae. Receptive fields on these body regions are among the smallest found in SII, though larger than corresponding receptive fields in SI. In particular, vibrissae receptive fields always include at least several adjacent whiskers, and paw receptive fields always include at least two adjacent digits. In regions representing proximal body parts, receptive fields are considerably larger, may include both contralateral and ipsilateral limb or trunk surfaces, and sometimes include the entire body and face. Responses to both somatosensory and auditory stimulation were consistently found in the body (i.e., trunk and limb) representation, but rarely found in the face region. The face is represented most anteriorly, and the hindlimb and tail most posteriorly. Forepaw and hindpaw digits and anterior aspects of the face (e.g., perioral sinus hairs and the incisors) are represented laterally, while the back, caudal head, and mystacial vibrissae are represented medially. Within SII, therefore, a \"musculus\" can be viewed as having an upright body orientation with the face area bordering the face representation within SI. By comparison with SI, SII is characterized by a less pronounced layer IV, which is of irregular thickness and packing density, and by less uniformity in the layering of pyramidal cells in lamina V. In addition, SII is generally thicker from pia to white matter than SI. These results are in general accord with earlier findings from evoked potential studies in mice, but are at variance with recent reports in mice and rats that the mystacial vibrissae have only a minimal, or no, representation within SII. Indeed, the present findings suggest that the representation of the whiskers in SII may have a specialized function paralleling that in SI.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"3 3","pages":"213-37"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144585","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14869024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immunochemical studies of substance P and cholecystokinin octapeptide recovery in dorsal horn following unilateral lumbosacral ganglionectomy.","authors":"P E Micevych,&nbsp;A Stroink,&nbsp;T Yaksh,&nbsp;V L Go","doi":"10.3109/07367228609144586","DOIUrl":"https://doi.org/10.3109/07367228609144586","url":null,"abstract":"<p><p>Deafferentation of the cat lumbosacral dorsal horn following unilateral ganglionectomy (L2-S3) produced an ipsilateral depletion of substance P (sP) and cholecystokinin octapeptide (CCK) immunoreactivity (IR). The loss of sP IR and CCK IR was most marked at 11 days postlesion, and partial recovery of sP IR and CCK IR was noted in the upper laminae of the dorsal horn ipsilateral to the lesion 14 days after deafferentation. The dorsal horn sP IR and CCK IR distribution and density of staining on the deafferented side were indistinguishable from those on the control side 1 month after ganglionectomy. The pattern and density of methionine-enkephalin (M-ENK) IR was not disrupted by deafferentation, demonstrating that the sP IR and CCK IR depletions were due to the deafferentation and not to nonselective vascular damage. The recovery of sP IR and CCK IR was not affected by midline myelotomy or thoracic cord transections, implying a local origin for the recovered sP IR and CCK IR. Moreover, capsaicin, a primary afferent neurotoxin, depleted sP IR and CCK IR only from the intact side. Thus, these studies indicate that the recovery of two immunochemically identified primary afferent transmitters in the dorsal horn does not involve intraspinal sprouting of primary afferents. Radioimmunoassay (RIA) analysis of the ganglionectomies followed by recovery periods ranging from 7 to 28 days confirmed the depletion and recovery of sP IR, but the RIA indicated a temporal shift in depletion and recovery. Maximal depletion was measured at 21 days and recovery was observed at 28 days after unilateral deafferentation.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"3 3","pages":"239-60"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144586","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13574198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensory innervation of the raccoon forepaw: 2. Response properties and classification of slowly adapting fibers.","authors":"D D Rasmusson,&nbsp;B G Turnbull","doi":"10.3109/07367228609144598","DOIUrl":"https://doi.org/10.3109/07367228609144598","url":null,"abstract":"<p><p>Physiological recordings were made from 136 slowly adapting (SA) fibers in the median and ulnar nerves that innervate the glabrous skin of the raccoon. It was found that wetting the skin produced large increases in fiber responsiveness and decreases in threshold. Their responses decreased rapidly with slight displacements of the stimulus away from the center of the receptive field. Responses also decreased with increases in the diameter of the tip of the stimulus probe. The length of time that an SA fiber responded to a prolonged indentation was related to the magnitude of the indentation, and was greater after wetting of the skin. The absence of any clear and consistent grouping of fibers into moderately SA (MSA) and very SA (VSA) units argues against the existence of two types of SA receptors differing in this property. However, the distinction between SA I and SA II fibers that has been made in other species was confirmed in the raccoon.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"4 1","pages":"63-75"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144598","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14914238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphology and synaptic connections of small myelinated primary trigeminal axons arborizing among neurons in the border zone of rat trigeminal nucleus oralis.","authors":"W M Falls,&nbsp;M M Alban","doi":"10.3109/07367228609144600","DOIUrl":"https://doi.org/10.3109/07367228609144600","url":null,"abstract":"<p><p>The anterograde transport of horseradish peroxidase (HRP) was used to examine the morphology and synaptic connections of a morphologically distinct group of small-diameter primary trigeminal axons that arborize throughout the border zone (BZ) of rat trigeminal nucleus oralis. Thinly myelinated parent branches (0.75-1.5 micron in diameter) descending in the spinal V tract (SVT) were seen to issue medially directed collaterals that entered BZ, where they branched and eventually terminated by giving rise to thin terminal strands characterized by several relatively widely spaced axonal endings. Based on the size and morphology of the parent branches in SVT, in the root entry zone, and in the sensory root of the trigeminal nerve, these primary axonal (P) endings are considered to be derived from small-diameter myelinated primary trigeminal axons (SDMA). The P endings measured 1-2 micron in diameter and contained numerous agranular spherical (40-60 nm) synaptic vesicles. In the BZ neuropil, most P endings lay in glomeruli, where each formed at least one asymmetrical axodendritic synapse on a dendritic shaft. It is at these synapses that this group of primary axons is thought to transfer its input directly to the dendritic arbors of BZ neurons. A small (0.5-1.5 micron) axonal (F) ending filled with flattened synaptic vesicles (29 X 60 nm) was observed to form at least one symmetrical to intermediate axoaxonic synapse on the P ending, as well as at least one axodendritic synapse on the same dendritic shaft receiving the primary input. Some F endings only contacted dendritic shafts. In view of their symmetrical to intermediate synaptic contacts, F endings are thought to belong to axons derived from at least one source that can inhibit or diminish the firing rate of BZ neurons in response to SDMA input. This would be accomplished either postsynaptically through the axodendritic synapses on the dendritic shafts, and/or presynaptically through the axoaxonic synapses on the P endings.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"4 2","pages":"97-110"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144600","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14928373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Light- and electron-microscopic localization of primary dental afferents to medullary dorsal horn (pars caudalis).","authors":"M A Henry,&nbsp;L E Westrum,&nbsp;L R Johnson","doi":"10.3109/07367228609144589","DOIUrl":"https://doi.org/10.3109/07367228609144589","url":null,"abstract":"<p><p>Light-microscopic (LM) and ultrastructural (electron-microscopic, or EM) identification of primary dental afferents to medullary dorsal horn (MDH) was demonstrated in the cat following injections of horseradish peroxidase (HRP) into pulpal chambers of unilateral maxillary and mandibular posterior teeth, including the cuspids. Use of a new osmication protocol improved and simplified the EM localization of reaction product within the brain stem terminals. LM examination showed that the projection pattern varied between the different levels of MDH. At caudal levels, the labeling was primarily confined to a narrow band consisting of a dense projection to the dorsomedial portion of laminae I and superficial II and a less intense projection to lamina V. The pattern to rostral levels became increasingly more dense and extensive within these same laminae. LM examination of the tooth apex region showed that a limited spread to the periodontal ligament occurred in some cases. EM investigation of the ipsilateral MDH demonstrated reaction product in terminals with synaptic vesicles that are presynaptic to small and medium-sized dendrites. Labeled axonal endings in close association with cell bodies were also observed. No labeled structures were identified in the contralateral MDH. Some of the reaction product found with EM was below the LM limit of resolution, and thus ultrastructural investigation is necessary for a complete analysis of any pathway when using HRP.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"3 4","pages":"291-307"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144589","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14614672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bicuculline-induced alterations in neuronal responses to controlled tactile stimuli in the second somatosensory cortex of the cat: a microiontophoretic study.","authors":"K D Alloway,&nbsp;H Burton","doi":"10.3109/07367228609144584","DOIUrl":"https://doi.org/10.3109/07367228609144584","url":null,"abstract":"<p><p>Single-neuron activity (n = 29) was recorded from the second somatosensory cortex of cats, and the effect of glutamate, gamma-amino-butyric acid (GABA), and bicuculline methiodide (BMI) on spontaneous and stimulus-induced responses were analyzed. Iontophoresis of glutamate produced dose-dependent increases in spontaneous activity, whereas GABA suppressed both spontaneous and glutamate-induced activity. Neuronal responses elicited by cutaneous stimuli were also inhibited by GABA in a dose-dependent fashion; current levels needed to produce at least a 25-50% decrease in stimulus-evoked activity ranged from 5 to 100 nA, with a mean of about 45 nA. Iontophoresis of BMI (10-75 nA) effectively antagonized GABA-induced inhibition of stimulus-evoked responses without altering spontaneous activity. Furthermore, BMI increased the magnitude of responses produced by ramp stimuli and caused a several-fold increase in receptive field size. For neurons responsive to sinusoidal stimulation, BMI caused an increase in the frequency-following probability at preferred frequencies, but failed to alter the response to nonpreferred frequencies. These results suggest that GABA-ergic circuits may limit response magnitude but not the submodality properties of somatosensory cortical neurons.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"3 3","pages":"197-211"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144584","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14011152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cerebral magnetic fields evoked by peroneal nerve stimulation.","authors":"E Kaukoranta,&nbsp;R Hari,&nbsp;M Hämäläinen,&nbsp;J Huttunen","doi":"10.3109/07367228609144590","DOIUrl":"https://doi.org/10.3109/07367228609144590","url":null,"abstract":"<p><p>We measured evoked magnetic fields and evoked potentials to peroneal nerve stimulation in healthy humans. The results were consistent with activation of the primary sensorimotor foot area on the mesial surface of the hemisphere during several deflections between 40 and 200 msec. A cortical origin is suggested for the electrical P40. Distinct magnetic field patterns were observed over the primary and secondary somatosensory cortices (SI and SII). At SII, responses to ipsilateral stimulation were weaker and had longer latencies than those to contralateral stimulation. Simulations were used to clarify the differences between electrical and magnetic patterns when SI and SII were simultaneously active.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"3 4","pages":"309-21"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144590","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14892499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological features of identified trigeminocerebellar projection neurons in the border zone of rat trigeminal nucleus oralis.","authors":"W M Falls,&nbsp;M M Alban","doi":"10.3109/07367228609144594","DOIUrl":"https://doi.org/10.3109/07367228609144594","url":null,"abstract":"<p><p>The retrograde transport of horseradish peroxidase (HRP) was used to assess the overall morphology of neurons in the dorsal half of the border zone (BZ) of rat trigeminal nucleus oralis (Vo) that project to ipsilateral orofacial portions of four major tactile areas (crura I and II, the paramedian lobule, and the uvula) of the cerebellar cortex. We wished to answer two important questions: Does this group of cells consist of one or more morphologically distinct types, each projecting to different cerebellar tactile areas? Does the overall morphology or morphologies of these BZ neurons resemble one or more of the five types of identified trigeminocerebellar neurons in the dorsomedial (DM) subdivision of Vo, or do these trigeminocerebellar cells represent an additional morphologically distinct type or types restricted to BZ? The morphology of BZ neurons innervating the orofacial portions of all four cerebellar tactile areas was similar and did not resemble that of any of the five types of DM cells. They were characterized by a pyramidal- to fusiform-shaped cell body measuring 10-13 X 20-25 microns, which emitted three or four primary dendrites; one was directed dorsally, while the others took a more ventral trajectory. The primary dendrites generated a dendritic arbor arranged as a flattened disk oriented parallel to the spinal V tract. The dendritic field was largely restricted to BZ; it measured up to 150 microns in width, and spanned up to 450 microns dorsoventrally and rostrocaudally. An axon arose from the dorsal aspect of the cell body and gave rise to a single short collateral within 10 microns of its origin. This collateral remained unbranched and generated several boutons within BZ, while the parent axon, without branching further, traveled dorsolaterally toward the inferior cerebellar peduncle. Frequently, a second axon arose ventrally from the soma, and after a short unbranched course entered a deep axon bundle, where it assumed a descending trajectory. The intranuclear portion of this second axon was characterized by several boutons en passant.</p>","PeriodicalId":77800,"journal":{"name":"Somatosensory research","volume":"4 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"1986-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3109/07367228609144594","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14914234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}