Visceral and somatic afferent convergence onto neurons near the central canal in the sacral spinal cord of the cat

1985 ◽  
Vol 53 (4) ◽  
pp. 1059-1078 ◽  
Author(s):  
C. N. Honda
Keyword(s):  
Spinal Cord ◽  
Gray Matter ◽  
Receptive Fields ◽  
Central Canal ◽  
The Body ◽  
Wide Range ◽  
Pelvic Viscera ◽  
Somatic Receptive Fields ◽  
Sacral Spinal Cord ◽  
Stimulation Of

One hundred and sixty extracellularly and intracellularly recorded unitary discharges from the sacral or caudal spinal segments of 30 anemically decerebrated cats were studied to examine the effects of somatic and visceral afferent stimulation on neurons near the central canal (CC). The recorded unitary activity was histologically verified (by dye marks or horseradish peroxidase, HRP) as having come from the gray matter surrounding the CC that approximates Rexed's lamina X. In the absence of intentional stimulation or apparent injury by the recording electrode, 62% of the units exhibited ongoing discharges. Each unit was tested for responses to the stimulation of somatic (cutaneous and subcutaneous) and visceral (bladder and colon) structures. Seventy-six (48%) of the units responded exclusively to the stimulation of somatic receptive fields, and 10 (6%) of the units were selectively responsive to stimulation of the pelvic viscera. The activity of the remaining 74 (46%) was influenced by activity in both somatic and visceral afferent fibers. Eighteen of the 160 neurons were intracellularly marked with HRP. Based on perikaryal size and dendritic extent, it was possible to divide these cells into two partially overlapping groups. One group consisted of seven neurons with small to medium-sized perikarya, dendritic arbors largely restricted to the gray matter surrounding the CC, and small, singular somatic receptive fields. The second group comprised 11 cells with medium to large-sized soma and dendrites extending out of lamina X. These larger neurons usually possessed multiple, widely distributed somatic receptive fields. The principal finding of the present study is that in the sacral spinal cord many cells near the CC receive primary afferent inputs converging from a wide range of receptor types in somatic and visceral structures. Such neurons are capable of integrating afferent information from somatic structures on both sides of the body with information originating in pelvic viscera and midline regions such as the genitals.

Responses of neurons in and near the thalamic ventrobasal complex of the rat to stimulation of uterus, cervix, vagina, colon, and skin

1993 ◽  
Vol 69 (2) ◽  
pp. 557-568 ◽  
Author(s):  
K. J. Berkley ◽  
G. Guilbaud ◽  
J. M. Benoist ◽  
M. Gautron
Keyword(s):  
Receptive Fields ◽  
The Body ◽  
Female Rats ◽  
Caudal Part ◽  
Response Characteristics ◽  
The Core ◽  
Ventrobasal Complex ◽  
Gentle Pressure ◽  
Somatic Receptive Fields ◽  
Stimulation Of

1. Previous studies in the rat and other species have shown that neurons in and near the ventrobasal complex (VB) can be activated by various visceral as well as somatic stimuli. 2. This study examined the responses of 84 single neurons in and near the rostral 2/3 of VB in 19 adult female rats in estrus to mechanical stimulation of the skin (brush, pressure, noxious pinch) and 4 different visceral stimuli, as follows: distension of both uterine horns, mechanical probing of the vagina, gentle pressure against the cervix, and distension of the colon. The rats were studied while under moderate gaseous anesthesia (33% O2-67% N2O + 0.5% halothane) and paralyzed (pancuronium bromide). 3. Of 77 neurons tested with both somatic and visceral stimuli, 70 were responsive to one type and/or the other. Responses to somatic stimuli were immediate with brief afterdischarges to the pinch stimuli. In contrast, responses to visceral stimuli were delayed an average of 9 s with long afterdischarges averaging 2 min. Most viscerally responsive neurons (74%) had somatic receptive fields, often (44%) to noxious pinch. 4. Of the 70 responsive neurons, 43 (61%) responded to 1 or more of the 4 visceral stimuli, primarily with excitation. Most of these 43 neurons (71%) were responsive to uterine distension, whereas fewer responded to stimulation of the cervix (45%), vagina (29%), or colon (34%). 5. Viscerally responsive neurons were preferentially located in regions bordering or near VB. Only 6 of 22 neurons within the core of VB (27%) responded to visceral stimuli, in contrast with 37 of 48 neurons bordering or near VB (77%). 6. The six viscerally responsive neurons within VB all had somatic receptive fields located primarily on the caudal part of the body and were responsive to only one or two of the four visceral stimuli, usually the uterus. The 37 viscerally responsive neurons bordering or near VB were of 3 types. Neurons of the first type (n = 15) were scattered throughout the areas bordering VB and responded to both somatic and visceral stimuli much like VB neurons, except that they showed more visceral convergence. Neurons of the second type (n = 11) were concentrated at the rostral and dorsal borders of VB and responded only to visceral stimuli, mainly the uterus. Neurons of the third type (n = 11) were concentrated ventrally and had very complex, long-lasting and history-dependent response characteristics to both visceral and somatic stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

External nucleus of inferior colliculus: auditory and spinal somatosensory afferents and their interactions

1978 ◽  
Vol 41 (4) ◽  
pp. 837-847 ◽  
Author(s):  
L. M. Aitkin ◽  
H. Dickhaus ◽  
W. Schult ◽  
M. Zimmermann
Keyword(s):  
Inferior Colliculus ◽  
Pure Tone ◽  
Tactile Stimulation ◽  
Receptive Fields ◽  
The Body ◽  
Central Nucleus ◽  
Auditory Input ◽  
Somatosensory Information ◽  
Somatic Receptive Fields ◽  
Stimulation Of

1. The discharges of 129 units were studied in the external nucleus of the inferior colliculus of 11 anesthetised and paralyzed cats. This region is known to receive fibers from auditory nuclei and the dorsal column nuclei. 2. Stimuli used were pure tone bursts, monaural or binaural, tactile stimulation of the body surface, and electrical stimulation of the dorsal columns (DC) at a low cervical level and of the contralateral and ipsilateral tibial nerves. 3. Forty-six percent of units were only influenced by one type of stimulation (26% auditory, 20% DC). Of the remaining bimodally influenced units, the majority was excited by pure tone stimuli and inhibited by DC stimulation. 4. A small proportion of the total population (18%) was excited by both DC and auditory input, and units sensitive to both tones and tactile stimulation of the skin were rare (4%). 5. Auditory tuning curves were generally very broad compared with those of units in the central nucleus of the inferior colliculus. Similarly, somatic receptive fields were large and usually extended over a whole limb. 6. The majority of tone-responsive units were influenced binaurally (70%); most somatic receptive fields were located on the contralateral fore- or hindlimb (16/18). 7. The results indicate that both auditory and somatosensory information is contained in the discharges of units in the external nucleus of the inferior colliculus. 8. Speculations are made about the role of this nucleus in descending auditory input to the spinal cord and in the comparison of auditory and cutaneous information during sound-evoked coordinated body movements.

Characterization of responses of T2-T4 spinal cord neurons to esophageal distension in the rat

1993 ◽  
Vol 69 (3) ◽  
pp. 868-883 ◽  
Author(s):  
I. Euchner-Wamser ◽  
J. N. Sengupta ◽  
G. F. Gebhart ◽  
S. T. Meller
Keyword(s):  
Spinal Cord ◽  
Spontaneous Activity ◽  
Receptive Fields ◽  
The Body ◽  
Male Rats ◽  
Response Threshold ◽  
Response Functions ◽  
Stimulus Response ◽  
Spinal Segments ◽  
Somatic Receptive Fields

1. Three hundred fifty neurons in the T2-T4 spinal segments of 38 intact, pentobarbital sodium-anesthetized, pancuronium-paralyzed male rats were examined for somatic receptive fields and responses to midthoracic esophageal distension (ED). Recordings were made at a depth of 0.1–1.45 mm from the dorsal spinal cord surface and from the midline to approximately 1.0 mm lateral. 2. Fifty-six of the 350 total neurons (16%) responded to ED, produced by air inflation of a latex balloon (0.5–1.5 ml). Most of these 56 neurons (84%) were excited by ED, and all except one were excited at a short latency (< 2 s) to stimulus onset. The response to ED in about one-half of all excited neurons terminated abruptly with termination of the stimulus; the other neurons exhibited an afterdischarge of 5 to > 80 s. Repeated ED at a constant intensity (1.25 ml, 30 s every 6 min) produced stable and reproducible responses of neurons excited by ED. Twenty-one percent of neurons that responded to ED were antidromically invaded from the spinomedullary junction. 3. Graded ED (0.5–1.5 ml, 30 s every 6 min) produced linear and accelerating stimulus-response functions in the 29 neurons tested. The mean threshold for distension, determined with a least-squares regression analysis, was extrapolated to near 0.5 ml of distending volume, and no difference in response threshold was found between neuronal groups with or without after-discharge. 4. The spontaneous activity of 7 of the 56 neurons (12.5%) that responded to ED was inhibited by the stimulus. Stimulus-response functions for four neurons inhibited by ED were intensity dependent. The spontaneous activity of these neurons was inhibited to a mean of 24.5% of the prestimulus control by 1.25 ml ED. 5. Two neurons of the total sample of 56 (3.5%) responded to ED (1.50 ml) in a biphasic excitatory-inhibitory manner. The excitatory component of excitatory-inhibitory neurons encoded the intensity of ED; the inhibitory component during the second half of ED was apparent only at greater distending volumes (1.25–1.5 ml). 6. Somatic receptive fields were found for 303/350 neurons, and 98% were located on the thorax and proximal forearm (all ipsilateral). Five neurons in T2–T4 spinal segments had their cutaneous receptive fields located on caudal parts of the body (tail, hindleg, scrotum).(ABSTRACT TRUNCATED AT 400 WORDS)

Anatomical and physiological studies of the gray matter surrounding the spinal cord central canal

1983 ◽  
Vol 220 (3) ◽  
pp. 321-335 ◽  
Author(s):  
Richard L. Nahin ◽  
Anne M. Madsen ◽  
Glenn J. Giesler
Keyword(s):  
Spinal Cord ◽  
Gray Matter ◽  
Central Canal ◽  
Physiological Studies

scholarly journals Cutaneous stimulation evokes long-lasting excitation of spinal interneurons in the turtle

1990 ◽  
Vol 64 (4) ◽  
pp. 1134-1148 ◽  
Author(s):  
S. N. Currie ◽  
P. S. Stein
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Action Potential ◽  
Receptive Fields ◽  
Neural Mechanisms ◽  
Cutaneous Afferents ◽  
Cutaneous Stimulation ◽  
Single Action ◽  
Single Action Potential ◽  
Stimulation Of

1. We demonstrated multisecond increases in the excitability of the rostral-scratch reflex in the turtle by electrically stimulating the shell at sites within the rostral-scratch receptive field. To examine the cellular mechanisms for these multisecond increases in scratch excitability, we recorded from single cutaneous afferents and sensory interneurons that responded to stimulation of the shell within the rostral-scratch receptive field. A single segment of the midbody spinal cord (D4, the 4th postcervical segment) was isolated in situ by transecting the spinal cord at the segment's anterior and posterior borders. The isolated segment was left attached to its peripheral nerve that innervates part of the rostral-scratch receptive field. A microsuction electrode (4-5 microns ID) was used to record extracellularly from the descending axons of cutaneous afferents and interneurons in the spinal white matter at the posterior end of the D4 segment. 2. The turtle shell is innervated by slowly and rapidly adapting cutaneous afferents. All cutaneous afferents responded to a single electrical stimulus to the shell with a single action potential. Maintained mechanical stimulation applied to the receptive field of some slowly adapting afferents produced several seconds of afterdischarge at stimulus offset. We refer to the cutaneous afferent afterdischarge caused by mechanical stimulation of the shell as "peripheral afterdischarge." 3. Within the D4 spinal segment there were some interneurons that responded to a brief mechanical stimulus within their receptive fields on the shell with short afterdischarge and others that responded with long afterdischarge. Short-afterdischarge interneurons responded to a single electrical pulse to a site in their receptive fields either with a brief train of action potentials or with a single action potential. Long-afterdischarge interneurons responded to a single electrical shell stimulus with up to 30 s of afterdischarge. Long-afterdischarge interneurons also exhibited strong temporal summation in response to a pair of electrical shell stimuli delivered up to several seconds apart. Because all cutaneous afferents responded to an electrical shell stimulus with a single action potential, we conclude that electrically evoked afterdischarge in interneurons was produced by neural mechanisms in the spinal cord; we refer to this type of afterdischarge as "central afterdischarge." 4. These results demonstrate that neural mechanisms for long-lasting excitability changes in response to cutaneous stimulation reside in a single segment of the spinal cord. Cutaneous interneurons with long afterdischarge may serve as cellular loci for multise

Response and receptive-field properties of spinomesencephalic tract cells in the cat

1986 ◽  
Vol 55 (1) ◽  
pp. 76-96 ◽  
Author(s):  
R. P. Yezierski ◽  
R. H. Schwartz
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Dynamic Range ◽  
Receptive Fields ◽  
The Body ◽  
Noxious Stimulation ◽  
Primary Afferent ◽  
Receptive Field Properties ◽  
Afferent Fibers ◽  
Primary Afferent Fibers

Recordings were made from 90 identified spinomesencephalic tract (SMT) cells in the lumbosacral spinal cord of cats anesthetized with alpha-chloralose and pentobarbital sodium. Recording sites were located in laminae I-VIII. Antidromic stimulation sites were located in different regions of the rostral and caudal midbrain including the periaqueductal gray, midbrain reticular formation, and the deep layers of the superior colliculus. Twelve SMT cells were antidromically activated from more than one midbrain level or from sites in the medial thalamus. The mean conduction velocity for the population of cells sampled was 45.2 +/- 21.4 m/s. Cells were categorized based on their responses to graded intensities of mechanical stimuli and the location of excitatory and/or inhibitory receptive fields. Four major categories of cells were encountered: wide dynamic range (WDR); high threshold (HT); deep/tap; and nonresponsive. WDR and HT cells had excitatory and/or inhibitory receptive fields restricted to the ipsilateral hindlimb or extending to other parts of the body including the tail, forelimbs, and face. Some cells had long afterdischarges following noxious stimulation, whereas others had high rates of background activity that was depressed by nonnoxious and noxious stimuli. Deep/tap cells received convergent input from muscle, joint, or visceral primary afferent fibers. The placement of mechanical lesions at different rostrocaudal levels of the cervical spinal cord provided information related to the spinal trajectory of SMT axons. Six axons were located contralateral to the recording electrode in the ventrolateral/medial or lateral funiculi while two were located in the ventrolateral funiculus of the ipsilateral spinal cord. Stimulation at sites used to antidromically activate SMT cells resulted in the inhibition of background and evoked responses for 22 of 25 cells tested. Inhibitory effects were observed on responses evoked by low/high intensity cutaneous stimuli and by the activation of joint or muscle primary afferent fibers. Based on the response and receptive-field properties of SMT cells it is suggested that the SMT may have an important role in somatosensory mechanisms, particularly those related to nociception.

Response properties and synaptic connections of mechanoafferent neurons in cerebral ganglion of Aplysia

1979 ◽  
Vol 42 (4) ◽  
pp. 954-974 ◽  
Author(s):  
S. C. Rosen ◽  
K. R. Weiss ◽  
I. Kupfermann
Keyword(s):  
Receptive Field ◽  
Motor Neurons ◽  
Receptive Fields ◽  
Cerebral Ganglion ◽  
The Body ◽  
Sensory Response ◽  
Tactile Stimuli ◽  
Dorsal Portion ◽  
Intracellular Stimulation ◽  
Stimulation Of

1. The cells of two clusters of small neurons on the ventrocaudal surface of each hemicerebral ganglion of Aplysia were found to exhibit action potentials following tactile stimuli applied to the skin of the head. These neurons appear to be mechanosensory afferents since they possess axons in the nerves innervating the skin and tactile stimulation evokes spikes with no prepotentials, even when the cell bodies are sufficiently hyperpolarized to block some spikes. The mechanosensory afferents may be primary afferents since the sensory response persists after chemical synaptic transmission is blocked by bathing the ganglion and peripheral structures in seawater with a high-Mg2+ and low-Ca2+ content. 2. The mechanosensory afferents are normally silent and are insensitive to photic, thermal, and chemical stimuli. A punctate tactile stimulus applied to a circumscribed region of skin can evoke a burst of spikes. If the stimulus is maintained at a constant forces, the mechanosensory response slowly adapts over a period of seconds. Repeated brief stimuli have little or no effect on spike frequency within a burst. 3. Approximately 81% of the mechanoafferent neurons have a single ipsilateral receptive field. The fields are located on the lips, the anterior tentacles, the dorsal portion of the head, the neck, or the perioral zone. Because many cells have collateral axons in the cerebral connectives, receptive fields elsewhere on the body are a possibility. The highest receptive-field density was associated with the lips. Within each area, receptive fields vary in size and shape. Adjacent fields overlap and larger fields frequently encompass several smaller ones. The features of some fields appear invariant from one animal to the next. A loose form of topographic organization of the mechanoafferent cells was observed. For example, cells located in the medial cluster have lip receptive fields, and most cells in the posterolateral portion of the lateral clusters have tentacle receptive fields. 4. Intracellular stimulation of individual mechanoafferents evokes short and constant-latency EPSPs in putative motor neurons comprising the identified B-cell clusters of the cerebral ganglion. On the basis of several criteria, these EPSPs appear to be several criteria, these EPSPs appear to be chemically mediated and are monosynaptic. 5. Repetitive intracellular stimulation of individual mechanoafferent neurons at low rates results in a gradual decrement in the amplitude of the EPSPs evoked in B cluster neurons. EPSP amplitude can be restored following brief periods of rest, but subsequent stimulation leads to further diminution of the response. 6. A decremented response cannot be restored by strong mechanical stimulation outside the receptive field of the mechanoafferent or by electrical stimulation of the cerebral nerves or connectives...

scholarly journals A comparison of the distribution and morphology of ChAT-, VAChT-immunoreactive and AChE-positive neurons in the thoracolumbar and sacral spinal cord of the pig

2008 ◽  
Vol 53 (No. 8) ◽  
pp. 434-444 ◽  
Author(s):  
J. Calka ◽  
M. Zalecki ◽  
K. Wasowicz ◽  
M.B. Arciszewski ◽  
M. Lakomy
Keyword(s):  
Spinal Cord ◽  
Mammalian Species ◽  
Cholinergic Neurons ◽  
Neuronal Population ◽  
Central Canal ◽  
Ventral Horn ◽  
Laboratory Animals ◽  
Unique Region ◽  
Intermediolateral Nucleus ◽  
Sacral Spinal Cord

Present knowledge concerning the organization of cholinergic structures of the spinal cord has been derived primarily from studies on small laboratory animals, while there is a complete lack of information concerning its structure in the pig. In the present study we employed choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) immunocytochemistry and acetylcholinesterase (AChE) histochemistry to identify the cholinergic neuronal population in the thoracolumbar and sacral spinal cord of the pig. The distribution of ChAT-, VAChT- and AChE-positive cells was found to be similar. Distinct groups of cholinergic neurons were observed in the gray matter of the ventral horn, intermediolateral nucleus, intermediomedial nucleus as well as individual stained cells were found in the area around the central canal and in the base of the dorsal horn. Double staining confirmed complete colocalization of ChAT with AChE in the ventral horn and intermediolateral nucleus although in the intermediomedial nucleus only 64% of the AChE-positive neurons expressed ChAT-immunoreactivity, indicating unique, region restricted, diversity of ChAT and AChE staining. Our results revealed details concerning spatial distribution and morphological features of the cholinergic neurons in the thoracolumbar and sacral spinal cord of the pig. We also found that the pattern of distribution of cholinergic neurons in the porcine spinal cord shows great similarity to the organization of the cholinergic system in other mammalian species studied.

Ventricular perfusion in cats with kaolin-induced hydrocephalus

1974 ◽  
Vol 41 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Howard M. Eisenberg ◽  
James E. McLennan ◽  
Keasley Welch
Keyword(s):  
Spinal Cord ◽  
Subarachnoid Space ◽  
Central Canal ◽  
Ventricular System ◽  
Ventricular Pressure ◽  
Content Type ◽  
Lateral Ventricles ◽  
Spinal Subarachnoid Space ◽  
Wide Range ◽  
Fine Print

✓ Cats were made hydrocephalic by cisternal instillation of kaolin. Three to 8 weeks later it was found by perfusion between the ventricular system and the spinal subarachnoid space that communication had been reestablished through a demonstrably dilated central canal of the spinal cord. Absorption of fluid from the ventricular system, measured both by ventriculospinal perfusion and, after ligation of the spinal cord, by perfusion between the lateral ventricles, was found to be indistinguishable from zero over a wide range of ventricular pressure.

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