摘要:

AbstractThe trigeminal system of the rat is characterized by a high degree of order. The pattern of the distribution of vibrissae follicles on the face is replicated at each synaptic station between face and somatosensory cortex (Belford and Killackey, '80). The present study details the development of the trigeminal nerve, its intrinsic organization, and its relationship with its peripheral and central targets. We have observed that at early embryonic ages (E12 and E13) the trigeminal ganglion neurons grow out in straight lines without crossing, and the distance between these neurons and their peripheral and central targets is very short. We have found that fibers reach the periphery before follicle formation is first detectable (E14). At all ages, the trigeminal fibers show a marked tendency to fasciculate. After the development of the pattern of vibrissae follicles on the face, the pattern of fasciculation within the nerve can be clearly related to the rows of vibrissae and the buccal pad. This peripherally related order in the nerve was experimentally verified by injecting horseradish peroxidase into the follicles of individual rows and selectively sectioning portions of the nerve. Further, we provide evidence that the discrete brainstem pattern reflecting vibrissae distribution develops after organization is detectable in the nerve and in a temporal sequence from lateral to medial, which replicates the developmental sequence of vibrissae follicles from ocular to nasal on the face. This sequence is detectable in both the distribution of afferent terminals as measured with succinic dehydrogenase histochemistry and of horseradish peroxidase back‐labeled trigeminothalamic relay cells. We interpret our results as suggesting that a number of factors may play a role in the establishment of specific neuronal topographies in the rodent trigeminal syste

ISSN:0092-7317    

DOI:10.1002/cne.902130402

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractElectrophysiological data were collected from the forelimb region of somatosensory cortex in barbiturate‐anesthetized cats using low‐impedance microelectrodes in both perpendicular and nearly horizontal penetrations. The data within cytoarchitectonic area 3b were classified according to receptive field locus and submodality. The forearm cortex was shown to consist of segregated regions of slowly adapting and rapidly adapting neurons arranged in a pattern unique to each animal. The general organization of each submodality consisted of interdigitating bands of submodality‐specific neurons. Horizontal penetrations confirmed data obtained from vertical penetrations.The somatotopic representation within the forearm region was arranged in a way that was complementary to the submodality segregation. Each part of the forearm appeared to be represented by both the slowly adapting and rapidly adapting neurons so that area 3b contained two complete maps of the forearm. Yet, the slowly and rapidly adapting maps were organized so that the same body part was found in only one part of the cortex; the slowly and rapidly adapting regions, for each body part tended to be adjacent to one another. Area 1 was incompletely sampled; however, there appeared to be a separate representation of the cutaneous surface located

ISSN:0092-7317    

DOI:10.1002/cne.902130403

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractConnections between the bed nucleus of the stria terminalis and the dorsomedial medulla oblongata have been examined by immunohistochemical detection of the tracer proteins horseradish peroxidase (HRP) or wheatgerm agglutinin (WGA). Two sets of four rats received 0.2 or 0.4 μl of eithertracer injected into the dorsomedial medulla oblongata, were fixed by perfusion 48 hours later, and were processed for immunohistochemical detection of the tracers. Rats receiving HRP showed only a few single neurons retrogradely labelled in the ipsilateral bed nucleus, and some anterogradely labelled fibers. Rats receiving WGA showed a large number of retrogradely labelled neurons in the ipsilateral bed nucleus. Labelled neurons were most concentrated in a group in the central, dorsal, and lateral aspects of the nucleus at the level of the anterior commissure and just caudal to this. Just ventral to this group was a dense cluster of anterogradely labelled fibers. The retrogradely labelled neurons ranged from 12 to 20 μm in size and were multipolar. These findings indicate that there are direct reciprocal connections between the bed nucleus of the stria terminalis and the autonomic centers of the dorsomedial medulla oblongata and strengthen the concept that this nucleus is involved in forebrain integration of autonomic function

ISSN:0092-7317    

DOI:10.1002/cne.902130404

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe occurrence and distribution of substance P (SP), somatostatin (SOM), and enkephalin (ENK) immunoreactive elements were examined in the spinal cord of the domestic fowl,Gallus domesticus. SP immunoreactive fibers and their varicosities were densest in laminae I and II, although they were also found within deeper regions of the dorsal horn. In contrast, the intermediate gray area, the area around the central canal, and the ventral horn, contained fewer SP immunoreactive fibers. The distribution of ENK immunoreactivity in the gray matter was similar to that described for SP although immunoreactive fibers were denser around the central canal and in the intermediate zone. Few SOM immunoreactive fibers were present in the dorsal horn the area around the central canal, and the ventral horn. All three peptidergic immunoreactive elements were found in and around the nucleus of Terni, an autonomic area. Throughout the lumbosacral enlargement SP, SOM, and ENK immunoreactive varicosities were found adjacent to the lumbosacral sinus and in fibers traversing the glycogen body. In addition, at caudal lumbar and rostral sacral levels a plexus of SP and SOM immunoreactive fibers was observed to be in close relationship with presumed motoneurons.

ISSN:0092-7317    

DOI:10.1002/cne.902130405

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution and origin of four peptide neurotransmitter candidates of primary afferents (substance P, SP; somatostatin, SS; cholecystokinin, CCK; and vasoactive intestinal polypeptide, VIP) were studied in the stingray with peroxidase‐antiperoxidase (PAP) immunohistochemistry. This elasmobranch has virtually no unmyelinated primary afferents, having instead only large and small myelinated afferents. SP‐like immunoreactivity was distributed densely in the superficial aspect of the substantia gelatinosa (SG), particularly laterally, and was scattered in the nucleus proprius, the intermediate zone, and the ventral horn. The distributions of SS‐, CCK‐, and VIP‐like immunoreactivities were similar to each other, but different from that of SP. Stained fibers appeared to issue from a prominent tract in the dorsolateral funiculus to form a plexus at the lateral margin of the nucleus proprius. The fibers spread dorsally and medially through the SG to terminate in a thin band at the superifical margin of the SG. Both SS and CCK were more dense in the lateral third of the SG, while VIP was more diffusely distributed within this structure. The remaining regions of the spinal gray matter contained immunoreactive fibers and terminals in variable densities. Many SS‐positive cell bodies were observed in the ventral horn, in the deep dorsal horn, and in the ependymal layer. CCK‐positive cells were observed in the medial ventral horn, and VIP‐positive cells were observed subjacent to the SG and within the dorsolateral funiculus. After unilateral dorsal rhizotomies, SP‐like immunoreactivity in the SG was depleted, while SP staining elsewhere and all SS, CCK, and VIP staining was indistinguishable from control. Thus all four peptides are present in the stingray spinal cord, although only SP appears to be a candidate primary aff

ISSN:0092-7317    

DOI:10.1002/cne.902130406

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe physiology and morphology of fusiform cells in the dorsal cochlear nucleus were studied using extracellular and intracellular recording and intracellular injection of horseradish peroxidase. Fusiform cells displayed a variety of responses to tone pips presented at the characteristic frequency; most often these cells exhibited the pauser/buildup pattern defined in earlier studies. The response pattern of each neuron was dependent on frequency and sound‐pressure level. Tone pips evoked short‐lasting depolarizations of about 10 mV and long‐lasting hyperpolarizations of about 10 mV in cells whose resting potentials were −50 to −65 mV. The time courses of both the excitation and the inhibition depended on frequency and sound‐pressure level. Generally the depolarization was sustained for the duration of the tone pip, whereas the hyperpolarization could last as long as 600 ms after the end of the tone pip. Often a neuron exhibited a sustained chopper pattern after microelectrode impalement. This was probably a result of a decrease in membrane potential which altered the relative effectiveness of the excitatory and inhibitory inputs. The large, bitufted fusiform cells had many apical dendrites, which branched one to five times and were covered with spines, and fewer basal dendrites, which exhibited little branching and had few appendages. The morphology of fusiform cells varied systematically as a function of location within the dorsal cochlear nucleus. Response patterns for tone pips were not exclusive to individual cell types as two nonfusiform cells were found to exhibit a buildup pattern. Axons of injected neurons left the nucleus via the dorsal acoustic stria and 14 of 15 had collaterals within the dorsal cochl

ISSN:0092-7317    

DOI:10.1002/cne.902130407

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractTo determine the correspondence between anatomical and physiological cell types in the ventral cochlear nucleus of the cat, intracellular injections of horseradish peroxidase were made into cells whose extracellular and intracellular responses to sound had been studied.Three identified cells responded to a short tone burst at their characteristic frequencies with an onset pattern. This pattern is characterized by a strong response to the onset of the stimulus. One was an octopus cell. The second cell, located in the octopus‐cell area, was a giant cell with a few somatic spines and thin tapering dendrites; the intracellular record revealed that even in the absence of sound it received continuous synaptic input, while tones at characteristic frequency produced a sustained depolarization. A third cell, which had an onset response at low intensities and a chopper response at high intensities, was a stellate cell located in the intermediate acoustic stria with dendrites oriented parallel to the fiber tract. This cell had an unusually broad dynamic range in response to changes in intensity.Two cells with transient chopper response patterns were stellate cells in the posteroventral cochlear nucleus with many branched and beaded dendrites. Three cells with more sustained chopper response patterns were stellate cells in the anteroventral cochlear nucleus with fewer, less‐branched, smooth dendrites.Two cells with primarylike responses to tones were bushy cells with numerous short, thin, highly branched dendrites in the posterior division of the anteroventral cochlear nucleus. Intracellular responses to tones at the characteristic frequency consisted of large brief depolarizations, which were not sustained.Another cell, which responded to tones in a phase‐locked fashion, was also located in the anteroventral cochlear nucleus. It was a small, stellate cell with relatively few, smooth dendrites.The labeled cells largely support previous attempts at physiological‐morphological correlations: (1) bushy cells exhibit primarylike pattern; (2) stellate cells exhibit chopper patterns; and (3) octopus cells exhibit an onset pattern. It was also demonstrated that more than one cell type can exhibit a particular response

ISSN:0092-7317    

DOI:10.1002/cne.902130408

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe activity of the olivocerebellar complex and the structures related in series with it have been studied using the complementary action of harmaline and 3‐acetylpyridine to isolate the two principal inputs to the cerebellar Purkinje cells. The activities of the various nuclei as well as the entire brain have been simultaneously monitored using the [14C]2‐deoxyglucose method under the various combined effects of the pharmacological agents.(1) Tremogenic doses of harmaline increased the frequency of discharge in selected parts of the olivocerebellar system, increasing climbing fiber input and reducing Purkinje cell simple spike discharges in corresponding parts of the cerebellar cortex. The metabolic activity increased in the inferior olive and in the red nucleus. The results are interpreted as a net reduction of Purkinje cell inhibition on their target neurons, leading to a facilitatory cerebellar output.(2) Systemic injection of neurotoxic doses of 3‐acetylpyridine selectively produced total degeneration of the neurons in the inferior olive, resulting in the suppression of complex spikes and a net increase in simple spike output from the Purkinje cells. The metabolic consequences were a reduction or absence in the inferior olive, decrease in the red nucleus, and increases in the Purkinje cell target neuron regions, including the intracerebellar and vestibular nuclei. The study of long survival times following the neu‐ rotoxic treatment revealed a transient metabolic marking of the inferior olive during the active glial processes accompanying the degeneration. In other parts the radioautographic changes caused by the destruction of the inferior olive persisted for about 1 month after the administration of the drug.(3) Tremogenic doses of harmaline were given to rats at different times following treatment with 3‐acetylpyridine. It was demonstrated that: (a)intoxication of the inferior olive started within the second hour after 3‐acetylpyridine administration, corresponding to the time at which the metabolic response to harmaline was also abolished; and (b) the increased metabolic activity produced by harmaline in the olivocerebellar complex was a consequence of an increased activity of the neurons of the inferior olive rather than a direct pharmacological effect of the drug.(4) Partial lesions of the inferior olive led to increased metabolic activity of those parts of the intracerebellar nuclei topographically related to the destroyed parts of the inferior olive.(5) In 3‐acetylpyridine‐treated animals, local ablation as well as local inactivation of the cerebellar cortex produced localized suppression of the intense labeling in the intracerebellar nuclei obtained in these animals. Since these regions receive synapses which are normally inhibitory, suppression of labeling clearly supports the hypothesis that regional marking may very well be produced by the activity of the presynaptic terminals themselves. The increased marking following suppression of the olivocerebellar system was thus interpreted as due to an increased activity in the simple spikes, producing an increased inhibitory influence of the Purkinje cell and therefore a disfacilitatory ce

ISSN:0092-7317    

DOI:10.1002/cne.902130409

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902130410

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.902130401

出版商:Alan R. Liss, Inc.    

年代:1983

数据来源: WILEY