Search PubMed⌕ Search

Biomedical subjects

D Tanaka

Publications and source records attributed to D Tanaka.

At least 55 records · Page 3Linked to original sources
PubMed1991

Delayed neurotoxic effects of bis (1-methylethyl) phosphorofluoridate (DFP) in the European ferret: a possible mammalian model for organophosphorus-induced delayed neurotoxicity.

This study examined the effects of the organophosphorus delayed neurotoxicant bis (1-methylethyl) phosphorofluoridate (DFP) on the central nervous system of the European ferret. Animals received subcutaneous injections of either 2 or 4 mg DFP/kg b.w. The extent of neuropathology was determined by the Fink-Heimer method, the activities of neuropathy target esterase (NTE) and cholinesterase (ChE) by enzyme assay methods, and the severity of clinical signs by a graded scale. In ferrets injected with 4 mg DFP/kg b.w., dense axonal and terminal degeneration were noted at 21 and 28 days post-DFP in the gracile, inferior vestibular, and lateral reticular nuclei, medial and dorsal accessory nuclei of the inferior olive, and in cerebellar folia I-IV. Degeneration was also noted in laminae VI-VII throughout most of the spinal cord and in the ventral motor nucleus at the level of the cervical enlargement. Both NTE and ChE activities were maximally inhibited at 6 hr post-dosing. NTE activity returned to control levels by 4 days while ChE activities reached control levels at 21 days. Clinical signs at 21 and 28 days post-DFP ranged from slight hindlimb weakness to severe ataxia or hindlimb paralysis. Less severe degeneration and clinical signs were noted in the animals exposed to 2 mg DFP/kg b.w. These findings indicate that the European ferret may be a model species for assessing the effects of organophosphorus delayed neurotoxicants.

Animals↗
PubMed1990

Exposure to triphenyl phosphite results in widespread degeneration in the mammalian central nervous system.

Previous studies in mammals have found that exposure to triphenyl phosphite results in cellular and axonal degeneration in the spinal cord and medulla. However, the nature of concomitant clinical signs suggested that other areas of the central nervous system might also be affected. In this study, the brains of ferrets receiving single subcutaneous injections of triphenyl phosphite were examined 8-12 days after dosing. Widespread areas of axonal, terminal, and somatic degeneration were seen in medullary, pontine, and thalamic nuclei. Extensive axonal and terminal degeneration were also noted in the cerebellar granule cell layer and in the cerebral cortical primary visual and sensorimotor areas. These data indicate that triphenyl phosphite exerts a potent neurotoxic effect, not only in the medulla and spinal cord, but also in the cerebellum, thalamus, and cerebral cortex.

Animals↗
PubMed1990

Selective axonal and terminal degeneration in the chicken brainstem and cerebellum following exposure to bis(1-methylethyl)phosphorofluoridate (DFP).

Utilizing a variation of the Fink-Heimer method, we examined the extent and location of axonal and terminal degeneration within the chicken cervical spinal cord, brainstem and cerebellum resulting from a single subcutaneous dose of bis(1-methylethyl)phosphorofluoridate (DFP). The effects of DFP on the activities of whole-brain neuropathy target esterase (NTE) and cholinesterase (ChE) were also assessed as were the development and severity of clinical signs characteristic of organophosphorus-induced delayed neuropathy (OPIDN). Both whole brain NTE and ChE activities were maximally inhibited during the first 24 h post-exposure, showing gradual recovery over a period of 3 weeks. OPIDN clinical signs were not observed at 7 days post-DFP but progressed to severe ataxia by day 14 and paralysis by day 21. There was a relative absence of degeneration at 7 days, a dramatic increase in degeneration density at 14 days, and high density degeneration at both 21 and 28 days. Cervical spinal and medullary tracts containing axonal degeneration included the fasciculus gracilis, dorsal and ventral spinocerebellar tracts, spinal lemniscus, and the intramedullary portions of the glossopharyngeal and vagus nerves. Brainstem nuclei containing terminal degeneration included the lateral cervical, gracile-cuneate, external cuneate, and inferior olivary nuclei, the nucleus tractus solitarius, and the lateral and paragigantocellular lateral reticular nuclei. Mossy fiber degeneration was also present in cerebellar folia I-Vb. These results show that exposure to DFP causes axonal and terminal degeneration in ascending spinal tracts, brainstem nuclei and cerebellar folia associated with the transmission of somatic and visceral sensory information.

Animals↗
PubMed1989

Degeneration patterns in the chicken central nervous system induced by ingestion of the organophosphorus delayed neurotoxin tri-ortho-tolyl phosphate. A silver impregnation study.

Exposure to certain organophosphorus compounds results in a neurological condition known as organophosphorus-induced delayed neurotoxicity (OPIDN). OPIDN is characterized clinically by an initial post-exposure delay period of 8-14 days after which signs of progressively developing ataxia and paralysis of the hindlimbs are observed. Although several studies have reported the presence of degeneration induced by organophosphorus delayed neurotoxins in specific central nervous system (CNS) structures, none have systematically examined CNS changes seen in the most frequently studied animal model for OPIDN--the domestic fowl. In the present study, we assessed the location and extent of anterograde degeneration in the chicken CNS following exposure to tri-o-tolyl phosphate (TOTP). All birds were dosed with 500 mg TOTP/kg body weight and killed after post-exposure periods of 1, 2, 3, or 4 weeks. The brains and spinal cords were processed with Fink-Heimer and Nissl stains. In the spinal cord, axon degeneration was noted in the fasciculus gracilis at cervical levels two weeks after exposure to TOTP. At 3 weeks, degeneration was also present in the cervical part of the dorsal spinocerebellar tract, in the lumbar part of the medial pontine-spinal tract, and in lamina VII in the lumbar ventral horn. In the medulla, moderate amounts of terminal and preterminal degeneration appeared at two weeks in the lateral vestibular, gracile, external cuneate, and lateral cervical nuclei. Lesser amounts of degeneration were noted in the solitary, inferior olivary, and raphae nuclei, in the medial, descending and lateral vestibular nuclei, and in the lateral paragigantocellular, gigantocellular, and lateral reticular nuclei. Fiber degeneration was also present in the medullary portions of the dorsal and ventral spinocerebellar tracts and spinal lemniscus. In the cerebellum, moderate amounts of terminal degeneration appeared in the deep cerebellar nuclei at one week while moderate mossy fiber degeneration was first noted in the granular layers of cerebellar folia I-V at 3 weeks. These results indicate (1) that, in the CNS, axonal and terminal degeneration resulting from TOTP intoxication appears to be confined to the spinal cord, medulla and cerebellum, (2) that the time of onset of degeneration in different fiber tracts and nuclei ranges from one to three weeks post-exposure, and (3) that the delay in the appearance of clinical signs of OPIDN is consistent with the delayed onset of degeneration in many of the affected CNS fiber systems.

Animals↗
PubMed1989

Delayed neurotoxic effects of tri-o-tolyl phosphate in the European ferret.

The development of organophosphorus-induced delayed neurotoxicity (OPIDN) was studied in the European ferret (Mustela putorius furo). A single oral or dermal dose of 250, 500, or 1000 mg tri-o-tolyl phosphate (TOTP)/kg body weight was administered to adult male ferrets. Corn oil served as the vehicle in the oral test and 95% ethanol was the vehicle in the dermal test. At 48 h posttreatment, half the animals in each group were killed by cervical dislocation for assessment of whole-brain neuropathy target esterase (NTE) activity. The remaining 5 animals per group were observed and examined neurologically on a daily basis for a subsequent 54 d. All ferrets dosed dermally with 1000 mg TOTP/kg body weight developed clinical signs characteristic of OPIDN ranging from ataxia to partial paresis. Ferrets administered 250 and 500 mg TOTP/kg body weight via the dermal route displayed variable degrees of hind limb weakness and ataxia. Of the animals dosed orally, only those in the 1000 mg TOTP/kg body weight group showed clinical signs indicative of OPIDN. These signs did not progress beyond mild ataxia. Small amounts of axonal degeneration were noted in the dorsolateral part of the lateral funiculus and in the fasciculus gracilis of spinal cords in ferrets receiving dermal doses of 1000 mg TOTP/kg body weight. Whole-brain neuropathy target esterase activity was also maximally inhibited (46%) in animals receiving 1000 mg TOTP/kg dermally. These results suggest that the ferret is a species that is susceptible to OPIDN.

Animals↗
PubMed1988

Cholinergic innervation of canine thalamostriatal projection neurons: an ultrastructural study combining choline acetyltransferase immunocytochemistry and WGA-HRP retrograde labeling.

Choline acetyltransferase (ChAT) immunocytochemistry and lectin-conjugated horseradish peroxidase (WGA-HRP) histochemistry were combined at the electron microscopic level to examine the morphology of cholinergic terminals in the canine centrum medianum-parafascicular complex (CM-Pf) and to localize cholinergic terminals making synaptic contact with retrogradely labeled CM-Pf thalamostriatal projection neurons. Following WGA-HRP injections into the caudate nucleus, CM-Pf neurons were heavily labeled with WGA-HRP reaction product. Examination with the electron microscope revealed retrogradely labeled neurons characterized by a large nucleus with deep infoldings of the nuclear envelope. ChAT-positive terminals were observed arising from small-diameter nonmyelinated axonal profiles. These terminals varied in size from 0.5 to 1.4 micron in long diameter. The smaller terminals (0.5-0.7 micron) were seen most frequently and established symmetrical or slightly asymmetrical synaptic contacts with small dendritic profiles. The larger ChAT-positive terminals (1.0-1.4 micron) were less frequently observed, contained several mitochondria and small clusters of pleomorphic vesicles, and contacted large dendritic shafts and cell somata. Some of the postsynaptic targets of both smaller and larger ChAT-positive terminals were identified as belonging to retrogradely HRP-labeled thalamostriatal neurons. These observations indicate that at least some thalamostriatal neurons within the CM-Pf complex are innervated by cholinergic terminals which probably arise from ChAT-positive cell bodies located within the pontomesencephalic tegmentum, particularly within the nucleus tegmenti pedunculopontinus and the laterodorsal tegmental nucleus. These findings provide evidence for direct influence by cholinergic brainstem nuclei over activities of thalamostriatal neurons.

Animals↗
PubMed1987

Neostriatal projections from cytoarchitectonically defined gyri in the prefrontal cortex of the dog.

The cytoarchitecture and neostriatal projections of the canine prefrontal cortex (PFC) were examined by using Nissl, silver degeneration, autoradiographic, and horseradish peroxidase techniques. Cytoarchitectonically, the PFC can be divided into six major gyral areas with each area corresponding to one of the major gyri--proreal, polar, pregenual, subproreal, paraorbital, and orbital--defined myeloarchitectonically by Kreiner (J. Comp. Neurol. 116:117-133, '61). Of the six major areas, only the proreal gyrus displays a distinctly granular layer IV. In all other gyri, layer IV is more difficult to distinguish. In both the orbital and polar gyri, layer IV is poorly defined and consists of scattered clusters of small cells between layers III and V. In the pregenual, subproreal, and paraorbital gyri, layer IV is not detectable. In all gyri, layer V consists of a thin lamina of small and medium-size pyramidal cells. The transition from layer III to layer V is marked by changes in cell density and size as well as staining intensity. Borders between layers V and VI are generally less distinct than those between layers III and V, with the exception of the pregenual gyrus, in which layer V is separated from layer VI by a distinct cell-poor lamina. In the subproreal and paraorbital gyri, the border between the underlying white matter and layer VI is particularly distinct, with large numbers of neurons oriented tangentially to the white matter. In contrast, the border between layer VI of the orbital gyrus and the white matter is less distinct and consists of palisades of neurons extending well into the white matter. The silver degeneration and autoradiographic methods revealed that prefrontostriatal projections terminate as dorsoventrally oriented longitudinal bands within the medial half of the head and body of the caudate nucleus. Projections from the polar and dorsal proreal gyri terminate most medially in the nucleus while projections from the lateral part of the proreal, subproreal, orbital, and paraorbital gyri terminate progressively more laterally within the medial half of the nucleus. There is apparent overlap between adjacent projection fields. A sparse projection was also noted to a small part of the putamen adjacent to the internal capsule. Injections of horseradish peroxidase into the medial and ventromedial parts of the head of the caudate nucleus resulted in widespread retrograde labeling in parts of the proreal, pregenual, paraorbital, subproreal, and central precruciate gyri. Labeled neurons were located primarily in the superficial part of layer V with smaller numbers of labeled cells in layers III, IV, and VI.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗
PubMed1987

Differential laminar distribution of corticostriatal neurons in the prefrontal and pericruciate gyri of the dog.

This investigation was undertaken to determine whether the laminar distribution of corticostriatal neurons differs between different anatomical and functional areas of the frontal lobe. Injections of lectin-conjugated horseradish peroxidase were made into the lateral, intermediate, and medial parts of the head of the caudate nucleus. After injections into the medial part of the caudate, most of the labeled neurons were found in the proreal and subproreal gyri of the prefrontal region. In both gyri, the majority of labeled cells were localized within layer V, and fewer neurons were located in the deeper part of layer III and in layers IV (proreal gyrus) and VI. No labeled neurons were noted in layer II. This distribution contrasted with that seen following injections into the intermediate and lateral parts of the caudate nucleus. In those cases, the majority of labeled cells were located in the pericruciate region (areas 4 and 6) and on the medial and lateral banks of the presylvian sulcus (paraorbital and internal composite areas, respectively). In the paraorbital and internal composite areas, the majority of labeled cells were still localized within layer V, but a larger percentage of labeled neurons were also noted in layer III. In areas 4 and 6, the laminar distribution shifted so that the majority of labeled cells were now located in layer III, with a widespread distribution of neurons throughout layers II-VI. These results indicate that corticostriatal neurons in the frontal lobe have different laminar distributions, depending on the particular anatomical or functional area in which they are located. The majority of neurons in the prefrontal region are located in infragranular layers, while those in the pericruciate region are located in supragranular layers.

Animals↗
PubMed1986

Thalamic afferents to cytoarchitectonic subdivisions of area 6 on the anterior sigmoid gyrus of the dog: a retrograde and anterograde tracing study.

The cytoarchitecture and thalamic afferents of cortical area 6 located on the anterior sigmoid gyrus were mapped and analyzed in the dog by means of cytoarchitectonic, horseradish peroxidase (HRP), and autoradiographic methods. Cytoarchitectonically, area 6 consists of medial and lateral subdivisions that correspond, respectively, to areas 6a alpha and 6a beta in the cat. In the dog, area 6a alpha is characterized by a wide layer III, the merging of borders between layers III and V, the presence of small-to-medium-size pyramidal cells in layer V, and a pallisade arrangement of cells in layer VI. Area 6a beta appears more stratified, with a relatively acellular layer present between layers V and VI and the presence of large pyramidal cells in layer V. Neither area 6a alpha nor 6a beta contains a layer IV. Data obtained from injections of HRP into areas 6a alpha or 6a beta revealed that labeled thalamic neurons were distributed in a longitudinal band extending from the rostral part of the ventral anterior nucelus (VA) through the caudal part of the mediodorsal nucleus (MD). Labeled cells were observed in the ventral lateral and ventral medial thalamic nuclei as well as in several of the intralaminar nuclei including the central lateral, central medial, parafascicular, and centrum medianum nuclei. A few labeled cells were also located in the suprageniculate nucleus. The densest thalamic labeling was present in VA and MD following injections into area 6a alpha. Equivalent or even larger injections into area 6a beta resulted in much less thalamic labeling. The band of labeled cells also extended into the hypothalamus, zona incerta, amygdala, claustrum, periaqueductal gray of the midbrain, and the nucleus of Darkschewitsch. Results from autoradiographic experiments showed that area 6 subdivisions receive a loosely organized topographic input from VA. Injections of tritiated amino acids were made into selected regions of VA and into the caudal part of MD, areas in which the largest numbers of HRP-labeled cells were located. Area 6a alpha receives afferents primarily from the rostromedial part of VA and the caudal part of MD while area 6a beta receives its principal input from the caudal and lateral parts of VA with minimal input from MD. Axons originating from VA terminate in both layers I and III of area 6 while those originating from the caudal part of MD terminate only in layer III.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1986

Thalamostriatal projections from the ventral anterior nucleus in the dog.

Thalamostriatal projections from the ventral anterior nucleus (VA) were mapped by using autoradiographic and horseradish peroxidase techniques in the dog. Injections of tritiated leucine and proline into the lateral, central, and medial parts of VA resulted in anterograde label over the dorsolateral, midlateral, and dorsal parts of the head of the caudate nucleus, respectively. The dorsolateral and midlateral parts of the caudate contained the heaviest label. No silver grains were located over the medial or ventral parts of the caudate. Light to moderate label was located over the most dorsal part of the putamen. After injections of lectin-conjugated horseradish peroxidase (WGA-HRP) into the dorsolateral or intermediate areas of the head of the caudate, retrogradely labeled cells were present in the lateral and central parts of VA, respectively. In cases with dorsolateral caudate injections, labeled cells formed a narrow dorsoventrally oriented band located in the lateral part of VA whereas in the case with a larger injection into midcaudate, large numbers of labeled neurons were scattered throughout the central area of VA. Retrogradely labeled cells were also found in the rostral part of the ventral lateral nucleus (VL). Injections of WGA-HRP into the medial part of the caudate resulted in only a few labeled cells located in the dorsomedial part of VA. Combining these data with those from other studies mapping neostriatal afferents from the cerebral cortex in the dog, it is apparent that the midlateral part of the caudate receiving input from VA also receives afferents from cortical area 6. Furthermore, the dorsolateral part of the caudate that receives input from the lateral part of VA also receives afferents from cortical area 4. These results indicate that the dorsal and lateral parts of the canine caudate nucleus may constitute important links in the transmission and integration of information related to complex motor activities.

Amino Acids↗
PubMed1986

Cholinergic and non-cholinergic projections from the canine pontomesencephalic tegmentum (Ch5 area) to the caudal intralaminar thalamic nuclei.

The distribution and morphology of cholinergic and non-cholinergic neurons projecting to the caudal intralaminar thalamic nuclei from the Ch5 area in the dog were examined using a technique combining horseradish peroxidase (HRP) retrograde labeling with choline acetyltransferase (ChAT) immunocytochemistry. After processing for ChAT, cholinergic neurons were found primarily within the nucleus tegmenti pedunculopontinus (PPN) and the central tegmental tract (ctt). ChAT positive neurons were also located in the nucleus cuneiformis and among the fibers of the lateral lemniscus and medial longitudinal fasciculus. On the basis of immunocytochemical and cytoarchitectonic data, PPN was divided into two distinct cell groups - a compact cell group located dorsolateral to the brachium conjunctivum and a diffuse cell group intermingled among the fibers of the brachium conjunctivum. Tissue processed for WGA-HRP and ChAT following injections of lectin-conjugated horseradish peroxidase into either the centrum medianum (CM) or parafascicular (Pf) nucleus resulted in double labeled cholinergic projection neurons in both PPN and ctt. Injections which involved CM and the caudal part of the central lateral thalamic nucleus (CL) resulted in more retrogradely labeled neurons than did those injections involving Pf. Injections of CM and CL also resulted in more double labeled cells in the dorsolateral compact portion of PPN than did injections confined to Pf. In all cases a small number of cholinergic neurons located in the contralateral PPN were retrogradely labeled as well. A substantial number of retrogradely labeled neurons were not ChAT positive, and in some cases, comprised up to 27% of the total population of projection neurons. Measurements of cell soma areas indicated that cells comprising the general cholinergic population were mostly medium (300-600 micrograms2) or large (greater than 600 micrograms2) in size. The majority of cholinergic projection neurons fell within the medium size category while the noncholinergic projection neurons were significantly smaller than their cholinergic counterparts. The results of this study suggest that in the dog, Ch5 cholinergic neurons which project to the caudal intralaminar thalamic nuclei are medium in size and are located primarily within PPN and ctt. In addition, a parallel projection to the caudal intralaminar nuclei exists which originates from smaller, non-cholinergic neurons in these same regions. Based on the results of this study, it appears that cholinergic projections to intralaminar thalamic nuclei which in turn project to the neostriatum may be one of the pathways over which PPN can affect basal ganglia activity.

Animals↗
PubMed1985

Corticostriate projections from area 6 in the raccoon.

Corticostriate projections from area 6 in the raccoon were studied using the autoradiographic tracing method. Following injections of tritiated amino acids into two different cytoarchitectonic subdivisions of area 6, widespread and dense anterograde label was found in both the ipsilateral and contralateral caudate nucleus and putamen. The densest label was located adjacent to the internal capsule in the lateral part of the head of the caudate nucleus. This bilateral projection pattern from area 6 to the caudate nucleus and putamen is consistent with the hypothesis that the neostriatum maintains a close anatomical and functional relationship with area 6.

Animals↗
PubMed1984

Contralateral corticothalamic projections from area 6 in the raccoon.

Contralateral corticothalamic projections from cytoarchitectonic area 6 in the raccoon were studied using the autoradiographic tracing technique. Following injections of tritiated amino acids, accumulations of silver grains were present over both the ipsilateral and contralateral ventral medial, central lateral, paracentral, central medial, parafascicular and mediodorsal thalamic nuclei. These nuclei are also known to receive a number bilateral subcortical motor inputs. The additional presence of bilateral area 6 inputs suggests that these thalamic nuclei may be critically involved in the bilateral control of movement.

Animals↗
PubMed1983

The ventral lateral thalamic nucleus in the dog: cytoarchitecture, acetylthiocholinesterase histochemistry, and cerebellar afferents.

The canine ventral lateral nucleus was defined on the basis of Nissl cytoarchitecture, acetylthiocholinesterase (AChE) chemoarchitecture, and the distribution of cerebellar afferents. It consists of at least two subdivisions: a dorsal and rostral division (VLd) that stains intensely for AChE and contains densely packed cells, and a larger principal division (VL), located ventrocaudally, that stains moderately for AChE and contains a mixture of cells with moderate packing density. Results from autoradiographic, silver degeneration, and AChE material indicate that both divisions receive input from the deep cerebellar nuclei.

Acetylcholinesterase↗
PubMed1983

Corticothalamic projections from postcruciate area 4 in the dog.

Corticothalamic projections from postcruciate area 4, located on the rostral part of the posterior sigmoid gyrus, were traced with the autoradiographic technique in the dog. Injections of tritiated amino acids were made into the lateral and medial parts of area 4 in regions corresponding to the forelimb and hindlimb areas of the primary motor cortex, respectively. In cases with injections placed in the lateral part of area 4, dense accumulations of label were present in the lateral part of the ventral anterior nucleus (VA), the central part of the ventral lateral nucleus (VL), the ventral half of the ventral posterior inferior nucleus (VPI), the caudal part of the central lateral nucleus (CL), and the centrum medianum (CM). Lighter label was also present in the lateral part of the cytoarchitectonically distinct VL region bordering the ventrobasal complex (VB), as well as in the ventrolateral part of the mediodorsal nucleus (MD), and in the lateral posterior nucleus (LP). In one case in which the injection site involved an adjacent part of area 3a, label was also seen ventrally in the medial division of the posterior nuclear group (POm). However, no detectable differences in VL, MD, or intralaminar labeling patterns were noted between this case and the four other cases with injections confined to the lateral part of area 4. In two cases with injections restricted to the medial part of area 4, dense label was present in the lateralmost part of VL, the ventral part of VPI, the caudal part of CL, and CM. Lighter label was also present in the VL region bordering the dorsolateral edge of VB and in LP. An additional case in which the injection also involved the rostral border of area 3a showed a similar pattern of thalamic labeling. Projections from both the lateral and medial parts of area 4 were also noted in the subthalamic nucleus, zona incerta, and nucleus of Darkschewitsch. These results suggest that corticothalamic projections from postcruciate area 4 to VL are organized topographically such that projections from the lateral part of area 4 project centrally within VL while those from the medial part of area 4 project more laterally. Both parts of area 4 also project topographically to a cytoarchitectonically distinct region of VL located immediately adjacent to VB. In contrast, the projections to the intralaminar nuclei do not appear to be topographically organized. The data from cases involving spread of the injection into area 3a suggest that projection patterns from area 3a to ventral, intralaminar, and medial thalamic nuclei are similar to those from area 4. However, it appears that at least the lateral part of area 3a also projects to POm.

Animals↗
PubMed1983

Corticostriate projections from reciprocally connected sectors of areas 4 and 5 in the dog.

Injections of tritiated leucine were made into area 4 on the medial part of the posterior sigmoid gyrus and area 5 on the rostral part of the lateral gyrus. Both areas were found to project to each other as well as to an overlapping area in the caudate nucleus. These data suggest that areas 4 and 5 in the dog may relate to each other not only through direct reciprocal connections but also through overlapping projections to the neostriatum.

Animals↗
PubMed1981

Corticostriate projections from the primary motor cortex in the dog.

Corticostriate projections from the hindlimb and forelimb areas of the primary motor cortex in the dog were traced using the autoradiographic technique. Injections of tritiated leucine into the hindlimb area resulted in discrete oval or semicircular patches of label confined to the dorsolateral corner of the head and body of the caudate nucleus. No label was found over the putamen. Injections into the forelimb area yielded irregularly shaped patches of label over the dorsolateral part of the head and body of the caudate nucleus as well as more diffuse label over the dorsal-most part of the putamen. In both instances diffuse terminal fields were noted in the dorsolateral part of the contralateral caudate nucleus. A comparison of results in the caudate nucleus indicates that projections from the forelimb area terminate somewhat more caudally and slightly more ventrally and medially than do projections from the hindlimb area. The results further suggest that although terminal fields from these areas may to some extent interdigitate with one another, they also overlap each other to a significant degree.

Animals↗