Download Course of spinocerebellar axons in the ventral and lateral funiculi of

Exp Brain Res (2005) 162: 250–256
DOI 10.1007/s00221-004-2132-6
RESEARCH ARTICLE
Qunyuan Xu . Gunnar Grant
Course of spinocerebellar axons in the ventral and lateral funiculi
of the spinal cord with projections to the posterior cerebellar
termination area: an experimental anatomical study in the cat,
using a retrograde tracing technique
Received: 7 May 2004 / Accepted: 28 September 2004 / Published online: 15 December 2004
# Springer-Verlag 2004
Abstract The course of retrogradely labeled spinocerebellar fibers in the ventral and lateral funiculi of the spinal
cord was studied following injections of wheat germ
agglutinin-conjugated horseradish peroxidase into the
posterior spinocerebellar termination area in the cat. Fibers
labeled from unilateral injections into the paramedian
lobule were found on the same side in the dorsal part of
the lateral funiculus (DLF), corresponding to the dorsal
spinocerebellar tract (DSCT), but contralaterally in the
ventral part of the lateral funiculus (VLF) and in the
ventral funiculus (VF), corresponding to the ventral
spinocerebellar tract (VSCT). Following injections into
the posterior vermis, labeled fibers were less numerous.
Most of them were found in the DSCT and only very few
in the VSCT. Previously identified cells of origin of these
spinocerebellar tracts were labeled in these experiments
and counted. They correlated well with the extents and the
locations of the injections that had been made into the two
termination sites. These results represent novel detailed
information on the location of axons projecting to the two
main posterior spinocerebellar termination sites in the
spinal white matter in the cat.
Keywords Ascending pathways . Cerebellum . WGAHRP . Retrograde transport
Abbreviations CCN: central cervical nucleus . DL:
dorsolateral nucleus . DLF: dorsal part of lateral
Q. Xu . G. Grant (*)
Department of Neuroscience, Karolinska Institutet,
171 77 Stockholm, Sweden
e-mail: [email protected]
Fax: +46-8-325325
Q. Xu
Capital Institute of Medicine,
Beijing, People’s Republic of China
Present address:
Q. Xu
The Beijing Center for Neural Regeneration and Repairing,
Capital University of Medical Sciences,
100054 Beijing, People’s Republic of China
funiculus . DSCT: dorsal spinocerebellar tract . RSCT:
rostral spinocerebellar tract . VF: ventral funiculus . VL:
ventrolateral nucleus . VLF: ventral part of lateral
funiculus . VSCT: ventral spinocerebellar tract . VIIB,
VIIIA, VIIIB: cerebellar sublobules according to Larsell
(1953)
Introduction
In an earlier study we used a retrograde tracing technique
to investigate the location and course of spinocerebellar
axons in the spinal cord of the cat following injections of
horseradish peroxidase (HRP) or wheat germ agglutinin
(WGA)-HRP into the anterior lobe, the main area of
termination of spinocerebellar fibers (Grant and Xu 1988a;
Xu and Grant 1994). The same technique had also been
used in two different studies on the spinocerebellar tracts
in the rat (Shirao 1987; Yamada et al. 1991). These studies
selectively visualized spinocerebellar axons at spinal level
for the first time using an anatomical approach. The same
approach, but with the use of Fluoro-Gold instead of HRP
or WGA-HRP, was applied later in a study in the North
American Opossum, Didelphis virginiana (Terman et al.
1998). Earlier anatomical studies on the location and
course of these tracts had been based on anterograde
tracing following either spinal cord lesions or injections of
tracer into areas of spinocerebellar cell groups. Neither of
these had allowed the selective visualization of spinocerebellar fibers. Combining the retrograde tracing with
spinal cord lesions at different levels or lesions of the
cerebellar peduncles allowed us to define the location and
course of axons from different segmental levels. In the
present study we have investigated the location and course
of spinocerebellar axons projecting to the posterior area of
termination, including the paramedian lobule and the
adjoining medial part of the dorsal paraflocculus,
sublobule VIIIB and parts of sublobules VIIB and VIIIA
of the posterior vermis (Grant 1962; Matsushita 1988;
Matsushita and Tanami 1987; Matsushita and Yaginuma
1989; Matsushita et al. 1985; Yaginuma and Matsushita
251
1987, 1989; Voogd 1964; Wiksten 1979b, 1987; Xu and
Grant 1990).
Materials and methods
Six adult cats, 3.9–6.5 kg at operation, were used in the
present study. The “principles of laboratory animal care”
were followed. All surgical procedures were made with the
animals under deep anesthesia. This was induced by
Rompun (10 mg/kg s.c.; Bayer) followed by Mebumal
(30 mg/kg i.p.; Abbott). The animals were fixed in a
stereotaxic frame during the operations, which were
carried out under sterile precautions. The posterior part
of the occipital bone was removed to give access to the
needle for injection of the tracer into the cerebellum. The
injections were made into the paramedian lobule and/or
the posterior vermis, using a Hamilton syringe. WGAHRP (0.8–1.9 μl) was injected and the wound was closed.
Following postoperative survival periods of 3–4 days,
the animals were reanesthetized deeply and perfused
through the ascending aorta with warm (about 36 °C)
Tyrode’s solution followed by a fixative containing 1%
paraformaldehyde, 1.5% glutaraldehyde and 5% sucrose
in 320 mOsm phosphate buffer (pH 7.4) at 4 °C. This was
followed by perfusion with 10% sucrose in the same
Fig. 1 Diagrams of unfolded
cerebellar cortex modified from
Grant (1962) showing the injection sites in each case. Solid
areas indicate strong WGAHRP activity, stippled areas
weak activity (Crus I and
Crus II anterior and posterior
parts of the ansiform lobule, N.f.
fastigial nucleus, N.i. interposed
nucleus, p.ant. pars anterior of
the paramedian lobule, p.cop.
pars copularis, p.post. pars posterior, pfl medial part of dorsal
paraflocculus, pmd paramedian
lobule, V–IX cerebellar lobules
according to Larsell 1953)
buffer. The central nervous system was dissected out, and
blocks were prepared from the cerebellum, brainstem and
cervical (C1, 2, 3, 5, 7, 8), thoracic (T5, 10, 13), lumbar
(L2, 3, 5, 6) and sacral (S2) spinal cord segments. The
blocks were kept in phosphate buffer containing 30%
sucrose (4 °C) overnight and sectioned in series at 60 μm
on a freezing microtome. The spinal cord and brainstem
sections were cut transversely and collected in groups of
ten and five, respectively. Two sections from each group
were incubated with tetramethylbenzidine (TMB) according to Mesulam (1978). The cerebellar sections were cut in
the sagittal plane and divided into groups of five. One
section from each group was incubated with TMB.
Labeled axons and neuronal cell bodies in the spinal
cord sections were identified in the microscope at ×25
objective magnification in brightfield illumination and
mapped, using an X-Y recorder device connected to the
microscope, as in our previous study (Xu and Grant 1994).
Only cells that were either labeled homogeneously or
showed a relatively clear nuclear outline were selected for
mapping. All of these cells were entered on summarizing
diagrams from the respective segments and counted (see
Grant and Xu 1988b). The injection sites, as seen in the
cerebellar sections, were examined under the microscope,
mostly at ×10 objective magnification, and mapped, using
an enlarging projector (×10). The extents of the injections
252
were summarized in diagrams of the unfolded cerebellar
cortex (Fig. 1).
Results
The injections into the cerebellum covered the posterior
spinocerebellar termination area to a different extent in
different cases (see Fig. 1). Two of them (C255 and C258)
comprised the main portion of the paramedian lobule area
of termination (the posterior part of this lobule, pars
copularis) completely. In one of these (C255), the
termination area in the medial part of dorsal paraflocculus
was also covered. There was no involvement of the area of
termination in the posterior vermis in any of these cases. In
another two cases (C254 and C257) the injections
comprised the termination site in sublobule VIIIB on
both sides, although less extensively in the rostral part in
one of them (C254), and not completely on the right side
in either of them. The termination site in sublobules VIIB
and VIIIA was covered by the injection in one of them
(C257). In this case there was also a very minor
involvement of the paramedian lobule bilaterally. Another
two cases (C253 and C256) had injections covering
sublobules VIIB, VIIIA and VIIIB, and parts of the
termination area in the paramedian lobule, most prominently in one of them (C253). In this case, the medial part
of dorsal paraflocculus was involved too. In both of these
cases there was also a slight involvement of a lateroposterior part of the fastigial nucleus and of the posterior
interposed nucleus. Two of the cases (C256 and 257)
showed some spread of tracer to the dorsal surface of the
brainstem on the left side, including the dorsal part of the
most caudal portion of the inferior vestibular nucleus.
Labeled axons were found in the lateral and ventral
funiculi of the spinal white matter in all six cases.
The findings in case C255, in which the injections had
affected both the paramedian lobule area of termination
and that of dorsal paraflocculus, will be described in detail
first. Labeled axons were present bilaterally in the spinal
white matter (Fig. 2). On the right side, the side of the
injection, they were found in the dorsal part of the lateral
funiculus (DLF), and on the left side, in the ventral part of
the lateral funiculus (VLF) and in the ventral funiculus
(VF). The amount of labeled fibers in the DLF was larger
than in the VLF. The findings in case C258 were almost
identical. In the DLF, labeled axons were present from
above the L3 segment (Fig. 2). They were located
peripherally, with fibers adding from deeper parts at
thoracic and up to mid-cervical levels. On the left side,
labeled axons were found in the VF at lower lumbar levels
(L3–L6), but more rostrally, up to upper cervical
segments, in the peripheral parts of the VLF. A large
number of labeled neuronal cell bodies (116) were found
in the column of Clarke and in laminae IV–VI on the right
side (T5–L3), and some (19) on that side in laminae V–VI
at the level of the cervical enlargement (C5–C8). On the
same side, there were many (41) labeled neuronal cell
bodies in the dorsolateral nucleus (DL; Grant et al. 1982)
Fig. 2 Diagrams showing distributions of WGA-HRP labeled
axons and perikarya for case C255. Each drawing represents one
section. Notches are on the right side dorsally
at L3–L6, a few (six on the left, two on the right) in the
medial group of lamina VII neurons at lumbosacral levels
(L5–S2; Grant et al. 1982) and some (16 on the left, six on
the right) in the central cervical nucleus (CCN; C1–C3).
In two of the cases with injections affecting the
termination area in the posterior vermis (C254 and 257),
there were only small amounts of labeled axons,
particularly in the one in which sublobule VIIIB was
less affected (C254). In this case, the termination sites in
sublobules VIIB and VIIIA were not involved at all. In the
case with less sparse labeling (C257; not illustrated), most
of the labeled axons were found in the DLF, mainly on the
left side, only very few bilaterally in the VLF, and only
single ones in the VF on the two sides. The single ones in
the VF were found at lower lumbar and at upper cervical
levels. Labeled neuronal cell bodies were present in small
amounts bilaterally in the medial group of lamina VII at
lumbosacral levels (17 on the left, 10 on the right; L5–S2).
Larger amounts were found in Clarke’s column and
laminae IV–VI at thoracolumbar levels (T5–L3), predominantly on the left side (40 versus 10). Moreover, there
were a large number of labeled neurons in the CCN. Most
of these were on the right side (118 versus 79; C1–C3).
Of the two remaining cases, C253 and C256—
representing sublobule VIIIB plus paramedian lobule
(C253) injections—case C253, which had the most
extensive affection of the posterior spinocerebellar termination sites, will be described in detail. In this case,
labeled axons were present bilaterally, both in the DLF and
in the VLF and VF (Fig. 3). There was an asymmetry,
however, in the sense that more axons were found in the
VLF and VF on the right side but in the DLF on the left.
The latter was the side where the injection had covered the
termination site in the paramedian lobule most extensively.
253
Discussion
Retrogradely labeled fiber tracts
Fig. 3 Diagrams showing distributions of WGA-HRP labeled
axons and perikarya for case C253. Each drawing represents one
section. Notches are on the right side dorsally
Otherwise, with one exception, the locations of the labeled
fibers were similar to what was found in case C255. The
exception concerned fibers appearing bilaterally in the VF
at upper cervical levels, which were not seen in case C255.
There was a large number of labeled neuronal perikarya in
the CCN in case C253 (153 on the left side, and 146 on the
right; C1–C3), but just a few (16 and 6, respectively) in
C255. Furthermore, there was a large number (245 on the
left side, 218 on the right) in Clarke’s column and laminae
IV–V at thoracic and upper lumbar levels (T5–L3), which
means twice as many perikarya with these loctions as in
case C255. About twice as many labeled neurons as in
case C255 were also found in the DL nucleus at L3–L6
(86 on the left, 31 on the right). Another striking
difference when compared with case C255 was that the
medial group of lamina VII had rather many labeled cell
bodies in case C253 (64 on the left, 65 on the right; L5–
S2), but just a few (six and two, respectively) in C255.
Case C256 had labeled axons distributed similarly to
case C253, although there was no clear asymmetry with
regard to the amount of labeled fibers in the VLF and VF
and in the DLF on the two sides. More axons were found
in the VF, however, particularly in the upper cervical
segments, but also at lower lumbar levels. There were
many more labeled neurons in the CCN (232 on the left,
255 on the right), but fewer medially in lamina VII at
lumbo-sacral levels (29 on the left, 30 on the right) and in
the DL nucleus at L3–L6 (47 on the left, 22 on the right).
The findings in the present study further demonstrate the
usefulness of selective retrograde labeling of spinal fiber
tracts following injections into areas of termination. In a
previous study in the cat we localized spinocerebellar
fibers with projections to the anterior lobe of the
cerebellum, the main area of termination of the spinocerebellar tracts (Xu and Grant 1994). This was also done
later in the North American Opossum, Didelphis virginiana (Terman et al. 1998). Here we have examined the
locations of spinocerebellar fibers projecting to the less
extensive, posterior termination area. This includes two
main sites, the posterior part (pars copularis) of the
paramedian lobule, with the adjoining medial portion of
dorsal paraflocculus, and parts of posterior vermis,
including sublobule VIIIB and portions of sublobules
VIIB and VIIIA (Grant 1962; Voogd 1964; Matsushita and
Tanami 1987; Matsushita and Yaginuma 1989; Matsushita
et al. 1985; Yaginuma and Matsushita 1987, 1989;
Wiksten 1979b, 1987). Retrogradely labeled axons were
found from both of these sites of termination, although
only in small amounts following injections into the
posterior vermis.
The locations of the labeled fibers corresponded to the
sites of the classical dorsal and ventral spinocerebellar
tracts (DSCT and VSCT, respectively; see for example Xu
and Grant 1994). The DSCT is found peripherally in the
DLF, with fibers adding from deeper parts at more rostral
levels, where additional cells of origin are found. The
VSCT is located in the VF at sacral and lower lumbar
levels and peripherally in the VLF at more rostral levels.
At the level of the cervical enlargement there were
contributions of fibers to the mid peripheral area of the
lateral funiculus, corresponding to the location of the
rostral spinocerebellar tract (RSCT; Matsushita et al. 1985;
Wiksten 1985; Wiksten and Grant 1986; Xu and Grant
1994). Finally, at high cervical levels labeled fibers
appeared in the VF in some of the cases. These could be
related to the CCN, which is present at C1–C4 in the cat
(Rexed 1954). It gives rise to crossing spinocerebellar
axons (Matsushita et al. 1979; Matsushita and Ikeda 1980;
Wiksten 1979a, 1987; Xu and Grant 1994).
Retrogradely labeled neuronal cell groups
Counting of labeled neuronal perikarya in the spinocerebellar cell groups was carried out in the different cases in
the same way as in our previous study (Xu and Grant
1994). This created a useful support for interpreting
variations in relative amounts of labeled axons at different
levels and locations. These cell groups have been
identified anatomically mainly by retrograde tracing
methods in the cat (Grant et al. 1982; Grant and Xu
1988a, 1988b; Matsushita et al. 1979; Matsushita and
Ikeda 1980; Wiksten 1975, 1979b, 1985; Xu and Grant
254
1994). Cells in the column of Clarke and laminae IV–VI
from L3 to upper thoracic levels give rise to uncrossed
fibers to the DSCT. The medial group of lamina VII at
lumbosacral levels and the DL nucleus at L3–L6 are
sources of the VSCT, the former with both crossed and
uncrossed axons, the latter with crossed axons. The VSCT
also originates from cells in the ventrolateral nucleus (VL)
in L4–L5, together with cells in a lateral group of lamina
VII, close to the DL nucleus (Grant et al. 1982). These
groups, however, which were not labeled in the present
experiments, project exclusively to the anterior lobe and
not to the posterior spinocerebellar termination sites (Xu
and Grant 1988). The RSCT takes its origin ipsilaterally
from cells in laminae V–VI at C5–C8. At upper cervical
levels, the CCN is a source of crossing spinocerebellar
axons.
Spinocerebellar fibers labeled from the area of the
paramedian lobule (C255 and C258)
The paramedian lobule injections (C255 and C258)
resulted in labeled fibers distributed bilaterally, but with
different locations. They were found in the DLF on the
side of the injection and in the VF and VLF on the other
side. The amount of fibers seemed to be larger in the DLF
than in the VLF. This is in agreement with the previouslyreported finding that the DSCT contributes more heavily to
the projection to the paramedian lobule than the VSCT
(Grant 1962). The ipsilateral fiber labeling could be
correlated to labeled cell bodies distributed ipsilaterally in
the column of Clarke and laminae IV-VI at thoracolumbar
levels and ipsilateral cells originating from the RSCT at
the level of the cervical enlargement. This would confirm
earlier findings by Matsushita and Ikeda (1980), who
found ipsilateral labeling of cells with these locations
following HRP injections into the paramedian lobule. The
contralateral fibers, in the VLF and VF, which appeared
from levels located far caudally, could be correlated to
cells originating from the DL nucleus on the side of the
injection, with axons crossing to the contralateral side of
the spinal cord, and to cells located bilaterally in the
medial group of lamina VII neurons at lumbosacral levels.
Cells from the DL nucleus projecting to the paramedian
lobule have been identified before (Xu and Grant 1988).
They correspond to the retrogradely labeled spinal border
cells and lateral lumbar nucleus neurons that were found in
the study by Matsushita and Ikeda (1980), following HRP
injections into the paramedian lobule. They found that the
axons cross twice, first at spinal level and then inside the
cerebellum, and therefore concluded that the projection to
the paramedian lobule was ipsilateral to the cells of origin.
Like Matsushita and Ikeda (1980), we have previously
demonstrated that axons from the DL nucleus (spinal
border cells and lateral lumbar nucleus of Matsushita and
Ikeda) project contralaterally in the spinal cord (Grant et
al. 1982; Grant and Xu 1988b). Furthermore, it is well
established that the VSCT has a mainly contralateral
termination in the cerebellum (Grant 1962; Voogd 1964).
Our results are therefore in complete agreement with the
conclusion of Matsushita and Ikeda. Some neurons were
also labeled bilaterally in the CCN, although their axons
were not identified in the ventral white matter. A bilateral
labeling of CCN neurons is in agreement with the
observations reported by Matsushita and Ikeda (1980).
They found occasional neurons labeled in the CCN on
both sides following injections into sublobules A2 and B1
(corresponding to parts of pars anterior and pars posterior)
of the paramedian lobule. Furthermore, anterograde
labeling with WGA-HRP following spinal cord hemisections above the level of injections into the CCN has
demonstrated bilateral projections to the paramedian
lobule, although predominantly contralateral to the cells
of origin (Matsushita and Tanami 1987).
Spinocerebellar fibers labeled from posterior vermis
(C254 and C257)
The posterior vermis injections (C254 and C257) gave rise
to only small amounts of labeled fibers, particularly in the
case in which sublobule VIIIB was less affected and the
termination sites in sublobules VIIB and VIIIA were not
involved (C254). In the case with less sparse labeling,
most of the labeled fibers were located in the DLF, and
only very few in the VLF and VF. This is in agreement
with the previously-reported finding that the DSCT
contributes more heavily to the projection to the posterior
vermis than the VSCT (Grant 1962). The small amount of
labeled neurons in the medial group of lamina VII at
lumbosacral levels goes in parallel with the very few
labeled axons in the VLF, and also in the VF at lower
lumbar levels. Matsushita and Ikeda (1980) found this
group to project to sublobule VIIIB. In the DLF, there
were more labeled fibers on the left side. This is
reasonably explained by the more extensive covering by
the injection of the vermis on that side. There were also
more labeled neuronal cell bodies in the column of Clarke
and laminae IV–VI on that side. A projection from the
column of Clarke to sublobule VIIIB was described earlier
(Matsushita and Ikeda 1980). The large number of labeled
neurons in the CCN explains the occurrence of labeled
axons in the VF at upper cervical levels. That these
neurons were mainly on the right side would be expected,
considering the contralateral dominance of the vermal
injection. A CCN projection to the posterior vermis was
described earlier (Wiksten 1979b, 1987; Matsushita and
Ikeda 1980).
Spinocerebellar fibers labeled from injections
affecting both the posterior vermis and the paramedian
lobule (C253 and C256)
The injections which affected both the paramedian lobule
and the posterior vermis (C253 and C256) resulted in
labeled fibers located bilaterally in both the DLF and the
VLF and VF. In the case with the most extensive injection
255
(C253) there was a clear asymmetry. More labeled axons
were found in the DLF on the left side but in the VLF and
VF on the right. This should reasonably be explained by
the more extensive involvement of the paramedian lobule
on the left side. In analogy with the findings in case C255,
this termination site should receive afferents from the
DSCT on the left side and from the VSCT on the right. In
contrast to the finding in case C255, there were labeled
axons distributed bilaterally in the VF at high cervical
levels. This is reasonably explained by the presence of a
large number of labeled neurons located bilaterally in the
CCN, as opposed to just a few in case C255. That the
labeled axons would be descending fibers, originating in
the left fastigial nucleus, which was involved by the
injection, should be possible to exclude. Labeled axons
were found bilaterally and the fastigiospinal projection has
been found to be exclusively unilateral, contralateral
(Fukushima et al. 1977; Matsushita and Hosoya 1978).
That there was a large number of labeled neurons in the
CCN in case C253 might be related to the projection to the
posterior vermis. The injection into this part of the
cerebellum in case C257 resulted in a large number of
labeled neurons in the CCN. On the contrary, an injection
into the paramedian lobule, in case C255, gave rise to just
a few. The large number of labeled neurons in Clarke’s
column and laminae IV–VI, compared to the situation in
case C255, might be explained by the involvement of both
the paramedian lobule and the posterior vermis, each of
which receive projections from these groups of neurons, as
discussed above. A retrograde labeling of some neurons in
these groups derived from collaterals of spinocerebellar
axons projecting to the fastigial and interposed nuclei
cannot be ruled out, however, considering the finding by
Matsushita and Ikeda (1970) that the DSCT sends
collaterals to these nuclei. They reported, furthermore,
that a similar projection was found also for the VSCT, and
that this tract represented the most important connection of
the two tracts. This could account for the larger number of
labeled neurons in the DL nucleus, compared to case
C255.
The distribution of labeled axons in case C256 was
similar to that in case C253, except that there were more
axons in the VF, particularly at upper cervical levels. This
could be explained by the larger number of CCN neurons
at these levels. No clear explanation can be offered,
however, for the larger amount of labeled axons in the VF
at lower lumbar levels. The lower number of labeled cells
in the medial group of lamina VII neurons, as well as in
the DL group, is most probably explained by the less
extensive involvement of the paramedian lobule compared
to case C253.
Comparisons with findings of retrograde labeling from
the anterior lobe
An interesting finding in the present study was the
asymmetry with regard to locations of fibers in the DLF
versus the VLF and VF, following injections into the
paramedian lobule. This may be expected, however,
considering the fact that fibers in the VSCT will have to
cross twice, first at their level of origin in the spinal cord,
and then again inside the cerebellum, whereas those of the
DSCT should pass uncrossed. Unilateral injections of
tracer into the anterior lobe, which also receives projections from both the DSCT and the VSCT, should result in
the same pattern. In our previous study on retrogradely
labeled fibers following injections into the anterior lobe,
such injections were however not made (Xu and Grant
1994).
With regard to retrogradely labeled cell bodies in
different spinocerebellar cell groups, many such cells were
found in the present study in the same groups as in our
previous study. This may be expected, considering the
results of another study, which dealt with collateral
projections from the lower part of the spinal cord to
anterior and posterior cerebellar termination areas (Xu and
Grant 1988). One principal difference, however, was that
no labeled neurons were found in the VL nucleus at L4–
L5, nor in the lateral group of lamina VII, close to the DL
nucleus, as discussed above. Those neurons project
exclusively to the anterior lobe and not to the posterior
spinocerebellar termination area (Xu and Grant 1988).
Conclusions
The findings in this study give novel detailed information
on the location of axons projecting to the two main
posterior spinocerebellar termination sites in the spinal
white matter in the cat. Fibers labeled from unilateral
injections into the paramedian lobule were found on the
same side in the dorsal part of the lateral funiculus (DLF),
corresponding to the dorsal spinocerebellar tract (DSCT),
but contralaterally in the ventral part of the lateral
funiculus (VLF) and in the ventral funiculus (VF),
corresponding to the ventral spinocerebellar tract
(VSCT). Following injections into the posterior vermis,
labeled fibers were less numerous. Most of them were
found in the DSCT and only very few in the VSCT.
Previously identified cells of origin of these spinocerebellar tracts were labeled in these experiments and counted.
They correlated well to the extents and locations of the
injections that had been made into the two termination
sites.
References
Fukushima K, Peterson BW, Uchino Y, Coulter JD, Wilson VJ
(1977) Direct fastigiospinal fibers in the cat. Brain Res
126:538–542
Grant G (1962) Spinal course and somatotopically localized
termination of spinocerebellar tracts. An experimental study
in the cat. Acta Physiol Scand 56(S193):61pp
Grant G, Xu Q (1988a) Course of spinocerebellar axons in the
ventral and lateral funiculi of the cat spinal cord. Soc Neurosci
Abstr 14:336
256
Grant G, Xu Q (1988b) Routes of entry into the cerebellum of
spinocerebellar axons from the lower part of the spinal cord. An
experimental neuroanatomical study in the cat. Exp Brain Res
72:543–561
Grant G, Wiksten B, Berkley KJ, Aldskogius H (1982) The location
of cerebellar-projecting neurons within the lumbosacral spinal
cord in the cat. An anatomical study with HRP and retrograde
chromatolysis. J Comp Neurol 204:336–348
Larsell O (1953) The cerebellum of the cat and monkey. J Comp
Neurol 99:135–190
Matsushita M (1988) Spinocerebellar projections from the lowest
lumbar and sacral-caudal segments in the cat, as studied by
anterograde transport of wheat germ agglutinin-horseradish
peroxidase. J Comp Neurol 274:239–254
Matsushita M, Hosoya Y (1978) The location of spinal projection
neurons in the cerebellar nuclei (cerebellospinal tract neurons)
of the cat. A study with the horseradish peroxidase technique.
Brain Res 142:237–248
Matsushita M, Ikeda M (1970) Spinal projections to the cerebellar
nuclei in the cat. Exp Brain Res 10:501–511
Matsushita M, Ikeda M (1980) Spinocerebellar projections to the
vermis of the posterior lobe and the paramedian lobule in the
cat, as studied by retrograde transport of horseradish peroxidase. J Comp Neurol 192:143–162
Matsushita M, Tanami T (1987) Spinocerebellar projections from
the central cervical nucleus in the cat, as studied by anterograde
transport of wheat germ agglutinin-horseradish peroxidase. J
Comp Neurol 266:376–397
Matsushita M, Yaginuma H (1989) Spinocerebellar projections from
spinal border cells in the cat as studied by anterograde transport
of wheat germ agglutinin-horseradish peroxidase. J Comp
Neurol 288:19–38
Matsushita M, Hosoya Y, Ikeda M (1979) Anatomical organization
of the spinocerebellar system in the cat, as studied by retrograde
transport of horseradish peroxidase. J Comp Neurol 184:81–
106
Matsushita M, Ikeda M, Tanami T (1985) The vermal projection of
spinocerebellar tracts arising from lower cervical segments in
the cat: an anterograde WGA-HRP study. Brain Res 360:389–
393
Mesulam M-M (1978) Tetramethyl benzidine for horseradish
peroxidase neurohistochemistry: a noncarcinogenic blue reaction product with superior sensitivity for visualizing neural
afferents and efferents. J Histochem Cytochem 26:106–117
Rexed B (1954) A cytoarchitectonic atlas of the spinal cord in the
cat. J Comp Neurol 100:297–379
Shirao K (1987) The course of spinocerebellar fibers in the spinal
cord and lower medulla in the rat. Study with the method of
retrograde transport. J Nippon Med Sch 54:83–95
Terman JR, Wang XM, Martin GF (1998) Origin, course, and
laterality of spinocerebellar axons in the North American
Opossum, Didelphis virginiana. Anat Rec 251:528–547
Voogd J (1964) The cerebellum of the cat. Structure and fibre
connexions. Thesis (Leiden). Van Gorcum, Assen, The Netherlands
Wiksten B (1975) The central cervical nucleus—A source of
spinocerebellar fibres, demonstrated by retrograde transport of
horseradish peroxidase. Neurosci Lett 1:81–84
Wiksten B (1979a) The central cervical nucleus in the cat. II. The
cerebellar connections studied with retrograde transport of
horseradish peroxidase. Exp Brain Res 36:155–173
Wiksten B (1979b) The central cervical nucleus in the cat. III. The
cerebellar connections studied with anterograde transport of 3Hleucine. Exp Brain Res 36:175–189
Wiksten B (1985) Retrograde HRP study of neurons in the cervical
enlargement projecting to the cerebellum in the cat. Exp Brain
Res 58:95–101
Wiksten B (1987) Further studies on the fiber connections of the
central cervical nucleus in the cat. Exp Brain Res 67:284–290
Wiksten B, Grant G (1986) Cerebellar projections from the cervical
enlargement: an experimental study with silver impregnation
and autoradiographic techniques in the cat. Exp Brain Res
61:513–518
Xu Q, Grant G (1988) Collateral projections of neurons from the
lower part of the spinal cord to anterior and posterior cerebellar
termination areas. Exp Brain Res 72:562–276
Xu Q, Grant G (1990) The projection of spinocerebellar neurons
from the sacrococcygeal region of the spinal cord in the cat. An
experimental study using anterograde transport of WGA-HRP
and degeneration. Arch Ital Biol 128:209–228
Xu Q, Grant G (1994) Course of spinocerebellar axons in the ventral
and lateral funiculi of the spinal cord with projections to the
anterior lobe: An experimental anatomical study in the cat with
retrograde tracing technique. J Comp Neurol 345:288–302
Yaginuma H, Matsushita M (1987) Spinocerebellar projections from
the thoracic cord in the cat, as studied by anterograde transport
of wheat germ agglutinin-horseradish peroxidase. J Comp
Neurol 258:1–27
Yaginuma H, Matsushita M (1989) Spinocerebellar projections from
the upper lumbar segments in the cat, as studied by anterograde
transport of wheat germ agglutinin-horseradish peroxidase. J
Comp Neurol 281:298–319
Yamada J, Shirao K, Kitamura Y, Sato H (1991) Trajectory of
spinocerebellar fibers passing through the inferior and superior
cerebellar peduncles in the rat spinal cord: A study using
horseradish peroxidase with pedunculotomy. J Comp Neurol
304:147–160