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P
parvicellular
part of the ventral posterior nucleus of the thalamus VPPC
retrouniens area central medial thalamic nucleusparafascicular
thalamic nucleusparvicellular part of the subparafascicular thalamic nucleus
oval paracentral thalamic nucleus paraventricular thalamic nuclei
rhomboid thalamic nucleus
VPPC
P
Classification of rat pallidofugal projection systems revealed by
singleneuron tracing study with a viral vector
1,2 1 1 1 1
1
2 JST, CREST
The main striatofugal system is divided into two neural populations, the
striatonigral neurons striatal direct pathway neurons and the striatopallidal
neurons striatal indirect pathway neurons. However, the striatal direct pathway
neurons also give collaterals in the globus pallidus GPe, which is a relay nucleus
in the indirect pathway of the basal ganglia Kawaguchi et al., 1990; Fujiyama
et al., 2011. We also found the targeted region in GPe were different between
the striatal direct and indirect pathway neurons Fujiyama et al., 2011. Our next
question is whether the GPe neurons located in the different regions targeted
by striatal direct and indirect pathway neurons show the same axonal trajectory
or not. To reveal it, the single GPe neurons in rat were labeled by recombinant
Sindbis virus that is designed to express the membranetargeted green fluorescent
protein. In the present study, we found two types of axonal trajectory of GPe
neurons in the different regions and discuss the possibility that the GPe can be
separated functionally to be involved in the different network of the basal ganglia.
P
A Morphological Analysis of Thalamocortical Axon Fibers of Rat
Posterior Nuclei: A Single Neuron Tracing Study with Viral Vectors
1,2 1 1 1 1
1,4 3 3 2 1
1
2
3 4 JST, CREST
The posterior thalamic nuclei POm receives inputs from the spinal cord and
trigeminal nuclei, and projects to the primary somatosensory S1 cortex and other
cortical areas. Although thalamocortical axons of single ventral posterior nuclei
neurons are well known to innervate layer L 4 of the S1 cortex with distinct
columnar organization, those of POm neurons have not been elucidated yet. In
the present study, we investigated complete axonal and dendritic arborizations
of single POm neurons in rats using Sindbis viral vectors. When we divided the
POm into anterior and posterior parts according to calbindin immunoreactivity,
dendrites of posterior POm neurons were wider but less numerous than those
of anterior neurons. More interestingly, axon fibers of anterior POm neurons
were preferentially distributed in L5 of the S1 cortex, whereas those of posterior
neurons were principally spread in L1 with wider and sparser arborization than
those of anterior neurons. These results suggest that the POm is functionally
segregated into anterior and posterior parts, and that the two parts may play
different roles in somatosensory information processing.
P
Morphological analysis of axon collaterals derived from single
corticospinal neurons in subcortical structures
The corticospinal tract which conveys the final command for control of voluntary
movement has been known to give axon collaterals to various cortical and
subcortical regions. The target regions thus receive the same information with that
gives rise to muscle actions. To assess the collaterals in the subcortical regions by
a morphological approach, we visualized axons of single corticospinal neurons
by injecting a recombinant sindbis virus expressing membranetargeted GFP into
the pyramidal tract. The labeled cortical neurons were distributed in layer V of
the motor cortex and motorsensory corticesareas FL and HL. The corticospinal
neurons gave multiple axon collaterals to various subcortical structures and
especially sent branches, with high frequency, to the striatum 71%, zona incerta
67%, pontine and reticulotegmental nuclei 100%, which are known to play a
role in control of voluntary movement or gating of peripheral inputs to thalamic
nuclei. These abundant subcortical collaterals suggest that the "copy" of final
motor command from the cortex plays an important role in motor and sensory
processing of the subcortical structures.
P
1 2 2 2
1
2
MCH
2VGLUT2
MCH
MCH VGLUT2
SD MCH
VGLUT2 mRNA in situ hybridizationISH
MCH
VGLUT2 cRNA
MCH
VGLUT2
MCH
MCH VGLUT2
VGLUT2
P
Projections from the amygdaloid anterior basomedial and anterior
cortical nuclei to MCHcontaining hypothalamic neurons of the rat
Dept. Anat. & Morphol. Neurosci., Shimane Univ. Sch. Med., Izumo, Japan
Melaninconcentrating hormone MCH is involve in the regulation of feeding
behavior, and MCHcontaining neurons are distributed mainly in the lateral
hypothalamus LH. The anterior bosomedial nucleus BMA and anterior cortical
nucleus ACo of the amygdala have been known to project to the LH, and to
form part of a circuit involved in processing olfactory, gustatory and visceral
information related to feeding. However, it is still unknown whether or not MCH
containing LH neurons are under the direct influence of the BMA and ACo. Here
the organization of projections from the BMA and ACo to MCHcontaining LH
neurons was examined and new data were provided as follows: 1 the prominent
overlap of the distribution field of the BMA or ACo fibers and that of the MCH
ir neurons is found in the ventrolateral LH; 2 the BMA and ACo axon terminals
make asymmetrical synapses with MCHir neurons; and 3 most of the BMA and
ACo neurons projecting to the ventrolateral LH are positive for VGLUT2 mRNA.
These data suggest that the BMA and ACo of the amygdala may exert excitatory
influence upon the MCHcontaining LH neurons for the regulation of feeding
behavior.