Afferent projections to the reticular thalamic nucleus from the globus pallidus and the substantia nigra in the rat

This study was designed to explore the thalamic output of the globus pallidus (GP) and the pars reticulata (SNR) of the substantia nigra (SN) upon the reticular thalamic nucleus (Rt) in the rat. Thus, 13 animals were deeply anesthetized and stereotaxically injected with horseradish peroxidase (HRP) conjugated with wheat germ agglutinin (HRP-WGA) mixed with HRP free in different portions of GP and SN. Next, we evaluated the anterograde terminal labeling in the rostral two-thirds of Rt. Confirmatory results were obtained in our case material about the entity of GP reticular projections, and some new data are presented here regarding the projections from GP and SNR upon Rt. Among them we emphasize the following for the rostral two-thirds of this thalamic nucleus: a) the projections from GP are more abundant than those arising from SNR; b) a dorsoventral topographical design appears to be clear in the organization of the afferent connections from GP to Rt; c) SNR projects more abundantly to the ventral sectors of Rt; and d) the central core of Rt is more innervated by GP than by SNR, which innervates Rt mainly in its peripheral portions. These results raise the possibility of multiple and differentiated assignments of the output nuclei of the basal ganglia upon the thalamus and its connectivity.

[1]  L. Hazrati,et al.  Substantia nigra pars reticulata projects to the reticular thalamic nucleus of the cat: a morphological and electrophysiological study , 1990, Brain Research.

[2]  R. Malach,et al.  Mosaic architecture of the somatic sensory-recipient sector of the cat's striatum , 1986, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[3]  G. Paxinos,et al.  The Rat Brain in Stereotaxic Coordinates , 1983 .

[4]  André Parent,et al.  Comparative neurobiology of the basal ganglia , 1986 .

[5]  H. Nauta.  Projections of the pallidal complex: An autoradiographic study in the cat , 1979, Neuroscience.

[6]  M. Mesulam,et al.  Tetramethyl benzidine for horseradish peroxidase neurohistochemistry: a non-carcinogenic blue reaction product with superior sensitivity for visualizing neural afferents and efferents. , 1978, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[7]  F. Reinoso-suárez,et al.  Topographical organization of the projections from the reticular thalamic nucleus to the intralaminar and medial thalamic nuclei in the cat , 1989, The Journal of comparative neurology.

[8]  The association cortex and the basal ganglia: a neuroanatomical view upon their relationship based on hodological studies. , 1991 .

[9]  K. Akert,et al.  A comparison of the retrograde tracer properties of [125I] wheat germ agglutinin (WGA) with HRP after injection into the corpus callosum , 1982, Brain Research.

[10]  A. Jayaraman.  Organization of thalamic projections in the nucleus accumbens and the caudate nucleus in cats and its relation with hippocampal and other subcortical afferents , 1985, The Journal of comparative neurology.

[11]  Finn A. GENnS.  Distribution of Acetyl Cholinesterase in the Hippocampal Region of the Guinea Pig , 1972 .

[12]  E. G. Jones,et al.  The morphology of physiologically identified GABAergic neurons in the somatic sensory part of the thalamic reticular nucleus in the cat , 1985, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[13]  A M Graybiel,et al.  Modular organization of projection neurons in the matrix compartment of the primate striatum , 1991, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[14]  D. Steindler.  Differences in the labeling of axons of passage by wheat germ agglutinin after uptake by cut peripheral nerve versus injections within the central nervous system , 1982, Brain Research.

[15]  A. Parent,et al.  Projection from the external pallidum to the reticular thalamic nucleus in the squirrel monkey , 1991, Brain Research.

[16]  M. Mesulam,et al.  Additional factors influencing sensitivity in the tetramethyl benzidine method for horseradish peroxidase neurohistochemistry. , 1980, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[17]  W. Nauta,et al.  Efferent connections of the ventral pallidum: Evidence of a dual striato pallidofugal pathway , 1985, The Journal of comparative neurology.

[18]  E. G. Jones,et al.  Some aspects of the organization of the thalamic reticular complex , 2004, The Journal of comparative neurology.

[19]  A. Scheibel,et al.  The organization of the nucleus reticularis thalami: a Golgi study. , 1966, Brain research.

[20]  S. R. Cajal.  Textura del Sistema Nervioso del Hombre y de los Vertebrados, 1899–1904 , 2019 .

[21]  A. Graybiel,et al.  Coexistence of glutamic acid decarboxylase- and somatostatin-like immunoreactivity in neurons of the feline nucleus reticularis thalami , 1983, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[22]  A. Parent,et al.  Basal forebrain cholinergic and noncholinergic projections to the thalamus and brainstem in cats and monkeys , 1988, The Journal of comparative neurology.

[23]  James E. Vaughn,et al.  GABA neurons are the major cell type of the nucleus reticularis thalami , 1980, Brain Research.

[24]  S. D. L. Heras,et al.  The Reticular Thalamic Nucleus and the Output Nuclei of the Basal Ganglia: A Neuroanatomical View Based on Hodological Studies , 1994 .