Efferent connections of the centromedian and parafascicular thalamic nuclei: An autoradiographic investigation in the cat

Abstract

The efferent projections of the centromedian and parafascicular (CM-Pf) thalamic nuclear complex were analyzed by the autoradiographic method. Our findings show that the CM-Pf complex projects in a topographic manner to specific regions of the rostral cortex. These fibers distribute primarily to cortical layers I and III; however, the projection to layer I is more extensive. Following an injection into the rostral portion of the CM-Pf complex, label is found within the lateral rostral cortex, particularly within the presylvian, anterior ectosylvian, and anterior lateral sulci, and within the rostral medial cortex where label is present within the cruciate and anterior splenial sulci and anterior cingulate gyrus. An injection into the caudal dorsal portion of the CM-Pf complex results in label within the more ventral portions of the rostral lateral cortex where it is present within the anterior sylvian gyrus, presylvian regions, and gyrus proreus; and within the rostral medial cortex, where it is present within the rostral cingulate gyrus, and within the cruciate sulcus, and an extensive region ventral to the cruciate sulcus which includes the anterior limbic area. Injections into the caudal ventral portion of the CM-Pf complex result in virtually no cortical label, although a few labeled fibers are found in the subcortical white matter. The subcortical projection from the CM-Pf complex terminates within the caudate nucleus, putamen, globus pallidus, subthalamic nucleus, zona incerta, fields of Forel, hypothalamus, thalamic reticular nucleus, and rostral intralaminar nuclei. Prominent silver grain aggregates are also present within the ventral lateral, ventral anterior, ventral medial, and lateral posterior nuclei, and ventrobasal complex. The aggregates in the thalamus appear to be fibers of passage, but whether these are also terminals cannot be determined with the techniques used in the present study.

An Essential Role for Frizzled5 in Neuronal Survival in the Parafascicular Nucleus of the Thalamus

“…The PFN and the adjacent centromedian nucleus provide major noncortical glutamatergic input to the striatum (Royce and Mourey, 1985;Sadikot et al, 1992a,b;Deschenes et al, 1996;Matsumoto et al, 2001;Yasukawa et al, 2004;Lacey et al, 2007;Smeal et al, 2007). The PFN also projects to the motor and anterior cingulate cortices (Vercelli et al, 2003;Parent and Parent, 2005).…”

Functional Neuroanatomy of the Basal Ganglia

“…This simplistic view, which only considered GABAergic input from the GPe and STN efferents targeting basal ganglia output nuclei, has been superseded by much experimental evidence that emerged shortly after the model was first introduced (see section, "Pathophysiology: A Summary," below). Besides the classical GABAergic projection from GPe neurons (second relay station of the indirect pathway), the STN also receives glutamatergic projections from the cerebral cortex (known as the hyperdirect pathway) (see Nambu et al 2002;Nambu 2004Nambu , 2005 and the ipsilateral thalamic caudal intralaminar nuclei Royce and Mourey 1985;Sadikot et al 1992a,b;Sidibé and Smith 1996;Marini et al 1999;Gonzalo et al 2002;Lanciego et al 2004Lanciego et al , 2009Castle et al 2005), as well as a minor projection from the contralateral caudal intralaminar nuclei (Gerfen et al 1982;Castle et al 2005). Finally, it is also worth noting that the STNalso receives a sparse dopaminergic projection from the SNc, as a part of the so-called nigro-extrastriatal projection system (for review, see Rommelfanger and Wichmann 2010).…”

Transcranial Direct Current Stimulation Targeting Primary Motor Versus Dorsolateral Prefrontal Cortices: Proof-of-Concept Study Investigating Functional Connectivity of Thalamocortical Networks Specific to Sensory-Affective Information Processing

“…These pain processing structures include parts of the thalamus, somatosensory, insular, cingulate, frontal, and parietal cortices. The thalamus is a key structure, as it is believed to serve as a relay center, receiving information from multiple ascending pathways and relating information to and from multiple cortical areas (Andersson et al, 1997;Herrero et al, 2002;Kenshalo and Isensee, 1983;Royce and Mourey, 1985). The primary motor (M1) and dorsolateral prefrontal cortices (DLPFCs) represent other key structures (Plow et al, 2012;Zaghi et al, 2009).…”