Organization of the thalamo-cortical connexions to the frontal lobe in the rhesus monkey

Abstract

In 25 rhesus monkeys horseradish peroxidase was injected in different parts of the frontal cortex. The retrogradely labelled thalamic neurons formed longitudinal bands, some of which crossed the internal medullary lamina, and extended from one thalamic nucleus into another. On the basis of these findings the frontal cortex was subdivided into seven transverse cortical strips which receive afferents from seven longitudinal bands of thalamic neurons. The most rostral transverse strip receives afferents from the most medial thalamic band which is oriented vertically and extends through the most medial part of the MD into the medial pulvinar. Progressively more caudally located transverse strips receive afferents from progressively more laterally located thalamic bands which in part are situated in the VL and show an increasing tilt towards the horizontal. Moreover, those parts of the various bands which are situated along the dorsal and lateral margin of the thalamus project to the medial portions of the transverse cortical strips, i.e. along the medial margin of the frontal lobe, while the other parts situated ventromedially in the thalamus project to the lateral portions of these strips, i.e. along the lateral margin of the frontal lobe. These data provide an alternative view of the organization of the thalamus and suggest that this structure contains a matrix of longitudinal cell columns which in some cases extend across specific nuclear borders and may represent the basic thalamic building blocks in respect to the thalamo-cortical connexions.

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

“…Medial thalamic structures, like MD, share reciprocal connections with cortical structures such as M1, DLPFC, and limbic areas to process emotional-affective information (Goldman-Rakic and Porrino, 1985;Kievit and Kuypers, 1977), which provides a clear direct anatomical substrate to explain the present findings. Furthermore, the present data corroborates the primary role of DLPFC in modulating the medial pathway (Lorenz et al, 2003) and emotionalaffective information processing (Apkarian et al, 2009;Godinho et al, 2006;Zubieta et al, 2001).…”

The monkey globus pallidus: neuronal discharge properties in relation to movement.

“…They claimed that the caudal portions of the medial pallidal segment established synaptic connections predominantly with neurones of the ventro-lateral nucleus of the thalamus, pars oralis (VLo), a region known to project to the precentral gyrus. By comparison more rostral parts of the internal pallidal segment were found by Kuo & Carpenter to project to the parvocellular component of the ventro-anterior nucleus of the thalamus, a region related anatomically with the premotor cortex (Kievit & Kuypers, 1977).…”

Unraveling the contributions of the diencephalon to recognition memory: A review

“…A further problem is posed by the concentration of white matter tracts that pass through the rostral thalamic area. These tracts include the inferior thalamic peduncle, which carries projections from the medial temporal lobe to the medial thalamic nuclei (Aggleton and Mishkin 1984;Aggleton et al 1986), and projections to and from the prefrontal cortex (Kievet and Kuypers 1977).…”

“…1). This region has many direct connections with other areas already implicated in recognition memory, most notably the medial temporal lobe (Aggleton and Saunders 1997;Saunders et al 2005) and the prefrontal cortex (Kievet and Kuypers 1977;Carmichael and Price 1995). The effects of damage to these connections on recognition memory are clearly relevant to the present review.…”