Viewpoint: the core and matrix of thalamic organization

“While in general it is difficult to identify the exact element activated by the electrical stimulation (Ranck, 1975), the EPSPs are likely attributable, at least in part, to fibers from the thalamic matrix to L1 (Jones, 1998), and IPSPs are likely attributable to endogenous neurons in L1 (Hestrin and Armstrong, 1996).”

“Layer 4 (L4) is well understood to be the primary target of thalamocortical sensory inputs (Douglas and Martin, 2004; Jones, 1998; Theyel et al., 2010).”

“Layer IV is commonly associated with receiving feedforward input from Layer III from lower cortical areas or from the thalamus [2], while Layers II-III and VI are implicated in receiving down-ward information flow (feedback) [3], which often originates from layer V. Layer I is thin and sparsely…”

“have spatially distinct projections, the matrix cells have diffuse cortical projections that are involved in the arousal and widespread activation of the cortex.(52)”

“…interactions in layer I are assumed to be a key substrate for the synchronization of large ensembles of neurons across extensive cortical territories and have been associated with changes in states of consciousness (Llinás & Ribary, 1993; Cauller, 1995; Steriade et al., 1997; Jones, 1998).”

“1 A ) (1, 2, 7–15).”

“Tracer studies have identified multiple synaptic inputs with reciprocal connections to and from the cerebral cortex [26–31].”

“…here may be recorded from rostral ILN subdivisions, CL or Pc (Schlag-Rey and Schlag, 1984a,b) or closely-related paralaminar regions of the median dorsalis nucleus rich in matrix cells (Jones (1998a)in fact has reclassified these areas of the primate median dorsalis nucleus as continuations of CL).”

“The existence of this class of neurons in the human brain is comparable with Sokolov’s hypothesis of the existence of a special group of neurons involved in the function of consciousness [12], and with the concepts of a series of investigators of the importance of various types of corticothalamocortical interactions a…”

“S25; Supplementary Data 10), as did PC3 to a lesser extent (Fig.”

“Second, lthough the thalamocortical projections to S1 and S2 involve multile lateral and central thalamic nuclei ( Friedman and Murray, 1986 ; ones, 1998 ; Krubitzer and Kaas, 1992 ), the limited spatial resolution f fMRI did not allow us to accurately localize the most relevant nuleus, VPL, in the…”

“The (non-specific) thalamic system (Jones, 1998) might also play a key role considering the timing and laminar profile of multisensory interplay in A1 (Budinger et al., 2006; Lakatos et al., 2007; Schroeder and Foxe, 2002).”

“…middle layers (Jones and Burton, 1976; Romanski et al., 1999b) and that these inputs are proposed to have distinct roles in information processing (Jones, 1998; Lakatos et al., 2007), it will be important to distinguish their influences at the level of the cortical columnar neuron ensemble using…”

“Layer V, the internal pyramidal layer, is comprised of pyramidal neurons that project to subcortical regions (Jones, 1998).”

“The major role of the thalamus is to gate and otherwise modulate the flow of information to the cortex, thus providing the most significant subcortical input to the neocortex (Jones, 1998).”

“Therefore, disc inflammation after disc injury may result in chronic changes in neural fibers in tracts for the transmission of pain signals from the peripheral to the central regions, specifically the thalamus, which are involved in sensorydiscriminative aspects of pain processing.(9) However, the neural signal proce…”

“It is known that PV containing thalamocortical neurons target middle cortical layers (Jones and Hendry 1989; Jones 1998) which is in accordance with previous findings showing that mediodorsal afferents terminate mainly in layer four and lower layer three in the primate PFC (Giguere and GoldmanRakic…”

“In fact, an early classification of the thalamus separated cells based on their calcium binding protein expression (Jones, 1998; Jones, 2001).”

“Recently, a novel classification of thalamic neurons has been proposed: core-type neurons and matrix-type neurons [50, 51].”

“1a red) to the apical layers, such as via the nonspeci fi c thalamus 35,37 or ascending arousal system (such as the LC or dorsal raphe) 45 will increase σ promoting connected bursting.”

“Calbindin 28K (CALB) is known to label the matrix, but show a diffuse decrease of labeling in striosomes (Gerfen et al., 1985; Difiglia et al., 1989; Jones, 1998; Matamales et al., 2009).”

“Previous studies of the connections between VA/VL and the motor cortex have focused on the indirect cortico-striato-pallidothalamic pathway (reviewed in Jones 2007; Sherman and Guillery 2013).”

“Our results that V2 receives the bulk of the pulvinar input, around 75% (Table 3), compared to V1, also draws comparisons to the core versus matrix distinction of the thalamus (Jones, 1998), where V1 receives the less driving matrix input from pulvinar and V2 receives driving core and matrix input.”

“The Label lists only those putative major thalamic nuclei in which we have a great degree of confidence in identification at these ages; other nuclei were also labeled (see also [56]).”

“In the thalamus, a distinction has been drawn (Jones, 1998) between its matrix and core nuclei.”

“, 1991 ) , and it is presently unclear whether these antibodies label proteins directly related to visual function or some indirect property such as cell size ( Jones , 1998 ) .”

“…that thalamic relay nuclei consist of two types of thalamocortical projection systems: topographically organized, specific projections originating in the ‘‘core’’ regions of thalamic nuclei, and more diffusely projecting nonspecific projections originating in the thalamic ‘‘matrix’’ (Jones, 1998).”

“Furthermore, the distribution of neurons immunoreactive to calbindin/calretinin and parvalbumin has been used to distinguish two types of relay cells in thalamic nuclei in primates, core and matrix, which differ in neural circuitry and physiological properties [Jones, 1998].”

“Besides, it is interesting to note that the methodology we have described in this study has been successful in showing both projection neurons and interneurons in the human thalamus [42].”

“impossible that part of these labelled elements is formed of More recently, studies of the distribution of CGRP-, branching dendrites of NADPH-d-positive neurons in the parvalbumin- and calbindin-immunoreactivity [7,21,24,30] nL.”

“…Marques, Nguyen, Fioreze, & Petreanu, 2018) and thalamocortical afferents from what Jones (Jones, 1998) has termed “matrix” thalamus (Avendano, Stepniewska, Rausell, & Reinoso- Suarez, 1990; Cruikshank et al., 2012; Jones, 1998; Rubio- Garrido, Perez- de- Manzo, Porrero, Galazo, & Clasca, 2009).”

“Broadly speaking, when considering the microscopic level, thalamic cells can be divided into two classes: core neurons projecting to the middle cortical layers, and matrix neurons projecting to the superficial or deep cortical layers (207, 208).”

“The expression of calbindin, and a related calcium-binding protein, parvalbumin, has also been instrumental for the classification of nuclear subdivisions within the mammalian thalamus (Jones, 1998; Jones, 2001).”

“The susceptibility to mechanical injury of cells in superficial cortical layers may be an indication for widespread superficial layer projections arising from a matrix of thalamic cells extending throughout the whole thalamus as recently proposed by Jones (1998).”

“…in calbindin and parvalbumin expression in the Rot and posterior/intralaminar complex (Dávila et al., 2000; Guirado et al., 2000), these markers do not allow us to discriminate clearly between the two hypotheses concerning the homologues of the reptilian Rot (Jones, 1998; Pritz and Siadati, 1999).”

“…patterns and sound sequences (Hu, 2003; Kelly et al., 1973; Layton et al., 1979), while the extralemniscal pathway projects principally to cortical layer I and is required for proper sensory integration and learning (Edeline, 1999; Hu, 2003; Jones, 1998; Lorente de Nó, 1992; Weinberger, 2004).”

“Jones (1998b) has suggested that the thalamic distribution of CB and PV provide a useful indicator for the identification of different anatomical and functional types of thalamocortical projection neurons.”

“…and an external ‘shell’ or diffuse region [reptiles: Balaban and Ulin ski, 1981; Browner et al., 1981; birds: Karten, 1967, 1968; Durand et al., 1992; Wild et al., 1993; mammals: Aitkin and Webster, 1972; Morest and Oliver, 1984; Faye-Lund and Osen, 1985; Huffman and Henson, 1990; Jones, 1998].”

“Thus, thalamic inputs may not be limited to L1, but are probably dual, as found in other mammals, with matrix (M) thalamic inputs arriving via L1 and core thalamic inputs passing through L4 (Jones 1998; Rubio-Garrido et al.”

“In the macaque thalamus (Morel et al., 1997; Jones, 1998), PV neurons are located mainly in the sensory and motor relay nuclei (the thalamic core) that project in a topographical manner to middle layers of modalityspecific cortical regions such as the primary somatosensory, auditory, visual, or…”

“Based on the existence of ‘core’ and ‘matrix’ thalamocortical connections (Jones, 1998, 2001) - which project to cortical layer IV and I-II, respectively - it has been hypothesized that sleep spindles can arise through either or both of these networks, possibly with a highly variable contribution…”

“Neurons within the nuclei of the thalamus present regional specializations overlaid onto a functional architecture of shared connectivity and cellular intrinsic properties (Bickford, 2015; Guillery & Sherman, 2002; Halassa & Acsády, 2016; Halassa & Sherman, 2019; Jones, 1998; Phillips et al., 2019).”

“Each sensory map received its inputs directly from a corresponding portion of the thalamus, in which a distinction has been drawn[20] between its matrix and core nuclei.”

“Based on the ‘‘core” and ‘‘matrix” model of the thalamocortical network (Jones, 1998, 2001), they proposed that acoustic information forms a driver input to layer 4 of the auditory cortex while rhythmic information forms a modulatory input to the supragranular layers.”

“…neurons, which form topographically organized projections to layers of cerebral cortical, and “matrix” neurons, which send more diffuse projections to the cortices that innervate the superficial layers of multiple cortical regions, crossing receptive fields and functional boundaries (Jones 1998).”

“The expression of specific calcium-binding proteins in GABAergic neurons, including calbindin (CB), parvalbumin (PV), and calretinin (CR), has been used as one of the criteria to delineate different cell types in neocortex, hippocampus, cerebellum and thalamus (Bastianelli, 2003; Hof et al., 1999; Jinno and Kosaka, 20…”

“the core and matrix systems, which produce focal or diffuse activation (Jones 1998).”

“Thalamocortical neurons with different chemical identities of are implicated with distinct roles in thalamic synchronisation (Jones, 1998).”

“…the core and shell regions of mesencephalic and diencephalic mammalian auditory nuclei, and the telencephalic auditory areas that receive projections from the core (the middle layers of the auditory cortex) and shell (layer I and the subplate) regions of diencephalic auditory nuclei (Jones, 1998).”

“Spiny stellate cells are the cells producing glutamate neurotransmitter in the cerebral cortex [40].”

“…correspond to the deep cortical layers, most likely layer IV– VI. Cortical layer IV plays a special role in thalamocortical processing (Berbel et al., 2010; Christianson et al., 2011); it serves as input of feed-forward excitation from thalamic core cells, neurons from VPL and VPM (Jones, 1998).”

“According to the calbindin and parvalbumin bindings of cells, nuclei have also been segregated into matrixcalbindin and core-parvalbumin groups, which involve the main parts of the central lateral and the parafascicular nuclei, and the centromedian and the reticular nuclei respectively [60,61].”

“A RSN of layer III has also an apical dendrite with two branches, called dendrites 4 and 5 respectively.”

“The thalamus contains different cell types [31, 41, 52], but it is still unknown whether besides nuclear (regional) specificity tau pathology also displays any cell-type specificity within this subcortical structure.”

“The pyramidal cells in turn send corticothalamic (CT) projections back to the relay neurons in the thalamus from cortical layers V/VI, which are the output layers of the cortex (Jones, 1998; Constantinople and Bruno, 2013).”

“Because the cortical middle layers mainly receive 2 types of projection, that is, feedforward corticocortical and thalamocortical projections (Rockland and Pandya 1979; Felleman and Van Essen 1991; Jones 1998), SLIT1 may thus play a role in how neurons receive and/or process these inputs.”

“Regions containing large populations of calbindin immunoreactive cells are associated with weak cytochrome oxidase staining as in other mammals (Rausell & Jones 1991a,b; Rausell et al. 1992; Jones 1998).”

“…work has furnished strong evidence for the existence of a matrix of diffusely projecting cells in all thalamic nuclei, providing a basis for a recruitment of cortical areas into collective action that is unconstrained by architectonic or functional boundaries between cortical fields (Jones, 1998).”