Dual termination modes of corticothalamic fibers originating from pyramids of layers 5 and 6 in cat visual cortical area 17

Ojima, Hisayuki; Murakami, Kunio; Kawakami, Kiyoshi

doi:10.1016/0304-3940(96)12538-6

Cited by 56 publications

(38 citation statements)

References 15 publications

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“…Large and small boutons were measured separately and systematically distinguished based on the results of the bouton population analyses presented earlier. Specifically, in agreement with previous studies (Schwartz et al, 1991;Ojima et al, 1996;Rouiller et al, 1998), small boutons had a maximum major diameter of ϳ1.4 m, and, therefore, all bigger terminals were considered as large. We used progressive mean analysis and a pilot study to determine the sampling fraction, which was 1 ⁄160 of the total volume of TRN and was achieved by setting the disector counting frame at 100 ϫ 100 m and the grid size at 400 ϫ 400 m. The total number of neurons or boutons counted in the systematic random samples was multiplied with the denominator of the sampling fraction to provide an estimate of the total number of labeled neurons or boutons.…”

Section: Stereological Analysissupporting

confidence: 83%

“…7C-E) (supplemental Movie 2, available at www.jneurosci.org as supplemental material). In a few occasions, large boutons branching out from the latter axons formed aggregated clusters, resembling bunches of grapes, as described for sensory cortical projections in several other thalamic nuclei but not TRN (Ojima, 1994;Bourassa et al, 1995;Ojima et al, 1996). Some axons with large en passant boutons formed round arbors at the termination sites, similar to those described for corticopulvinar projections (Rockland, 1996).…”

Section: Dual-termination Mode Of Prefrontal Axons In Trnsupporting

confidence: 66%

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Prefrontal Projections to the Thalamic Reticular Nucleus form a Unique Circuit for Attentional Mechanisms

2006

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The inhibitory thalamic reticular nucleus (TRN) intercepts and modulates all corticothalamic and thalamocortical communications. Previous studies showed that projections from sensory and motor cortices originate in layer VI and terminate as small boutons in central and caudal TRN. Here we show that prefrontal projections to TRN in rhesus monkeys have a different topographic organization and mode of termination. Prefrontal cortices projected mainly to the anterior TRN, at sites connected with the mediodorsal, ventral anterior, and anterior medial thalamic nuclei. However, projections from areas 46, 13, and 9 terminated widely in TRN and colocalized caudally with projections from temporal auditory, visual, and polymodal association cortices. Population analysis and serial EM reconstruction revealed two distinct classes of corticoreticular terminals synapsing with GABA/parvalbumin-positive dendritic shafts of TRN neurons. Most labeled boutons from prefrontal axons were small, but a second class of large boutons was also prominent. This is in contrast to the homogeneous small TRN terminations from sensory cortices noted previously and in the present study, which are thought to arise exclusively from layer VI. The two bouton types were often observed on the same axon, suggesting that both prefrontal layers V and VI could project to TRN. The dual mode of termination suggests a more complex role of prefrontal input in the functional regulation of TRN and gating of thalamic output back to the cortex. The targeting of sensory tiers of TRN by specific prefrontal areas may underlie attentional regulation for the selection of relevant sensory signals and suppression of distractors.

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Section: Stereological Analysissupporting

confidence: 83%

Section: Dual-termination Mode Of Prefrontal Axons In Trnsupporting

confidence: 66%

Prefrontal Projections to the Thalamic Reticular Nucleus form a Unique Circuit for Attentional Mechanisms

2006

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“…Previous studies have indicated that there are at least two different types of corticothalamic cells (Ojima, 1996;Deschênes et al, 1994;Bourassa et al, 1995). In the cat striate cortex, corticogeniculate neurons are restricted to layer VI (Gilbert and Kelly, 1975), and innervate the dLGN with thin (type I) axons and RS terminals that primarily make simple axodendritic synaptic contacts on the distal dendrites of thalamocortical cells (Vidnyánszky and Hámori, 1994;Paré and Smith, 1996;Eriºir et al, 1997).…”

Section: Two Types Of Corticopulvinar Cells and Fibers And Their Relamentioning

confidence: 99%

Ultrastructural analysis of projections to the pulvinar nucleus of the cat. I: Middle suprasylvian gyrus (areas 5 and 7)

et al. 2005

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The mammalian pulvinar nucleus (PUL) establishes heavy interconnections with the parietal lobe, but the precise nature of these connections is only partially understood. To examine the distribution of corticopulvinar cells in the cat, we injected the PUL with retrograde tracers. Corticopulvinar cells were located in layers V and VI of a wide variety of cortical areas, with a major concentration of cells in area 7. To examine the morphology and distribution of corticopulvinar terminals, we injected cortical areas 5 or 7 with anterograde tracers. The majority of corticopulvinar axons were thin fibers (type I) with numerous diffuse small boutons. Thicker (type II) axons with fewer, larger boutons were also present. Boutons of type II axons formed clusters within restricted regions of the PUL. We examined corticopulvinar terminals labeled from area 7 at the ultrastructural level in tissue stained for γ-aminobutyric acid (GABA). By correlating the size of the presynaptic and postsynaptic profiles, we were able to quantitatively divide the labeled terminals into two categories: small and large (RS and RL, respectively). The RS terminals predominantly innervated small-caliber non-GABAergic (thalamocortical cell) dendrites, whereas the RL terminals established complex synaptic arrangements with dendrites of both GABAergic interneurons and non-GABAergic cells. Interpretation of these results using Sherman and Guillery's recent theories of thalamic organization (Sherman and Guillery [1998] Proc Natl Acad Sci U S A 95:7121-7126) suggests that area 7 may both drive and modulate PUL activity. Indexing termscortex; thalamus; visual system; sensorimotor; ultrastructure The feline pulvinar nucleus (PUL) receives input from a wide array of cortical areas (Raczkowski and Rosenquist, 1983) as well as the pretectum (PT;Berman, 1977;Berson and Graybiel, 1978;Schmidt et al., 2001;Baldauf et al., 2005). However, the contribution of these inputs to the response properties of PUL neurons is unknown. The cells of the PUL have large visual receptive fields that often lack clear boundaries; they respond more robustly to diffuse illumination than to small visual cues (Godfraind et al., 1972;Mason, 1981 by saccadic eye movements. Sudkamp and Schmidt (2000) identified three general classes of neurons in the feline PUL: "S" neurons are active during saccadic eye movements, "V" neurons are responsive to visual stimuli and unresponsive to eye movements, and "SV" neurons respond to both stationary ON and OFF stimuli and to sudden stimulus shifts.These response properties are similar in many respects to those of neurons in the parietal cortex, an area that establishes extensive reciprocal connections with the PUL (de V Clüver and Campos-Ortega, 1969;Heath and Jones, 1971;Robertson and Cunningham, 1981;Niimi et al., 1983;Raczkowski and Rosenquist, 1983;Avendaño et al., 1985;Olson and Lawler, 1987). In the cat, these cortical areas are primarily located within the middle suprasylvian gyrus (MSg) or cytoarchitectonically in areas 5 and 7 (Gu...

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“…Tracer injections confined to areas 17 and 18 label type II corticothalamic terminals in the LP nucleus that originate from layer V cells and type I corticothalamic terminals in the dorsal lateral geniculate nucleus (dLGN) that originate from layer VI cells (Ojima et al, 1996). In the LP nucleus, area 17 corticothalamic terminals are RL profiles that participate in glomeruli (Vidnyánszky et al, 1996;Feig and Harting, 1998), whereas, in the dLGN, area 17 corticothalamic terminals are RS profiles that contact small caliber dendrites outside of glomeruli (Jones and Powell, 1969;Vidnyánszky and Hamori, 1994;Vidnyánszky et al, 1996;Erisir et al, 1997).…”

Section: Nih Public Accessmentioning

confidence: 99%

“…Figure 13 schematically summarizes the findings of the current study and those of previous studies. It has been well documented that layer VI cells in area 17 project to the dLGN (Gilbert and Kelly, 1975;Deschênes et al, 1994;Bourassa and Deschênes, 1995;Ojima et al, 1996), where they innervate the distal dendrites of projection cells (P, gray) with type I terminals/RS profiles (black circles) (Guillery, 1966;Jones and Powell, 1969;Robson, 1983;Vidnyánszky and Hamori, 1994;Murphy and Sillito, 1996;Vidnyánszky et al, 1996;Erisir et al, 1997). The dLGN in turn innervates layers IV and VI of area 17 (LeVay and Gilbert, 1976;Ferster and LeVay, 1978;Humphrey et al, 1985a,b;Boyd and Matsubara, 1996;Kawano, 1998).…”

Section: Ultrastructure Of Area Pmls Corticothalamic Terminalsmentioning

confidence: 99%

Distribution, morphology, and synaptic targets of corticothalamic terminals in the cat lateral posterior-pulvinar complex that originate from the posteromedial lateral suprasylvian cortex

et al. 2006

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The lateral posterior (LP) nucleus is a higher order thalamic nucleus that is believed to play a key role in the transmission of visual information between cortical areas. Two types of cortical terminals have been identified in higher order nuclei, large (type II) and smaller (type I), which have been proposed to drive and modulate, respectively, the response properties of thalamic cells (Sherman and Guillery [1998] Proc. Natl. Acad. Sci. U. S. A. 95:7121-7126). The aim of this study was to assess and compare the relative contribution of driver and modulator inputs to the LP nucleus that originate from the posteromedial part of the lateral suprasylvian cortex (PMLS) and area 17. To achieve this goal, the anterograde tracers biotinylated dextran amine (BDA) or Phaseolus vulgaris leucoagglutinin (PHAL) were injected into area 17 or PMLS. Results indicate that area 17 injections preferentially labelled large terminals, whereas PMLS injections preferentially labelled small terminals. A detailed analysis of PMLS terminal morphology revealed at least four categories of terminals: small type I terminals (57%), medium-sized to large singletons (30%), large terminals in arrangements of intermediate complexity (8%), and large terminals that form arrangements resembling rosettes (5%). Ultrastructural analysis and postembedding immunocytochemical staining for γ-aminobutyric acid (GABA) distinguished two types of labelled PMLS terminals: small profiles with round vesicles (RS profiles) that contacted mostly non-GABAergic dendrites outside of glomeruli and large profiles with round vesicles (RL profiles) that contacted non-GABAergic dendrites (55%) and GABAergic dendritic terminals (45%) in glomeruli. RL profiles likely include singleton, intermediate, and rosette terminals, although future studies are needed to establish definitively the relationship between light microscopic morphology and ultrastructural features. All terminals types appeared to be involved in reciprocal corticothalamocortical connections as a result of an intermingling of terminals labelled by anterograde transport and cells labelled by retrograde transport. In conclusion, our results indicate that the origin of the driver inputs reaching the LP nucleus is not restricted to the primary visual cortex and that extrastriate visual areas might also contribute to the basic organization of visual receptive fields of neurons in this higher order nucleus. *Correspondence to: Christian Casanova, Laboratoire des Neurosciences de la Vision, École d'Optométrie, Université de Montréal, C.P. 6128 Succ. Centre-Ville, Montréal, Québec, Canada H3C 3J7. E-mail: christian.casanova@umontreal.ca. D. Boire's current address is Département de Chimie-Biologie, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada. The cat lateral posterior (LP) and pulvinar nuclei receive input from a wide array of cortical areas concerned with vision or visuomotor control. These areas include cortical areas 17, 18, 19, 20, and 21 as well as the variety of visual areas t...

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Dual termination modes of corticothalamic fibers originating from pyramids of layers 5 and 6 in cat visual cortical area 17

Cited by 56 publications

References 15 publications

Prefrontal Projections to the Thalamic Reticular Nucleus form a Unique Circuit for Attentional Mechanisms

Prefrontal Projections to the Thalamic Reticular Nucleus form a Unique Circuit for Attentional Mechanisms

Ultrastructural analysis of projections to the pulvinar nucleus of the cat. I: Middle suprasylvian gyrus (areas 5 and 7)

Distribution, morphology, and synaptic targets of corticothalamic terminals in the cat lateral posterior-pulvinar complex that originate from the posteromedial lateral suprasylvian cortex

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