Serial electron microscopic reconstruction of axon terminals on physiologically identified thalamocortical neurons in the cat ventral lateral nucleus

Sato, Fumi; Nakamura, Yasuhisa; Shinoda, Yoshikazu

doi:10.1002/(sici)1096-9861(19971201)388:4<613::aid-cne9>3.0.co;2-5

Cited by 25 publications

(25 citation statements)

References 56 publications

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“…The second panel depicts each compartment (N = 1416) of the model, with the areas of squares being proportional to compartment membrane area. (B) Uniform area density of inhibitory synapses (heavy lines; top (Sato et al, 1997), bottom (Sato et al, 1997;Liu et al, 1995)) contrasts with non-uniform densities of excitatory synapses from "cortical" (upper thin line) and "sensory" (lower thin line) afferents. Based on serial reconstructive electron microscopy data (Sato et al, 1997;Liu et al, 1995).…”

Section: Methodsmentioning

confidence: 99%

“…Considering the number of inhibitory synapses received by TCNs (Liu et al, 1995;Sato et al, 1997) and their uniform area density (Fig. 1B), δ = 0.01λ corresponds to one synapse per compartment on average.…”

Section: Methodsmentioning

confidence: 99%

“…1B). Studies using reconstructive serial electron microscopy indicate that GABA synapses are located throughout TCN dendrites (Liu et al, 1995;Sato et al, 1997), at densities ranging from 3 to 12 synapses per 10 m of length depending inversely on distance from the soma. By factoring in dendrite diameters (Dr. Fumi Sato, personal communication), we found that the number of synapses per unit area is relatively constant (heavy lines).…”

Section: Synapse Distributionsmentioning

confidence: 99%

“…Note that the standard discritization matches the spatial resolution of the 3D reconstruction data. It also approximates the number of inhibitory synapses per TCN (Liu et al, 1995;Sato et al, 1997).…”

Section: Discritizationmentioning

confidence: 99%

“…This is not the case in the rodent ventrobasal thalamus, where inhibition derives from a single structure-the thalamic reticular nucleus-and occurs directly on dendritic shafts at synapses located throughout the arbor (Benson et al, 1992;Harris et al, 1987;Jones, 1991;Liu et al, 1995;Ohara and Lieberman, 1993;Sato et al, 1997;Williams and Faull, 1987). Moreover, the thalamic reticular nucleus is comprised of single class of neurons, as is the rodent ventrobasal thalamus, which makes it an ideal system for studying synaptic variability.…”

Section: Introductionmentioning

confidence: 99%

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Variability of quantal synaptic currents in thalamocortical neurons

Neubiga

2003

THL

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Broad amplitude variability and skewed distributions are characteristic features of quantal synaptic currents (minis) at central synapses. The relative contributions of the various underlying sources are still debated. Through computational models of thalamocortical neurons, we separated intra-from extra-synaptic sources. Our simulations indicate that the external factors of local input resistance and dendritic filtering generate equally small amounts of negatively skewed synaptic variability. The ability of these two factors to reduce positive skew increased as their contribution to variability increased, which in control trials for morphological, biophysical, and experimental parameters never exceeded 10% of the range. With these dendritic factors ruled out, we tested multiple release models, which led to distributions with clearly non-physiological multiple peaks. We conclude that intra-synaptic organization is the primary determinant of synaptic variability in thalamocortical neurons and, due to extra-synaptic mechanisms, is more potent than the data suggested. Thalamortical neurons, especially in rodents, constitute a remarkably favorable system for molecular genetic studies of synaptic variability and its functional consequence.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Synapse Distributionsmentioning

confidence: 99%

Section: Discritizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Variability of quantal synaptic currents in thalamocortical neurons

Neubiga

2003

THL

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Thalamic terminal morphology and distribution of single corticothalamic axons originating from layers 5 and 6 of the cat motor cortex

Kakei

Shinoda

2001

J of Comparative Neurology

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We investigated the axonal morphology of single corticothalamic (CT) neurons of the motor cortex (Mx) in the cat thalamus, using a neuronal tracer, biotinylated dextran amine (BDA). After localized injection of BDA into the Mx, labeled CT axons were found ipsilaterally in the thalamic reticular nucleus (TRN), the ventroanterior-ventrolateral complex (VA-VL), the central lateral nucleus (CL), the central medial nucleus, and the centromedian nucleus, but with the primary focus in the VA-VL. The terminals in the VA-VL formed a large laminar cluster, which extended approximately in parallel with the internal medullary lamina. The laminar organization mirrored morphologic features of single CT axons. We reconstructed the trajectories of 25 single CT axons that arose from layer V (16 axons) or layer VI (9 axons) and terminated in the VA-VL. Terminals of single CT axons that originated from both layer V and layer VI were confined within a laminar structure about 700 microm thick, suggesting the existence of laminar input organization in the VA-VL. Otherwise, the two groups of the CT axons showed contrasting features. All of the CT axons derived from layer VI gave rise to a few short collaterals to the TRN and then formed extensive arborization with numerous small, drumstick-like terminals in the VA-VL. On the other hand, the CT axons arising from layer V gave rise to collaterals whose main axons descended into the cerebral peduncle. Each collateral projected to the VA-VL or CL without projection to the TRN and formed a few small clusters of giant terminals. The two groups of CT neurons in the same cortical column had convergent rather than segregated termination in the VA-VL. However, the terminals of layer VI CT neurons were distributed diffusely and widely in the VA-VL, whereas the terminals of layer V CT neurons were much more focused and surrounded by the terminals of the former group. These contrasting features of the two types of CT projections appear to represent their different functional roles in the generation of motor commands and control of movements in the Mx.

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Axonal Trajectories of Single Climbing and Mossy Fiber Neurons in the Cerebellar Cortex and Nucleus

Shinoda

Sugihara

2021

Handbook of the Cerebellum and Cerebellar Disorders

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A major factor in determining the function of a particular cerebellar cortical region depends upon its afferent and efferent connections. Two distinct afferent pathways convey information to the cerebellar cortex: climbing fibers and mossy fibers. A large amount of fundamental knowledge about afferent projections to the cerebellum from various precerebellar nuclei has been accumulated using new anatomical methods, including knowledge about the axonal trajectories of single

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Serial electron microscopic reconstruction of axon terminals on physiologically identified thalamocortical neurons in the cat ventral lateral nucleus

Cited by 25 publications

References 56 publications

Variability of quantal synaptic currents in thalamocortical neurons

Variability of quantal synaptic currents in thalamocortical neurons

Thalamic terminal morphology and distribution of single corticothalamic axons originating from layers 5 and 6 of the cat motor cortex

Axonal Trajectories of Single Climbing and Mossy Fiber Neurons in the Cerebellar Cortex and Nucleus

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