Aspects of the organization of neurons and dendritic bundles in primary somatosensory cortex of the rat

Skoglund, Thomas; Pascher, R.; Berthold, Claes‐Henric

doi:10.1016/j.neures.2004.06.017

Cited by 22 publications

(14 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9E,F) and that the interbundle interval was 56 Ϯ 14 m (mean Ϯ SD). Interestingly, this interval was very close to that of dendritic bundles formed by L5 pyramidal neurons in the rat S1 cortex [ϳ50 m in the study by Feldman and Peters (1974) and 49 Ϯ 16 m in the study by Skoglund et al (2004)]. More interestingly, the thick axons of L4 neurons descended in close proximity with CTN dendritic bundles (Fig.…”

Section: Discussionsupporting

confidence: 70%

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Tanaka

Tanaka²,

Konno³

et al. 2011

J. Neurosci.

View full text Add to dashboard Cite

Corticothalamic projection neurons in the cerebral cortex constitute an important component of the thalamocortical reciprocal circuit, an essential input/output organization for cortical information processing. However, the spatial organization of local excitatory connections to corticothalamic neurons is only partially understood. In the present study, we first developed an adenovirus vector expressing somatodendritic membrane-targeted green fluorescent protein. After injection of the adenovirus vector into the ventrobasal thalamic complex, a band of layer (L) 6 corticothalamic neurons in the rat barrel cortex were retrogradely labeled. In addition to their cell bodies, fine dendritic spines of corticothalamic neurons were well visualized without the labeling of their axon collaterals or thalamocortical axons. In cortical slices containing retrogradely labeled L6 corticothalamic neurons, we intracellularly stained single pyramidal/spiny neurons of L2-6. We examined the spatial distribution of contact sites between the local axon collaterals of each pyramidal neuron and the dendrites of corticothalamic neurons. We found that corticothalamic neurons received strong and focused connections from L4 neurons just above them, and that the most numerous nearby and distant sources of local excitatory connections to corticothalamic neurons were corticothalamic neurons themselves and L6 putative corticocortical neurons, respectively. These results suggest that L4 neurons may serve as an important source of local excitatory inputs in shaping the cortical modulation of thalamic activity.

show abstract

Section: Discussionsupporting

confidence: 70%

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Tanaka

Tanaka²,

Konno³

et al. 2011

J. Neurosci.

View full text Add to dashboard Cite

show abstract

“…While equivalent in density to other minicolumnar elements, these structures may serve to integrate and coordinate input to several neighboring radial cell columns. In fact, the structure of those bundles varies according to cytoarchitectonic area (Viebahn 1990;Peters, Cifuentes et al 1997;Skoglund, Pascher et al 2004) and among species (Schmolke and Künzle 1997). Increased branching complexity and spine density of basal dendritic arbors in the peripheral neuropil of human prefrontal cortex in comparison with that of old and new world monkeys suggests that altered morphometry of this compartment in humans results in increased integration of inputs among minicolumns.…”

Section: Discussionmentioning

confidence: 99%

Recursive trace line method for detecting myelinated bundles: A comparison study with pyramidal cell arrays

Konkachbaev

Switala

Elmaghraby

2008

Journal of Neuroscience Methods

View full text Add to dashboard Cite

Minicolumns are thought to be the smallest cortical modules within the hierarchical organization of the isocortex. Several reports suggest alterations in minicolumnar morphometry may be involved in psychiatric disorders such as autism, dyslexia, and schizophrenia. Thus far anatomical studies of minicolumns have primarily relied on measurements of pyramidal cell arrays. This study expands on a recursive trace line segmentation method used to define morphometric measures for myelinated axon bundles. The results were compared against those of pyramidal cell arrays derived from immediately adjacent serial sections. Width estimates based on cell somas and myelinated axon bundles were highly correlated (r = 0.9888). Histograms of signal intensity using the recursive trace line method produced expected features of myeloarchitectonics; that is, bundles of Meynert and intervening interradiary plexus. The close correspondence of derived values for myelinated axon bundles and pyramidal cell arrays suggests their participation and interaction within the same modular arrangement of the isocortex.

show abstract

“…Physiological variations in glial coverage have been shown to alter glutamate diffusion in the extracellular space (Piet et al, 2004). The ability of psychedelic hallucinogens to enhance either spillover, or detection of spillover, in the prefrontal cortical slice may arise from the density of 5-HT 2A receptors on apical dendrites of layer V neurons (Blue et al, 1988;Cornea-Hebert et al, 1999;Hamada et al, 1998;Jakab and Goldman-Rakic, 1998;Willins et al, 1997;Xu and Pandey, 2000;Miner et al, 2003), together with the arrangement of these apical dendrites in bundles (Gabbott and Bacon, 1996;Skoglund et al, 2004). These structural features may contribute to the ability of psychedelic hallucinogens to enhance spillover or detection of spillover in the medial prefrontal cortex.…”

Section: Physical Arrangement Favors Spillovermentioning

confidence: 99%

Hallucinogen-Induced UP States in the Brain Slice of Rat Prefrontal Cortex: Role of Glutamate Spillover and NR2B-NMDA Receptors

Lambe

Aghajanian

2005

Neuropsychopharmacol

View full text Add to dashboard Cite

Psychedelic hallucinogens (eg LSD or DOI) induce disturbances of mood, perception, and cognition through stimulation of serotonin 5-HT 2A receptors. While these drugs are not proconvulsant, they have been shown by microdialysis to increase extracellular glutamate in the prefrontal cortex. Electrophysiological studies in the rat prefrontal slice have shown that both LSD and DOI enhance a prolonged, late wave of glutamate release onto layer V pyramidal neurons after an electrical stimulus. Here, we hypothesize that the network activity underlying this UP state involves glutamate spillover from excitatory synapses. To test this hypothesis, we raised the viscosity of the extracellular solution by adding the inert macromolecule dextran (B1 mM) that is known to retard glutamate overflow into the extrasynaptic space. Dextran suppressed the UP state or late excitatory postsynaptic current (EPSC), but neither the fast EPSC, the traditional polysynaptic EPSC, nor a synaptic form of 5-HT 2A -mediated transmission (serotonin-induced spontaneous EPSCs). Consistent with the previous work showing that extrasynaptic glutamate transmission in adult depends on NR2B-containing NMDA receptors, we found that NR2B-selective antagonists, ifenprodil and Ro25-6981, also suppressed the late EPSCs. The effect of psychedelic hallucinogens on UP states could be partially mimicked by inhibiting glutamate uptake but only after blocking inhibitory group II metabotropic glutamate receptors. This difference suggests that hallucinogens increase glutamate spillover in a phasic manner unlike glutamate uptake inhibitors. Increases in glutamate spillover have been suggested to recruit synapses not directly in the pathway activated by the electrical stimulus. Such recruitment could account for certain cognitive, affective, and sensory perturbations generated by psychedelic hallucinogens.

show abstract

Aspects of the organization of neurons and dendritic bundles in primary somatosensory cortex of the rat

Cited by 22 publications

References 47 publications

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Local Connections of Excitatory Neurons to Corticothalamic Neurons in the Rat Barrel Cortex

Recursive trace line method for detecting myelinated bundles: A comparison study with pyramidal cell arrays

Hallucinogen-Induced UP States in the Brain Slice of Rat Prefrontal Cortex: Role of Glutamate Spillover and NR2B-NMDA Receptors

Contact Info

Product

Resources

About