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Quantitative mapping of the local and extrinsic sources of GABA and Reelin to the layer Ia neuropil in the adult rat neocortex

Ramos Moreno, Tania LU and Clasca, Francisco (2014) In Brain Structure and Function 219(5). p.1639-1657
Abstract
Inputs to apical dendritic tufts have been considered to be crucial for associative learning, attention and similar ''feedback'' interactions and are located in neocortical layer Ia. Excitatory thalamic projections to apical tufts in layer Ia have been well characterized and their role in the cortical circuit has been emphasized. In addition, the neuropil and the extracellular matrix surrounding apical tufts are highly reactive to GABA and to the glycoprotein Reelin, respectively. Recently it has been shown that the GABA inhibition on apical dendrites can reduce the output of pyramidal cells in layer V, however, the origin of 89 % of the symmetric synapses in layer I still remains unknown. In the present study we have systematically... (More)
Inputs to apical dendritic tufts have been considered to be crucial for associative learning, attention and similar ''feedback'' interactions and are located in neocortical layer Ia. Excitatory thalamic projections to apical tufts in layer Ia have been well characterized and their role in the cortical circuit has been emphasized. In addition, the neuropil and the extracellular matrix surrounding apical tufts are highly reactive to GABA and to the glycoprotein Reelin, respectively. Recently it has been shown that the GABA inhibition on apical dendrites can reduce the output of pyramidal cells in layer V, however, the origin of 89 % of the symmetric synapses in layer I still remains unknown. In the present study we have systematically analyzed the origin of the GABAergic neuropil in neocortical layer Ia in a qualitative and quantitative manner, and investigated the possible extrinsic origin of the rich extracellular Reelin content of the same layer. We show that the inhibitory inputs in a given spot in layer I come from cortical projections and arise mainly from Martinotti cells located directly under that same spot. Double bouquet and bipolar cells may also project to layer Ia although to a lesser extent and the external globus pallidus and zona incerta provide the remaining inhibitory inputs. Finally, our results suggest that Martinotti cells are also the main source of Reelin in layer Ia. The present data will help in the understanding of the cortical circuit and why it changes in pathological conditions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Interneuron, Martinotti cells, Apical tuft, Somatostatin, Cortical, circuitry, Neocortical column
in
Brain Structure and Function
volume
219
issue
5
pages
1639 - 1657
publisher
Springer
external identifiers
  • wos:000341375500010
  • scopus:84929042957
ISSN
1863-2661
DOI
10.1007/s00429-013-0591-x
language
English
LU publication?
yes
id
1089d4a8-1908-4cf3-b004-e7eae6f5c91b (old id 4713931)
date added to LUP
2014-11-03 07:15:49
date last changed
2017-09-19 14:58:15
@article{1089d4a8-1908-4cf3-b004-e7eae6f5c91b,
  abstract     = {Inputs to apical dendritic tufts have been considered to be crucial for associative learning, attention and similar ''feedback'' interactions and are located in neocortical layer Ia. Excitatory thalamic projections to apical tufts in layer Ia have been well characterized and their role in the cortical circuit has been emphasized. In addition, the neuropil and the extracellular matrix surrounding apical tufts are highly reactive to GABA and to the glycoprotein Reelin, respectively. Recently it has been shown that the GABA inhibition on apical dendrites can reduce the output of pyramidal cells in layer V, however, the origin of 89 % of the symmetric synapses in layer I still remains unknown. In the present study we have systematically analyzed the origin of the GABAergic neuropil in neocortical layer Ia in a qualitative and quantitative manner, and investigated the possible extrinsic origin of the rich extracellular Reelin content of the same layer. We show that the inhibitory inputs in a given spot in layer I come from cortical projections and arise mainly from Martinotti cells located directly under that same spot. Double bouquet and bipolar cells may also project to layer Ia although to a lesser extent and the external globus pallidus and zona incerta provide the remaining inhibitory inputs. Finally, our results suggest that Martinotti cells are also the main source of Reelin in layer Ia. The present data will help in the understanding of the cortical circuit and why it changes in pathological conditions.},
  author       = {Ramos Moreno, Tania and Clasca, Francisco},
  issn         = {1863-2661},
  keyword      = {Interneuron,Martinotti cells,Apical tuft,Somatostatin,Cortical,circuitry,Neocortical column},
  language     = {eng},
  number       = {5},
  pages        = {1639--1657},
  publisher    = {Springer},
  series       = {Brain Structure and Function},
  title        = {Quantitative mapping of the local and extrinsic sources of GABA and Reelin to the layer Ia neuropil in the adult rat neocortex},
  url          = {http://dx.doi.org/10.1007/s00429-013-0591-x},
  volume       = {219},
  year         = {2014},
}