Limits...
"Subpial Fan Cell" - A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex.

Gabbott PL - Front Neuroanat (2016)

Bottom Line: SPF-SPF cell innervation was not observed.The distribution and connectivity of SPF cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation.The main synaptic output of SPF cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monkey PFC.

View Article: PubMed Central - PubMed

Affiliation: Neural Architectonics CentreOxford, UK; Department of Life, Health, and Chemical Sciences, The Open UniversityMilton Keynes, UK; University Department of Pharmacology, University of OxfordOxford, UK.

ABSTRACT
Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class - termed "subpial fan (SPF) cell" - described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A - presumed excitatory) and symmetric (S - presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata - with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells indicated a unique class of CRet+/GABA- neuron in adult monkey PFC - possibly a subtype of persisting Cajal-Retzius cell. The distribution and connectivity of SPF cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation. The main synaptic output of SPF cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monkey PFC.

No MeSH data available.


Related in: MedlinePlus

Calretinin immunopositive (CRet+) neurons in layer 1 of monkey PFC — Classes 6–8 (A–F). (A,B) Class 6. Perpendicular views of two deep horizontal bipolar CRet+ neurons (a, area 25; b, area 9) in lower layer 1. Fine axonal processes are indicated (arrows). Composite drawing of cells a and b. Scale bar: 100 μm. (C) Class 6. Area 24c. Surface view showing a deep horizontal bipolar CRet+ neuron in lower layer 1. Profiles of CRet+ neurons in upper layer 2 (lying deeper in the section) are seen (asterisks). (Axon, ax). Scale bar: 50 μm. (D) Class 7. Area 24c. Simple unipolar CRet+ neuron (n). (Dendrite arrowed). Scale bar: 50 μm. (E) Class 8. Area 46d. CRet+ SPF cell (arrow). CRet+ neurons in layer 2 (asterisk). Pial surface is indicated (oblique view). Scale bar: 50 μm. (F) Reconstruction of the cell in (D). Note unipolar soma and elaborate fan-like arrangement of higher order dendrites which give rise to numerous thorns. An axon arises proximally along the primary dendrite. Scale bar: 50 μm. Morphometric analysis of dendritic arbors (G–J). (G) Dendrograms for the eight classes of CRet+ neurons in layer 1 of adult monkey showing the lengths, nodal points. and main dendritic segments (filamentous and thorn processes are not indicated, asterisks). A single representative cell in each class is shown. (H) Bar charts of the distribution (absolute number) of dendritic node locations as a function of maximum dendritic arbor length (100%). [Data from 12 cells in each class are presented. Total absolute numbers of nodes (Σ) are given]. Note the highly characteristic distribution of nodes for class 8 SPF cells. (Means of distributions, red arrows). (I) Dendritic tree topologies of the 8 CRet+ cell classes presented in H together with the corresponding WeST values (1.0–9.8). (J) Outlines of 20 SPF cell dendritic boundaries superimposed over their major caliper axes. Somata centroids act as root points.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4829592&req=5

Figure 3: Calretinin immunopositive (CRet+) neurons in layer 1 of monkey PFC — Classes 6–8 (A–F). (A,B) Class 6. Perpendicular views of two deep horizontal bipolar CRet+ neurons (a, area 25; b, area 9) in lower layer 1. Fine axonal processes are indicated (arrows). Composite drawing of cells a and b. Scale bar: 100 μm. (C) Class 6. Area 24c. Surface view showing a deep horizontal bipolar CRet+ neuron in lower layer 1. Profiles of CRet+ neurons in upper layer 2 (lying deeper in the section) are seen (asterisks). (Axon, ax). Scale bar: 50 μm. (D) Class 7. Area 24c. Simple unipolar CRet+ neuron (n). (Dendrite arrowed). Scale bar: 50 μm. (E) Class 8. Area 46d. CRet+ SPF cell (arrow). CRet+ neurons in layer 2 (asterisk). Pial surface is indicated (oblique view). Scale bar: 50 μm. (F) Reconstruction of the cell in (D). Note unipolar soma and elaborate fan-like arrangement of higher order dendrites which give rise to numerous thorns. An axon arises proximally along the primary dendrite. Scale bar: 50 μm. Morphometric analysis of dendritic arbors (G–J). (G) Dendrograms for the eight classes of CRet+ neurons in layer 1 of adult monkey showing the lengths, nodal points. and main dendritic segments (filamentous and thorn processes are not indicated, asterisks). A single representative cell in each class is shown. (H) Bar charts of the distribution (absolute number) of dendritic node locations as a function of maximum dendritic arbor length (100%). [Data from 12 cells in each class are presented. Total absolute numbers of nodes (Σ) are given]. Note the highly characteristic distribution of nodes for class 8 SPF cells. (Means of distributions, red arrows). (I) Dendritic tree topologies of the 8 CRet+ cell classes presented in H together with the corresponding WeST values (1.0–9.8). (J) Outlines of 20 SPF cell dendritic boundaries superimposed over their major caliper axes. Somata centroids act as root points.

Mentions: The tangential boundary distributions of the SPF cell dendritic arbors were assessed by calculating their major caliper axis. Arbors were then superimposed along the major axis with somatic centroids as root points. Arbor boundaries were transformed so that their maximal extents along the major axis were the same (100%) — providing an overall comparison of SPF cell dendritic arbor polarization (Figure 3J).


"Subpial Fan Cell" - A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex.

Gabbott PL - Front Neuroanat (2016)

Calretinin immunopositive (CRet+) neurons in layer 1 of monkey PFC — Classes 6–8 (A–F). (A,B) Class 6. Perpendicular views of two deep horizontal bipolar CRet+ neurons (a, area 25; b, area 9) in lower layer 1. Fine axonal processes are indicated (arrows). Composite drawing of cells a and b. Scale bar: 100 μm. (C) Class 6. Area 24c. Surface view showing a deep horizontal bipolar CRet+ neuron in lower layer 1. Profiles of CRet+ neurons in upper layer 2 (lying deeper in the section) are seen (asterisks). (Axon, ax). Scale bar: 50 μm. (D) Class 7. Area 24c. Simple unipolar CRet+ neuron (n). (Dendrite arrowed). Scale bar: 50 μm. (E) Class 8. Area 46d. CRet+ SPF cell (arrow). CRet+ neurons in layer 2 (asterisk). Pial surface is indicated (oblique view). Scale bar: 50 μm. (F) Reconstruction of the cell in (D). Note unipolar soma and elaborate fan-like arrangement of higher order dendrites which give rise to numerous thorns. An axon arises proximally along the primary dendrite. Scale bar: 50 μm. Morphometric analysis of dendritic arbors (G–J). (G) Dendrograms for the eight classes of CRet+ neurons in layer 1 of adult monkey showing the lengths, nodal points. and main dendritic segments (filamentous and thorn processes are not indicated, asterisks). A single representative cell in each class is shown. (H) Bar charts of the distribution (absolute number) of dendritic node locations as a function of maximum dendritic arbor length (100%). [Data from 12 cells in each class are presented. Total absolute numbers of nodes (Σ) are given]. Note the highly characteristic distribution of nodes for class 8 SPF cells. (Means of distributions, red arrows). (I) Dendritic tree topologies of the 8 CRet+ cell classes presented in H together with the corresponding WeST values (1.0–9.8). (J) Outlines of 20 SPF cell dendritic boundaries superimposed over their major caliper axes. Somata centroids act as root points.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829592&req=5

Figure 3: Calretinin immunopositive (CRet+) neurons in layer 1 of monkey PFC — Classes 6–8 (A–F). (A,B) Class 6. Perpendicular views of two deep horizontal bipolar CRet+ neurons (a, area 25; b, area 9) in lower layer 1. Fine axonal processes are indicated (arrows). Composite drawing of cells a and b. Scale bar: 100 μm. (C) Class 6. Area 24c. Surface view showing a deep horizontal bipolar CRet+ neuron in lower layer 1. Profiles of CRet+ neurons in upper layer 2 (lying deeper in the section) are seen (asterisks). (Axon, ax). Scale bar: 50 μm. (D) Class 7. Area 24c. Simple unipolar CRet+ neuron (n). (Dendrite arrowed). Scale bar: 50 μm. (E) Class 8. Area 46d. CRet+ SPF cell (arrow). CRet+ neurons in layer 2 (asterisk). Pial surface is indicated (oblique view). Scale bar: 50 μm. (F) Reconstruction of the cell in (D). Note unipolar soma and elaborate fan-like arrangement of higher order dendrites which give rise to numerous thorns. An axon arises proximally along the primary dendrite. Scale bar: 50 μm. Morphometric analysis of dendritic arbors (G–J). (G) Dendrograms for the eight classes of CRet+ neurons in layer 1 of adult monkey showing the lengths, nodal points. and main dendritic segments (filamentous and thorn processes are not indicated, asterisks). A single representative cell in each class is shown. (H) Bar charts of the distribution (absolute number) of dendritic node locations as a function of maximum dendritic arbor length (100%). [Data from 12 cells in each class are presented. Total absolute numbers of nodes (Σ) are given]. Note the highly characteristic distribution of nodes for class 8 SPF cells. (Means of distributions, red arrows). (I) Dendritic tree topologies of the 8 CRet+ cell classes presented in H together with the corresponding WeST values (1.0–9.8). (J) Outlines of 20 SPF cell dendritic boundaries superimposed over their major caliper axes. Somata centroids act as root points.
Mentions: The tangential boundary distributions of the SPF cell dendritic arbors were assessed by calculating their major caliper axis. Arbors were then superimposed along the major axis with somatic centroids as root points. Arbor boundaries were transformed so that their maximal extents along the major axis were the same (100%) — providing an overall comparison of SPF cell dendritic arbor polarization (Figure 3J).

Bottom Line: SPF-SPF cell innervation was not observed.The distribution and connectivity of SPF cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation.The main synaptic output of SPF cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monkey PFC.

View Article: PubMed Central - PubMed

Affiliation: Neural Architectonics CentreOxford, UK; Department of Life, Health, and Chemical Sciences, The Open UniversityMilton Keynes, UK; University Department of Pharmacology, University of OxfordOxford, UK.

ABSTRACT
Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class - termed "subpial fan (SPF) cell" - described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A - presumed excitatory) and symmetric (S - presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata - with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells indicated a unique class of CRet+/GABA- neuron in adult monkey PFC - possibly a subtype of persisting Cajal-Retzius cell. The distribution and connectivity of SPF cells suggest they act as integrative hubs in upper layer 1 during postnatal maturation. The main synaptic output of SPF cells likely provides a transminicolumnar excitatory influence across swathes of apical dendritic tufts - thus affecting information processing in discrete patches of layer 1 in adult monkey PFC.

No MeSH data available.


Related in: MedlinePlus