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"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

Summary diagram of the afferent and efferent synaptic connectivity of identified SPF cells in adult monkey PFC. (A)Dendrites: Asymmetric (A-type) synaptic inputs from CRet- boutons are more frequent along distal dendritic shafts, with symmetric (S-type) synapses more common on proximal shafts. (S-types inputs are derived from both CRet+ and CRet- boutons). Dendritic “thorns” are richly innervated by A-type (CRet-) and S-type (CRet- and CRet+) synaptic inputs. The bases of thorns receive CRet- A-type input (asterisk). Dendritic spines (sp) receive A-type and S-type (both CRet-) inputs. Soma: Synaptic input to the soma derives from A-type and S-type boutons. A-type axosomatic boutons are subdivided into CRet+ and CRet- types — with the latter predominant. (CRet+ A-type boutons were not derived from SPF cells). Axonal boutons: CRet+ boutons establish exclusively A-type junctions with CRet- post-synaptic targets. (B) The summary bar charts show the post-synaptic compartments innervated by SPF cell axonal boutons (Table 1). Data for axonal boutons lying “local” and “distant” to parent somata are given separately. Post-synaptic compartments: dendritic spine, sp; dendritic shaft, sh; cell body, cb; axon initial segment, ais; and unidentified elements?
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Figure 12: Summary diagram of the afferent and efferent synaptic connectivity of identified SPF cells in adult monkey PFC. (A)Dendrites: Asymmetric (A-type) synaptic inputs from CRet- boutons are more frequent along distal dendritic shafts, with symmetric (S-type) synapses more common on proximal shafts. (S-types inputs are derived from both CRet+ and CRet- boutons). Dendritic “thorns” are richly innervated by A-type (CRet-) and S-type (CRet- and CRet+) synaptic inputs. The bases of thorns receive CRet- A-type input (asterisk). Dendritic spines (sp) receive A-type and S-type (both CRet-) inputs. Soma: Synaptic input to the soma derives from A-type and S-type boutons. A-type axosomatic boutons are subdivided into CRet+ and CRet- types — with the latter predominant. (CRet+ A-type boutons were not derived from SPF cells). Axonal boutons: CRet+ boutons establish exclusively A-type junctions with CRet- post-synaptic targets. (B) The summary bar charts show the post-synaptic compartments innervated by SPF cell axonal boutons (Table 1). Data for axonal boutons lying “local” and “distant” to parent somata are given separately. Post-synaptic compartments: dendritic spine, sp; dendritic shaft, sh; cell body, cb; axon initial segment, ais; and unidentified elements?

Mentions: A summary map of the synaptic connectivity of SPF cells is presented in Figure 12.


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

Gabbott PL - Front Neuroanat (2016)

Summary diagram of the afferent and efferent synaptic connectivity of identified SPF cells in adult monkey PFC. (A)Dendrites: Asymmetric (A-type) synaptic inputs from CRet- boutons are more frequent along distal dendritic shafts, with symmetric (S-type) synapses more common on proximal shafts. (S-types inputs are derived from both CRet+ and CRet- boutons). Dendritic “thorns” are richly innervated by A-type (CRet-) and S-type (CRet- and CRet+) synaptic inputs. The bases of thorns receive CRet- A-type input (asterisk). Dendritic spines (sp) receive A-type and S-type (both CRet-) inputs. Soma: Synaptic input to the soma derives from A-type and S-type boutons. A-type axosomatic boutons are subdivided into CRet+ and CRet- types — with the latter predominant. (CRet+ A-type boutons were not derived from SPF cells). Axonal boutons: CRet+ boutons establish exclusively A-type junctions with CRet- post-synaptic targets. (B) The summary bar charts show the post-synaptic compartments innervated by SPF cell axonal boutons (Table 1). Data for axonal boutons lying “local” and “distant” to parent somata are given separately. Post-synaptic compartments: dendritic spine, sp; dendritic shaft, sh; cell body, cb; axon initial segment, ais; and unidentified elements?
© Copyright Policy
Related In: Results  -  Collection

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

Figure 12: Summary diagram of the afferent and efferent synaptic connectivity of identified SPF cells in adult monkey PFC. (A)Dendrites: Asymmetric (A-type) synaptic inputs from CRet- boutons are more frequent along distal dendritic shafts, with symmetric (S-type) synapses more common on proximal shafts. (S-types inputs are derived from both CRet+ and CRet- boutons). Dendritic “thorns” are richly innervated by A-type (CRet-) and S-type (CRet- and CRet+) synaptic inputs. The bases of thorns receive CRet- A-type input (asterisk). Dendritic spines (sp) receive A-type and S-type (both CRet-) inputs. Soma: Synaptic input to the soma derives from A-type and S-type boutons. A-type axosomatic boutons are subdivided into CRet+ and CRet- types — with the latter predominant. (CRet+ A-type boutons were not derived from SPF cells). Axonal boutons: CRet+ boutons establish exclusively A-type junctions with CRet- post-synaptic targets. (B) The summary bar charts show the post-synaptic compartments innervated by SPF cell axonal boutons (Table 1). Data for axonal boutons lying “local” and “distant” to parent somata are given separately. Post-synaptic compartments: dendritic spine, sp; dendritic shaft, sh; cell body, cb; axon initial segment, ais; and unidentified elements?
Mentions: A summary map of the synaptic connectivity of SPF cells is presented in Figure 12.

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