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Calretinin neurons in human medial prefrontal cortex (areas 24a,b,c, 32′, and 25)
Author(s) -
Gabbott Paul L.A.,
Jays Paul R.L.,
Bacon Sarah J.
Publication year - 1997
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19970519)381:4<389::aid-cne1>3.0.co;2-z
Subject(s) - calretinin , axon , biology , prefrontal cortex , laminar organization , calbindin , somatic cell , cerebral cortex , population , neuron , cortex (anatomy) , neuroscience , anatomy , biophysics , microbiology and biotechnology , immunohistochemistry , biochemistry , cognition , demography , sociology , gene , immunology
The calcium‐binding protein calretinin (CR) is present in a subpopulation of local‐circuit neurons in the mammalian cerebral cortex containing γ‐aminobutyric acid. This light microscopic investigation provides a detailed qualitative and quantitative morphological analysis of CR‐immunoreactive (CR + ) neurons in the medial prefrontal cortex (mPFC; areas 24a,b,c, 32′, and 25) of the normal adult human. The morphology of CR + neurons and their areal and laminar distributions were consistent across human mPFC. The principal organisational features of CR + labelling were the marked laminar distribution of immunoreactive somata and the predominantly vertical orientation of labelled axon‐like and dendritic processes. Several types of CR + neurons were present in layer 1, including horizontally aligned Cajal‐Retzius cells. In layers 2‐6, CR + neurons displayed a variety of morphologies: bipolar cells (49% of CR + population), vertically bitufted cells (35%), and horizontally bitufted cells (3.5%). These neuron types were mainly located in layer 2/upper layer 3, and their dendritic processes were commonly aspiny and sometimes highly beaded. Aspiny (8%) and sparsely spiny multipolar (5%) CR + neurons were also found. The mean somatic profile diameter of CR + cells was 11.6 ± 0.3 μm (mean ± S.D). CA + puncta formed pericellular baskets around unlabelled circular somatic profiles in layers 2/3 and around unlabelled pyramidal‐shaped somata in layers 5/6. The somatic sizes of these unlabelled cell populations were significantly different. Immunolabelled puncta were also found in close contact with CR + somata. Cortical depth distribution histograms and laminar thickness measurements defined the proportions of the overall CR + cell population in each layer: 7% in layer 1, 78% in layers 2/3, 14% in layers 5/6, and 1% in the white matter. In the tangential plane, CR + neurons were distributed uniformly at all levels of the cortex. By using stereological counting procedures on immunoreacted Nissl‐stained sections, CR + neurons were estimated to constitute a mean 8.0% (7.2‐8.7%) of the total neuron population in each cortical area. These data are compared with similar information obtained for the mPFC in monkey and rat (Gabbott and Bacon [1996b] J. Comp. Neurol. 364:657‐608; Gabbott et al., [1997] J. Comp. Neurol. 377:465‐499). This study provides important morphological insights into a neurochemically distinct subclass of local‐circuit inhibitory neurons in the human mPFC. J. Comp. Neurol. 381:389‐410, 1997. © 1997 Wiley‐Liss, Inc.