Local circuit neurons in the medial prefrontal cortex (areas 24a,b,c, 25 and 32) in the monkey: II. Quantitative areal and laminar distributions

Abstract

The companion paper (Gabbott and Bacon [1996] J. Comp. Neurol.) describes the morphology of calretinin (CR)-, parvalbumin (PV)-, calbindin (CB)-, and GABA-immunoreactive neurons, and NADPH diaphorase-reactive cells, in the medial prefrontal cortex (mPFC; areas 24a, 24b, 24c, 25 and 32) of the adult monkey. Since these local circuit neurons play crucial functional roles, the aim of this study was to provide supportive quantitative data defining their areal and laminar distribution in mPFC. The numerical densities of neurons (Nv, number of cells per mm3) in each area and layer were calculated stereologically. The mean total neuronal NV estimates across mPFC was 55,727 +/- 3,319 per mm3 (mean +/- S.D.; n = 3); values ranged from 50,489 +/- 8,374 per mm3 (area 24a) to 59,938 +/- 7,214 per mm3 (area 24c). Interareal differences were not significant. Cortical depth measurements and neuronal NV estimates for each area allowed the absolute number of neurons in a column of cortex under 1 mm2 of surface to be calculated; values varied between 86,457 +/- 15,063 (area 24a) and 128,464 +/- 24,050 (area 24c). Using immunolabelled Nissl-stained sections of mPFC, CR+ neurons constituted 11.2%, PV+ neurons 5.9%, and CB+ neurons 5.0% of the total neuron population. GABA+ neurons represented an overall 24.9% (23.5-27.3%) of neurons in the mPFC. Differences between areas were not significant. The cortical depth distribution histograms of CR+, PV+, CB+, and GABA+ cell populations in each area were derived and the percentage of a given cell population in each layer subsequently calculated. Peaks in the cortical depth distributions of CR+ and CB+ neurons occurred in layer 2 and upper layer 3, respectively; the peak distribution of PV+ neurons occurred between lower layer 3 and upper layer 5. The depth distribution of GABA+ cells reflected the combined distributions of CR+, PV+ and CR+ neurons. In all areas, the majority (74.4-84.0%) of the GABA cell population was located in layers 2/3. The depth distributions for each cell type were similar between areas. Diaphorase-reactive neurons accounted for 0.25% (0.2-0.32%) of all cortical neurons in mPFC and were distributed in two horizontal strata, in midlayer 3 and in mid/upper layer 6. A large population of diaphorase-reactive cells was present in the white matter. The absolute numbers of CR+, PV+, CB+ and GABA+ neurons within individual layers in a column of cortex under 1 mm2 and 50 x 50 microns of cortical surface have been derived. The data presented provide the basis for a quantitative definition of cortical circuits in monkey mPFC.

Repeated phencyclidine in monkeys results in loss of parvalbumin-containing axo-axonic projections in the prefrontal cortex

“…More recently, it has been observed that, in the primate principal sulcus (PS; area 46), PV-immunoreactive (ir) neurons are concentrated in the middle layers, are non-pyramidal, and classified as either wide arbor (basket) or chandelier cells (Williams et al 1992). Furthermore, there is evidence that, in the monkey prefrontal cortex, the different calcium-binding proteins, PV, calbindin D-28K, or CR, are segregated in populations of local circuit neurons that have distinct laminar distribution patterns (Conde et al 1994;Gabbott and Bacon 1996;Lund and Lewis 1993).…”

“…The laminar distribution of PV-ir and CR-ir cells in the PS reported here was also similar to a previous study in the rhesus monkey (Dombrowski et al 2001). Another report has shown similar laminar distribution of PV-ir and CR-ir cells in other prefrontal cortical regions, anterior cingulate (area 24), prelimbic (area 32), and infralimbic (area 25) cortices of female cynomolgus monkeys (Gabbott and Bacon 1996). Dombrowski et al (2001), however, reported fewer CR-ir cells than PV-ir cells in area 46 of rhesus monkeys in contrast to our study where the number of CRir cells exceeds the number of PV-ir cells.…”

“…Dombrowski et al (2001), however, reported fewer CR-ir cells than PV-ir cells in area 46 of rhesus monkeys in contrast to our study where the number of CRir cells exceeds the number of PV-ir cells. Gabbott and Bacon (1996) have reported more CR-ir cells than PV-ir cells in the prefrontal regions they examined. Again, differences in monkey species or ages of subjects may explain this divergence.…”

Selective alterations in prefrontal cortical GABA neurotransmission in schizophrenia: a novel target for the treatment of working memory dysfunction

“…Interestingly, in mice the majority of cortical GABA neurons are born in the ganglionic eminences, whereas this region contributes only about a third of cortical GABA neurons in humans (Anderson et al 1997;Letinic et al 2002). Together, these findings may explain why the density of PVpositive cells clearly exceeds that of CR-positive cells in rodent cortex (Gabbott et al 1997), while in primate DLPFC CR-positive cells outnumber PV-positive cells by 2:1 (CondØ et al 1994;Gabbott and Bacon 1996). Maturational differences among subtypes of GABA neurons are also evident postnatally.…”

Computational modeling of psychiatric illnesses via well-defined neurophysiological and neurocognitive biomarkers

“…(Gabbott and Bacon, 1996). This simulation was used to shed light on A c c e p t e d M a n u s c r i p t 14 the relative contribution of various interneuron subtypes to the maintenance and stability of WM representations.…”