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Comparative density of CCK- and PV-GABA cells within the cortex and hippocampus.

Whissell PD, Cajanding JD, Fogel N, Kim JC - Front Neuroanat (2015)

Bottom Line: However, the relationship and balance between CCK- and PV-GABA neurons in the inhibitory networks of the brain is currently unclear as the distribution of these cells has never been compared on a large scale.The reverse trend was observed for PV-GABA cells.The intersectional genetic labeling approach employed in the current study expands upon the ability to study molecularly defined subsets of GABAergic neurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Toronto, Toronto ON, Canada.

ABSTRACT
Cholecystokinin (CCK)- and parvalbumin (PV)-expressing neurons constitute the two major populations of perisomatic GABAergic neurons in the cortex and the hippocampus. As CCK- and PV-GABA neurons differ in an array of morphological, biochemical and electrophysiological features, it has been proposed that they form distinct inhibitory ensembles which differentially contribute to network oscillations and behavior. However, the relationship and balance between CCK- and PV-GABA neurons in the inhibitory networks of the brain is currently unclear as the distribution of these cells has never been compared on a large scale. Here, we systemically investigated the distribution of CCK- and PV-GABA cells across a wide number of discrete forebrain regions using an intersectional genetic approach. Our analysis revealed several novel trends in the distribution of these cells. While PV-GABA cells were more abundant overall, CCK-GABA cells outnumbered PV-GABA cells in several subregions of the hippocampus, medial prefrontal cortex and ventrolateral temporal cortex. Interestingly, CCK-GABA cells were relatively more abundant in secondary/association areas of the cortex (V2, S2, M2, and AudD/AudV) than they were in corresponding primary areas (V1, S1, M1, and Aud1). The reverse trend was observed for PV-GABA cells. Our findings suggest that the balance between CCK- and PV-GABA cells in a given cortical region is related to the type of processing that area performs; inhibitory networks in the secondary cortex tend to favor the inclusion of CCK-GABA cells more than networks in the primary cortex. The intersectional genetic labeling approach employed in the current study expands upon the ability to study molecularly defined subsets of GABAergic neurons. This technique can be applied to the investigation of neuropathologies which involve disruptions to the GABAergic system, including schizophrenia, stress, maternal immune activation and autism.

No MeSH data available.


Related in: MedlinePlus

Abundance of PV-GABA cells in the parietal cortex. (Top) Sections of the intermediate parietal cortex from CCK- and PV-Frepe mice. (Bottom) Relative contribution of CCK- and PV-GABA cells to the total GABA neuron population by subregion of the parietal cortex. PV-GABA cells were comparatively more numerous in every subregion but the PtaM. Abbreviations: PtaL, lateral parietal association area, PtaM, medial parietal association area, PtaP, posterior parietal association area, S1, primary somatosensory area, S1bf, somatosensory area (barrel), S1tr, somatosensory area (trunk), S1ulp, somatosensory area (upper lip region), S2, secondary somatosensory area. Significance at the p < 0.05 level is denoted with an asterisk. Scale bar = 500 μM.
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Figure 4: Abundance of PV-GABA cells in the parietal cortex. (Top) Sections of the intermediate parietal cortex from CCK- and PV-Frepe mice. (Bottom) Relative contribution of CCK- and PV-GABA cells to the total GABA neuron population by subregion of the parietal cortex. PV-GABA cells were comparatively more numerous in every subregion but the PtaM. Abbreviations: PtaL, lateral parietal association area, PtaM, medial parietal association area, PtaP, posterior parietal association area, S1, primary somatosensory area, S1bf, somatosensory area (barrel), S1tr, somatosensory area (trunk), S1ulp, somatosensory area (upper lip region), S2, secondary somatosensory area. Significance at the p < 0.05 level is denoted with an asterisk. Scale bar = 500 μM.

Mentions: Due to the substantial volume of the parietal cortex, we elected to sample intermediate subregions only. Specifically, GFP-labeled cells were counted in several subdivisions of the primary somatosensory cortex (S1bf, S1tr, S1ulp, S1), parietal association cortex (PtaL, PtaM, and PtaP) and in the secondary somatosensory cortex (S2) (Table 1, Figure 4). Two-way ANOVA detected a main effect of genotype on the percentage of GFP-labeled cells in the parietal cortex [F(1,71) = 179.3, p < 0.0001], but not an interaction of genotype × brain region. In all regions of the parietal cortex but the PtaM, PV-GABA cells were significantly more numerous than CCK-GABA cells (all ps < 0.05, Figure 4). These data support the notion that PV-GABA cells are the most abundant perisomatic interneurons in the parietal cortex (Lee et al., 2010).


Comparative density of CCK- and PV-GABA cells within the cortex and hippocampus.

Whissell PD, Cajanding JD, Fogel N, Kim JC - Front Neuroanat (2015)

Abundance of PV-GABA cells in the parietal cortex. (Top) Sections of the intermediate parietal cortex from CCK- and PV-Frepe mice. (Bottom) Relative contribution of CCK- and PV-GABA cells to the total GABA neuron population by subregion of the parietal cortex. PV-GABA cells were comparatively more numerous in every subregion but the PtaM. Abbreviations: PtaL, lateral parietal association area, PtaM, medial parietal association area, PtaP, posterior parietal association area, S1, primary somatosensory area, S1bf, somatosensory area (barrel), S1tr, somatosensory area (trunk), S1ulp, somatosensory area (upper lip region), S2, secondary somatosensory area. Significance at the p < 0.05 level is denoted with an asterisk. Scale bar = 500 μM.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585045&req=5

Figure 4: Abundance of PV-GABA cells in the parietal cortex. (Top) Sections of the intermediate parietal cortex from CCK- and PV-Frepe mice. (Bottom) Relative contribution of CCK- and PV-GABA cells to the total GABA neuron population by subregion of the parietal cortex. PV-GABA cells were comparatively more numerous in every subregion but the PtaM. Abbreviations: PtaL, lateral parietal association area, PtaM, medial parietal association area, PtaP, posterior parietal association area, S1, primary somatosensory area, S1bf, somatosensory area (barrel), S1tr, somatosensory area (trunk), S1ulp, somatosensory area (upper lip region), S2, secondary somatosensory area. Significance at the p < 0.05 level is denoted with an asterisk. Scale bar = 500 μM.
Mentions: Due to the substantial volume of the parietal cortex, we elected to sample intermediate subregions only. Specifically, GFP-labeled cells were counted in several subdivisions of the primary somatosensory cortex (S1bf, S1tr, S1ulp, S1), parietal association cortex (PtaL, PtaM, and PtaP) and in the secondary somatosensory cortex (S2) (Table 1, Figure 4). Two-way ANOVA detected a main effect of genotype on the percentage of GFP-labeled cells in the parietal cortex [F(1,71) = 179.3, p < 0.0001], but not an interaction of genotype × brain region. In all regions of the parietal cortex but the PtaM, PV-GABA cells were significantly more numerous than CCK-GABA cells (all ps < 0.05, Figure 4). These data support the notion that PV-GABA cells are the most abundant perisomatic interneurons in the parietal cortex (Lee et al., 2010).

Bottom Line: However, the relationship and balance between CCK- and PV-GABA neurons in the inhibitory networks of the brain is currently unclear as the distribution of these cells has never been compared on a large scale.The reverse trend was observed for PV-GABA cells.The intersectional genetic labeling approach employed in the current study expands upon the ability to study molecularly defined subsets of GABAergic neurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Toronto, Toronto ON, Canada.

ABSTRACT
Cholecystokinin (CCK)- and parvalbumin (PV)-expressing neurons constitute the two major populations of perisomatic GABAergic neurons in the cortex and the hippocampus. As CCK- and PV-GABA neurons differ in an array of morphological, biochemical and electrophysiological features, it has been proposed that they form distinct inhibitory ensembles which differentially contribute to network oscillations and behavior. However, the relationship and balance between CCK- and PV-GABA neurons in the inhibitory networks of the brain is currently unclear as the distribution of these cells has never been compared on a large scale. Here, we systemically investigated the distribution of CCK- and PV-GABA cells across a wide number of discrete forebrain regions using an intersectional genetic approach. Our analysis revealed several novel trends in the distribution of these cells. While PV-GABA cells were more abundant overall, CCK-GABA cells outnumbered PV-GABA cells in several subregions of the hippocampus, medial prefrontal cortex and ventrolateral temporal cortex. Interestingly, CCK-GABA cells were relatively more abundant in secondary/association areas of the cortex (V2, S2, M2, and AudD/AudV) than they were in corresponding primary areas (V1, S1, M1, and Aud1). The reverse trend was observed for PV-GABA cells. Our findings suggest that the balance between CCK- and PV-GABA cells in a given cortical region is related to the type of processing that area performs; inhibitory networks in the secondary cortex tend to favor the inclusion of CCK-GABA cells more than networks in the primary cortex. The intersectional genetic labeling approach employed in the current study expands upon the ability to study molecularly defined subsets of GABAergic neurons. This technique can be applied to the investigation of neuropathologies which involve disruptions to the GABAergic system, including schizophrenia, stress, maternal immune activation and autism.

No MeSH data available.


Related in: MedlinePlus