The distribution of clones of neurons in the rat somatosensory cortex

Moore, R. Brantingham; Price, Jack

doi:10.1007/bf01181588

“…Both consisted of -70% single-cell clones. This figure corresponds closely to the overall percentage of single-cell clones reported previously both in vivo and in culture (Luskin et al, 1988;Price and Thurlow, 1988;Moore and Price, 1992;Walsh and Cepko, 1992;Grove et al, 1993), although some investigators have failed to find single-cell clones (Acklin and Van der Kooy, 1993;Mione er al., 1994). Single-cell neuronal clones would be expected to arise because the retrovirus is only inherited by one daughter of the originally infected cell .…”

Section: Clonal Relationships Of Different Neurotransmitter Phenotypessupporting

confidence: 87%

The Specification of Neuronal Fate: A Common Precursor for Neurotransmitter Subtypes in the Rat Cerebral Cortex In Vitro

Götz

¹

,

Williams

²

,

Bolz

³

et al. 1995

Eur J of Neuroscience

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Neurotransmitter choice is a crucial step in neural development. In the cerebral cortex, pyramidal neurons use the excitatory neurotransmitter glutamate, whereas non-pyramidal cells use the inhibitory neurotransmitter GABA. We are interested in how these two neuronal types are generated. We labelled precursor cells from embryonic rat cerebral cortex with a retroviral vector in dissociated cell cultures, and examined the neurotransmitter phenotype of their progeny immunohistochemically after 2 weeks in vitro. We discovered, first, that precursor cells in culture generate glutamatergic and GABAergic neurons in proportions similar to those in vivo. Second, we found that neuronal precursor cells gave rise to both GABAergic and glutamatergic neurons. These results suggest that neuronal precursor cells in the cerebral cortex have the potential to generate both neuronal subtypes. Moreover, these data are consistent with a stochastic model of neurotransmitter specification.

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“…According to the radial unit hypothesis, the areal location of neurons in the cortex is determined by their point of origin in the ventricular zone and therefore requires that migration from the ventricular zone to the cortical plate be predominantly radial (Rakic, 1988). A number of recent cell lineage studies using retroviral-mediated labeling or transgene expression by precursors in the ventricular zone have detected variable amounts of tangential dispersion of clonally related neurons going from a few hundred microns (Luskin et al, 1988;Price and Thurlow, 1988;Moore and Price, 1992;Luskin et al, 1993;Soriano et al, 1995) to several millimeters (Austin and Cepko, 1990;Walsh and Cepko, 1992;Reid et al, 1995). However, some of the tangential dispersion demonstrated by these lineage studies concerns migration of precursors and therefore is not at odds with a predominantly radial migration (Reid et al, 1995).…”

Section: Can Temporal and Spatial Patterns Of Histogenesis Be Inferred From Cortical Labeling In The Adult?mentioning

confidence: 99%

The timetable of laminar neurogenesis contributes to the specification of cortical areas in mouse isocortex

Polleux

¹

,

Dehay

²

,

Kennedy

³

1997

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In the primate visual cortex, the birthdate of neurons in homologous layers differ on either side of the 17-18 border suggesting that there might be different timetables of laminar histogenesis in these two areas (Dehay et al. [1993] Nature 366:464-466 and Kennedy et al. [1996] Soc. Neurosci. Abst. 22:525). Because of the potential importance of these findings for understanding mechanisms that generate areal identity, we have developed an experimental approach that makes it possible to accurately compute the timetable of laminar histogenesis from birthdating experiments. Here we report the results of an exhaustive examination of the tempo of layer production in five cortical areas of the mouse. Tritiated thymidine pulse injections were made during embryonic development and labeled neurons were examined in three frontoparietal areas (areas 3, 4, and 6) and two occipital areas (areas 17 and 18a) of the adult cortex. The correlation between the radial distribution of neurons and the intensities of labeling enabled us to reliably identify first generation neurons (i.e., those neurons that quit the cell-cycle in the first round of mitosis after injection). For each cortical layer, the percentage of first generation neurons with respect to the total number of neurons defined a laminar labeling index. Changes of the laminar labeling index over time determined the timetable of layer formation. The onset and duration of layer formation was identical in the two occipital areas. This finding contrasted with the frontoparietal areas where there were important differences in the timing of infragranular and granular layer formation and noticeably production of layers VIa, V, and IV occurs earlier in area 3 than in area 6. The timing of laminar production of areas 17 and 18a resembles more that of area 3 than that of area 6. With respect to areas 3 and 6, area 4 shows an intermediate but significantly different timetable of layer production. These marked areal differences in the timetable of laminar histogenesis contrasted with the relative homogeneity within areas so that we have been able to demonstrate that the interareal differences are not merely the expression of known neurogenic gradients. These results suggest that in the mouse frontoparietal isocortex, neighbouring regions of the ventricular zone that will give rise to distinct areas follow distinct programs of layer production. These areal differences occur before thalamic innervation and suggest an early regionalisation of laminar histogenesis.

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“…According to the radial unit hypothesis, the areal location of neurons in the cortex is determined by their point of origin in the ventricular zone and therefore requires that migration from the ventricular zone to the cortical plate be predominantly radial (Rakic, 1988). A number of recent cell lineage studies using retroviral-mediated labeling or transgene expression by precursors in the ventricular zone have detected variable amounts of tangential dispersion of clonally related neurons going from a few hundred microns (Luskin et al, 1988;Price and Thurlow, 1988;Moore and Price, 1992;Luskin et al, 1993;Soriano et al, 1995) to several millimeters (Austin and Cepko, 1990;Walsh and Cepko, 1992;Reid et al, 1995). However, some of the tangential dispersion demonstrated by these lineage studies concerns migration of precursors and therefore is not at odds with a predominantly radial migration (Reid et al, 1995).…”

Section: Can Temporal and Spatial Patterns Of Histogenesis Be Inferred From Cortical Labeling In The Adult?mentioning

confidence: 99%

The timetable of laminar neurogenesis contributes to the specification of cortical areas in mouse isocortex

Polleux¹,

Dehay²,

Kennedy³

1997

View full text Add to dashboard Cite

In the primate visual cortex, the birthdate of neurons in homologous layers differ on either side of the 17-18 border suggesting that there might be different timetables of laminar histogenesis in these two areas (Dehay et al. [1993] Nature 366:464-466 and Kennedy et al. [1996] Soc. Neurosci. Abst. 22:525). Because of the potential importance of these findings for understanding mechanisms that generate areal identity, we have developed an experimental approach that makes it possible to accurately compute the timetable of laminar histogenesis from birthdating experiments. Here we report the results of an exhaustive examination of the tempo of layer production in five cortical areas of the mouse. Tritiated thymidine pulse injections were made during embryonic development and labeled neurons were examined in three frontoparietal areas (areas 3, 4, and 6) and two occipital areas (areas 17 and 18a) of the adult cortex. The correlation between the radial distribution of neurons and the intensities of labeling enabled us to reliably identify first generation neurons (i.e., those neurons that quit the cell-cycle in the first round of mitosis after injection). For each cortical layer, the percentage of first generation neurons with respect to the total number of neurons defined a laminar labeling index. Changes of the laminar labeling index over time determined the timetable of layer formation. The onset and duration of layer formation was identical in the two occipital areas. This finding contrasted with the frontoparietal areas where there were important differences in the timing of infragranular and granular layer formation and noticeably production of layers VIa, V, and IV occurs earlier in area 3 than in area 6. The timing of laminar production of areas 17 and 18a resembles more that of area 3 than that of area 6. With respect to areas 3 and 6, area 4 shows an intermediate but significantly different timetable of layer production. These marked areal differences in the timetable of laminar histogenesis contrasted with the relative homogeneity within areas so that we have been able to demonstrate that the interareal differences are not merely the expression of known neurogenic gradients. These results suggest that in the mouse frontoparietal isocortex, neighbouring regions of the ventricular zone that will give rise to distinct areas follow distinct programs of layer production. These areal differences occur before thalamic innervation and suggest an early regionalisation of laminar histogenesis.

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The distribution of clones of neurons in the rat somatosensory cortex

Cited by 10 publications

References 30 publications

The Specification of Neuronal Fate: A Common Precursor for Neurotransmitter Subtypes in the Rat Cerebral Cortex In Vitro

The Specification of Neuronal Fate: A Common Precursor for Neurotransmitter Subtypes in the Rat Cerebral Cortex In Vitro

The timetable of laminar neurogenesis contributes to the specification of cortical areas in mouse isocortex

The timetable of laminar neurogenesis contributes to the specification of cortical areas in mouse isocortex

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