Laminar specific alterations of thalamocortical projections in organotypic cultures following layer 4 disruption in ferret somatosensory cortex

  title={Laminar specific alterations of thalamocortical projections in organotypic cultures following layer 4 disruption in ferret somatosensory cortex},
  author={Sidney L. Palmer and Stephen C. Noctor and Beata Jabłońska and Sharon L. Juliano},
  journal={European Journal of Neuroscience},
The developing neocortex influences the growth of thalamocortical projections. Layer 4 in particular receives the majority of input from the thalamus and is important in instructing thalamic afferents to terminate. Previous in vivo experiments demonstrated that disruption of layer 4 during corticogenesis in ferret somatosensory cortex by application of methylazoxy methanol acetate (MAM) prevents proper termination of thalamic afferents in appropriate cortical regions. To further explore the… 

Disruption of layer 4 development alters laminar processing in ferret somatosensory cortex.

It is concluded that normal thalamic terminations, an intact layer 4 and subsequent intracortical processing are integral to proper encoding of stimulus features.

Alteration of interneuron migration in a ferret model of cortical dysplasia.

It is reported that GABA(A) receptor activation is crucial to the proper positioning of interneurons migrating into the cortex from the GE in normal and MAM-treated animals.

GABAA receptors reorganize when layer 4 in ferret somatosensory cortex is disrupted by methylazoxymethanol (MAM).

The redistribution of inhibitory receptors suggests that layer 4 plays an important role in regulating thalamic terminations and also in the resulting ability to refine processing of incoming stimuli.

N-Cadherin Regulates Ingrowth and Laminar Targeting of Thalamocortical Axons

Data indicate that N-cadherin has multifaceted roles in establishing the thalamocortical projection, governing aspects of both thalamic axon ingrowth and laminar targeting by acting as a layer IV stop signal, which progressively change in parallel with the maturational state of the cortex.

Targeted disruption of layer 4 during development increases GABAA receptor neurotransmission in the neocortex.

It is demonstrated that small amounts of toxins delivered during corticogenesis can result in long-lasting changes in ambient expression of GABAAR that influence intrinsic neuronal properties.

Altered migratory behavior of interneurons in a model of cortical dysplasia: the influence of elevated GABAA activity.

A model of cortical dysplasia in ferrets involving administration of methylaxozymethanol acetate to pregnant ferrets on gestational day 33, leading to dramatic reduction of layer 4 in the neocortex is developed and a direct correlation between increased GABAA and KCC2 expression with impaired migration and ability to explore the environment is shown.

Influence of radial glia and Cajal-Retzius cells in neuronal migration.

It is suggested that early interruption of cell division eliminates a population of cells and a factor important for maintaining proper cortical development, specifically providing cues maintaining elongation of radial glia.

Afferent influences on striatal development in organotypic cocultures

The importance of afferent innervation in the maturation of striatal neurons in organotypic cultures is demonstrated, as well as the importance of spontaneous and cortically evoked activity in striatal medium spiny neurons.



Disruption of Layers 3 and 4 during Development Results in Altered Thalamocortical Projections in Ferret Somatosensory Cortex

The findings emphasize the importance of layer 4 in determining the normal laminar pattern of thalamic termination and suggest that, although its absence is likely to impact on complex neocortical functional responses, topographic organization does not arise from the influence oflayer 4.

Development of local connections in ferret somatosensory cortex

This study of the development of the somatosensory cortex confirms the ubiquitous nature of column‐like connections throughout the neocortex and provides a novel view of the radial nature of early neocortical maturation.

Formation of specific afferent connections in organotypic slice cultures from rat visual cortex cocultured with lateral geniculate nucleus

The results suggest that thalamic projection neurons have an innate mechanism that allows them to recognize their cortical target cells and play a significant role in the laminar specification of cortical connections during development.

Guidance of thalamocortical innervation.

The proposed sequence of individually simple mechanisms influences the pattern of thalamocortical innervation, which itself contributes to the determination of regional differentiation of the neocortex, suggesting that the topographic distribution of thalamic fibres in vivo does not depend on regional chemospecificity.

Mechanisms Underlying the Early Establishment of Thalamocortical Connections in the Rat

Results indicate that the topography of thalamic axons is maintained throughout the pathway and that they reach the cortex by associating with the projections of a number of preexisting cells, including the preplate scaffold.

Development of Signals Influencing the Growth and Termination of Thalamocortical Axons in Organotypic Culture

The sequence of expression of these signals suggests that they play a part in vivo in controlling the outgrowth of thalamic fibers, their accumulation under the cortical plate, their invasion of the plate, and their arborization in layer 4.

Interference with the development of early generated neocortex results in disruption of radial glia and abnormal formation of neocortical layers.

It is demonstrated that if early development of the neocortex is interrupted by injection of MAM during embryogenesis, a distinct laminar pattern fails to form properly in the parietal cortex and is consistent with the idea that early generated layers are important in providing factors that maintain the environment necessary for subsequent neuronal migration and formation of neocortical layers.

Lack of regional specificity for connections formed between thalamus and cortex in coculture

The possibility that each cortical area exerts a selective trophic influence on axons from its appropriate thalamic nucleus, and vice versa, is tested by coculturing explants of different regions of the thalamus and cortex taken at various stages of development.

The relationship between the geniculocortical afferents and their cortical target cells during development of the cat's primary visual cortex

  • C. ShatzM. Luskin
  • Biology
    The Journal of neuroscience : the official journal of the Society for Neuroscience
  • 1986
The prenatal development of connections between the lateral geniculate nucleus (LGN) and the primary visual cortex in the cat and the tritiated thymidine method indicates that by E57 the majority of cells destined to belong to layer 4 have already completed their migrations and assumed positions superficial to the cells of layers 5 and 6.

Formation of target-specific neuronal projections in organotypic slice cultures from rat visual cortex

It is shown that specific connections are established in an organotypic culture system in which rat visual cortex slices are co-cultured with another slice of the visual cortex or with a thalamic slice, raising the possibility that chemotropic attraction from the target areas may play an important part in the development of the cortical projection pattern.