Picrotoxin-Induced Epileptogenic Hippocampal Organotypic Slice Cultures (hOTCs).

Cultured organotypic hippocampal slices (hOTCs) have become increasingly popular as a model for studying brain function. This model offers significant advantages over traditional in vitro methods, as they allow the examination of mid to long-term manipulations while preserving the structure of the dentate gyrus (DG) in the hippocampus. In this chapter, we focus on a protocol based on hOTCs of mouse entorhinal cortex and hippocampus, which by integrating techniques such as retroviral injections, immunohistochemistry, and microscopy imaging, physiological or pathological processes can be easily investigated.

Evolutionary convergence of sensory circuits in the pallium of amniotes.

The amniote pallium contains sensory circuits that are structurally and functionally equivalent, yet their evolutionary relationship remains unresolved. We used birthdating analysis, single-cell RNA and spatial transcriptomics, and mathematical modeling to compare the development and evolution of known pallial circuits across birds (chick), lizards (gecko), and mammals (mouse). We reveal that neurons within these circuits' stations are generated at varying developmental times and brain regions across species and found an early developmental divergence in the transcriptomic progression of glutamatergic neurons.

HB-EGF activates EGFR to induce reactive neural stem cells in the mouse hippocampus after seizures.

Hippocampal seizures mimicking mesial temporal lobe epilepsy cause a profound disruption of the adult neurogenic niche in mice. Seizures provoke neural stem cells to switch to a reactive phenotype (reactive neural stem cells, React-NSCs) characterized by multibranched hypertrophic morphology, massive activation to enter mitosis, symmetric division, and final differentiation into reactive astrocytes. As a result, neurogenesis is chronically impaired.

Does the plasticity of neural stem cells and neurogenesis make them biosensors of disease and damage?

Postnatal and adult neurogenesis takes place in the dentate gyrus of the hippocampus in the vast majority of mammals due to the persistence of a population of neural stem cells (NSCs) that also generate astrocytes and more NSCs. These are highly plastic and dynamic phenomena that undergo continuous modifications in response to the changes brain homeostasis. The properties of NSCs as well as the process of neurogenesis and gliogenesis, are reshaped divergently by changes in neuronal activity and by different types of disease and damage.