# Structured population activity across developing neocortex
# Abstract
The cerebral cortex exhibits spontaneous and sensory evoked patterns of activity during fetal and postnatal development that are crucial for the activity-dependent formation and refinement of circuits. Knowing the source and flow of these activity patterns locally and globally is crucial to understanding self-organization in the developing brain. Here we describe a system for imaging patterns of activity throughout the developing neocortex at the 'mesoscopic' level of resolution in transgenic mice expressing the genetic calcium indicator GCaMP3. Ongoing activity in the neonatal cerebral cortex was characterized by discrete and repetitively active domains measuring 100s of microns in diameter. This technique offers an unprecedented ability to study functional connectivity within and between the cerebral hemispheres at a scope and scale which bridges the microscopic or macroscopic resolutions offered by traditional neurophysiology and neuroimaging (fMRI) based recordings and will provide a practical means to assess cortical connectivity with high spatial resolution in pathophysiological models for autism, epilepsy, and schizophrenia.
# Introduction
- Activity and development
- Neural activity, drugs, and birth defects
- epilepsy
- autism
- What is the activity?
- instructive or permissive?
- EEG slow oscillations not detectable until P10 in rodent.
- slice work
- leinekukel and khazipov work
- ucla konnerth imaging work
- human occipital cortex and my retinal wave paper
- is the activity completely random? Or Is it organized in space and time, and at what scale?
- the little that we know is from work in second postnatal week, not earlier, olavarria work, interneuon migration, synaptic formation, and anatomical studies indicates significant development decisions are being made in first postnatal week
