Spindle Bursts in Neonatal Rat Cerebral Cortex

Abstract

Spontaneous and sensory evoked spindle bursts represent a functional hallmark of the developing cerebral cortex in vitro and in vivo. They have been observed in various neocortical areas of numerous species, including newborn rodents and preterm human infants. Spindle bursts are generated in complex neocortical-subcortical circuits involving in many cases the participation of motor brain regions. Together with early gamma oscillations, spindle bursts synchronize the activity of a local neuronal network organized in a cortical column. Disturbances in spindle burst activity during corticogenesis may contribute to disorders in cortical architecture and in the activity-dependent control of programmed cell death. In this review we discuss (i) the functional properties of spindle bursts, (ii) the mechanisms underlying their generation, (iii) the synchronous patterns and cortical networks associated with spindle bursts, and (iv) the physiological and pathophysiological role of spindle bursts during early cortical development.

Sensory input drives rapid homeostatic scaling of the axon initial segment in mouse barrel cortex

“…At the network level, early spontaneous whisker deflections as well as passive stimulation by the mother and littermates trigger cortical bursts (Akhmetshina et al, 2016). These synchronous and spatially confined spindle bursts persist during the early postnatal period (Khazipov et al, 2004;Yang et al, 2016) and begin to wear off from P3 onwards (McCabe et al, 2007).…”

Early patterns of activity in the developing cortex: Focus on the sensorimotor system

“…The first organized activity patterns, notably delta waves and delta-brushes in human preterm neonates, and homologues delta waves and spindle/gamma-bursts in rodents are expressed during the period of the most intense period of neuronal growth and synaptogenesis, the so-called "brain spurt" occurring during the second half of gestation in humans and during the postnatal period (from the postnatal days P0 to P10) in rodents. There are several reviews describing the features of the early cortical activity patterns and their developmental roles in the activity-dependent wiring of cortical neuronal networks including circuit development [1,2], network mechanisms and synaptic plasticity [3][4][5][6][7][8][9][10][11][12][13][14][15], methodological aspects of recording early brain activity [16][17][18][19], development in the state-dependence of the brain activity [20,21] and emergence of consciousness [22]. This review focuses on the most recent advance in the mechanisms underlying the early activity patterns obtained in the developing sensorimotor system of rodents and on the relevance of these findings to human fetal development.…”

Active Sleep Promotes Functional Connectivity in Developing Sensorimotor Networks

“…Early oscillatory activity in vivo has been most extensively – but not exclusively – described in the cortex and hippocampus . In these forebrain structures, fragmented oscillatory activity is thought to assist in the development of local neuronal networks, with effects on synapse formation, neuronal differentiation and migration, programmed cell death (apoptosis), and formation and refinement of topographic maps …”

“…For example, in the newborn rat sensorimotor cortex, twitch‐related reafference triggers spindle bursts . Spindle bursts are thought to contribute to the anatomical and functional development of the cortex . Although spindle bursts can be generated endogenously, their occurrence decreases threefold (i.e., only ≈30% of spindles remain) in the absence of peripheral sensory input .…”