A complete biomechanical model of contractile behaviors, from neural drive to muscle to movement.

How does neural activity drive muscles to produce behavior? The recent development of genetic lines in that allow complete calcium imaging of both neuronal and muscle activity, as well as systematic machine learning quantification of behaviors, makes this small cnidarian an ideal model system to understand and model the complete transformation from neural firing to body movements. To achieve this, we have built a neuromechanical model of 's fluid-filled hydrostatic skeleton, showing how drive by neuronal activity activates distinct patterns of muscle activity and body column biomechanics. Our model is based on experimental measurements of neuronal and muscle activity and assumes gap junctional coupling among muscle cells and calcium-dependent force generation by muscles.

Regulation of Spontaneous Propagating Waves in the Embryonic Mouse Brainstem.

Spontaneous activity (SA) modulates many aspects of neural development, including neuronal phenotype, axon path-finding and synaptic connectivity. In the embryonic mouse brainstem, SA initially is recorded in isolated cells at embryonic day (E) 9.5, and 48 h later takes the form of propagating waves.

Looping circuit: a novel mechanism for prolonged spontaneous [Ca2+]i increases in developing embryonic mouse brainstem.

Most cells maintain [Ca(2+)]i at extremely low levels; calcium entry usually occurs briefly, and within seconds it is cleared. However, at embryonic day 12.5 in the mouse brainstem, trains of spontaneous events occur with [Ca(2+)]i staying close to peak value, well above baseline, for minutes; we termed this 'bash bursts'.

Hyperpolarization of resting membrane potential causes retraction of spontaneous Ca(i)²⁺ transients during mouse embryonic circuit development.

Abstract  Spontaneous activity supports developmental processes in many brain regions during embryogenesis, and the spatial extent and frequency of the spontaneous activity are tightly regulated by stage. In the developing mouse hindbrain, spontaneous activity propagates widely and the waves can cover the entire hindbrain at E11.5.

Na(V)1.1 channels are critical for intercellular communication in the suprachiasmatic nucleus and for normal circadian rhythms.

Na(V)1.1 is the primary voltage-gated Na(+) channel in several classes of GABAergic interneurons, and its reduced activity leads to reduced excitability and decreased GABAergic tone. Here, we show that Na(V)1.

Timing and mechanism of a window of spontaneous activity in embryonic mouse hindbrain development.

Spontaneous activity (SA) in the developing vertebrate brain is required for correct wiring of circuits and networks. In almost every brain region studied to date, SA is recorded during a period of synaptogenesis, and may deploy ionic mechanism(s) that are not expressed in the adult structure. Eventually the conditions in the immature neurons that allow SA are replaced with ion channels found in the mature neuron; this replacement may itself require SA.

Differential expression of membrane conductances underlies spontaneous event initiation by rostral midline neurons in the embryonic mouse hindbrain.

Spontaneous activity is expressed in many developing CNS structures and is crucial in correct network development. Previous work using [Ca(2+)](i) imaging showed that in the embryonic mouse hindbrain spontaneous activity is initiated by a driver population, the serotonergic neurons of the nascent raphe. Serotonergic neurons derived from former rhombomere 2 drive 90% of all hindbrain events at E11.

Spontaneous activity in the developing mouse midbrain driven by an external pacemaker.

Central nervous system (CNS) development depends upon spontaneous activity (SA) to establish networks. We have discovered that the mouse midbrain has SA expressed most robustly at embryonic day (E) 12.5.

Properties and mechanisms of spontaneous activity in the embryonic chick hindbrain.

Spontaneous activity regulates many aspects of central nervous system development. We demonstrate that in the embryonic chick hindbrain, spontaneous activity is expressed between embryonic days (E) 6-9. Over this period the frequency of activity decreases significantly, although the events maintain a consistent rhythm on the timescale of minutes.

Ion channel development, spontaneous activity, and activity-dependent development in nerve and muscle cells.

At specific stages of development, nerve and muscle cells generate spontaneous electrical activity that is required for normal maturation of intrinsic excitability and synaptic connectivity. The patterns of this spontaneous activity are not simply immature versions of the mature activity, but rather are highly specialized to initiate and control many aspects of neuronal development. The configuration of voltage- and ligand-gated ion channels that are expressed early in development regulate the timing and waveform of this activity.

Midline serotonergic neurones contribute to widespread synchronized activity in embryonic mouse hindbrain.

Spontaneous, synchronous activity occurs in motor neurones of the embryonic mouse hindbrain at the stage when rhombomeric segmentation disappears (embryonic day 11.5). The mechanisms generating and synchronizing the activity, however, and the extent to which it is widespread in the hindbrain, are unknown.

Spontaneous, synchronous electrical activity in neonatal mouse cortical neurones.

Spontaneous [Ca2+]i transients were measured in the mouse neocortex from embryonic day 16 (E16) to postnatal day 6 (P6). On the day of birth (P0), cortical neurones generated widespread, highly synchronous [Ca2+]i transients over large areas. On average, 52% of neurones participated in these transients, and in 20% of slices, an average of 80% participated.