Nerve and muscle control
Variability in motor control is largely provided by systems that modulate the output of motor circuits by adjusting the properties of their neurons. One neuromodulatory system which controls movement is the C bouton system. Using acetylcholine to send its messages, termed cholinergic, C boutons are derived from a small cluster of spinal interneurons known as ventral horn interneuron (V0C). This subset of interneurons fine-tune motor neuron firing and muscle activation according to the task being undertaken. If acetylcholine output is reduced for genetic reasons, for example, then the ability to increase muscle activation is lost, but only partially. As this suggests some compensatory mechanism, the 'Modulating motor output in the mammalian spinal cord' (MODULATIONSPINALCORD) project set up a virus-based system to manipulate the V0C activity using light. The researchers then examined the impact on movement following inactivation or forced activation. Recent research has indicated that the cocaine amphetamine regulated transcript (Cart) neurotransmitter is present in the cell bodies and terminals of V0C neurons. Using confocal microscopy and Volocity software, the project researchers confirmed Cart presence in presynaptic spaces. The researchers are considering the glutamergic ventral interneurons (V0G) as another potential modulator that works in conjunction with V0C. Work already completed has shown that V0C form synapses (junctions) with V0G cell bodies and vice versa. The team is currently analysing the effects of V0G inactivation on movement. MODULATIONSPINALCORD results will be used to obtain new insight about the function and operation of these nerve networks. The research can be extended to control of neuronal circuits in other regions of the central nervous system.
Keywords
Motor, nervous system, neurons, neuromodulatory, C bouton, ventral horn interneuron, muscle, Volocity software, glutamergic, cell bodies
