Use the mouse to move click and drag neurons and synapses. Placing the mouse over the neuron body will reveal two arrows; clicking the up arrow increases the neuron's firing threshold, while pressing the down arrow decreases this threshold. This firing threshold is represented by the number in the center of the neuron. Right clicking and dragging while over the neuron body creates a new synapse. Entire neurons or single synapses can be removed by dragging them to the trash.