Between each presynaptic and postsynaptic neuron is a that is the fluid-filled space between them. Each presynaptic neuron releases that binds with receptors in the segment of a postsynaptic neuron. The channels of the receptive segment open when these molecules bind. Specific ions then cross the membrane, initiating a potential in the postsynaptic neuron. This local potential is a small voltage change in the potential. Graded potentials that occur in postsynaptic neurons are specifically called potentials.

The correct terms or fillers are -

1. Synaptic cleft

2.Neurotransmitter

3. Postsynaptic

4. Gated

5. Graded

6. Resting membrane

7. Receptive

Explanation:

Between each presynaptic and postsynaptic neuron is a Synaptic cleft  that is the fluid-filled space between them. Each presynaptic neuron releases Neurotransmitter  that binds with receptors in the Postsynaptic  segment of a postsynaptic neuron. The Gated  channels of the receptive segment open when these molecules bind. Specific ions then cross the membrane, initiating a Graded potential in the postsynaptic neuron. This local potential is a small voltage change in the Resting membrane  potential.

Graded potentials that occur in postsynaptic neurons are specifically called  Receptive potentials.

a covalent bond, specfically triple bond