What happens in the postsynaptic neuron when excitatory neurotransmitters bind to receptors?

it causes the depolarization of the target cell

Explanation:

Glutamate is an excitatory amino acid neurotransmitter that binds to specific receptors on the surface of target cells and thus causes its depolarization. During glutamate-mediated depolarization, the difference in charge inside and outside the cell is lost due to the entry of sodium and calcium positive ions into the postsynaptic cell (neuron) through specific ion channels. Moreover, glutamate binding also leads to the exit of potassium ions from the cell, thereby resulting in excitation. Through this mechanism, glutamate regulates many signaling pathways, such as those involved in memory, learning, emotions, cognition, motor control, etc.

i think this picture will you.