Long-term potentiation is best described as:

Long-term potentiation (LTP) is indeed characterized by an increased likelihood of action potential firing in neurons following specific patterns of synaptic activity. This phenomenon occurs when the synapses between two neurons are repeatedly stimulated, leading to a sustained increase in the strength of those synaptic connections.

In simple terms, LTP enhances the efficiency of communication between neurons, allowing for stronger and more reliable signaling. This process is crucial for various forms of learning and memory, as it reflects how experiences can lead to lasting changes in neuronal function and connectivity.

In the context of memory formation, LTP is particularly significant because it underlies the mechanisms of encoding and retaining information. The repeated activation of synapses leads to various biochemical changes within the neurons, promoting the synthesis of proteins and the formation of additional receptors that improve synaptic transmission. Therefore, the correct answer captures the essence of LTP's role in facilitating neural communication and its importance in learning processes.