Final answer:
Rm represents membrane resistance, and Ri represents intracellular resistance, referring to the resistance to current flow across the cell's membrane and within the cytoplasm of the neuron, respectively.
Step-by-step explanation:
In the context of neurophysiology, Rm represents membrane resistance, and Ri represents intracellular resistance. Membrane resistance (Rm) is the resistance to current flow across a cell's membrane, while intracellular resistance (Ri) is the resistance to current flow within the cytoplasm of the neuron. Ohm's law tells us that current (I) is proportional to the potential difference (V) and inversely proportional to resistance (R), as represented by the equation I = V/R. This relationship shows how both Rm and Ri can critically influence the flow of electrical current within a neuron.