**Core Concept**
Synaptic potentials refer to the transient changes in the membrane potential of a neuron that occur due to the flow of ions across the cell membrane at a synapse. These potentials are crucial for the transmission of signals between neurons.

**Why the Correct Answer is Right**
The correct answer involves the use of a technique called **intracellular recording**, which allows for the direct measurement of the electrical activity within a neuron. This is typically achieved using a glass microelectrode that is inserted into the cell, allowing for the recording of the electrical potential changes that occur at the synapse. The most commonly used method for intracellular recording is **sharp electrode recording**.

**Why Each Wrong Option is Incorrect**
**Option A:** Extracellular recording involves measuring the electrical activity outside of the cell, which is not sufficient for detecting synaptic potentials. This method is often used for **field potential** recordings, which can detect changes in the electrical activity of a group of cells.
**Option B:** Electromyography (EMG) is a technique used to measure the electrical activity of muscles, which is not relevant to synaptic potentials.
**Option C:** Electroencephalography (EEG) measures the electrical activity of the brain, but it is not sensitive enough to detect synaptic potentials at the level of individual neurons.

**Clinical Pearl / High-Yield Fact**
Intracellular recording is a critical technique in neuroscience research, allowing for the detailed study of synaptic transmission and the underlying mechanisms of neurological disorders.

**Correct Answer: D. Intracellular recording using a sharp electrode.**