Why must subdermal needle electrodes be inserted symmetrically over homologous brain areas?

The need to insert subdermal needle electrodes symmetrically over homologous brain areas primarily relies on the intention to prevent artificial amplitude asymmetries. When electrodes are placed symmetrically, they can accurately reflect the electrical activity from corresponding regions in the brain. This alignment is crucial for a reliable comparison of data, ensuring that any recorded potential differences are due to actual physiological variations rather than discrepancies in electrode placement or recording technique.

By maintaining symmetry, the risk of introducing variations that could misrepresent the functional state of the brain is minimized. This is especially important in intraoperative monitoring, where the fidelity of the data can significantly affect clinical decision-making. Thus, symmetrical electrode placement contributes not only to the clarity of the signals being monitored but also ensures the integrity of the neurophysiological data collected during surgical procedures.