neurophysiology (ION) evolved from existing technologies in evoked potentials, electromyography (EMG), and nerve-conduction studies to give real-time information for surgeons performing procedures that may imperil nervous system structures. The usage of ION has spread over time from skull-based surgeries—monitoring acoustic nerve function with brainstem auditory evoked potentials—to the now more common usage in adult spinal surgeries.

Every surgery carries an inherent risk, however small, with central and peripheral nervous system constituents at risk from stretching, dissection of neuronal tissue, hematoma formation, compression of neural structures, and ischemia that may occur during surgical manipulation. The presumed benefit of ION, regardless of the anatomical site of interest, is that ION provides a minute by minute safety check that can help avoid damage to the nervous system [1]. The investigation of the value of ION must focus not only on the purported benefits of intraoperative monitoring but also on the costs, to provide a clearer picture of the economic arguments surrounding ION.

In vitro approaches are not appropriate for all neurophysiological studies. As the slice is removed from the network of which it is normally a part, it follows that studies of network properties are generally inappropriate for in vitro approaches. Most slice preparations preserve monosynaptic junctions well and allow for the controlled neurophysiological study of pre- and/or postsynaptic properties of the preserved synapse.