Very Fast Oscillations Evoked by Median Nerve Stimulation in the Human Thalamus and Subthalamic Nucleus

Abstract

Dostrovsky. Very fast oscillations evoked by median nerve stimulation in the human thalamus and subthalamic nucleus. J Neurophysiol 92: 3171-3182, 2004. First published May 19, 2004 doi:10.1152/ jn.00363.2004. Very fast oscillations (VFOs; 500 -1,500 Hz) are associated with sensory-evoked potentials (SEPs), but their origin is unknown. To characterize the origins of VFOs, we studied 35 patients with deep brain stimulation (DBS) electrodes [15 with thalamic and 20 with the subthalamic nucleus (STN) electrodes]. We recorded median nerve stimulation-evoked SEPs from the thalamus and STN with microelectrodes during stereotactic surgery and from the contacts of the DBS electrodes postoperatively. We also examined the firing of individual neurons in thalamus in relation to the VFOs. In the thalamus, VFOs with frequencies around 1,000 Hz were superimposed on slow potentials. Both slow and fast SEP components showed phase reversals in the somatosensory thalamus [ventralis caudalis (Vc)]. Median nerve poststimulus time histograms showed that single thalamic neurons fired at preferred times at intervals between 0.8 to 1.2 ms that were synchronous with the VFOs, although the neurons fired only once or a few times per trial. In the STN, low-amplitude SEPs with VFOs were observed at a latency similar to the thalamic SEPs. The VFOs from STN probably represent volume conduction, possibly from the medial lemniscus. We conclude that the thalamic VFOs are generated within Vc and that they induce time-locked firing in a network of neurons.

Dorsolateral subthalamic neuronal activity enhanced by median nerve stimulation characterizes Parkinson’s disease during deep brain stimulation with general anesthesia

“…However, sensory input, such as MNS, has been shown to modulate the firing characteristics of the STN and induce very fast oscillations. 7 Sensory stimulation could change motor cortex excitability, and a sensory-conditioned stimulus such as MNS could inhibit the motor cortex, which may indirectly lead to the increased oscillation of STN neurons. 21 Additionally, MNS has been used as a reliable tool to identify basal ganglia structures from SSEP recordings and has been even more widely applied toward neural firing characterization and elucidation of the mechanisms of neural oscillation.…”

“…Nonetheless, our observation that the PSD of beta-band firing-which has been evaluated further during dorsolateral STN analysis-was remarkably augmented during MNS suggests that MNS can also enhance low-frequency oscillation in addition to ultra-fastfrequency oscillation, and facilitate single-unit recording of STN neurons during general anesthesia. 7 Although we can achieve recording of the STN under general anesthesia, we did encounter several difficulties that may explain why the mean firing rate was lower under desflurane general anesthesia. First, prolonged surgical duration may cause an accumulation of anesthetic concentration.…”

Subcortical Interactions Between Somatosensory Stimuli of Different Modalities and Their Temporal Profile

“…For a better measurement of latency and amplitude of thalamic SEPs, we used a frequency band-pass of 5 to 500 Hz, intended to cut off most of the high-frequency oscillations (HFOs) recently described in thalamic recordings (Hanajima et al 2004b;Klostermann et al 1999Klostermann et al , 2000Klostermann et al , 2002a. In three subjects, we also evaluated changes in HFOs by measuring the number of reproducible negative peaks in recordings in which the high-frequency cutoff was increased to 5,000 Hz.…”

“…Both low-and highfrequency components reflect locally restricted near-field activity (Hanajima et al 2004b(Hanajima et al , 2006Klostermann et al 2002b), probably generated in local neuronal firing within somatosensory relay thalamic nuclei. The function of the HFOs may be to synchronize and perhaps prolong important inputs, thus increasing the signal-to-noise ratio (Hanajima et al 2004b).…”

Human Central Nervous System Circuits Examined in Patients with Parkinson's Disease Using the Electrodes Implanted for Deep Brain Stimulation

“…The latter were characterized by Hanajima et al (2004a), who identified them with intrathalamic neuronal firing at intervals between 0.8 and 1.2 ms (a frequency of about 1000 Hz) and found the site of phase reversal at about the nucleus ventralis caudalis. The same authors (Hanajima et al, 2004b) recorded from the thalamic electrode a large somatosensory EP with a mean latency of 17.9+/-1.7 ms, which had a phase reversal at the level of the inter-commissural line.…”