The median nerve N20 and P22 SEP components constitute the initial response of the primary somatosensory cortex to somatosensory stimulation of the upper extremity. Knowledge of the underlying generators is important both for basic understanding of the initial sequence of cortical activation and to identify landmarks for eloquent areas to spare in resection planning of cortex in epilepsy surger...

OBJECTIVE The somatosensory evoked potential (SEP) elicited by median nerve stimulation consists of the N20 peak together with the concurrent high frequency oscillation (HFO, > 500 Hz). We describe the conditions for HFO detection in ECoG and scalp EEG in intraoperative recordings. METHODS During neurosurgical interventions in six patients under propofol anesthesia, the SEP was recorded from ...

The Geophysical Fluid Dynamics Laboratory (GFDL) three-dimensional general circulation/tracer model has been used to investigate the stratospheric behavior of N20 under a range of photodestruction hypotheses. A comparison of observations with these simulations shows that the atmospheric N20 lifetime lies between 100 and 130 years. For the three experiments conducted, it was found that the model...

We have studied the effect of i.v. midazolam on median nerve somatosensory evoked potentials (SSEP) in 10 unpremedicated adults. Anaesthesia was induced with midazolam by bolus administration (0.2 mg kg-1) followed by infusion (5 mg h-1). The latency and amplitudes of the SSEP responses over the second cervical vertebrae (SC2) and sensory cortex (P17, N20, P25) were recorded before and for 10 m...

BACKGROUND The bilateral absence of the cortical N20 median-nerve somatosensory evoked potential (SSEP) is a strong predictor of poor outcome from coma. However, when N20s are present, accurate prognostication is challenging. Here, we investigated the potential for later SSEP components to help disambiguate outcome in these cases. METHODS In a retrospective review of data from two intensive c...

30 31 Objective: The median nerve N20 and P22 SEP components constitute the initial 32 response of the primary somatosensory cortex to somatosensory stimulation of the 33 upper extremity. Knowledge of the underlying generators is important both for basic 34 understanding of the initial sequence of cortical activation and to identify landmarks 35 for eloquent areas to spare in resection planning...

The neurophysiological mechanism of interhemispheric inhibition (IHI) between the human primary sensory cortices (S1s) is poorly understood. Here we used a paired median nerve somatosensory evoked potential protocol to observe S1-S1 IHI from the dominant to the nondominant hemisphere with electroencephalography. In 10 healthy, right-handed individuals, we compared mean peak-to-peak amplitudes o...

C ischemia after cardiac arrest is one of the most common causes of coma in the United States. At one year after hypoxic-ischemic coma, 53% died, 32% remain in persistent vegetative state (PVS) and only 32% have displayed some evidence of cognition.1 The search for a reliable method to confidently predict outcome post cardiac arrest is crucial for early decisions surrounding continued life supp...