|Title||Visual P2-N2 complex and arousal at the time of encoding predict the time domain characteristics of amnesia for multiple intravenous anesthetic drugs in humans.|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Pryor KO, Reinsel RA, Mehta M, Li Y, Wixted JT, Veselis RA|
|Date Published||2010 Aug|
|Keywords||Adolescent, Adult, Amnesia, Anesthetics, Intravenous, Arousal, Electroencephalography, Evoked Potentials, Visual, Female, Humans, Male, Memory, Middle Aged, Parietal Lobe, Predictive Value of Tests, Psychomotor Performance, Reaction Time, Young Adult|
BACKGROUND: Intravenous anesthetics have marked effects on memory function, even at subclinical concentrations. Fundamental questions remain in characterizing anesthetic amnesia and identifying affected system-level processes. The authors applied a mathematical model to evaluate time-domain components of anesthetic amnesia in human subjects.
METHODS: Sixty-one volunteers were randomized to receive propofol (n = 12), thiopental (n = 13), midazolam (n = 12), dexmedetomidine (n = 12), or placebo (n = 12). With drug present, subjects encoded pictures into memory using a 375-item continuous recognition task, with subsequent recognition later probed with drug absent. Memory function was sampled at up to 163 time points and modeled over the time domain using a two-parameter, first-order negative power function. The parietal event-related P2-N2 complex was derived from electroencephalography, and arousal was repeatedly sampled. Each drug was evaluated at two concentrations.
RESULTS: The negative power function consistently described the course of amnesia (mean R = 0.854), but there were marked differences between drugs in the modulation of individual components (P < 0.0001). Initial memory strength was a function of arousal (P = 0.005), whereas subsequent decay was related to the reaction time (P < 0.0001) and the P2-N2 complex (P = 0.007/0.002 for discrete components).
CONCLUSIONS: In humans, the amnesia caused by multiple intravenous anesthetic drugs is characterized by arousal-related effects on initial trace strength, and a subsequent decay predicted by attenuation of the P2-N2 complex at encoding. The authors propose that the failure of normal memory consolidation follows drug-induced disruption of interregional synchrony critical for neuronal plasticity and discuss their findings in the framework of memory systems theory.
|PubMed Central ID||PMC2910207|
|Grant List||K08 GM083213-01 / GM / NIGMS NIH HHS / United States |
K08 GM083213-04 / GM / NIGMS NIH HHS / United States
K08GM083213 / GM / NIGMS NIH HHS / United States