Abstract ID: A7

Abstract Title: Thalamocortical dysrrhythmia a possible objective cause of neuropathic pain diagnosed in magnetoencephalography

Poster Type: Poster

ABSTRACT BODY

Introduction:Thalamocortical Dysrhythmias (TCDs) have been defined as a set of pathophysiological syndromes which underlie instances of neurological and psychiatric disorders including Parkinson’s disease, schizophrenia, OCD, tinnitus, and neuropathic pain. TCDs are characterized by aberrant oscillations localized to symptom-specific thalamocortical modules.
Continuous neuromagnetic activity was recorded from subjects with deafferentation pain and from healthy controls. Recordings were performed with whole-head MEG (4-D Neuroimaging) in a shielded room for 5 minutes (bandpass 1-100 Hz, sample rate 508 Hz). Multi-taper spectral estimation was implemented on the MEG time series. Mean spectral energy ratios (MSE) were calculated for the high theta (7-9 Hz) and mid-alpha (9-11 Hz) ranges. Independent components (ICs) were derived from each time series using the EEGLAB Matlab package. Highly-ranked components with dipolar sensor distributions and theta-range spectral peaks were localized in a common scaled probabilistic sourcespace. A recursive weighted minimum norm algorithm was used to calculate inverse solutions for current density.
MSE values demonstrated a statistically-significant difference in theta:alpha ratios between control and deafferentation groups. In addition, theta-range ICs were localized to sensory areas which are somatotopically-relevant to perceived pain, and in one case, to limbic regions as well.
These results suggest that pain may be generated by intrinsic neuronal properties -- namely, hyperpolarization-induced deinactivation of low-threshold conductances in the thalamocortical system -- and that specific symptoms may be determined by the particular modules oscillating in this manner. Furthermore, these results illustrate the potential utility of MEG as a diagnostic measure in neuropathic pain
•Support: NIH NRSA (NS42973), NIH/NYU GCRC (RR00096).•

Materials and Methods:

Results:

Discussion:

ATTACHED FILES

Reg Anesth Pain Med 2004; 29(2):A7