Abstract Details

Title Effects of Opioids on Intracranial EEG- Frequency distribution and Phase coupling in various brain regions

Topic Pain

Presentation(s) Pain and Palliative Care Posters (7:00 AM-5:00 PM)

Poster/Presentation
Number 001

Background Neural activity patterns related to opioid effects and drug addiction have traditionally been investigated in humans using non-invasive technologies like MEG, EEG, PET, and fMRI. Intracranial electrode data allow the observation of neurophysiological data at a finer spatial scale, on par with animal studies; single unit activity and local field potentials can be detected.

Objective

We sought to examine if opioid drug administration affects rhythmic activity differently in various brain regions.

Design/Methods

We performed retrospective analysis of already collected iEEG data from adult epileptic patients requiring monitoring with bilateral depth electrodes and receiving opioid analgesics to control postoperative pain.

We examined changes in power before and after opioid drug administration in the following bands: delta (1-3 Hz), theta (4-7 Hz), alpha (8-13 Hz), beta (14-30 Hz), Gamma (31-80 Hz), ripples (81-200 Hz) and fast ripples (201-500 HZ). We also examined interactions within and between areas using standard measures such as coherence. A total of 4 patients were included in the study approved by the local IRB.

Results We observed clear changes in spectral content after opioid drug administration. We observed significant and striking increases in theta and alpha band power in limbic structures. In contrast, neocortical leads showed a greater change in higher frequency activity after opioid administration—for example, gamma power decreased. We examined the coherence in these bands, and though the results were variable, we saw significant coherence changes after drug administration in the alpha band.

Conclusions Opioid administration decreases high frequency activity in neocortical structures while increasing lower frequency activity in limbic structures. Our preliminary analysis suggests there are interaction changes (e.g., coherence and cross-frequency coupling) within structures and subregions (e.g., interactions within the amygdala or amygdala-hippocampal interactions). Our ongoing analysis will allow us to elucidate the dynamics and regions critical to commonly used opioid drugs (oxycodone, hydrocodone).

Authors/Disclosures
Aashit K. Shah, MD, FAAN (Carilion Clinic) PRESENTER	The institution of Dr. Shah has received research support from Eisai pharma .
	No disclosure on file
Mark Witcher (VaTech/Carilion Division of Neurosurgery)	No disclosure on file
Chinekwu Anyanwu, MD (Carilion Clinic)	Dr. Anyanwu has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Liva Nova.
	No disclosure on file
Aashit K. Shah, MD, FAAN (Carilion Clinic)	The institution of Dr. Shah has received research support from Eisai pharma .