CNS BOLD fMRI Effects of Sham-Controlled Transcutaneous Electrical Nerve Stimulation in the Left Outer Auditory Canal – a Pilot Study.

CNS BOLD fMRI effects of sham-controlled transcutaneous electrical nerve stimulation in the left outer auditory canal – A pilot study.

Brain Stimul. 2013 Feb 13;
Kraus T, Kiess O, Hösl K, Terekhin P, Kornhuber J, Forster C

BACKGROUND: It has recently been shown that electrical stimulation of sensory afferents within the outer auditory canal may facilitate a transcutaneous form of central nervous system stimulation. Functional magnetic resonance imaging (fMRI) blood oxygenation level dependent (BOLD) effects in limbic and temporal structures have been detected in two independent studies. In the present study, we investigated BOLD fMRI effects in response to transcutaneous electrical stimulation of two different zones in the left outer auditory canal. It is hypothesized that different central nervous system (CNS) activation patterns might help to localize and specifically stimulate auricular cutaneous vagal afferents. METHODOLOGY: 16 healthy subjects aged between 20 and 37 years were divided into two groups. 8 subjects were stimulated in the anterior wall, the other 8 persons received transcutaneous vagus nervous stimulation (tVNS) at the posterior side of their left outer auditory canal. For sham control, both groups were also stimulated in an alternating manner on their corresponding ear lobe, which is generally known to be free of cutaneous vagal innervation. Functional MR data from the cortex and brain stem level were collected and a group analysis was performed. RESULTS: In most cortical areas, BOLD changes were in the opposite direction when comparing anterior vs. posterior stimulation of the left auditory canal. The only exception was in the insular cortex, where both stimulation types evoked positive BOLD changes. Prominent decreases of the BOLD signals were detected in the parahippocampal gyrus, posterior cingulate cortex and right thalamus (pulvinar) following anterior stimulation. In subcortical areas at brain stem level, a stronger BOLD decrease as compared with sham stimulation was found in the locus coeruleus and the solitary tract only during stimulation of the anterior part of the auditory canal. CONCLUSIONS: The results of the study are in line with previous fMRI studies showing robust BOLD signal decreases in limbic structures and the brain stem during electrical stimulation of the left anterior auditory canal. BOLD signal decreases in the area of the nuclei of the vagus nerve may indicate an effective stimulation of vagal afferences. In contrast, stimulation at the posterior wall seems to lead to unspecific changes of the BOLD signal within the solitary tract, which is a key relay station of vagal neurotransmission. The results of the study show promise for a specific novel method of cranial nerve stimulation and provide a basis for further developments and applications of non-invasive transcutaneous vagus stimulation in psychiatric patients. HubMed – addiction


The multiple facets of opioid receptor function: implications for addiction.

Curr Opin Neurobiol. 2013 Feb 28;
Lutz PE, Kieffer BL

Addiction is characterized by altered reward processing, disrupted emotional responses and poor decision-making. Beyond a central role in drug reward, increasing evidence indicate that opioid receptors are broadly involved in all these processes. Recent studies establish the mu opioid receptor as a main player in social reward, which attracts increasing attention in psychiatric research. There is growing interest in blocking the kappa opioid receptor to prevent relapse, and alleviate the negative affect of withdrawal. The delta opioid receptor emerges as a potent mood enhancer, whose involvement in addiction is less clear. All three opioid receptors are likely implicated in addiction-depression comorbidity, and understanding of their roles in cognitive deficits associated to drug abuse is only beginning. HubMed – addiction


Comparing statistical methods for analyzing skewed longitudinal count data with many zeros: An example of smoking cessation.

J Subst Abuse Treat. 2013 Feb 27;
Xie H, Tao J, McHugo GJ, Drake RE

Count data with skewness and many zeros are common in substance abuse and addiction research. Zero-adjusting models, especially zero-inflated models, have become increasingly popular in analyzing this type of data. This paper reviews and compares five mixed-effects Poisson family models commonly used to analyze count data with a high proportion of zeros by analyzing a longitudinal outcome: number of smoking quit attempts from the New Hampshire Dual Disorders Study. The findings of our study indicated that count data with many zeros do not necessarily require zero-inflated or other zero-adjusting models. For rare event counts or count data with small means, a simpler model such as the negative binomial model may provide a better fit. HubMed – addiction


Rewarding early abstinence in Veterans Health Administration addiction clinics.

J Subst Abuse Treat. 2013 Feb 27;
Hagedorn HJ, Noorbaloochi S, Simon AB, Bangerter A, Stitzer ML, Stetler CB, Kivlahan D

This study investigates the addition of a contingency management (CM) intervention to Veterans Health Administration substance use disorders treatment on during- and post-treatment outcomes for Veterans diagnosed with alcohol dependence only (n=191) or stimulant dependence (n=139). Participants were randomly assigned to 8weeks of usual care or usual care plus CM. Follow-up assessments occurred at 2, 6 and 12months. In the alcohol dependent subgroup, CM participants submitted significantly more negative samples (13 versus 11 samples, Cohen’s d=0.54), were retained significantly longer (7 versus 6weeks, d=0.47), achieved significantly longer median durations of abstinence (16 versus 9 consecutive visits; median difference=7, 95% CI=4-8), and submitted significantly more negative samples at follow-ups (unstandardized effect size=0.669, se=0.2483) compared to usual care participants. Intervention effects were non-significant for the stimulant dependent subgroup. The study provides support for the effectiveness of CM interventions for alcohol dependent patients. HubMed – addiction