Resting-state synchrony in short-term versus long-term abstinent alcoholics

Abstract

Background: We previously reported that when compared with controls, long-term abstinent alcoholics (LTAA) have increased resting-state synchrony (RSS) of the inhibitory control network and reduced synchrony of the appetitive drive network, and hypothesized that these levels of synchrony are adaptive and support the behavioral changes required to maintain abstinence. In this study, we investigate whether these RSS patterns can be identified in short-term abstinent alcoholics (STAA).

Methods: Resting-state functional magnetic resonance imaging data were collected from 27 STAA, 23 LTAA, and 23 nonsubstance abusing controls (NSAC). We examined baseline RSS using seed-based measures.

Results: We found ordered RSS effects from NSAC to STAA and then to LTAA within both the appetitive drive and executive control networks: increasing RSS of the executive control network and decreasing RSS of the reward processing network. Finally, we found significant correlations between strength of RSS in these networks and (i) cognitive flexibility, and (ii) current antisocial behavior.

Conclusions: Findings are consistent with an adaptive progression of RSS from short- to long-term abstinence, so that, compared with normal controls, the synchrony (i) within the reward network progressively decreases, and (ii) within the executive control network progressively increases.

Figure 1

(A) Nucleus accumbens and (B) subgenual anterior cingulate cortex (ACC) seeds used to examine strength of resting state synchrony overlaid on Montreal Neurological Institute brain in neurological orientation (right is right).

Figure 2

(A) Three-dimensional MNI brain in neurological orientation with slice cut at z=22 showing region (in blue) in which LTAA showed significantly higher strength of RSS than NSAC in the NAcc network in our previous study (J. Camchong et al. 2012). (B) Bar graph showing a significant linear trend between groups in strength of RSS between NAcc and left DLPFC: intermediate in STAA (green bar) when compared to LTAA (beige bar) and NSAC (blue bar). Red lines represent significant post-hoc differences between groups. MNI, Montreal neurological institute; LTAA, long-term abstinent alcoholics; STAA, short-term abstinent alcoholics; NSAC, non-substance abusing controls; RSS, resting state synchrony; NAcc, nucleus accumbens; DLPFC, dorsolateral prefrontal cortex.

Figure 3

(A) Three-dimensional MNI brain in neurological orientation with slices cut at z=21 and z=43 showing regions (in blue) in which LTAA showed significantly higher strength of RSS between sgACC and DLPFC than NSAC in our previous study (J. Camchong et al. 2012). (B) Bar graph showing a significant linear trend between groups in strength of RSS between sgACC and right DLPFC: intermediate in STAA (green bar) when compared to LTAA (beige bar) and NSAC (blue bar). Red lines represent significant post-hoc differences between groups. MNI, Montreal neurological institute; LTAA, long-term abstinent alcoholics; STAA, short-term abstinent alcoholics; NSAC, non-substance abusing controls; RSS, resting state synchrony; sgACC, subgenual anterior cingulate cortex; DLPFC, dorsolateral prefrontal cortex.

Figure 4

(A) Three-dimensional MNI brain in neurological orientation with slices cut at z=57, z=14, z=10 showing regions (in orange) in which LTAA showed significantly lower strength of RSS with NAcc than NSAC in our previous study (J. Camchong et al. 2012). (B) Bar graphs show RSS with NAcc in STAA (green bars), LTAA (beige bars) and NSAC (blue bars). Red lines represent significant post-hoc differences between groups. MNI, Montreal neurological institute; LTAA, long-term abstinent alcoholics; NSAC, non-substance abusing controls; RSS, resting state synchrony; NAcc, nucleus accumbens; MD-thal, medial dorsal thalamus; AN-thal, anterior nucleus of the thalamus; IPL, inferior parietal lobule.

Figure 5

(A) Three-dimensional MNI brain in neurological orientation with slice cut at z=12 showing region (in orange) in which LTAA showed significantly lower strength of RSS between sgACC and bilateral anterior nucleus of the thalamus than NSAC in our previous study (J. Camchong et al. 2012). (B) Bar graph shows a significant linear trend between groups in strength of RSS between NAcc and AN-thal: intermediate in STAA (green bars) when compared to LTAA (beige bars) and NSAC (blue bars). Red lines represent significant post-hoc differences between groups. MNI, Montreal neurological institute; LTAA, long-term abstinent alcoholics; NSAC, non-substance abusing controls; RSS, resting state synchrony; ACC, anterior cingulate cortex; AN-thal, anterior nucleus of the thalamus.

Figure 6

Regression plot showing a significant positive correlation between strength of RSS in executive control regions and IED (intradimensional/extradimensional set-shift task) performance. Higher IED performance score reflects better performance (lower error rate). Individual STAA participants are represented by circles. RSS, resting state synchrony; STAA, short-term abstinent alcoholics.