ABSTRACT: Previous animal and neuroimaging studies have demonstrated that brain function in heroin addicted users is impaired. However, the posterior cingulate cortex (PCC) has not received much attention. The purpose of this study was to investigate whether chronic heroin use is associated with craving-related changes in the functional connectivity of the PCC of heroin addicted users.
Fourteen male adult chronic heroin users and fifteen age and gender-matched healthy subjects participated in the present study. The participants underwent a resting-state functional magnetic resonance imaging (fMRI) scan and a cue-induced craving task fMRI scan. The activated PCC was identified in the cue-induced craving task by means of a group contrast test. Functional connectivity was analyzed based on resting-state fMRI data in order to determine the correlation between brain regions. The relationship between the connectivity of specific regions and heroin dependence was investigated.
The activation of PCC, bilateral anterior cingulate cortex, caudate, putamen, precuneus, and thalamus was significant in the heroin group compared to the healthy group in the cue-induced craving task. The detectable functional connectivity of the heroin users was stronger between the PCC and bilateral insula, bilateral dorsal striatum, right inferior parietal lobule (IPL) and right supramarginal gyrus (P < 0.001) compared to that of the healthy subjects in the resting-state data analysis. The strength of the functional connectivity, both for the PCC-insula (r = 0.60, P < 0.05) and for PCC-striatum (r = 0.58, P < 0.05), was positively correlated with the duration of heroin use.
The altered functional connectivity patterns in the PCC-insula and PCC-striatum areas may be regarded as biomarkers of brain damage severity in chronic heroin users.
Chinese medical journal 02/2013; 126(4):734-9. · 0.86 Impact Factor
ABSTRACT: Drug cues can induce craving for drugs of abuse. Dysfunctional regulation of emotion and motivation regarding rewarding objects appears to be an integral part of addiction. It has been found that cognitive strategies decreased the intensity of craving in addicts. Reappraisal strategy is a type of cognitive strategy that requires participants to reinterpret the meaning of an emotional situation. In addition, studies have found that activation of the dorsal anterior cingulate cortex (dACC) is associated with the selection and application of cognitive reappraisal. In present study, we sought to determine whether such cognitive regulation engages the dACC and improves inhibition of craving in smokers.
Sixteen smokers underwent functional magnetic resonance imaging (fMRI) during performance of a cigarette reward-conditioning procedure with cognitive reappraisal. We focused our analyses on the dACC as a key structure of cognitive control of craving. Cue induced craving under different conditions was obtained. Correlational analysis between the functional response in the dACC and the subjective craving was performed.
We found that using a cognitive reappraisal was successful in decreasing the conditioned craving. Right dACC (BA 24/32) engaged in the cognitive reappraisal. In addition, the individual's subjective craving was negatively correlated with the right dACC activation.
These findings suggest that the dACC are important substrates of Inhibition of cue induced craving in smokers. Cognitive regulation by cognitive reappraisal may help addicted individuals avoid the anticipated situations where they are exposed to conditioned cues.
PLoS ONE 01/2012; 7(8):e43598. · 4.09 Impact Factor
ABSTRACT: Previous studies with animal experiments, autopsy, structural magnetic resonance imaging (MRI) and task-related functional MRI (fMRI) have confirmed that brain functional connectivity in addicts has become impaired. The goal of this study was to investigate the alteration of resting-state functional connectivity of the ventral anterior cingulate cortex (vACC) in the heroin abusers' brain.
Fifteen heroin abusers and fifteen matched healthy volunteers were studied using vACC as the region-of interest (ROI) seed. A 3.0 T scanner with a standard head coil was the imagining apparatus. T2*-weighted gradient-echo planar imaging (GRE-EPI) was the scanning protocol. A ROI seed based correlation analysis used a SPM5 software package as the tool for all images processing.
This study showed a functional connection to the insula vACC in heroin abusers. Compared with controls, heroin users showed decreased functional connectivity between the nucleus accumbens (NAc) and vACC, between the parahippocampala gyrus/amgdala (PHC/amygdala) and vACC, between the thalamus and vACC, and between the posterior cingulated cortex/precuneus (PCC/pC) and vACC.
The altered resting-state functional connectivity to the vACC suggests the neural circuitry on which the addictive drug has an affect and reflects the dysfunction of the addictive brain.
Chinese medical journal 06/2010; 123(12):1582-8. · 0.86 Impact Factor
ABSTRACT: The breathhold contrast-enhanced three-dimensional magnetic resonance angiography (MRA) using T1-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla.
The time-of-flight protocol was based on a two-dimensional T1-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects.
Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of approximately 300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20 degrees-30 degrees. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel.
The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.
Chinese medical journal 09/2009; 122(18):2111-6. · 0.86 Impact Factor