Aim: -Investigate relationship between Chronic Heroine use & effects on the Posterior Cingulate Cortex (PCC). Wanted to see if Heroine changes brain functions. Look at brain damage compare to control group.
Sample: 14 Heroin addicts matched to 15 controls, aged 35, from drug rehabilitation in China. Been using Heroin for 89 months. All physically and mentally clear.
Procedure: Lab experiment using MRI looking at blood flow & neurological activity.
All Participants tested for opiate use, were clear of all drugs but nicotine & were able to spend 40 mins in FMRI.
Resting state scanned, having to focus attention on a target for 5 minutes.
Immediately after was a cue-induced experiment, after 10 seconds participants exposed 24 pictures of drug related activity & 24 neutral. Each 2 seconds long
Between each picture an inter-stimulus interval shown 4-12 seconds. & Data compared over the 2 conditions.
Analysis look for differences in brain connection in control & heroin users.
Results: Cue related: Heroin addicts craved drug during cue-stimulating pictures, MRI showed heroine cue tasks have S.D on activation areas in Posterior Cingulate Cortex & regions associated with reward pathway of heroine.
Heroin users had higher activity and connectivity between posterior cingulate cortex & other areas while controls did not have connectivity/links of PCC with same extent.
Resting State: Addicts have higher connectivity between PCC and other areas (Bilateral Insula & Bilateral dorsal stratium) while controls had no connectivity/links of PCC.
Positive correlation between connectivity of region & length of time on heroin.
Conclusion: During cue tasks associated with rewards system, the Posterior Cingulate Cortex is more active and affects the limbic pathway linked to reward & craving which strongly related to Heroin explaining why addicts relapse due to drug stimulus.
Chronic Heroin addicts have connections between areas for reward & addiction linked to dependency.
| Strength | Weaknesses |
| Validity – can’t control their regions of brain during the FMRI scan e.g when PCC activated – no chance of socially desirable characteristics. Natural behave
Application – connectivity in heroin users have changed links created in dependency & reward pathway established with drug use – bio therapies needed to cure drug addiction. Ethical – FMRI scans are non-invasive & easy to perform & convenient for both researchers & ppts- no ppts suffered physical harm. Reliable – use of FMRI scans to see links of dependency & reward pathway by use of heroin – produce objective data which can be replicated |
Generalisability – small male only sample of 14 heroin addicts to 15 controls – sample limits study as can only generalise to this sample
Internal validity – scanning during cue related task taking place it would involve a lot of other thoughts – individual differences lead to looking at confounding variables. Ecological validity – took place at a uni which can be unnatural to heroin addicts – result in unnatural behaviour & thinking patterns reflected in FMRI Task Validity – looking at random images, including heroin related paraphernalia is not an everyday task – lacks mundane realism as unnatural for ppt |