Contemporary Study: Li et al. (2013) “Abnormal Brain Function in Heroin Users”: Flashcards
What is the PCC?
Part of default mode network. More active when individual not involved in task. PCC stimulated daydreaming. Balanced internally and externally focused attention.
What is the Aim of Li et al?
To investigate if the PCC is active when given drug related cues. To investigate if PCC activation is stronger in Heroin addiction compared to controls, suggesting possible brain damage.
Who were the sample of Li et al?
Experimental group: 14 male Heroin users, drug rehabiliation centre, mean age 35, previously used Heroin but had to be Heroin free.
Control group: 15 males macthed to experimental group, hanedness, education level, age.
All ppts were smokers. No head trauma, disorder, gave written consent.
What was the Procedure of Li et al?
fMRI scan. Scan 1: Structural Scan. Scan 2: 5 min resting fMRI scan focusing on cross hair. Scan 3: fMRI lasted 490 seconds were 48 pictures, half neutral, and rest related to Heroin. Each was presented for 2 seconds with an interval of 8. Before and after had to complete a self report on cravings 0-10 scale (0= no craving).
What were the results of Li et al?
H users scored higher (3.21) compared to C (2.23) after. PCC was more active in H users. Positive correlation between activity in PCC and length of time being a H addict, brains reward pathway becomes linked. Stronger connectivity between PCC and insula (Decision Making) and PCC and Dorsal Striatum (Drug taking behaviour) was found in H users. Drug related images activated the brain in H explaining higher cravings but not in C. C more connectivity with PCC.
What was the conclusion of Li et al?
PCC activity was different in H users than non-users and activity levels are linked to the amount of time a person has used H causing the brain to change over time. This can explain when exposed to certain environmental cues they can relapse.
One strength: Extraneous Variables:
One strength of having a control group is that extraneous variables such as handedness, sex, age and educational level were controlled for when measuring the PCC activity between this group and the heroin users. This means the results on PCC activation in heroin users are more valid and accurate.
One weakness: Sample:
One weakness of the sample is that it was restricted to only 14 male heroin users only. This means the results have low generalisability when understanding the role of the PCC in all heroin users including female users and are less representative of the whole population of heroin addicts.
