MENTAL TIME TRAVEL INTO THE PAST IN CANNABIS USERS: AN FMRI STUDY

Background and Aim : Episodic Memory (EM) involves re-experiencing personal events, with phenomenological details situated in a specific time and place in the past. This study aimed to compare EM in Cannabis users relative to healthy control, using fMRI and a neuropsychological assessment.Methods : 20 right-handed current Cannabis users (diagnosed with moderate to severe Cannabis use disorder by DSM-5) and 20 healthy controls between 18-40 years of age were recruited in this study. Groups were matched in age, gender, and educational level. Baseline assessments for inclusion, including Edinburgh handedness test, Beck anxiety inventory, Beck depression inventory, and Montreal cognitive assessment carried out before the neuroimaging session. The Farsi version of Rey s Auditory Verbal Learning Test (RAVLT) was employed. 10 episodic cues were extracted from an autobiographical events list and were recorded to be presented by an MRI compatible headphone during the scanning. For each cue, subjects were asked to recall a relevant event with as many details as possible, and then rate the vividness of their retrieval on a Likert scale using the response box. Structural and functional MRIs were acquired on a Siemens MAGNETOM Prisma 3Tesla MRI scanner. fMRI analysis was performed using the fMRI Expert Analysis Tool (FEAT), part of FMRIB’s Software Library (FSL).Results : fMRI analysis results showed a significant difference in BOLD responses between 2 groups (non-users> users), while recalling past autobiographical events; in regions such as Inferior Frontal Gyrus Pars Triangularis (z-value: 6.24) which is associated with Brodmann Area (BA) 45, left Caudate (z-value: 4.17) which is located in BA 23 and Subcallosal Cingulate Gyrus (z-value: 3.92) including BA 25 and parts of BA 24. Moreover, there was a significant difference in the scores of delayed recall in RAVLT between Cannabis users (M=10.05, SD=0.55) and control groups (M= 10.81,SD= 0.61) (U= 22, p-value<0.01).Conclusion : Our results provide both neuroimaging and neuropsychological evidence that the chronic use of cannabis negatively affects EM functions. These findings are consistent with previous studies in this field.

کلیدواژه ها:

Episodic Memory ، Cannabis ، Functional Magnetic Resonance Imaging ، fMRI ، RAVLT