Changes in alcohol-related brain networks across the first year of college: a prospective pilot study using fMRI effective connectivity mapping

Abstract

The upsurge in alcohol use that often occurs during the first year of college has been convincingly linked to a number of negative psychosocial consequences and may negatively affect brain development. In this longitudinal functional magnetic resonance imaging (fMRI) pilot study, we examined changes in neural responses to alcohol cues across the first year of college in a normative sample of late adolescents. Participants (N=11) were scanned three times across their first year of college (summer, first semester, second semester), while completing a go/no-go task in which images of alcoholic and non-alcoholic beverages were the response cues. A state-of-the-art effective connectivity mapping technique was used to capture spatiotemporal relations among brain regions of interest (ROIs) at the level of the group and the individual. Effective connections among ROIs implicated in cognitive control were greatest at the second assessment (when negative consequences of alcohol use increased), and effective connections among ROIs implicated in emotion processing were lower (and response times were slower) when participants were instructed to respond to alcohol cues compared to non-alcohol cues. These preliminary findings demonstrate the value of a prospective effective connectivity approach for understanding adolescent changes in alcohol-related neural processes.

Figure 1

ROIs and cluster-corrected brain activity (versus fixation) averaged across three waves during the respond alcohol (top) and respond neutral (bottom) task conditions overlaid on an MNI template brain. ROIs are the same in both images, with dACC and rACC in the sagittal slice (left), left and right DLPFC and dACC in the coronal slice (middle), and left and right OFC and left and right amygdala in the axial slice (right).

Figure 2

Effect of wave on mean negative consequences of alcohol use in the past year. Bars represent standard deviations. Differences significant by paired t-test: *p < .05; **p < .01.

Figure 3

A final effective connectivity map for the respond alcohol condition at wave 1 for a single participant. The model fit the data well: CFI=1.00, NNFI=1.00, SRMR=.050, RMSEA=.000. Thick arrows represent group-level connections; thin arrows represent individual-level connections; solid lines represent contemporaneous relations; dashed lines represent lagged relations; all arrows have beta-values associated with them.

Figure 4

Effects of response condition and wave on mean connections among ROIs within the cognitive control network (bilateral DLPFC, rACC, dACC). Black lines represent connections present during the respond alcohol condition, with negative standard deviation bars; gray lines represent connections present during the respond neutral condition, with positive standard deviation bars. Differences significant by paired t-test: *p < .05; **p < .01.