Alcohol dose and different patterns of prefrontal brain activation
While participants were performing both pre- and post-dosing Go/No-go tasks, hemodynamic brain activity was acquired using Kernel Flow1To investigate brain activation patterns associated with our Go/No-go inhibition task, we employed a GLM framework, and modeled the activity of each channel as a function of the two block types (go-only and go-no-go) as well as other commonly used task-irrelevant regressors (“Prefrontal brain activation during an inhibitory control task under the influence of different alcohol doses as quantified by generalized linear models. (Looking across post-dose GLM results, it appeared that the strength and spread of the right prefrontal activity during go-no-go blocks (compared to go-only), as well as the overall patterns of lateralization varied according to alcohol dose (Fig. Because the aforementioned analysis contrasted averaged responses between the go-no-go and go-only blocks, it might obscure changes in the time courses of activation patterns within each condition. Thus, to obtain a more granular view into the temporal dynamics of lateralization, we sought to define lateralization metrics that took into account the time courses of activity averaged over occurrences of each block type, within each hemisphere (Fig. Time courses of prefrontal lateralization for different alcohol doses. Epoched time course of left (green) and right (orange) prefrontal activity for go-no-go blocks (top) and go-only blocks (bottom) separated by session. From left to right, pre-dose and placebo-, low-, and moderate-dose time courses are shown (mean ± s.e.m). Solid and dashed lines represent HbO and HbR, respectively. Note the (expected) opposite trends in the two chromophores.The epoched HbO/HbR time courses during go-no-go blocks (Fig. It has been suggested that total hemoglobin (HbT = HbO + HbR) is more robust in mapping cerebral activation (i.e. less contaminated by superficial signals)Altered patterns of prefrontal lateralization with different alcohol doses. (The direction metric, while informative, is still a coarse measure of lateralization that does not take into account time-locked covariability between left and right prefrontal activity. To further characterize how the time courses of left and right prefrontal activity co-varied, we inspected the parametric curves defined by the right versus left prefrontal HbT through time within each block type separately (Fig. The distributions of angle metric as seen in Fig. Could these lateralization metrics differentiate participants who felt a placebo-effect from those that did not? In our population, almost half of the participants (n = 23) reported a placebo effect (“These lateralization metrics, taken together, provide a foundation for distinguishing intoxicated brain activity. Interestingly, when using only the 850 nm mean moment we were able to replicate these findings, and we have the addition of statistically significant differences between the low and moderate doses (Supplementary Figs. 