Hostname: page-component-74656f9884-rngvg Total loading time: 0 Render date: 2026-11-06T09:59:31.614Z Has data issue: false hasContentIssue false

Regular recreational Cannabis users exhibit altered neural oscillatory dynamics during attention reorientation

Published online by Cambridge University Press:  22 September 2021

Seth D. Springer
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
Rachel K. Spooner
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
Mikki Schantell
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
Yasra Arif
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
Michaela R. Frenzel
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
Jacob A. Eastman
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
Tony W. Wilson*
Affiliation:
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
*
Author for correspondence: Tony W. Wilson, E-mail: tony.wilson@boystown.org
Rights & Permissions [Opens in a new window]

Abstract

Background

Cannabis is the most widely used illicit drug in the United States and is often associated with changes in attention function, which may ultimately impact numerous other cognitive faculties (e.g. memory, executive function). Importantly, despite the increasing rates of cannabis use and widespread legalization in the United States, the neural mechanisms underlying attentional dysfunction in chronic users are poorly understood.

Methods

We used magnetoencephalography (MEG) and a modified Posner cueing task in 21 regular cannabis users and 32 demographically matched non-user controls. MEG data were imaged in the time−frequency domain using a beamformer and peak voxel time series were extracted to quantify the oscillatory dynamics underlying use-related aberrations in attentional reorienting, as well as the impact on spontaneous neural activity immediately preceding stimulus onset.

Results

Behavioral performance on the task (e.g. reaction time) was similar between regular cannabis users and non-user controls. However, the neural data indicated robust theta-band synchronizations across a distributed network during attentional reorienting, with activity in the bilateral inferior frontal gyri being markedly stronger in users relative to controls (p's < 0.036). Additionally, we observed significantly reduced spontaneous theta activity across this distributed network during the pre-stimulus baseline in cannabis users relative to controls (p's < 0.020).

Conclusions

Despite similar performance on the task, we observed specific alterations in the neural dynamics serving attentional reorienting in regular cannabis users compared to controls. These data suggest that regular cannabis users may employ compensatory processing in the prefrontal cortices to efficiently reorient their attention relative to non-user controls.

Information

Type
Original Article
Copyright
Copyright © The Author(s), 2021. Published by Cambridge University Press
Figure 0

Fig. 1. Posner cueing task and behavioral performance. (A) A fixation cross was first presented for 1500 (±50) ms, followed by a cue (green bar) presented to the left or right of the fixation cross for 100 ms. After 200 ms, the target stimulus (box with opening) appeared in either the left or right hemifield for 2500 ms. Participants responded as to whether the opening was on the bottom or top of the target with their index and middle finger, respectively. Validly cued trials (cue location on the same side as the impending target) were presented for 50% of the trials, and a total of 200 trials (both valid and invalidly cued) were completed by each participant. (B) Behavioral performance of all subjects is shown on the y-axis (i.e. reaction time on the left, accuracy on the right) with condition (valid or invalid) on the x-axis. Reaction times were significantly slower during invalid trials compared to valid ones, while accuracy was unchanged as a function of task condition. ***p < 0.001.

Figure 1

Fig. 2. Sensor-level analyses during attentional reallocation. Grand-averaged time−frequency spectrogram from a sensor near the left posterior parietal cortex, with time (ms) shown on the x-axis and frequency (Hz) denoted on the y-axis. A color scale bar shown above the spectrogram denotes the percent power change relative to the baseline period (−600 to 0 ms). The data per spectrogram have been averaged across all trials (both valid and invalid) and participants. Strong increases in theta (3–6 Hz) were observed following cue (blue dashed line) and target (white dashed line) onset. Additionally, robust decreases in alpha (9–13 Hz) and beta (15–23 Hz) activity were observed following target presentation.

Figure 2

Fig. 3. Theta activity during target processing. Theta beamformer images (inset top right of each panel) were computed across both conditions and then averaged across all participants. The images are shown in pseudo-t units following the neurological convention (right hemisphere on the right side). Increases in theta activity were observed in the following regions: (A) bilateral primary visual cortices, (B) right dorsolateral prefrontal cortex, (C) left inferior frontal gyrus, and (D) right inferior frontal gyrus. From the peak voxel exhibiting the strongest neural activity (yellow dot), time courses were extracted to evaluate changes in neural response as a function of group (controls: orange; users: blue) and task condition (valid: solid line; invalid: dashed line) during the target processing time window identified through the sensor level analysis (i.e. 350–700 ms; shaded area). Average reaction times across all participants for valid and invalid trials are denoted in red solid and dashed lines, respectively. Bar graphs represent the neural validity effect (i.e. invalid—valid) with error bars reflecting SEM. *p < 0.05; #p = 0.0502. Insets showing occipital responses are in units of pseudo-t values scaled from 8.0 to 12.0 while the other insets are scaled from 5.0 to 6.0.

Figure 3

Fig. 4. Beta activity during target processing. Beta beamformer images (inset) were computed across conditions and then averaged across all participants. The output images are shown in pseudo-t units following the neurological convention (right hemisphere on the right side). Decreases in beta activity were observed in the following regions: (A) lateral occipital gyri and (B) right superior parietal lobule. Time courses (i.e. line graphs) of beta activity from the peak voxel (i.e. yellow dot on beamformer images) in each region were averaged over the beamforming window (i.e. 300–900 ms; gray box) and the difference was calculated across conditions (i.e. invalid – valid) to determine the neural validity effect (bar graphs). Asterisks mark significant neural validity effects (p < 0.05), with error bars reflecting SEM. The inset showing occipital responses is in units of pseudo-t values scaled from 12.0 to 16.0 while the other inset is scaled from 13.0 to 21.0.

Figure 4

Fig. 5. Spontaneous theta activity during the baseline period. Spontaneous theta activity averaged over the baseline period (−600 to 0 ms) is shown for each spatially defined peak in our beamformer analysis. Basal theta power was significantly reduced in all regions in chronic cannabis users compared to non-user controls. Asterisks mark significant baseline differences between groups (p < 0.05), with error bars reflecting SEM.

Supplementary material: Image

Springer et al. supplementary material

Springer et al. supplementary material 1

Download Springer et al. supplementary material(Image)
Image 483.8 KB
Supplementary material: Image

Springer et al. supplementary material

Springer et al. supplementary material 2

Download Springer et al. supplementary material(Image)
Image 17.6 MB
Supplementary material: File

Springer et al. supplementary material

Springer et al. supplementary material 3

Download Springer et al. supplementary material(File)
File 26.3 KB