The aim of this study is to assess the value of resting-state fMRI in detecting the acute effects of alcohol on healthy human brains. Thirty-two healthy volunteers were studied by conventional MR imaging and resting-state fMRI prior to and 0.5 hours after initiation of acute alcohol administration. The fMRI data, acquired during the resting state, were correlated with different breath alcohol concentrations (BrAC). We use the posterior cingulate cortex/precuneus as a seed for the default mode network (DMN) analysis. ALFF and ReHo were also used to investigate spontaneous neural activity in the resting state. Conventional MR imaging showed no abnormalities on all subjects. Compared with the prior alcohol administration, the ALFF and ReHo also indicated some specific brain regions which are affected by alcohol, including the superior frontal gyrus, cerebellum, hippocampal gyrus, left basal ganglia, and right internal capsule. Functional connectivity of the DMN was affected by alcohol. This resting-state fMRI indicates that brain regions implicated are affected by alcohol and might provide a neural basis for alcohol’s effects on behavioral performance.
Alcohol impairs cognitive function and is associated with a variety of behavioral changes resulting in deficits in perceptual and emotional function. Alcohol consumption has immediate effects on multiple cognitive-motor processing domains and leads to damage of multiple attentional abilities [
Recently, resting-state fMRI techniques have been applied to demonstrate abnormalities in various neuropsychiatric disorders [
Regional homogeneity (ReHo), a novel method that measures the functional connectivity, has been developed to analyze the local synchronization of spontaneous fMRI BOLD signals, reflecting the coherence of spontaneous neuronal activity [
To assess the ability of fMRI to detect the acute effects of alcohol on healthy human brains, we used resting-state fMRI methods to investigate changes in the brain; we hypothesized that acute alcohol administration may alter connectivity measures of the resting-state DMN and have different ReHo and ALFF values in some brain areas when compared with controls.
Thirty-two healthy right-handed volunteers (17 men, 15 women; 25–27 years old) were examined by MRI before and after administration of alcohol. To be eligible for the study, potential volunteers were interviewed via telephone and asked a number of questions concerning their general health and medical history, in addition to questions especially related to their history of alcohol use and abuse. All participants provided written informed consent to the study, which was approved by the local ethics committee of the university hospital and institutional review boards. Participants consumed alcohol at a frequency of less than once per week and had no self-reported history of neurological disease, substance abuse, head trauma, CNS tumors, or psychoactive prescriptive medication usage. To ensure that the alcohol dose received in the study would be within the participants’ normal range of experience, we excluded very heavy drinkers. To avoid interfering with alcohol absorption, subjects were requested to avoid consuming alcohol for 24 h and refrain from eating for 6 h prior to the study appointment. All participants were given a hand-held breathalyzer test to measure baseline alcohol levels, assuring participants were not already under the influence of alcohol.
Before and after alcohol administration, subjects were asked to evaluate their subjective sense of headache, excitement, dizziness, sleepiness, or confusion.
Subjects passing the screening process were invited to participate in the study. Before alcohol administration, we performed BOLD imaging using MRI to determine the baseline, making each participant serve as a control for the individual alcohol effect. After the examination, each received a dose of 0.65 g of alcohol per kilogram body weight orally within 10 minutes. The alcohol was given in the form of spirit (53° Maotai spirit, 2010, Renhuai, Guizhou, China). All drinks were mixed with some food, such as peanuts. BrAC is an index helping to estimate blood alcohol levels. BrAC was measured before and after each scan session using a hand-held breathalyzer 0.5 hours after alcohol administration. The subjects had to wait for 30 minutes until the BrAC reached its approximate maximum after alcohol administration [
All anatomical and BOLD-sensitive MRI data were acquired using gradient-echo echo-planar imaging (EPI) sequences in a 1.5T MRI scanner (GE) with an eight-channel-phased array head coil. Foam pads were used to reduce head movements and scanner noise. To measure the individual fMRI data, the imaging parameters were set as follows: slice thickness = 5 mm, slice gap = 1 mm, TR = 2,000 ms, TE = 30 ms, FOV = 24 cm × 24 cm, flip angle = 90°, and matrix = 64 × 64. 180 volumes (20 slices per volume) were acquired during 360 s of an fMRI run. During data acquisition, subjects were required to relax with eyes closed, not to fall asleep, and to move as little as possible. For anatomic data sets, we used a 3D-BRAVO sequence (thickness: 1.4 mm (no gap), TR = 8.2 ms, TE = 1.0 ms, FOV = 24 cm × 24 cm, flip angle = 25°, and matrix = 256 × 256).
Preprocessing of fMRI data was carried out using SPM8 and DPARSF software (
The functional connectivity of DMN was calculated using the REST software (
ReHo was defined as Kendall’s coefficient of concordance (KCC) to study the similarity of the time series within a functional cluster based on the regional homogeneity hypothesis [
ALFF was calculated using DPARSF software (
To determine brain regions that showed significant positive correlations, one-sample
One-sample two-sided
Alcohol consumption changed the mood and behavior of the persons tested. Subjects in the low BrAC group complained of headache (
The one-sample
Brain regions with significant differences of functional connectivity are shown between control and high BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
High BrAC group < control | ||||||
Fusiform gyrus | L | 61 | −36 | −9 | −45 | −5.4005 |
Parahippocampal gyrus | R | 47 | −21 | 3 | −33 | −4.3482 |
Hippocampal gyrus | R | 20 | 27 | −15 | −24 | −3.7402 |
L | 27 | −24 | −15 | −15 | −3.735 | |
Superior temporal gyrus | L | 68 | −51 | −6 | −27 | −4.2768 |
Rectus gyrus | L | 27 | 3 | 39 | −27 | −3.5673 |
Frontal orbital gyrus | L | 25 | −15 | 33 | −18 | −4.616 |
Superior frontal gyrus | L | 31 | −12 | 48 | 21 | −4.1603 |
High BrAC group > control | ||||||
Cerebellum | R | 19 | 3 | −84 | −27 | 4.0301 |
Cuneus | L | 35 | −3 | −102 | −3 | 4.1482 |
Occipital gyrus | L | 22 | −27 | −75 | 12 | 3.9603 |
Superior parietal lobe | R | 32 | 15 | −51 | 57 | 3.7574 |
Superior frontal gyrus | R | 21 | 6 | 0 | 66 | 3.8591 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with significant differences of functional connectivity are shown between control and low BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
Low BrAC group < control | ||||||
Cerebellum | R | 56 | 51 | −75 | −39 | −4.6375 |
Occipital lobe | L | 25 | −39 | −78 | 36 | −3.6973 |
Superior frontal gyrus | L | 213 | −9 | 24 | 54 | −6.2182 |
Middle frontal gyrus | L | 19 | −6 | 48 | −12 | −3.3188 |
Inferior parietal lobe | L | 24 | −33 | −48 | 54 | −3.6218 |
Low BrAC group > control | ||||||
Cuneus | R | 31 | 15 | −99 | 24 | 3.7814 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with significant differences of functional connectivity are shown between high and low BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
High BrAC < low BrAC group | ||||||
Hippocampal gyrus | R | 46 | 24 | −18 | −27 | −3.7115 |
Rectus gyrus | L | 18 | 0 | 15 | −24 | −3.8389 |
Cerebellum | L | 25 | −54 | −63 | −24 | −3.7455 |
Superior temporal gyrus | R | 21 | 45 | 0 | −15 | −3.7535 |
Fusiform gyrus | R | 18 | 42 | −30 | −21 | −4.5647 |
Superior temporal gyrus | L | 44 | −45 | −6 | −15 | −3.8467 |
Superior frontal lobe | R | 25 | 6 | 48 | 33 | −4.248 |
High BrAC > low BrAC group | ||||||
Cerebellum | R | 19 | 45 | −60 | −39 | 3.7278 |
Cingulate gyrus | R | 22 | 15 | 6 | 45 | 6.7489 |
Superior frontal lobe | L | 31 | −9 | 21 | 51 | 5.2161 |
40 | −27 | 21 | 51 | 5.3112 | ||
18 | −15 | −9 | 57 | 3.5353 | ||
Medial frontal lobe | L | 35 | −27 | 63 | 3 | 4.1768 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Intragroup maps of connectivity to PCC/PCu of resting-state networks in control group by correlation analysis of resting-state fMRI (
To investigate the ALFF and ReHo difference, a two-sample
Brain regions with significant differences in ALFF are shown between control and high BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
High BrAC group < control | ||||||
Superior frontal gyrus | R | 654 | 27 | 12 | 63 | −6.2074 |
L | 12 | −12 | 39 | 51 | −3.1304 | |
Inferior frontal gyrus | R | 33 | 54 | 24 | 27 | −4.113 |
R | 16 | 39 | 33 | 12 | −3.6202 | |
Middle frontal gyrus | R | 17 | 39 | 30 | 36 | −4.1579 |
Prefrontal lobe | R | 17 | 48 | −6 | 24 | −3.9148 |
Cerebellum | L | 13 | −9 | −84 | −27 | −4.0663 |
Middle temporal gyrus | R | 12 | 63 | −39 | −9 | −3.3521 |
High BrAC group > control | ||||||
Hippocampal gyrus | L | 26 | −24 | 0 | −15 | 3.6595 |
Caudate | L | 11 | −12 | 6 | 24 | 3.6771 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with significant differences in ALFF are shown between control and low BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
Low BrAC group < control | ||||||
Cerebellum | L | 48 | −15 | −78 | −42 | −3.9843 |
R | 20 | 6 | −48 | −51 | −3.8325 | |
R | 13 | 45 | −60 | −51 | −3.5829 | |
R | 13 | 24 | −72 | −45 | −3.2777 | |
Middle temporal gyrus | R | 13 | 66 | −42 | 6 | −3.9775 |
Low BrAC group > control | ||||||
Basal ganglia | L | 33 | −21 | 6 | −12 | 4.0375 |
Inferior frontal gyrus | L | 10 | −24 | 24 | −21 | 4.0273 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with ALFF differences are shown between high and low BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
High BrAC < low BrAC group | ||||||
Superior frontal gyrus | R | 68 | 6 | 21 | 60 | −5.8642 |
R | 41 | 30 | 30 | 57 | −5.8892 | |
R | 20 | 27 | 69 | 9 | −5.7126 | |
R | 10 | 30 | 66 | −12 | −5.8208 | |
L | 32 | −12 | 39 | 51 | −4.9698 | |
L | 24 | −21 | 12 | 63 | −4.6472 | |
High BrAC > low BrAC group | ||||||
Middle temporal gyrus | R | 15 | 63 | −48 | 6 | 5.2313 |
Parietal lobe | R | 11 | 33 | −54 | 66 | 6.0077 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with significant ReHo differences are shown between control and high BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
High BrAC group < control | ||||||
Superior frontal gyrus | R | 750 | 15 | 21 | 57 | −4.6134 |
R | 39 | 12 | 39 | −24 | −3.7952 | |
Inferior frontal gyrus | R | 37 | 54 | 21 | 18 | −4.4388 |
Hippocampal gyrus | R | 39 | 18 | −6 | −33 | −4.6794 |
Inferior temporal gyrus | R | 30 | 33 | 9 | −45 | −4.2946 |
High BrAC group > control | ||||||
Middle frontal gyrus | L | 100 | −27 | 45 | 3 | 4.7207 |
R | 42 | 12 | −21 | 60 | 6.4199 | |
Basal ganglia | L | 468 | −27 | 12 | −3 | 5.7696 |
Cerebellum | R | 114 | 9 | 48 | −24 | 6.8909 |
Internal capsule | R | 39 | 9 | 0 | 6 | 3.9489 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with a difference in ReHo are shown between control and low BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
Low BrAC group < control | ||||||
Anterior cingulate | L | 33 | −6 | 30 | −3 | −4.3213 |
Middle temporal gyrus | R | 31 | 66 | −42 | 6 | −4.3893 |
Hippocampal gyrus | R | 30 | 30 | 9 | −39 | −6.1679 |
Low BrAC group > control | ||||||
Basal ganglia | L | 89 | −12 | 6 | −3 | 5.9914 |
Superior frontal gyrus | R | 48 | 3 | 24 | 45 | 3.7264 |
Internal capsule | R | 44 | 9 | 0 | 6 | 4.6701 |
Caudate | L | 39 | −27 | 6 | 6 | 3.9281 |
Cerebellum | L | 25 | −36 | −42 | −42 | 4.7058 |
Hippocampal gyrus | L | 25 | −24 | −15 | −15 | 3.9891 |
Precuneus | L | 25 | −9 | −75 | 39 | 3.9728 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Brain regions with significant differences in ReHo are shown between high and low BrAC group (
Brain regions | Voxels |
|
|
|
|
|
---|---|---|---|---|---|---|
High BrAC < low BrAC group | ||||||
Superior frontal gyrus | L | 848 | −3 | 21 | 57 | −7.1615 |
Middle frontal gyrus | R | 28 | 51 | 51 | 0 | −4.7089 |
Superior frontal gyrus | R | 28 | 21 | 15 | −15 | −3.7462 |
Inferior temporal gyrus | R | 61 | 45 | −9 | −36 | −5.9454 |
Middle temporal gyrus | R | 40 | 66 | −21 | −6 | −4.6233 |
Cerebellum | L | 27 | −48 | −51 | −30 | −3.9455 |
High BrAC > low BrAC group | ||||||
Middle frontal gyrus | L | 25 | −30 | 48 | −3 | 5.0651 |
Fusiform gyrus | L | 105 | −30 | −57 | −3 | 4.7939 |
Fusiform gyrus | R | 47 | 24 | −78 | −15 | 3.8855 |
Occipital gyrus | L | 37 | −27 | −87 | −9 | 5.1128 |
Midbrain | 84 | −9 | −21 | −12 | 5.2828 | |
Middle temporal gyrus | R | 65 | 51 | −51 | 3 | 4.5885 |
Cerebellum | R | 42 | 21 | −51 | −18 | 4.2606 |
Cerebellum | L | 28 | −18 | −42 | −21 | 4.6673 |
Cerebellum | L | 35 | −27 | −66 | −24 | 4.3434 |
MNI: Montreal Neurological Institute; L: left; R: right.
A positive
Alcohol leads to dysfunction of cognitive control, causing behavioral disinhibition. The mechanism of alcohol action on brain is still not well understood. Recently, a published study used DTI to detect cytotoxic brain edema after acute effects of alcohol on healthy human brain [
This study investigated the effects of alcohol by detecting the functional connectivity of DMN and using ALFF and ReHo. During a resting state, it may be helpful to further understand abnormalities of brain activity in participants under the acute effect of alcohol, because the absence of demanding cognitive activities and instructions makes it more straightforward to compare brain activity across groups that may differ in motivation or cognitive abilities. To determine which brain regions of healthy person are implicated under the influence of acute alcohol, we examined the acute effects of low (
Previous study examining the brain activation during the fMRI Go/No-Go task suggests decrease in brain activation within the basal ganglia and cerebellum, which comprise parts of networks known to be important for movement and cognition [
Images showing significant increase in ReHo of left basal ganglia in both low (a) and high (b) BrAC group compared with control group (
Recently, a study indicated significant decrease in connectivity between the frontal-temporal-basal ganglia and cerebellar components during alcohol condition, which might be a vulnerable point to impair one’s order cognitive function and motor planning [
There is another region drawing our attention: it is the hippocampal gyrus. The bilateral hippocampal gyri show difference of functional connectivity, ALFF, and ReHo in both high and low BrAC group. A study using DTI to examine the brain indicated that the frontal lobes, thalamus, and middle cerebellar peduncle are especially vulnerable to the effects of alcohol [
In the current study, the voxel-based functional connectivity using the PCC/PCu as a seed reveals that the positive correlation brain regions are similar to the DMN. This helps to indicate the PCC/PCu is a central node in the DMN [
Resting-state fMRI could detect brain regions including the superior frontal gyrus, cerebellum, hippocampal gyrus, basal ganglia, and internal capsule which were affected by alcohol. These different brain regions which are related to memory, motor control, cognitive ability, and spatial functions might provide a neural basis for alcohol’s effects on behavioral performance.
The authors declare that they have no conflict of interests.
This work was supported by the Natural Science Foundation of Guangdong Province, China (Grant no. S2012010008974), and the Science and Technology Planning Project of Guangdong Province, China (Grant no. 2010B031600129), and was sponsored by Shantou University Medical College Clinical Research Enhancement Initiative, China.