Annotated Bibliography: Effect of video games or screen time on brain function
Article #1 Summary
Hong, S.-B., Zalesky, A., Cocchi, L., Fornito, A., Choi, E.-J., Kim, H.-H., … Yi, S.-H. (2013). Decreased Functional Brain Connectivity in Adolescents with Internet Addiction. PLoS ONE, 8(2), e57831. https://doi.org/10.1371/journal.pone.0057831
The researcher sought to explore the why people are spending so much time in online games. The number of people who have become dependent and create their lives around online gaming has increased worldwide. This study asked why is there such an increase in the number of people who are using online gaming and is there any between group differences in connectivity strength between healthy control and young men diagnosed with internet addiction. Is internet addiction something which is created or a biological tendency where was always there and just addicted to the internet.
Theory of the Research Question
The world has seen an increase in use of computers and smartphone screens, specifically computer games by children. Internet addiction has been suggested as a possible disorder which needs to be examined by the American Psychiatric Association. Previous studies reported significant changes in brain function and structure associate with internet addiction. Other researcher used fMRI scans and they found frontal and striatal regions involved with internet addiction. The use of positron emission tomography (PET) found a decrease in dopamine D2 receptor availability and a decreased striatal dopamine transporter expression level in adults with internet addiction. These finding indicate internet addiction share the same mode of reinforcement with as with other addiction behaviors.
Hypotheses and Methodology
The authors hypotheses adolescents with internet addiction will show altered inter-regional connectivity between frontal and striatal regions with possible involvement of the parietal cortex and insula. The study recruited twelve right-handed male adolescent participants with internet addiction , IA, and eleven right-handed and gender-matched healthy control. Participant level of internet addiction was determined using the Young Internet Addiction Scale to evaluate the degree of problems caused by internet use twenty item based on a five-point Likert scale and the Kiddie-Schedule for affective disorders and schizophrenia-present and lifetime reason is to exclude other diagnosis. The twelve IA subjects based on answers on tolerance, withdrawal when not able to game, preoccupation with playing and repeated unsuccessful attempts to reduce or stop gaming, negatively influenced mood when attempting to reduce online gaming and neglecting important relationships or activities because of online gaming. The resting state fMRI images were acquired on a 3T Siemens scanner set to a repetition time 2700 ms:echo time 30 ms; acquisition matrix 64X64; field of view 192 X 192 mm flip angle 90 deg voxel size 3.0 mm x 3.00 mm x 3.0 mm; slices 40. The total time of the scan was 6 minutes 45 seconds for the whole procedure. The authors used Data Processing Assistant software for Resting-state fMRI to Preprocessing of fMRI. All data was detrended and low frequency fluctuations (0.01-0.08 Hz) were filtered out in order to detect signals from gray matter and reduce the effect of noise on the data. The differences of this regression consisted of 90 brain regions based on the Automated Anatomical Labeling atlas. Pair-wise associations were calculated creating a 90 by 90 connectivity matrix for each subject. Network-based statistic identified regional brain networks exhibiting significant between-group difference in inter-regional functional connectivity. A t-test for a between-group difference in the correlations coefficient at each of the 90 x (90-1)/2 + 4005 showed unique regional pairings. To analysis the interconnected network connections with a t=statistic greater that t>3.0 were examined. A FWE-correct p-value was calculated for each interconnected network as a proportion of the permutations. The authors examined two alternative hypotheses, addiction greater than control and addiction less than control. The study tested between group average clustering coefficient, characteristic path length and small-worldness ration. The connectivity matrices was binarized to connection densities with a range of 10% or 30% then the network measurements were calculated with respect to the density and the clustering coefficient and characteristic neural path length were obtained.
The study found only one significant difference between the two research groups which was the YIAS scores. One network did exhibited a significant (p< 0.05, FWE-corrected) decrease in connectivity in adolescents with internet addiction. This network is made up of 59 links, which involves 38 regions of the brain, including the cortical and subcortical regions and their corresponding lobes. A difference between the two groups in the Fronto-temporo-parietal connections was discovered, however the occipital lobe was not included in the affected network.
The study found the internet addiction group to have reduced links between the subcortical regions and frontal and parietal cortices. To examine these regions each subcortical lobe were examined separately to examine if it may be contributing to the reduction in these areas of the brain. The study found a reduction in the hippocampus globus pallidus, putamen and the bilateral putamen had the highest level of reduction. The concluded the IGD participant amygdala and caudate nucleus did not have significant reduction.
Discussion (Implications, importance, and limitations)
The authors found evidence of decreased brain function connectivity in adolescents with internet addiction thus proving their hypothesis. The studies finding cortico-subcortical pathology fits with the current understanding of the addiction process. The study found a difference of 24% of the connections between the two groups and 27% additional linked subcortical and parietal areas were found to be involved with internet addiction. Due to the data-driven analysis of the links between networks the finding provided strong induction of the involvement of these systems in internet addiction. Other studies have found the involvement in these areas of the brain in regard to internet and other addictive disorders.
The authors pointed out an interesting note, they stated the National Institute on Drug Abuse believes behavioral addictions might be the most pure model for all addictions because the brain’s chemical makeup is not changed. The study states the addiction behavior is not contaminated by the chemical process of habituation of the body to the addition of certain chemical into the body, creating a need for the body to try to create a balance within itself and thus changing the brain by the very action of trying to create homeostasis.
One of the main limitation brought up in the study is the decrease in the connectivity of the brain due to the internet addiction or is the addiction to internet the result of having lower connectivity in the brain. The authors point out that few neuroimaging studies of addiction have addressed the functional integration between bilateral hemispheres. The current study may indicate these interhemispheric changes reflect a possible vulnerability for addictive behavior or a neural correlation of addictive behavior rather than long term internet addiction. The study also find the decreased functional connectivity between frontal and parietal regions may be a common characteristic with all addiction types. With these limitation in mind the study did find that internet addiction had the same pathology of striatal circuits that many other addictions.
One of the most interesting findings in this study was the strong involvement of the putamen. This brain structure modulates several neurotransmitter including dopamine. A reduced function of dopamine in the systems has been strongly implicated as one of the mechanisms of addiction and addictive behavior. The involvement of this system may explain the results of this study and the low connectivity between structures of the brain.
Another limitation of the study is the sample size. The small same size likely limited the power of the study and this indicate more studies need to be performed to replicate the studies finding. Further studies might include longitudinal studies comparing brain development across the course of a decade and comparisons of the areas of involvement between other behavioral disorders and internet addiction. These studies would give a better understanding of the addiction process and if it is a underlying tendency toward addiction is and function of the brain areas.
Article #2 Summary
Kim, Y.-R., Son, J.-W., Lee, S.-I., Shin, C.-J., Kim, S.-K., Ju, G., … Ha, T. H. (2012). Abnormal brain activation of adolescent internet addict in a ball-throwing animation task: Possible neural correlates of disembodiment revealed by fMRI. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 39(1), 88–95. https://doi.org/10.1016/j.pnpbp.2012.05.013
The study explores the regions of the brain which active and are associated with disembodiment. The study also explore and identify the relationship between those regions of the brain and regions of the brain associated with internet use.
Theory of the Research Question
As the use of the internet grows so does the tendency for abuse and addiction. The current study reports that 38% of South Korean high school students report behavior exhibit an addiction to the internet. The psychological factors for internet addiction include such disorders as depression and impulsivity. Another factor which may be coming into play with the use of the internet is the ability to escape from reality or to create virtual interpersonal relationships. This study is perprosing that this escape from reality and the creation of virtual relationships promotes the tendencies for avoiding reality and real relationships. The study suggest when someone maintains anonymity online which interacting with people in cyberspace it can promote the tendency to feel outside the normal physical boundaries of the body. Disembodiment is similar with dissociation and is based on the concept of embodiment or being in a body and acting out of that body.This experience can be found in disorders such as schizophrenia or severe depression. Research as suggested the involvement of several areas of the brain including bilateral temporo-parietal junction, the occipito-temporal and the parahippocampal gyrus and the precentral gyrus. There is also reports of the posterior thalamus and precuneus is involved in the experience as well. This study examined if would participants experience disembodied self, as when they played a game and clicked a mouse when experiencing changing viewpoints. No study this far has been able to induce a sense of disembodiment in a participation during a video game.
Hypotheses and Methodology
The study age matched seventeen adolescent diagnosed with internet addiction and seventeen normal adolescents who had no history of head injury or other neurological disorders. The Korean Adolescent Internet Addiction Scale (K-AIAS) which consists of 20 statements rating using a scale from 1-5. The criteria for diagnosis with at least 40 points. The study used a block design and the experimental stimuli were similar to other similar studies. Participants reacted to three types of 6-second animations each with a different viewpoint. The common configuration in each animation consists of three players, red, blue and grey standing in a triangle. The red player throws a ball to the second, blue, player; who in turn throws it to the grey player. The sequence ends when the ball is back to the start. The first viewpoint is from behind the grey player, the second was off center so the red player and the blue player stood on either side of the screen. The final point of view the eye-balls of the grey player so the participant saw the play of action as if they were in the game.
Two type of tasks were assigned. First was a “Agency Task” in which the participant clicked the mouse when the grey character received the ball but before he threw it to the red character. The goal was to associate the mouse click with the throwing of the ball. The second was the “Location Task”, in this task the participant clicked the mouse when the ball was thrown from the red character to the blue character while the ball was in mid air.
Two kinds of blocks were formed from the three viewpoints. The blocks were composed of four animations named “Fixed View” and “Changing View”. In the “Fixed View” block the participants point of view was consistent and the “changing View block the participants view was constantine rotating through the animations. This created a 2 x 2 x 2 factorial design between task, view and group. The study had 12 blocks with three blocks for each condition and each block was 30s with a total duration of the fMRI scan was 9 minute 15s. The blocks were presenting in a random order to the participate.
The fMRI scanner used for the study was a ISOL Technology FORTE and the software the blood-oxygen-level-dependent (BOLD) technique using the echo planar imaging sequence. A 5mm thick imaging slice was without any gaps between the slices was taken at each image. A total of thirteen slice were taken on the the axial section of the brain. Imaging data was analysed by the SPMS software and a general linear model was applied and the data was corrected for motion.
The Task-View interaction was analyzed using the Agency Task under the Changing condition. This would require reassigning the player which we consider to be ourselves to a different position in the field of play. This would theoretically make the participant experience themselves as a new character as themselves, thus invoking the feeling of disembodiment.
A one sample t-test was performed for each group after each cluster was passed the voxel-level uncorrected threshold of p< .0005. After this a two-sample t-test was performed to verify the areas of increased or decreased brain activities in the addiction group when compared to the control group. Functional regions of interest for the between-group results were analysis for significance.
There was a distinct difference between the addiction group and the control group in the following areas left precentral gyrus, right precentral gyrus, left middle frontal gyrus, right middle frontal gyrus, left thalamus, left cuneus, left postcentral gyrus and the right inferior parietal lobule. There were significant finding of higher activation rates in all of these areas when compared to the control group. In addition to this no area had a higher rate of activation in the control group in comparison to the addiction group. The study examined the results between the two groups for the left thalamus, right middle front gyrus, left postcentral gyrus, posterior area of the middle temporal gyrus, and right uncus were activated at a higher level in the addiction group than the control group.
A correlation between each ROI region’s effect and the K-AIAS score and the duration of internet use were investigated. The following areas were found to have a correlation the K-AIAS score and the right parahippocampal gyrus and duration of weekly internet use, as well as duration of weekly internet use and the left middle temporal gyrus to have a significant correlation. A significant correlation was found in the addiction with scores and the middle occipital gyrus and the left middle temporal gyrus and the left thalamus and left postcentral gyrus. Only the addiction group had a significant correlation in these areas to the amount of weekly internet game play.
Discussion (Implications, importance, and limitations)
The study’s research question is might participant with internet addiction experience a feeling of a “disembodied self” when they perceive the character acting as themselves. To induce this experience the study employed the interaction between agency, clicking the mouse when the ball was thrown and changing view. This forced the participant to identify with different characters throughout the experiment. In previous studies have concluded the right inferior parietal lobe is a part of the right TP junction and is most closely related to what influences the feeling of being disembodied. The study found a significant difference between the two group in other areas previously thought to relate the the experience of disembodiment, the areas of study are the right middle frontal gyrus, precentral gyrus and the thalamus.
There were several areas where the two group differed in their brain activation. Included in these difference was a different in the TPO junction and this junction has already been implicated in the experience of “drift away”. The TP and TPO junction is a area of the vestibular cortex. When this area is affected and is dysfunctional it can lead to a feeling of altered body ownership and being disembodied. This can also occur with an increased activation of the right parahippocampal gyrus and left precentral gyrus.
The study found additional activation in areas which related to body ownership and self-generated movement. The authors concluded this is a compensatory mechanism for the disembodiment-related brain activation. The question arises of with better graphics and more game play would the brain activate more of the body ownership or more of the disembodiment areas of the brain and this is the subject of further study.
The results of the correlation between scores and the duration of internet use were significant in the addiction group. So as the duration of internet game play increase the possibility of disembodiment also increased. This is significant for adolescents because adolescents for developing identity and sense of self. The authors suggest that if the disembodiment-related areas of activation occurs on a regular basis there might be a tendency for the brain to redistribute the embodiment-related brain area and have serious effects on identity formation.
Article #3 Summary
Dieter, J., Hoffmann, S., Mier, D., Reinhard, I., Beutel, M., Vollstädt-Klein, S., … Leménager, T. (2017). The Role of Emotional Inhibitory Control in Specific Internet Addiction – An fMRI Study. Behavioural Brain Research, 324, 1–14. https://doi.org/10.1016/j.bbr.2017.01.046
The current study hypothesized individuals with internet addiction, both internet gaming and social media, would show impaired emotional inhibitory control especially when faced with anxiety evoking stimuli. The anxiety related portion of the experiment challenged the participant with stronger interference stimuli and exposure to socially anxious words. The second hypothesis the study tested if people who suffer from internet addiction when compared to social media addiction have a stronger inhibitory demands then the controls in response to social anxiety-related stimuli and have altered dACC activation during performance. The finally hypothesis being tested in this study is to measure the difference between people addicted to
internet games and social network users.
Theory of the Research Question
Internet addiction is see as the fastest growing form of addiction and is gaining worldwide attention. Internet gaming and excessive use of social media are the two most common used of internet addiction. Both of these forms of internet use require communication and social cognition but neither have been explored in a specific combination before. Internet gaming addiction has been associated with increase social and general anxiety, impulsivity and poor emotion competence. There have been few studies which also link social network usage to the same social anxiety and impulsivity as internet gaming addicts. The use of the internet to communicate might help people with poor social skills to communicate and compensate for the perceived lack of social support they feel in their lives.
Hypotheses and Methodology
The study recruited participants at the local day clinic of the Department of Addictive Behavior and Addiction Medicine and by means of advertisement on the web page of the central Institute of Mental Health and Mannheim University. The authors ran the study with 23 healthy male controls and 25 specific, 13 internet gaming and 12 social media, male internet addicts. Neither groups had any axis-1 or psychiatric disorders or other substance use. The addiction groups and the control group score significantly different in only one area of internet usage per day.
The participants of the study were screened for internet use and addiction by mean of an interview based on the AICA developed by Wolfling, Beutel and Muller to qualify the two groups. The study was able to quantify the group and the severity of the internet addiction by using scase of <13.5 and >7 as a cut off for internet addiction and <7 as an indicator of normal internet use. The Barrett Impulsiveness Scale was used to qualify impulsivity and feeling of stress were measured using the Perceived Stress Scale. The participants degree of social anxiety were explored with a questionnaire and their degree of social competence. The participants answered an emotional competence questionnaire to ascertain the degree of awareness of their own emotions and empathy towards others.
A German language version of the Affective Go/No Go task was administered to assess the participants emotional response inhibition. The test outcome was the commission error where lower number of commission reflected the ability to inhibit unwanted behavior in an emotional context and the higher level of commision error indicated the participant had a harder time of inhibiting their emotions. The test consisted of 13 blocks of either 18 positive, negative or anxious words and neutral words. The goal was to press the button when the target, positive, negative and anxious words came up and inhibit response when the neutral words came up.
An Emotional Stroop Task was carried out during an fMRI test in a 3 T whole body tomography machine. The test consist of for categories of words, positive, negative, socially anxious or neutral, in four different colors. The participant was to push the corresponding colored button for the word color on the screen as fast a possible. For the study the words and the color order were randomized and the blocks for each category were presented in a Latin square. After the fMRI scan all the words present to the participant were rated by the participant via paper and pencil with regard to each words valence and arousal on a 9 point scale.
Neither group showed any significant difference in the arousal or valence between groups. However, the within-group analyses found significant differences in all comparisons except the comparison between socially anxious and negative words between internet addicts and the healthy group. Another interesting find is a Kruskal-Wallis test between subgroups found internet gaming addicts rated the valence of positive words significantly lower than the social network addicts. The study also found significant difference in valence and arousal between each category of words except between negative and socially anxious words.
The study revealed significant deficits in impulsivity and perceived stress on all scales of social anxiety and emotional competence in both groups of internet addicts when compared to the healthy controls. Between group analysis found a difference in social anxiety between the social network addicts and both other groups and social network addicts experienced lower emotional competencies. Between the two internet addiction groups two traits, interaction anxiety and loneliness, showed significance.
The main outcome measure, emotional response inhibition, internet addicts and healthy controls showed significantly more commission errors at positive words then negative or anxious words. However, the study found the first hypothesis found no significant differences in commision errors on anxious stimuli between either social media addicts or gaming addicts and healthy control. However, the study did find with a Spearman correlation between addiction severity and AGN anxiety-related commision error that emotional response inhibition ability in anxiety-block decreased with increasing addiction severity.
The fMRI study found the left DLPFC, superior frontal gyrus, superior temporal gyrus and the inferior parietal lobe had a significant activation during positive relative to neutral world blocks of the test. The analysis for other contrast, negative vs neutral, socially anxious vs. neutral and social anxious vs rest, revealed no significant difference. The study examined the between group activation and found no significant difference except for a hyperactivation of the left middle and superior temporal gyrus and a lower activation in the cluster within the left middle and superior temporal gyrus during social anxious words of internet gaming addict. The study was not able to explain this finding and further research is warranted.
Discussion (Implications, importance, and limitations)
The authors’ results revealed specific internet addicts to have higher social anxiety, poor emotional competence, impulsivity and perceived stress. In addition to this the internet gaming addict also report higher degree of loneliness and social withdrawal relative to healthy groups. This is also shown with the longer response time for socially anxious words when compared to other categories. This result was not observed in the social network addiction group. This may indicate social anxiety-related interferences may play a part in internet gaming addiction.
The finding of hypoactivation of the left middle and superior temporal gyrus of internet gaming addicts is involved with the retrieval of semantic knowledge and the left middle temporal gyrus is associated with retrieval of words or expression during communication. These finding may suggest during the a social experience an internet gaming addict has a harder time retrieving social axiouse words and cuse when compared to positive or negative words. This suggests social distrust, loneliness and lack of social support may factor identify the use of the internet for social behaviors.
While these finding are interesting the results cannot be said to truly capture the fullness and the complexity of human experience. The study used all male participants with an average age of 25 years old. This exclues woman both of the same age and older men to see if this was a trait specific with young men or specific to internet addiction. This study has some interesting finding and may be a starting place to see if this social anxiety for certain section of the population can be help with behavioral treatment plans.
Article #4 Summary
Dong, G., Wu, L., Wang, Z., Wang, Y., Du, X., & Potenza, M. N. (2018). Diffusion-weighted MRI Measures Suggest Increased White-Matter Integrity in Internet Gaming Disorder: Evidence From the Comparison with Recreational Internet Game Users. Addictive Behaviors, 81, 32–38. https://doi.org/10.1016/j.addbeh.2018.01.030
The study hypothesis it will find lower white matter in the regions of executive-control and decreased integrity in internet game addicts when compared to regular internet users. The study further hypothese it will find better white matter integrity in reward circuitry in individual with internet gaming addiction when compared to regular internet users.
Theory of the Research Question
The studies authors state internet gaming disorder is characterized by difficulties in controlling the urges to play online games regardless of the consequence to their personal life. Even though the disorder has yet to be added to the American Psychiatric Disorder Manual an increase in the number of people affected by this unique behavioral addiction has grown worldwide. The use of diffusion tensor imaging, a non-invasive MRI-based technology, may help scientist characterize the microstructural white matter organization of the brain to see what changes have occured.
Data suggests that many long axonal connections are established in early brain development but the diameter and microtubular structure of the axons continue to develop and change over time. Both experience and environment may affect the axonal structures and change the integrity of the brain over time. Prior studies have associate internet game disorder with functional impairment and behavioral problems. In fact many studies have found conflicting results in trying to understand what is happening to the human brain with extended internet gaming use.
Decrease area of FA within the right para-hippocampal gyrus in individuals with internet game disorder when compared with healthy controls. Other studies have found decreases in the OFC, corpus callosum, cingulum, inferior fronto-occipital fasciculus, corona radiata, and internal and external capsules. All of these changes suggest lower white-matter integrity in individuals with internet disorder. However, another study for internet gamers showed increased FA values in the right longitudinal fasciculus and decreases RD in the anterior thalamus when compared to healthy controls. One study found an increase in the thalamus and left posterior cingulate cortex in people suffering from Internet Gaming disorder.
Several explanation for these different finding may be attributed to the what the researcher was focusing on measuring. For example the decreased in FL region relating to executive control may relate to poor cognitive control when has been observed in Internet gaming disorder. On the other hand increases in the FA regions relating to reward-related drives or craving might be explained with the increase of goal driven behavior of Internet Gaming Disorder. The indication of increased gray matter in the striatum fits with this theory and the reliance on behaviors involving sensitivity and craving. One of the potential confound of any study when relating to people with internet gaming disorder and regular internet users is the difference in time spent participating in online activities. Repetitive and frequent engagement of gaming behaviors could increase the connections in the brain responsible for visual and auditory processing and motor control.
Hypotheses and Methodology
A diffusion tensor imaging(DTI) was used in this study. This technology is a non-invasive MRI-based technology which maps water diffusion in biological tissues. Four different diffusion parameters are regarded as indices of white matter integrity in the brain. These four pattern are fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD). FA reflect the directionality of the water diffusion and thus may estimate coherence of white matter fiber tracts. the AD measure may reflect axonal morphological changes, the RD measure may reflect characteristics related to myelination . The MD measures the overall magnitude of water diffusion through the brain. When taken together all of these measure give insight in the makeup and structure of the brain.
The participants of this study were recruited advertisement at the Zhejiang Normal University and the study used eighty-six participant broken down into forty-two IGD and forty-four healthy controls. To control for types of gaming the study only recruited subjects who regularly played League of Legends and played the game for at least one year. Participants with Internet Gaming Disorder was determined by their scores on Young’s online internet addiction test. To be included in the IGD group the participant needed to score <50 on the Younge’s test and met at least 5 of the 9 criteria for the IGD score per the DSM-definition. To examine if amount of time on the on the computer had any effect on brain matter the RGU, regular gaming use, were selected because they did play games but did not have the addiction qualities of the IGD group. This group had to have a > 55 on the Young’s IAT instrument, fewer than 4 of the 9 criteria and no report of interference from the internet in their life. In addition to the above criteria to qualify the RGU participants had to be playing games for at least two years without having dependent symptoms occur.
For scanning equipment he study used a 3.0T Siemens Trio scanner to acquire images. The images used a 64 non-collinear gradient and used b-value images 0 and 1000 s/mm2 with 50 contiguous slices. The software the authors’ used to evaluate the data for preprocessing and data analysis was PANDA which is a pipeline software using the FSL diffusion toolbox. To correct for any motion in the participant all images were aligned to b=0. A BET tool extracted a brain mask for each subject and non-brain tissues deleted in order to extract diffusion parameters. Tensor models and diffusion tensors created a least-square fit of all five of the b , FA, tensor values which describes the data. A probability model of each diffusion at each voxel created a probability tractor of the water diffusion through the brain. The study used post-hoc test to examine between group differences.
A whole brain analysis showed the IGD group with an increased FA in the bilateral anterior thalamic radiation, the anterior limb of the internal capsule, the bilateral corticospinal tract, the corpus callosum, bilateral inferior fronto-occipital fasciculus and bilateral inferior longitudinal fasciculus. However, the study did not find the any decreased in brain integrity between the IGD and the RGU subjects. The between group analysis of different areas did find some significant findings. A correlation between the FA values of different groups and internet-addiction severity did show a significant increase in FA in the IGD group. The FA correlated with the participants IT scores.
Discussion (Implications, importance, and limitations)
The FA measurement is a small part of the tensors which can be assigned to anisotropic diffusion. The higher FA values show an increase in the directionality of the diffusion and represents more cohesive neural organization. The study has shown the hypothesis to be wrong that the IGD group actually has an increased integrity of white matter in specific white-matter structures. The results of the study indicate IGD is associated with increased FA in the thalamic radiation bilaterally. There is also a higher connection between the anterior thalamic radiation and dorsomedial with the prefrontal cortex, this connection has been implicated in the brain’s reward system.
One of the limitation of this study is that lack of a non-playing control. The study was expecting to find specific deficits in the IGD group and decided to rule out the neural strengthening of habitual internet use. However, because of the lack of a limited internet use control there is no way to say that any internet uses increases white matter integrity. The question still remains is IGD a result of playing internet based games or is this just another addiction for people who are predisposed to addiction to become involved with.