## 10 Discussion
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Study** & **Analysis** & \begin{tabular}{c} **Type of Injury and** \\ **Baseline Group** \\ \end{tabular} & **Affected Areas** \\ \hline \hline \multicolumn{4}{c}{**Meta-analysis**} \\ \hline [PERSON] et al. [22] & Volumetric changes & \begin{tabular}{c} 9 TBI ranging from mild to \\ severe patients vs. 9 HC \\ \end{tabular} & \begin{tabular}{c} \(\downarrow\) GM volumes in the frontal and temporal \\ cortex, cingulate gyrus, subcortical area, \\ and cerebellum \\ \end{tabular} \\ \hline [PERSON] et al. [23] & Volumetric changes & 77 mTBI patients vs. 42 HC & \begin{tabular}{c} \(\uparrow\) GM volumes in the right dorsal anterior \\ cingulate cortex, and dorsal posterior \\ cingulate cortex \\ \end{tabular} \\ \hline [PERSON] et al. [24] & Volumetric changes & 34 mTBI patients vs. 16 HC & \begin{tabular}{c} \(\downarrow\) GM volumes of precuneus, medial \\ orbitofrontal gyrus \\ age-dependent accelerated hippocampal \\ volume loss \\ \end{tabular} \\ \hline [PERSON] et al. [25] & Volumetric changes & 50 mTBI patients vs. 21 HC & \begin{tabular}{c} \(\downarrow\) GM volumes of the right \\ anterior—parietal and left \\ temporal—pocural areas (headache + mTBI vs. non-headache + mTBI), \\ \(\downarrow\) GM volumes of the left thalamus \\ (non-headache + mTBI vs. HC) \(\downarrow\) GM \\ volumes of the left temporal—pocural, temporal—parietal, superior frontal gyrus, and of the right middle frontal/superior \\ frontal gyrus, and the anterior-parietal \\ gyrus (headache + mTBI vs. HC) \\ \end{tabular} \\ \hline [PERSON] et al. [26] & \begin{tabular}{c} Combined morphometry \\ and ReHo analysis \\ \end{tabular} & \begin{tabular}{c} 18 diffuse axonal injury \\ patients vs. 18 HC \\ \end{tabular} & \begin{tabular}{c} \(\downarrow\) GM density in bilateral thalami \\ \end{tabular} \\ \hline \multicolumn{4}{c}{**Systematic review**} \\ \hline [PERSON] et al. [10] & \begin{tabular}{c} VBM, cognitive \\ performance, GCS, total \\ intracranial volume \\ \end{tabular} & 50 mTBI patients vs. 35 HC & \begin{tabular}{c} Significant positive correlation between \\ GM volume in left and right insular \\ cortices and cognitive performance \\ testing scores \\ \end{tabular} \\ \hline [PERSON] et al. [27] & Volumetric changes & 26 mTBI vs. 12 HC & \begin{tabular}{c} \(\uparrow\) GM volumes in the ventromedial \\ prefrontal cortex and right fusiform cortex \\ \end{tabular} \\ \hline [PERSON] et al. [28] & Volumetric changes & \
\begin{tabular}{c} 12 TBI ranging from mild to \\ severe patients \\ \end{tabular} & no GM changes \\ \hline [PERSON] et al. [29] & Volumetric changes & 46 mTBI patients vs. 36 HC &
\begin{tabular}{c} \(\downarrow\) GM and WM volumes in thalamus and \\ bilateral pallidum. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of the main findings and characteristics of the studies included in the present review and meta-analysis. In our analysis, suggested that the frontal and temporal cortices seem to be mainly affected, showing a significant decrease in GM volume in mTBI patients. Since the frontal and temporal cortices are implicated in cognitive processes, such as attention, prospective memory, and cognitive flexibility, and stimuli perception, emotional processing, and memory formation, respectively, it could be suggested that the general negative outcomes of mTBIs could be associated with cognitive impairments regarding the mentioned processes. In this way, the most frequent condition following mTBs is the post-concussion syndrome, characterized by headaches, postural and balance impairments, and attention and concentration deficits [3], all of which are short-termed and fully reversible. Frontal and temporal lobes (Brodmann areas: 11, 45, 10, 21) showed significant volume loss, while 23 Brodmann areas that correspond to cingulate/paracingulate gyri and 9 that corresponds to the middle frontal gyrus, as well as the caudate nucleus, showed significant GM volume increase.