Characteristic brain function and network activity patterns in adolescent first-episode depression: a resting-state functional magnetic resonance imaging study

Background The characteristic brain function and network activity patterns in adolescents with first-episode depression (FED) remain systematically underexplored. This study aims to investigate abnormalities in cerebral function and networks in adolescent FED patients through analyses of the amplitude of low-frequency fluctuations (ALFF), fractional amplitude of low-frequency fluctuations (fALFF), and independent component analysis (ICA). Materials and methods A cohort of 36 adolescents with first-episode depression (patient group, PT) and 34 healthy controls (HC group) were enrolled. Depressive symptoms were assessed using the Hamilton Depression Rating Scale (HAMD) and Children’s Depression Inventory (CDI). All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI). Neuronal activity and functional network alterations were analyzed via ALFF, fALFF, and ICA methodologies. Results Compared to the HC group, the PT group exhibited increased ALFF values in the left fusiform gyrus (FusiformL), left middle temporal gyrus (TemporalMidL), right middle occipital gyrus (OccipitalMidR), right middle temporal gyrus (TemporalMidR), right calcarine cortex (CalcarineR), right angular gyrus (AngularR), and left calcarine cortex (CalcarineL). Elevated fALFF values were observed in the right calcarine cortex (CalcarineR) and left superior temporal gyrus (TemporalSupL), while decreased fALFF values were detected in the left superior temporal pole (TemporalPoleSupL), right medial superior frontal gyrus (FrontalSupMedialR), left superior frontal gyrus (FrontalSupL), and left precuneus (PrecuneusL). Connectivity differences within the visual network (VIN) were identified between groups, with a peak difference in the right inferior temporal gyrus (TemporalInfR), where the PT group demonstrated hyperconnectivity. Conclusion In summary, neurofunctional abnormalities in adolescent FED patients involve the temporal lobe emotion-processing network, prefrontal executive control system, and default mode network (DMN). Aberrant low-frequency activity in the temporal pole and superior frontal gyrus may exacerbate emotion dysregulation, whereas hyperactivation of the precuneus and visual cortex could potentiate negative self-referential processing. Notably, the right middle occipital gyrus may represent a distinctive biomarker of adolescent depression. These findings provide novel insights into the early neural mechanisms underlying adolescent depression and suggest that non-invasive neuromodulation techniques targeting specific brain regions (e. g. , transcranial magnetic stimulation, TMS) hold therapeutic potential.