Metaphors are seen as psycholinguistic phenomena that reveal human cognition. However, their neural basis in naturalistic contexts remains underexplored, although it offers insights into how metaphors shape everyday cognition at the neural level. In this study, we examine how metaphors are reflected in brain activity using electroencephalography (EEG). We analyze EEG data collected during naturalistic reading conditions, where participants read texts without explicit cues indicating the presence of metaphors. Using MetaPro, an advanced metaphor processing tool, we aim to identify the neural signatures of metaphor perception in real-world contexts. Our results reveal significant differences in EEG patterns between metaphorical and literal language. Metaphorical cognition is associated with increased high-frequency EEG variability and enhanced functional connectivity in the left hemisphere. Case studies suggest that different metaphorical concept mappings correspond to distinct neurocognitive patterns. These findings provide important neural evidence for the use of metaphorical concept mappings to analyze and differentiate cognitive processes.