## 4 Discussion
This is consistent with [PERSON] et al., where tasks like Digit Cancellation, Symbol Search, and Digit Symbol Coding assessed cognitive gains through correct responses, highlighting the role of structured training in enhancing cognitive function in older adults [16]. After applying a 4-week, 12-session drumming-based cognitive and physical training intervention, the significant increase in success rate (19.44%, \(p\) = 0.0001) suggests improved task accuracy and learning efficiency. These findings are consistent with previous studies showing that physical activity and multimodal training contribute to cognitive resilience by enhancing executive function, attentional control, and neuroplasticity [17; 18]. No significant changes were observed in GDS scores. This may be due to the overall low baseline levels of depressive symptoms (mean \(\approx\) 8.3), which may have limited the potential for measurable emotional improvement. Although the score distribution does not strongly indicate a floor effect across the sample, it may have influenced the results for some individuals. The final measurements obtained from each optode were expressed as the mean total oxygenated hemoglobin (HbO \(\upmu\)m). A total of 15 channels were strategically positioned across both hemispheres, focusing on specific prefrontal regions: the dorsolateral prefrontal cortex (DLPFC) (channels 2, 3, 12, 14), the orbitofrontal cortex (OFC) of channels 1, 4, 7, 10, 13, and 15, and the frontopolar prefrontal cortex (FPPFL) of channels 5, 6, 8, 9, and 11 [19]. Regarding their exact placement, channel 1 was located on the right lateral OFC, while channels 4 and 7 were positioned in the right medial OFC. Channels 2 and 3 were mapped onto the right DLPFC, whereas channel 15 was assigned to the left lateral OFC. Furthermore, channels 10 and 13 corresponded to the left medial OFC, channels 12 and 14 were designated for the left DLPFC, and channels 5, 6, 8, 9, and 11 covered the frontopolar prefrontal cortex. This distribution ensured a comprehensive assessment of hemodynamic activity in these key cognitive regions [19]. In the results, the mean HbO \(\upmu\)m channel 15 located on the left OFC of the experimental group, was statistically significant when compared to the control group (\(p\) = 0.0285). The orbitofrontal cortex (OFC) integrates sensory information with reward-related and affective processing, linking reinforcement to hedonic experience [20; 21]. Additionally, the OFC enables flexible decision-making by updating outcome expectations [22]. In our study, the rhythmic and feedback-rich nature of the drumming task likely engaged OFC-mediated processes by promoting reward expectancy and emotional salience. Furthermore, older adults tend to rely more on OFC-based affective strategies than on dorsolateral prefrontal executive functions [23; 24], which may explain the regional specificity observed. Previous research has also shown that OFC plays a key role in reversal learning, where individuals adjust stimulus-reward associations based on feedback. Lesion studies demonstrate that OFC damage impairs this ability, while other forms of cognitive flexibility are linked to the vIPFC (ventrolateral prefrontal cortex) [25, 26]. Functional neuroimaging confirms increased OFC activation during reversal learning, particularly after negative feedback [27]. Moreover, the OFC is involved in emotional regulation via its interaction with the amygdala [28, 29]. In this study, after a 4-week, 12-session drumming-based cognitive and physical training intervention, the mean HbO concentration in channel 15, located in the left OFC of the experimental group, was significantly higher compared to the control group (\(p\) = 0.0285). This finding contrasts with our previous study, which examined healthy adults and found significant activation in the right dorsolateral prefrontal cortex (DLPFC, Channel 2) and right medial OFC (Channels 7 and 10) during a single drumming session [9]. Given that the OFC is primarily involved in affective and reinforcement learning [30].