The article discusses the functional role of cross-frequency coupling (CFC) in neuronal computation, communication, and learning. CFC, particularly phase-amplitude CFC, is observed across different brain areas and tasks, where the strength of coupling varies dynamically in response to sensory, motor, and cognitive events. Low-frequency brain rhythms, such as theta and alpha, are entrained by external and internal events, while high-frequency rhythms, such as gamma, reflect local cortical processing. CFC serves as a mechanism to integrate information from large-scale brain networks to local cortical processing, facilitating effective computation and synaptic modification. The review examines various types of CFC, empirical evidence, methods for assessing CFC, and its role in learning and memory. It highlights the dynamic and transient nature of CFC, its relationship with task performance, and its potential as a marker for learning and memory. The cellular and network origins of CFC are also discussed, emphasizing the importance of interneurons in generating and modulating different frequency bands. Overall, the article suggests that CFC plays a crucial role in integrating multi-scale networks and regulating synaptic connections vital for memory and learning.The article discusses the functional role of cross-frequency coupling (CFC) in neuronal computation, communication, and learning. CFC, particularly phase-amplitude CFC, is observed across different brain areas and tasks, where the strength of coupling varies dynamically in response to sensory, motor, and cognitive events. Low-frequency brain rhythms, such as theta and alpha, are entrained by external and internal events, while high-frequency rhythms, such as gamma, reflect local cortical processing. CFC serves as a mechanism to integrate information from large-scale brain networks to local cortical processing, facilitating effective computation and synaptic modification. The review examines various types of CFC, empirical evidence, methods for assessing CFC, and its role in learning and memory. It highlights the dynamic and transient nature of CFC, its relationship with task performance, and its potential as a marker for learning and memory. The cellular and network origins of CFC are also discussed, emphasizing the importance of interneurons in generating and modulating different frequency bands. Overall, the article suggests that CFC plays a crucial role in integrating multi-scale networks and regulating synaptic connections vital for memory and learning.