The study explores the diversity of neurons and their temporal dynamics in the hippocampal CA1 area, highlighting the role of GABAergic interneurons in regulating the activity of pyramidal cells. It reveals that distinct GABAergic cell types subdivide the surface of pyramidal cells and act in discrete time windows, either on the same or different subcellular compartments. These interneurons interact with glutamatergic inputs in a domain-specific manner, supporting synaptic dynamics, network oscillations, and cognitive processing. The spatiotemporal specializations in cortical circuits show that cellular diversity and temporal dynamics co-evolved, enabling complex cognitive functions. Pyramidal cells in the CA1 area encode spatial and episodic memories and provide glutamatergic output to other brain regions. They are supported by a rich diversity of GABAergic interneurons that provide inhibition and regulate pyramidal cell activity. These interneurons are distinguished by their firing patterns, molecular profiles, and innervation of distinct subcellular domains of pyramidal cells. Different types of GABAergic interneurons innervate distinct subcellular domains of pyramidal cells, contributing to spatiotemporal GABAergic conductance matrices that change during different brain states. The firing patterns of interneurons are temporally coordinated with network oscillations, such as theta and gamma oscillations, which are critical for cognitive processing. During theta oscillations, O-LM cells become active and modulate pyramidal cell dendrites. During gamma oscillations, different types of interneurons contribute to the temporal modulation of pyramidal cell subcellular domains. The unique spike timing and molecular design of GABAergic cells support sparse coding in cell assemblies. The study also shows that the same domain of pyramidal cells receives differentially timed GABAergic input from distinct sources, highlighting the importance of temporal coordination in cortical circuits. GABAergic projection neurons support the coordination of network states across cortical areas, contributing to the temporal organization of brain states. The dynamic cooperation of pyramidal cells and specific GABAergic interneurons in cell assemblies enables nonlinear emergence of cell assemblies through state-dependent effects and combinatorial GABAergic inputs. In conclusion, the diversity of cortical neurons is accompanied by sophisticated temporal differentiation of their activity, which is essential for cognitive functions. The study emphasizes the importance of temporal coordination and the role of GABAergic interneurons in regulating cortical circuits.The study explores the diversity of neurons and their temporal dynamics in the hippocampal CA1 area, highlighting the role of GABAergic interneurons in regulating the activity of pyramidal cells. It reveals that distinct GABAergic cell types subdivide the surface of pyramidal cells and act in discrete time windows, either on the same or different subcellular compartments. These interneurons interact with glutamatergic inputs in a domain-specific manner, supporting synaptic dynamics, network oscillations, and cognitive processing. The spatiotemporal specializations in cortical circuits show that cellular diversity and temporal dynamics co-evolved, enabling complex cognitive functions. Pyramidal cells in the CA1 area encode spatial and episodic memories and provide glutamatergic output to other brain regions. They are supported by a rich diversity of GABAergic interneurons that provide inhibition and regulate pyramidal cell activity. These interneurons are distinguished by their firing patterns, molecular profiles, and innervation of distinct subcellular domains of pyramidal cells. Different types of GABAergic interneurons innervate distinct subcellular domains of pyramidal cells, contributing to spatiotemporal GABAergic conductance matrices that change during different brain states. The firing patterns of interneurons are temporally coordinated with network oscillations, such as theta and gamma oscillations, which are critical for cognitive processing. During theta oscillations, O-LM cells become active and modulate pyramidal cell dendrites. During gamma oscillations, different types of interneurons contribute to the temporal modulation of pyramidal cell subcellular domains. The unique spike timing and molecular design of GABAergic cells support sparse coding in cell assemblies. The study also shows that the same domain of pyramidal cells receives differentially timed GABAergic input from distinct sources, highlighting the importance of temporal coordination in cortical circuits. GABAergic projection neurons support the coordination of network states across cortical areas, contributing to the temporal organization of brain states. The dynamic cooperation of pyramidal cells and specific GABAergic interneurons in cell assemblies enables nonlinear emergence of cell assemblies through state-dependent effects and combinatorial GABAergic inputs. In conclusion, the diversity of cortical neurons is accompanied by sophisticated temporal differentiation of their activity, which is essential for cognitive functions. The study emphasizes the importance of temporal coordination and the role of GABAergic interneurons in regulating cortical circuits.