A major goal of neuroscience is to reveal mechanisms supporting collaborative actions of neurons in local and larger-scale networks.
However, no clear overall principle of operation has emerged despite decades-long experimental efforts. Here, we used an unbiased
method to extract and identify the dynamics of local postsynaptic network states contained in the cortical field potential. Field
potentials were recorded by depth electrodes targeting a wide selection of cortical regions during spontaneous activities, and sensory,
motor, and cognitive experimental tasks. Despite different architectures and different activities, all local cortical networks generated
the same type of dynamic confined to one region only of state space. Surprisingly, within this region, state trajectories expanded and
contracted continuously during all brain activities and generated a single expansion followed by a contraction in a single trial. This
behavior deviates from known attractors and attractor networks. The state-space contractions of particular subsets of brain regions
cross-correlated during perceptive,motor, and cognitive tasks. Our results imply that the cortex does not need to change its dynamic to
shift between different activities, making task-switching inherent in the dynamic of collective cortical operations. Our results provide
a mathematically described general explanation of local and larger scale cortical dynamic.