FoundationalConceptsNeuroscience

of stability, in metastable states poised to react to perturbations from
incoming signals and make transitions from one state of global oscil-
latory activity to another.
Freeman proposes that cerebrocortical neuropil may be described
at the neurodynamic level as a uniquely unified system capable of
undergoing something like “phase transitions” into states of global
cooperativity, where aspects of neural activity (at least in part mea-
surable with EEG) are brought together in synchrony across the entire
cerebral cortex. The nature of these cooperative states depends upon
all the complexity of existing connections in the cortex, a vast net-
work that has been assembled over a lifetime of experience. In this
way, the cooperative synchrony of the neuropil functions to access
memories related to present states of activity—and these memories
inform the evolving experience of the perceptions that develop in
association with sensory stimuli. This is what gives a perception
meaning—linking it with memories (stored knowledge) of prior per-
ceptual experiences. These states of global cooperative synchrony are
the neural correlates of consciousness.
The global synchrony within the cortex unites sensory and motor
areas and results in action potentials in the motor system. Behavioral
actions result. Between sensation, perception, and action are neural
processes of unfathomable complexity, involving trillions of synaptic
processes and ephaptic couplings in the cortical neuropil. The high
level of ongoing brain activity—the dark energy—serves as the sub-
strate for manipulating and coupling sensory input and motor out-
put: perception and action.
To recap: activity in specific neural circuits (for example, signals
from sensory organs) impacts large-scale patterns of oscillatory
activity in the cortical neuropil, which in turn impacts activity in
specific neural circuits (for example, signals to muscles generating