Titolo della tesi: Criticality in the Macaque Cortex
The healthy brain is believed to operate near "Criticality", a transition phase
between ordered and disordered states. This transition phase, known as the
critical state, has remarkable properties that are highly beneficial for the
brain. For example, it provides maximal sensitivity to perturbations, a large
repertoire of dynamical states, and enhanced capacity to store, process, and
transfer information. Here, we have investigated criticality in the awake
macaque cortex using extracellular recordings from specific areas of the brain,
such as the frontal pole and the dorsal premotor cortex (PMD) during different
task-free epochs of the object-in-place paradigm. Using the maximum likeli-
hood estimation (MLE) method and the KS test, we detected avalanches with
true power-law distributions and obtained accurate critical exponents. The
results revealed differences between regions during different epochs of the
task. To measure proximity to criticality quantitatively, the DCC parameter,
which is defined based on the scaling relation between critical exponents, has
been used. The DCC indicated that the frontal pole area remained near the
critical state regardless of the task epoch, whereas the PMD area deviated from
criticality during Inter-Trial Intervals. However, in longer pauses between the
task, such as white screen and resting sessions, both areas approached the
critical state. In addition, the frontal pole area was closer to it and showed
smaller variations in its distance during the resting-state epoch compared to
the PMD area.
keywords: Criticality, the MLE method, KS test, DCC parameter.