A Long-Range Fronto-Parietal 5- to 10-Hz Network Predicts "Top-Down" Controlled Guidance in a Task-Switch Paradigm

Abstract

The capacity to rapidly adjust behavioral strategies according to changing task demands is closely associated with coordinated activity in lateral and medial prefrontal cortices. Subdivisions within prefrontal cortex are implicated to encode attentional task sets and to update changing task rules, particularly when changing task demands require top-down control. Here, we tested whether these top-down processes precede stimulus processing and constitute a preparatory attentional state that functionally couples with parietal cortex. We examined this functional coupling by recording from intracranial EEG electrodes in macaques during performance of a task-switching paradigm that separates task performance that is based on controlled top-down guidance from automatic, stimulus-triggered processing modes. We identify a prefrontal-parietal network that phase synchronizes at 5-10 Hz, particularly during preparatory states that indicate top-down controlled task-processing modes. Phase relations in the network suggest that medial and lateral prefrontal cortices synchronize bidirectionally, with medial prefrontal cortex showing a phase-lead relative to left parietal recorded 5- to 10-Hz preparatory signals. These findings reveal a 5- to 10-Hz coordinated, long-range fronto-parietal network prior to actual task-relevant stimulus processing, particularly when subjects engage in controlled task processing modes.

Theta–gamma coordination between anterior cingulate and prefrontal cortex indexes correct attention shifts

“…Our main finding characterized the statistical relation of two band-limited activity fluctuations comprising a narrow ∼5-to 10-Hz (peak at 7 Hz) theta band and a ∼35-to 55-Hz (peak at 40 Hz) gamma band. Previous studies have documented that a 5-to 10-Hz theta band is a widespread LFP signature in ACC/PFC that increases with specific demands to control goal-directed behavior (22)(23)(24)(25). Our study corroborates these reports (Fig.…”

Corticostriatal Coordination through Coherent Phase-Amplitude Coupling

“…Our data extend these findings by showing that the peak frequencies of corticostriatal theta and gamma oscillations scale with movement speed. This suggests that theta and gamma oscillations are also involved in corticostriatal processing in the most basic functional domain of the corticobasal ganglia system, motor behavior (Marsden, 1982;Phillips et al, 1993;Mink, 1996;Turner and Desmurget, 2010).…”

“…The striatum is the main input structure of the basal ganglia (Alexander et al, 1986;Parent and Hazrati, 1995) and is thought to be involved in reinforcement learning and procedural memory (Bar-Gad et al, 2003;Schultz et al, 2003;Yin and Knowlton, 2006). Furthermore, the striatum also has an important role in motor behavior.…”

Creating external reminders for delayed intentions: Dissociable influence on “task-positive” and “task-negative” brain networks

“…Likewise, White et al (2013) concluded that in their fMRI-EEG study "it is likely that the frontal theta recorded currently has a medial frontal DMN [default mode network] source" (p. 2940; see also Michels et al, 2010 for a similar conclusion). Phillips et al (2014) provided direct evidence in the macaque for a role of theta-band oscillations in cognitive control, with a medial frontal source. It is unclear why the increased theta power recorded with EEG should be accompanied by reduced BOLD signal recorded with fMRI, but one possibility, supported by both theoretical and empirical arguments, is that periods of increased theta power may be accompanied by a decrease in power in higher frequencies such as gamma, and hence a net reduction in metabolic demand (Hsieh & Ranganath, 2014;Kilner et al, 2005).…”