Executive processes

Executive processes are higher order, self-regulatory, cognitive processes that aid in the monitoring and control of thought and action (Carson, 2005). They are necessary for the cognitive control of behaviour: selecting and successfully monitoring behaviours that facilitate the attainment of chosen goals.

Example of executive functions include: attentional control, cognitive inhibtion, inhibitory control, working memory, and cognitive flexbility.

Distinctions in executive processes: automatic vs controlled behaviour, and bottom-up vs top-down control.

Prefrontal cortex:

• involved with information processing such as integrating different dimensions of cognition and behaviour
• Patients with frontal lobe damage show deficits in executive functions (i.e Phinease Gage case study)
• Dysexecutive or frontal lobe syndrome (that which is associated with head injury or stroke affecting prefrontal cortex) generally disrupts executive functions too
• Patients with frontal lobe impairment take longer to plan and make decisions (Rowe et al, 2001), and fail to plain in an organised or coordinated way (Shallice & Burgess, 1991)
• They also have difficulties in correcting errors and trouble shooting (Milner, 1963), and overcoming habitual responses, as in the stroop test (Perret, 1974)

Supervisory Attentional System (Norman & Shallice, 1986):

• controlled behaviour arises through selection and implementation of schemas. Schema selection can be triggered in two ways: contention scheduling (primarily bottom-up triggering in routine situations), and supervisory attentional system (additional top-down control in non-routine situations)
• This explains why patients with impaired frontal lobe perform badly. In the stroop task, once activated, dominant schema "read word" persists in absence of inhibition
• In multiple errands test, disruption to selection and appropriate sequencing of schema leads to disorganised behaviour
• Distractability - task-unrelated schemas capture attention
• Evidence that goes against the single executive system asks why some patients fail some executive tasks, but perform well on others. Also, fMRI indicates that distinct frontal regions may play different roles in executive tasks