Cingulate Cortex

Anterior Cingulate Cortex

The ACC underlies functions such as attention, motor control, emotional processing, regulation of cognitive processes, and social thinking. Research has identified separate subregions of the ACC involved in cognition (dorsal ACC), motor control (caudal ACC), and emotion (rostral ACC).

Cognitively, functions of the ACC include modulating attention, monitoring competing demands, detecting novelty or error, and motivating one’s own behavior. The ACC is likely to be activated by tasks that are deemed cognitively demanding or require an individual to process competing demands and choices. The ACC plays an important role in evaluating and monitoring “mismatches” between an individual’s goals and behavior. In this way, the ACC initiates adjustments in an individual’s thinking or behavior with the aim of achieving a desired goal. The ACC also helps an individual to select appropriate behaviors when faced with a wide range of novel choices. The ACC’s connections with [Page 256]the lateral prefrontal cortex, parietal cortex, and supplemental motor area allow it to influence a broad range of cognitive and motor processing. As such, the ACC plays a crucial role in self-regulating one’s own thinking and behavior.

The ACC also plays a role in motor functioning, or more specifically, premotor functioning. In fact, influence of the ACC occurs well before movement occurs. The ACC helps to determine whether or not a movement is necessary and assists in selecting which movement is needed. Its connections with the supplemental motor are crucial in this regard, and disruption of these pathways may result in sensorimotor processing impairments such as neglect (i.e., impairment in awareness of visual and other stimuli). Motor neglect and other sensorimotor and premotor processing impairments may result from interruption of these connections.

Emotional processing also is mediated, at least in part, by the ACC. In particular, the ACC helps to evaluate the salience of emotional cues and assists an individual in regulating emotional responses. Studies have shown that electrical stimulation of specific ACC regions evokes a range of emotional responses, including fear, agitation, and pleasure. Not surprisingly, the ACC has also been linked to the experience of pain. Lesions of the ACC typically impact emotional functioning, precipitating symptoms such as apathy or emotional lability.

Posterior Cingulate Cortex

Whereas the ACC links external cues to goal-directed behavior, the PCC appears to play an important role in self-reflection. That is, the PCC becomes activated when an individual directs attention to internal stimuli or thoughts. It plays a central role in a brain network known as the default mode network (DMN), which becomes active when the brain is at wakeful rest and an individual is not focused on the external or outside world. Functions that activate the PCC include retrieving autobiographical memories, planning for the future, and daydreaming. PCC activity is also sensitive to changes in awareness that are associated with different sleep stages.

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