Final answer:
The prefrontal lobe of the frontal cortex is the region most associated with behavioural spontaneity. Damage or alterations in the basal ganglia and dopaminergic systems can affect this aspect of behavior and cognitive function. Such impacts can be observed in various neurological and psychiatric conditions.
Step-by-step explanation:
The region of the brain responsible for behavioural spontaneity is located in the prefrontal lobe of the frontal cortex. The prefrontal lobe is associated with a variety of cognitive functions including personality, short-term memory, and consciousness, and its connection to behavioural spontaneity encompasses these cognitive abilities. When there is damage to specific regions within the frontal lobe, such as from a stroke or in clinical conditions like Parkinson's disease, behavioural alterations and deficits in cognitive functions are often evident.
Damage to the basal ganglia, a group of nuclei linked with the control of movement and motivated behaviors, can also influence behavioural spontaneity. For example, basal ganglia lesions may reduce an individual's spontaneous behavior, as seen in cases where external stimuli are required to prompt normal functioning. Furthermore, alterations in the dopaminergic innervation, as studied in the striatum and prefrontal cortex, have implications for motor control, motivation, cognition, and therefore, behavioural spontaneity.