The striatum and other parts of the basal ganglia
We have seen that the orbitofrontal cortex and amygdala are involved in decoding the stimuli that provide the rewards for feeding, and in connecting these signals to hunger/satiety signals. How do these brain regions further connect to behavioural systems? One path is via the hypothalamus, which is involved in autonomic responses during feeding (such as the need for increased blood flow to the gut, to facilitate the assimilation of food into the body), and also in the rewarding aspects of food. Another route is via the striatum (one part of the basal ganglia, requiring dopamine to function – see chapter 3) and then on through the rest of the basal ganglia (see figure 5.5). This route is important as a behavioural output/feeding system, because disruption of striatal function results in aphagia (lack of eating) and adipsia (lack of drinking) in the context of a general akinesia (lack of voluntary movement) (Rolls, 1999; Rolls & Treves, 1998). Neurons in the ventral striatum also respond to visual stimuli of em otional or motivational significance (i.e. associated with rewards or punishments; Williams et al., 1993), and to types of reward other than food, including drugs such as amphetamine (Everitt, 1997; Everitt & Robbins, 1992).
We have seen that the orbitofrontal cortex and amygdala are involved in decoding the stimuli that provide the rewards for feeding, and in connecting these signals to hunger/satiety signals. How do these brain regions further connect to behavioural systems? One path is via the hypothalamus, which is involved in autonomic responses during feeding (such as the need for increased blood flow to the gut, to facilitate the assimilation of food into the body), and also in the rewarding aspects of food. Another route is via the striatum (one part of the basal ganglia, requiring dopamine to function – see chapter 3) and then on through the rest of the basal ganglia (see figure 5.5). This route is important as a behavioural output/feeding system, because disruption of striatal function results in aphagia (lack of eating) and adipsia (lack of drinking) in the context of a general akinesia (lack of voluntary movement) (Rolls, 1999; Rolls & Treves, 1998). Neurons in the ventral striatum also respond to visual stimuli of em otional or motivational significance (i.e. associated with rewards or punishments; Williams et al., 1993), and to types of reward other than food, including drugs such as amphetamine (Everitt, 1997; Everitt & Robbins, 1992).
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