Dept. of Physiology. University of Oslo - Oslo. A hypofunctioning meso-cortical dopamine system will produce frontal cortical hypofunctioning resulting in cognitive impulsiveness. Further, these systems are not operating in isolation, but are closely linked to other neurotransmitter and neuromodulator systems.
Frontal cortex receives a major dopamine input from the ventral tegmental area.
The reinforcing effect is largest when the reinforcer is delivered immediately after the occurrence of the response and wanes as a function of the delay of the delivery of the reinforcer. Therefore, a normal delay gradient will shape and maintain integrated chains of behaviour. This will generate overactivity as gradually more reinforcers act on the behaviour that is taking place in a particular situation. Increased behavioural variability. In contrast to the normal delay gradient, mostly short IRTs may be reinforced and maintained by a short delay gradient Fig.