Table 1.
Neurocognitive domain | Definition | Task | Neural system | Neurochemistry | Pharmacological probes |
---|---|---|---|---|---|
Motor impulsivity | Impaired ability to stop motor responses following environmental change | Go/No-Go (GNG) for stopping responses before they have been initiated; Stop signal reaction time task (SSRT) for stopping an already triggered motor response. |
Right inferior frontal gyrus and subcortical (including subthalamic) connections | Norepinephrine | Reduced by methylphenidate and atomoxetine. |
Disadvantageous Decision-making | Difficulty weighing options and taking appropriate risks based on available information | Decision-making or gambling tasks (e.g., Cambridge Gambling Task (CANTAB), Iowa Gamble Task) | OFC and subcortical connections | Cortex: serotonin Subcortical circuitry: serotonin/dopamine |
Reduced by methylphenidate |
Choice impulsivity | Excessive discounting of delayed reinforcement | Delay-discounting task (DDT) | VMPFC, OFC. Valuation: Substantia nigra, ventral striatum and VMPFC, Cognitive control: Anterior cingulate cortex and VMPFC, Imagery/prospection: Medial temporal lobe and white matter connections |
VMPFC: serotonin OFC: dopamine |
Increased by D1 dopamine receptor antagonist and alpha2 adrenergic receptor agonist. Reduced by methylphenidate. for experimental rewards (but not for hypothetical rewards) |
Reflection impulsivity | Reduced tendency to collect salient information from the environment before decision-making | Information-sampling tasks; e.g., Cambridge Information Sampling Task (IST) |
Not known | Serotonin | Increased by 5-HT2R antagonist; Reduced by 5-HT2R agonist |
OFC = Orbitofrontal cortex; VMPFC = Ventromedial prefrontal cortex; CANTAB = Cambridge Neuropsychological Test Automated Battery