| Cognitive deficits |
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| Working memory |
Dorsolateral prefrontal, parietal, and cerebellar cortices; subcortial white matter |
Dopamine, norepinephrine, ?acetylcholine |
Overlaps with attentional deficit |
| Short-term memory |
Frontal and hippocampal cortices |
acetylcholine |
Remote memory typically intact |
| Attention |
Frontal, cingulate and parietal cortices, subcortical white matter, reticular activating system |
Dopamine, norepinephrine acetylcholine |
“Top-down” processing may be impaired in TBI of all severities, “bottom-up” (arousal) more often in severe TBI |
| Processing speed |
Subcortical white matter tracts |
Catecholamines, acetylcholine |
Underlies complaints of “slowed thinking” |
| Dysexecutive syndromes |
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|
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| Disinhibition/social comportment |
Orbitofrontal subcortical circuit |
Complex interaction of GABA, catecholamines serotonin and others |
Emotional responses including anger out of proportion to precipitant |
| Cognitive dysexecutive |
Dorsolateral prefrontal cortex |
Interaction of GABA, catecholamines and others |
Overlaps with cognitive deficits described above |
| Disorders of motivated behavior |
Medial frontal cortex, anterior cingulate, related reward circuitry |
dopamine, norepinephrine |
Often presents as apathy and can be confused with depression |
| Psychiatric disorders |
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|
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| Depression |
?left anterior frontal cortex, temporo-limbic circuitry |
? dopamine, norepinephrine serotonin |
Associated with poor short and long-term outcome |
| Substance abuse |
Components of reward circuitry (nucleus accumbens, frontal cortex) |
Dopamine, norepinephrine, opiod system? |
Often present before injury but can arise de novo
|
| PTSD |
Medial and orbitofrontal cortices, amygdala, hippocampus |
? serotonin, norepinephrine, dopamine |
Cognitive deficits increase risk of PTSD |
