Table 2.

Examples of human features and animal model correlates for mental health conditions: Neuroimaging and neurochemical correlates.

	Human neuroimaging features		Neurochemical correlates in animal models
ADHD	fMRI	Reduced blood flow in fronto-striatal, fronto-cerebellar, and fronto-striato-parieto-cerebellar networks	Dysregulated dopamine metabolism and transmission
		Increased blood flow in posterior parietal lobe, PCC, and regions of dlPFC
	PET	Abnormal dopamine transporter binding, dopamine receptor binding, and dopamine metabolism in right caudate	Dysregulated (increased or decreased) extracellular dopamine and/or norepinephrine concentrations
		Decreased ${\mathrm{D}}_2/{\mathrm{D}}_3$ receptor availability in left caudate
		Decreased dopamine transporter density in midbrain	Decreased spontaneously active ventral tegmental area dopaminergic neurons
	DTI	Abnormal white matter structural anatomical connectivity in fronto-striatal circuitry, fronto-cerebellar circuitry, and executive functioning and attentional networks	Impaired modulation of cortico-striato-thalamo-cortical circuits
SUD	fMRI	Hypoactive PFC during cognitive tasks	Increased dopamine signaling
	rsMRI	Decreased connectivity in the default mode network	Increased activity in mesolimbic pathway
	PET	Reduced regional brain glucose metabolism in PFC and ACC
	EEG	Altered P300 on reward processing tasks	Dysregulated hypothalamic-pituitary-adrenal activity
MDD	fMRI	Increased activity in mPFC, amygdala, and hippocampus	Increased circulating glucocorticoids and decreased glucocorticoid receptors
		Decreased activity in IPFC, and striatum
	PET	Hyperactivity in the mPFC	Increased pro-inflammatory cytokines and decreased anti-inflammatory cytokines
		Altered metabolism and neural activity in the PCC, insula, hippocampus, and amygdala
		Altered serotonin receptor binding	Decreased serotonin levels
	DTI	Abnormal white matter integrity in superior longitudinal fasciculus, corpus callosum, and uncinate fasciculus	Decreased hippocampal brain derived neurotrophic factor expression
	MRI/VBM	Decreased volume in mPFC, IPFC, striatum, amygdala, and hippocampus
OCD	rsMRI	Abnormal functional connectivity in OFC and ACC	Altered cortico-basal ganglia-thalamo-cortical activity
	PET/SPECT	Intrusive thought-induced hyperactivity in the OFC	Altered dopamine receptor subtype composition and dopamine receptor binding
		Anxiety related hyperactivity in the ACC	Disturbed redox balance
		OCD stimuli-induced increased activity in OFC and ACC	Altered firing and postsynaptic currents in bed nucleus of the stria terminalis neurons
	MRI/CT/VBM	Structural changes in OFC, ACC, basal ganglia, and thalamus	Altered cyclic adenosine-monophosphate phosphodiesterase signaling
			Altered serotonin reuptake transporter expression
PTSD	fMRI	Hyperactivity in the amygdala	Increased stress hormones
		Hypoactivity in the mPFC and ACC	Increased epigenetic methylation of brain-derived neurotrophic factor gene in hippocampus
		Reduced hippocampal activity	Upregulated corticotropin releasing factor receptors in stria terminalis
	MRI/MRS	Structural changes in hippocampus, amygdala, and mPFC	Decreased hippocampal plasticity
			Increased cortical and hippocampal expression of glucocorticoid receptors

Note: ADHD findings summarized in Weyandt et al. (2013) and Russell (2005, 2007). SUD findings summarized in Cabrera et al. (2016) and Koob and Simon (2009). MDD findings summarized in Wise et al. (2014), Krishnan and Nestler (2011), and Wang et al. (2017). OCD findings summarized in Holzschneider and Mulert (2011) and Szechtman et al. (2017). PTSD findings summarized in Holzschneider and Mulert (2011) and Borghans and Homberg (2015). Endogenous event-related potentials between 300–600 ms after cue (P300). ACC, anterior cingulate cortex; ADHD, attention deficit/hyperactivity disorder; CT, computerized tomography; d, dorsal; DTI, diffusion tensor imaging; EEG, electroencephalogram; fMRI, functional MRI; IPFC, inferior prefrontal cortex; l, lateral; m, medial; MDD, major depressive disorder; mPFC, medial prefrontal cortex; MRI, magnetic resonance imaging; MRS, magnetic resonance spectroscopy; OCD, obsessive compulsive disorder; OFC, orbitofrontal cortex; PET, positron emission tomography; PFC, prefrontal cortex; PCC, posterior cingulate cortex; PTSD, posttraumatic stress disorder; rsMRI, resting state MRI; SPECT, single photon emission computerized tomography; SUD, substance use disorder; VBM, voxel based morphometry.