Table 2

Summary of SPECT, PET and fMRI studies of psychogenic amnesia

Study, participants	Impairment	Method	Critical comparison	Changes
Markowitsch 199729—Single case	Probable psychogenic amnesia, retrograde	SPECT (resting perfusion), PET (activation)	SPECT 3 weeks post onset. PET 6 months post onset. Episodic retrieval: old sentences (information heard one day prior to scanning) vs new sentences	Resting SPECT: ⇓right inferior frontal and anterior temporal cortex PET: ⇑bilateral precuneus and parietal, right lateral PFC (BA 8) and PCC. ⇓Left middle temporal gyrus and superior temporal gyrus, bilateral premotor cortex, left thalamus and cerebellum
Markowitsch 200030—Single case	Psychic shock induced mnestic block syndrome	FDG-PET (resting)	2 vs 12 months after syndrome onset each in comparison with controls, some recovery at 12 month mark. ROI in temporal lobes and thalami only	At 2 months: ⇓left temporal mesial cortex and thalamus. At 12 months: normalised metabolism.
Yasuno 200031—Single case, 12 healthy controls	Psychogenic amnesia, retrograde	PET (activation)	Interaction: famous face versus gender discrimination, 2 vs 12 months after syndrome onset. No direct statistical comparison with controls.	⇑Left medial frontal cortex and right hippocampal region at 12 relative to 2 months ⇓Left ACC and parieto-occipital junction, right occipital cortex, middle lateral PFC (BA 9, DLPFC) and anterior medial temporal region including the amygdala at 12 relative to 2 months
Yang 200532—Single case	Selective retrograde psychogenic amnesia, after a severe stressful event.	fMRI	Recognisable faces of pre-amnesic period friends. Unrecognisable faces of post-amnesia period friends. Unfamiliar faces. No direct statistical comparison	Recognisable faces: ⇑amygdala, hippocampus, parahippocampal gyrus and insula. Unrecognisable and unfamiliar faces: ‘significantly less activation in the limbic area’
Botzung 200733—Single case	Psychogenic autobiographical memory loss for period to age 16	fMRI	Recall of residual autobiographical memories from amnesic period vs recall from preserved period (rather than successful inhibition of memories from amnesic period)	⇑Left superior temporal gyrus, insula, posterior inferior temporal gyrus, precuneus, superior parietal gyrus, cerebellum. Right inferior occipital gyrus, temporo-occipital junction, superior parietal gyrus. Bilateral retrosplenial and PCC. ⇓Left parahippocampal gyrus, ACC, precuneus, DLPC, middle frontal gyrus.
Hennig-Fast 200834—Single case, 9 healthy controls	Persistent retrograde amnesia following a dissociative fugue	FDG-PET (resting, acute state only), fMRI	fMRI: Presentation of autobiographical versus various types of non-autobiographical information. Acute state vs one year post-onset. No direct statistical analysis of interaction	Resting PET: Reduced metabolism right temporo-mesial area. fMRI, acute state, autobiographical: ⇑dorsal ACC and PCC, precentral and subcallosal gyrus, medial PFC ○temporo–occipital cortex Temporo–occipital activation normalised one year post-onset.
Brand 200935—14 patients	Dissociative amnesia, with variable antereograde and executive impairments.	FDG-PET (resting)		⇓Right inferolateral PFC ⇓Left hippocampus in 2 out of 14 patients.
Kikuchi 201036—Two patients	Dissociative amnesia	fMRI	‘Unrecognised’ (but previously known) faces from amnesia period vs recognised faces from remembered period	⇑Bilateral DLPFC and ventrolateral PFC ⇓Hippocampus

⇑, increased activation; ⇓, decreased activation; ○, lack of expected activation.
ACC, anterior cingulate cortex; DLPFC, dorsolateral prefrontal cortex; FDG-PET, (18F) fluorodeoxyglucose–positron emission tomography; fMRI, functional MRI; OFC, orbitofrontal cortex; PCC, posterior cingulate cortex; PFC, prefrontal cortex; SFG, superior frontal gyrus; SPECT, single photon emission computed tomography; vmPFC, ventromedial prefrontal cortex.