Limits...
Intrusive memories to traumatic footage: the neural basis of their encoding and involuntary recall.

Clark IA, Holmes EA, Woolrich MW, Mackay CE - Psychol Med (2015)

Bottom Line: Signal change associated with intrusive memory involuntary recall was modelled using finite impulse response basis functions.We found a widespread pattern of increased activation for Intrusive v. both Potential and Control scenes at encoding.The left inferior frontal gyrus and middle temporal gyrus showed increased activity in Intrusive scenes compared with Potential scenes, but not in Intrusive scenes compared with Control scenes.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry,University of Oxford,Warneford Hospital,Oxford OX3 7NG,UK.

ABSTRACT

Background: A hallmark symptom after psychological trauma is the presence of intrusive memories. It is unclear why only some moments of trauma become intrusive, and how these memories involuntarily return to mind. Understanding the neural mechanisms involved in the encoding and involuntary recall of intrusive memories may elucidate these questions.

Method: Participants (n = 35) underwent functional magnetic resonance imaging (fMRI) while being exposed to traumatic film footage. After film viewing, participants indicated within the scanner, while undergoing fMRI, if they experienced an intrusive memory of the film. Further intrusive memories in daily life were recorded for 7 days. After 7 days, participants completed a recognition memory test. Intrusive memory encoding was captured by comparing activity at the time of viewing 'Intrusive scenes' (scenes recalled involuntarily), 'Control scenes' (scenes never recalled involuntarily) and 'Potential scenes' (scenes recalled involuntarily by others but not that individual). Signal change associated with intrusive memory involuntary recall was modelled using finite impulse response basis functions.

Results: We found a widespread pattern of increased activation for Intrusive v. both Potential and Control scenes at encoding. The left inferior frontal gyrus and middle temporal gyrus showed increased activity in Intrusive scenes compared with Potential scenes, but not in Intrusive scenes compared with Control scenes. This pattern of activation persisted when taking recognition memory performance into account. Intrusive memory involuntary recall was characterized by activity in frontal regions, notably the left inferior frontal gyrus.

Conclusions: The left inferior frontal gyrus may be implicated in both the encoding and involuntary recall of intrusive memories.

No MeSH data available.


Related in: MedlinePlus

Experimental procedure. Participants completed baseline questionnaires andmeasures of their current mood. They then viewed film footage with traumaticcontent, including scenes of death and serious injury, while undergoing functionalmagnetic resonance imaging (fMRI). On film completion participants were removedfrom the scanner and mood measurements were administered. Participants were thentrained to identify intrusive memories. They were then returned to the scannerindicating with a button press if they experienced an intrusive memory of the filmwhile undergoing fMRI. For the following week participants kept a diary of anyfurther intrusive memories, returning at 1 week to perform a recognition memorytest of the film contents. BDI-II, Beck Depression Inventory-II; STAI-T,State–Trait Anxiety Inventory, trait scale; VAS, visual analogue scale.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4697303&req=5

fig01: Experimental procedure. Participants completed baseline questionnaires andmeasures of their current mood. They then viewed film footage with traumaticcontent, including scenes of death and serious injury, while undergoing functionalmagnetic resonance imaging (fMRI). On film completion participants were removedfrom the scanner and mood measurements were administered. Participants were thentrained to identify intrusive memories. They were then returned to the scannerindicating with a button press if they experienced an intrusive memory of the filmwhile undergoing fMRI. For the following week participants kept a diary of anyfurther intrusive memories, returning at 1 week to perform a recognition memorytest of the film contents. BDI-II, Beck Depression Inventory-II; STAI-T,State–Trait Anxiety Inventory, trait scale; VAS, visual analogue scale.

Mentions: The experimental procedure is shown in Fig. 1.After completing baseline and mood measures (online Supplementary material) participantsviewed traumatic film footage, including scenes of actual and threatened death andserious injury, while undergoing fMRI. The film comprised 15 short clips which included20 Possible intrusive scenes and 16 Control scenes. Scene type was determined using datafrom approximately 200 participants who had taken part in previous behaviouralexperiments. ‘Possible’ scenes were scenes that had induced intrusive memories inprevious participants (e.g. emergency personnel at an accident with an injured victim),‘Control’ scenes were those that had never induced intrusive memories (e.g. emergencypersonnel around the accident but no visible death or injury). Possible scenes werelater classified as either ‘Intrusive’ scenes (recalled involuntarily by thatparticipant) or ‘Potential’ scenes (not recalled involuntarily by that participant, butrecalled involuntarily by previous participants) depending on the diary data (seeIntrusive memory diary below). All scenes had unique topic content to facilitateintrusive memory identification. Scene length was matched as closely as possible betweenPossible (length, 5–37 s; mean 22.5 s) and Control scenes (length, 5–36 s; mean 16.4 s)(t34 = 1.94, n.s.); see the online Supplementarymaterial (online Supplementary Tables S1 and S2) for the exact duration of each scene.Scenes were distributed evenly throughout the whole film. These constraints wereincluded to take into account the relative slowness of the haemodynamic response (Buxtonet al.2004). Fig. 1.


Intrusive memories to traumatic footage: the neural basis of their encoding and involuntary recall.

Clark IA, Holmes EA, Woolrich MW, Mackay CE - Psychol Med (2015)

Experimental procedure. Participants completed baseline questionnaires andmeasures of their current mood. They then viewed film footage with traumaticcontent, including scenes of death and serious injury, while undergoing functionalmagnetic resonance imaging (fMRI). On film completion participants were removedfrom the scanner and mood measurements were administered. Participants were thentrained to identify intrusive memories. They were then returned to the scannerindicating with a button press if they experienced an intrusive memory of the filmwhile undergoing fMRI. For the following week participants kept a diary of anyfurther intrusive memories, returning at 1 week to perform a recognition memorytest of the film contents. BDI-II, Beck Depression Inventory-II; STAI-T,State–Trait Anxiety Inventory, trait scale; VAS, visual analogue scale.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4697303&req=5

fig01: Experimental procedure. Participants completed baseline questionnaires andmeasures of their current mood. They then viewed film footage with traumaticcontent, including scenes of death and serious injury, while undergoing functionalmagnetic resonance imaging (fMRI). On film completion participants were removedfrom the scanner and mood measurements were administered. Participants were thentrained to identify intrusive memories. They were then returned to the scannerindicating with a button press if they experienced an intrusive memory of the filmwhile undergoing fMRI. For the following week participants kept a diary of anyfurther intrusive memories, returning at 1 week to perform a recognition memorytest of the film contents. BDI-II, Beck Depression Inventory-II; STAI-T,State–Trait Anxiety Inventory, trait scale; VAS, visual analogue scale.
Mentions: The experimental procedure is shown in Fig. 1.After completing baseline and mood measures (online Supplementary material) participantsviewed traumatic film footage, including scenes of actual and threatened death andserious injury, while undergoing fMRI. The film comprised 15 short clips which included20 Possible intrusive scenes and 16 Control scenes. Scene type was determined using datafrom approximately 200 participants who had taken part in previous behaviouralexperiments. ‘Possible’ scenes were scenes that had induced intrusive memories inprevious participants (e.g. emergency personnel at an accident with an injured victim),‘Control’ scenes were those that had never induced intrusive memories (e.g. emergencypersonnel around the accident but no visible death or injury). Possible scenes werelater classified as either ‘Intrusive’ scenes (recalled involuntarily by thatparticipant) or ‘Potential’ scenes (not recalled involuntarily by that participant, butrecalled involuntarily by previous participants) depending on the diary data (seeIntrusive memory diary below). All scenes had unique topic content to facilitateintrusive memory identification. Scene length was matched as closely as possible betweenPossible (length, 5–37 s; mean 22.5 s) and Control scenes (length, 5–36 s; mean 16.4 s)(t34 = 1.94, n.s.); see the online Supplementarymaterial (online Supplementary Tables S1 and S2) for the exact duration of each scene.Scenes were distributed evenly throughout the whole film. These constraints wereincluded to take into account the relative slowness of the haemodynamic response (Buxtonet al.2004). Fig. 1.

Bottom Line: Signal change associated with intrusive memory involuntary recall was modelled using finite impulse response basis functions.We found a widespread pattern of increased activation for Intrusive v. both Potential and Control scenes at encoding.The left inferior frontal gyrus and middle temporal gyrus showed increased activity in Intrusive scenes compared with Potential scenes, but not in Intrusive scenes compared with Control scenes.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry,University of Oxford,Warneford Hospital,Oxford OX3 7NG,UK.

ABSTRACT

Background: A hallmark symptom after psychological trauma is the presence of intrusive memories. It is unclear why only some moments of trauma become intrusive, and how these memories involuntarily return to mind. Understanding the neural mechanisms involved in the encoding and involuntary recall of intrusive memories may elucidate these questions.

Method: Participants (n = 35) underwent functional magnetic resonance imaging (fMRI) while being exposed to traumatic film footage. After film viewing, participants indicated within the scanner, while undergoing fMRI, if they experienced an intrusive memory of the film. Further intrusive memories in daily life were recorded for 7 days. After 7 days, participants completed a recognition memory test. Intrusive memory encoding was captured by comparing activity at the time of viewing 'Intrusive scenes' (scenes recalled involuntarily), 'Control scenes' (scenes never recalled involuntarily) and 'Potential scenes' (scenes recalled involuntarily by others but not that individual). Signal change associated with intrusive memory involuntary recall was modelled using finite impulse response basis functions.

Results: We found a widespread pattern of increased activation for Intrusive v. both Potential and Control scenes at encoding. The left inferior frontal gyrus and middle temporal gyrus showed increased activity in Intrusive scenes compared with Potential scenes, but not in Intrusive scenes compared with Control scenes. This pattern of activation persisted when taking recognition memory performance into account. Intrusive memory involuntary recall was characterized by activity in frontal regions, notably the left inferior frontal gyrus.

Conclusions: The left inferior frontal gyrus may be implicated in both the encoding and involuntary recall of intrusive memories.

No MeSH data available.


Related in: MedlinePlus