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A 7 tesla FMRI study of amygdala responses to fearful faces.

van der Zwaag W, Da Costa SE, Zürcher NR, Adams RB, Hadjikhani N - Brain Topogr (2012)

Bottom Line: A paradigm based on the presentation of fearful faces was used for stimulation.Previously, opposite effects have been found for presentation of averted and direct gaze fearful faces.Here, we show that (1) sufficiently high temporal SNR values are reached in the amygdalae for detection of small BOLD signal changes and (2) that the BOLD signal in the amygdalae for presentation of a direct or averted gaze in a fearful face depends on stimulus duration.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, University of Lausanne, Switzerland.

ABSTRACT
The amygdalae are involved in the perception of emotions such as happiness, anger and fear. Because of their proximity to the sinuses, the image signal intensity in T2* weighted fMRI data is often affected by signal loss due to through-slice dephasing, especially at high field strength. In this study, the feasibility of fMRI in the amygdalae at 7 Tesla was investigated. A paradigm based on the presentation of fearful faces was used for stimulation. Previously, opposite effects have been found for presentation of averted and direct gaze fearful faces. Here, we show that (1) sufficiently high temporal SNR values are reached in the amygdalae for detection of small BOLD signal changes and (2) that the BOLD signal in the amygdalae for presentation of a direct or averted gaze in a fearful face depends on stimulus duration.

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a Amygdalae from the Harvard–Oxford subcortical atlas. b Temporal SNR map from a representative subject for the area of the fMRI acquisition volume. Shown tSNR values range from 50 to 300. Crosshair lines are positioned at −18, −5, −17 in MNI space. Note that tSNR in the medial part of the amygdala is lower than in the lateral region due to through-slice dephasing
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Fig1: a Amygdalae from the Harvard–Oxford subcortical atlas. b Temporal SNR map from a representative subject for the area of the fMRI acquisition volume. Shown tSNR values range from 50 to 300. Crosshair lines are positioned at −18, −5, −17 in MNI space. Note that tSNR in the medial part of the amygdala is lower than in the lateral region due to through-slice dephasing

Mentions: Data were acquired on a 7 Tesla scanner (Siemens, Germany) with eight channel rf-coil (Rapid Biomedical, Germany). A multi-slice EPI sequence (Speck et al. 2008) with sinusoidal read-out, to limit the helium boil-off, was used for functional acquisition (40 1.5 mm thick slices, oriented 30° from AC-PC, TR = 3,000 ms, TE = 21 ms, flip 60°, FOV 160 mm2, matrix 64 × 64, 2.5 × 2.5 × 1.5 mm). Slices were positioned at an approximately 30° angle from the AC-PC line (Robinson et al. 2004), while ensuring that the eyes and mobile parts of the brainstem were not included in the imaging slab to avoid motion-induced Nyquist ghosting (Fig. 1b). The relatively thin slice thickness was chosen to further reduce through-slice signal dephasing in the medial part of the amygdalae.Fig. 1


A 7 tesla FMRI study of amygdala responses to fearful faces.

van der Zwaag W, Da Costa SE, Zürcher NR, Adams RB, Hadjikhani N - Brain Topogr (2012)

a Amygdalae from the Harvard–Oxford subcortical atlas. b Temporal SNR map from a representative subject for the area of the fMRI acquisition volume. Shown tSNR values range from 50 to 300. Crosshair lines are positioned at −18, −5, −17 in MNI space. Note that tSNR in the medial part of the amygdala is lower than in the lateral region due to through-slice dephasing
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3298740&req=5

Fig1: a Amygdalae from the Harvard–Oxford subcortical atlas. b Temporal SNR map from a representative subject for the area of the fMRI acquisition volume. Shown tSNR values range from 50 to 300. Crosshair lines are positioned at −18, −5, −17 in MNI space. Note that tSNR in the medial part of the amygdala is lower than in the lateral region due to through-slice dephasing
Mentions: Data were acquired on a 7 Tesla scanner (Siemens, Germany) with eight channel rf-coil (Rapid Biomedical, Germany). A multi-slice EPI sequence (Speck et al. 2008) with sinusoidal read-out, to limit the helium boil-off, was used for functional acquisition (40 1.5 mm thick slices, oriented 30° from AC-PC, TR = 3,000 ms, TE = 21 ms, flip 60°, FOV 160 mm2, matrix 64 × 64, 2.5 × 2.5 × 1.5 mm). Slices were positioned at an approximately 30° angle from the AC-PC line (Robinson et al. 2004), while ensuring that the eyes and mobile parts of the brainstem were not included in the imaging slab to avoid motion-induced Nyquist ghosting (Fig. 1b). The relatively thin slice thickness was chosen to further reduce through-slice signal dephasing in the medial part of the amygdalae.Fig. 1

Bottom Line: A paradigm based on the presentation of fearful faces was used for stimulation.Previously, opposite effects have been found for presentation of averted and direct gaze fearful faces.Here, we show that (1) sufficiently high temporal SNR values are reached in the amygdalae for detection of small BOLD signal changes and (2) that the BOLD signal in the amygdalae for presentation of a direct or averted gaze in a fearful face depends on stimulus duration.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, University of Lausanne, Switzerland.

ABSTRACT
The amygdalae are involved in the perception of emotions such as happiness, anger and fear. Because of their proximity to the sinuses, the image signal intensity in T2* weighted fMRI data is often affected by signal loss due to through-slice dephasing, especially at high field strength. In this study, the feasibility of fMRI in the amygdalae at 7 Tesla was investigated. A paradigm based on the presentation of fearful faces was used for stimulation. Previously, opposite effects have been found for presentation of averted and direct gaze fearful faces. Here, we show that (1) sufficiently high temporal SNR values are reached in the amygdalae for detection of small BOLD signal changes and (2) that the BOLD signal in the amygdalae for presentation of a direct or averted gaze in a fearful face depends on stimulus duration.

Show MeSH