Townsend Jennifer D, Muller Angela Martina, Naeem Zanib, Beckett Alexander, Kalisetti Bhavesh, Abbasi-Asl Reza, Liao Congyu, Vu An Thanh
Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States.
VA Advanced Imaging Research Center, San Francisco Veteran Affairs Health Care System, San Francisco, CA, United States.
Front Neuroimaging. 2025 Jun 3;4:1537440. doi: 10.3389/fnimg.2025.1537440. eCollection 2025.
To facilitate high spatial-temporal resolution fMRI (≦1mm) at more broadly available field strengths (3T) and to better understand the neural underpinnings of joy, we used SE-based generalized Slice Dithered Enhanced Resolution (gSLIDER). This sequence increases SNR efficiency utilizing sub-voxel shifts along the slice direction. To improve the effective temporal resolution of gSLIDER, we utilized the temporal information within individual gSLIDER RF encodings to develop gSLIDER with Sliding Window Accelerated Temporal resolution (gSLIDER-SWAT). We first validated gSLIDER-SWAT using a classic hemifield checkerboard paradigm, demonstrating robust activation in primary visual cortex even with stimulus frequency increased to the Nyquist frequency of gSLIDER (i.e., TR = block duration). gSLIDER provided ~2× gain in tSNR over traditional SE-EPI. GLM and ICA results suggest improved signal detection with gSLIDER-SWAT's nominal 5-fold higher temporal resolution that was not seen with simple temporal interpolation. Next, we applied gSLIDER-SWAT to investigate the neural networks underlying joy using naturalistic video stimuli. Regions significantly activated during joy included the left amygdala, specifically the basolateral subnuclei, and rostral anterior cingulate, both part of the salience network; the hippocampus, involved in memory; the striatum, part of the reward circuit; prefrontal cortex, part of the executive network and involved in emotion processing and regulation [bilateral mPFC/BA10/11, left MFG (BA46)]; and throughout visual cortex. This proof of concept study demonstrates the feasibility of measuring the networks underlying joy at high resolutions at 3T with gSLIDER-SWAT, and highlights the importance of continued innovation of imaging techniques beyond the limits of standard GE fMRI.
为了在更广泛可用的场强（3T）下实现高时空分辨率功能磁共振成像（≦1mm），并更好地理解喜悦的神经基础，我们使用了基于自旋回波（SE）的广义切片抖动增强分辨率（gSLIDER）序列。该序列利用沿切片方向的亚体素移位提高信噪比效率。为了提高gSLIDER的有效时间分辨率，我们利用单个gSLIDER射频编码内的时间信息开发了具有滑动窗口加速时间分辨率的gSLIDER（gSLIDER-SWAT）。我们首先使用经典的半视野棋盘格范式验证了gSLIDER-SWAT，结果表明即使刺激频率增加到gSLIDER的奈奎斯特频率（即，重复时间TR = 块持续时间），初级视觉皮层仍有强烈激活。与传统的自旋回波平面回波成像（SE-EPI）相比，gSLIDER的tSNR提高了约2倍。广义线性模型（GLM）和独立成分分析（ICA）结果表明，gSLIDER-SWAT标称的5倍更高时间分辨率改善了信号检测，而简单的时间插值则没有这种效果。接下来，我们应用gSLIDER-SWAT，使用自然主义视频刺激来研究喜悦背后的神经网络。在喜悦过程中显著激活的区域包括左侧杏仁核，特别是基底外侧亚核，以及吻侧前扣带回，它们都是显著性网络的一部分；海马体，参与记忆；纹状体，奖励回路的一部分；前额叶皮层，执行网络的一部分，参与情绪处理和调节[双侧内侧前额叶皮质/BA10/11，左侧额中回（BA46）]；以及整个视觉皮层。这项概念验证研究证明了使用gSLIDER-SWAT在3T下以高分辨率测量喜悦背后网络的可行性，并强调了在标准梯度回波功能磁共振成像（GE fMRI）极限之外持续创新成像技术的重要性。
