| 摘要: | 先前的研究發現視覺空間注意力具有採樣節律的特質，並在4-8 Hz的theta和8-16 Hz的alpha頻率下震盪，且與視覺系統內的神經振盪的相位振幅耦合有關。許多研究指出此注意取樣節奏與不同的試驗需求有關，例如：刺激物數量、干擾物的數量以及試驗難度等因素。然而，目前對於試驗需求與注意力節律及其神經調節之間關聯性的了解仍不充分。本研究旨在研究空間預期心理對注意力採樣節律的影響，並利用腦電波（EEG）探討神經振盪和行為節律的關係。我們使用類Posner注意力實驗，結合不同空間提示效度（100％和50％），並在不同時間點（300毫秒至1300毫秒）呈現閾值Landolt環以形成行為節律，並應用全息希爾伯特頻譜分析（Holo-Hilbert Spectral Analysis; HHSA）和全息希爾伯特跨頻相位聚集網絡（Holo-Hilbert Cross-frequency Phase Clustering; HHCFPC）對腦波數據進行分析，研究注意力採樣期間腦波的動態變化。研究結果顯示，空間預期性提高了回應的精確度並降低注意力採樣節律從beta頻帶（15 Hz和19 Hz）到theta頻帶（4 Hz）。此外，腦波資料顯示，在完全可預期的情況下，枕葉的alpha-band振幅受到前額區域theta-band的調節，而前額區域和頂-枕區域之間的低頻振動（1.2-5.7 Hz）在不同試驗之間呈現顯著的相位對齊。在目標物出現之前的枕葉神經活動，也可以預測不同空間預期性的情形下反應的精確度。總體而言，我們的研究結果顯示，不同程度的空間預期性可以導致不同的準備過程，並能在行為節律中體現出來。這些結果提供了神經振盪和行為節律之間關聯性的證據，並表明它們在大腦中作為一種進行資源分配機制的重要角色。;One characteristics of attention is to facilitate relevant information and inhibit irrelevant distractors. Recent studies demonstrate that behavioral performance during visual spatial attention fluctuates at theta (4-8 Hz) and alpha (8-16 Hz) frequencies, linked to phase amplitude coupling of neural oscillations within the visual system (i.e., frontal-parietal network and visual cortex). Moreover, previous studies suggest that attentional sampling rhythms are task-dependent. This is evidenced with varying behavioral performance at different frequencies when comparing spatial resolutions, numbers of distractors, and task difficulties. However, the role of prior spatial prediction in behavioral rhythms remains unclear. To address this issue, we employed an adaptive Posner-like discrimination task with variable CTOA durations ranging from 300 ms to 1300 ms in steps of 20 ms while manipulating spatial prediction via cue validity (100% & 50%), with concurrently electroencephalography (EEG) recording. An adaptive analytical method, namely the Holo-Hilbert Spectral Analysis (HHSA) and Holo-Hilbert Cross-frequency Phase Clustering (HHCFPC) was applied for the EEG data analysis to explore the dynamic changes of perception during sustained attention. Our findings indicate that informative cues enhance spatial and temporal modulation, improving response precision for near-threshold Landolt rings. Furthermore, spatial prediction influences the speed of behavioral rhythms at the theta-band (4 Hz) with certain predictions and at alpha & beta bands (15 & 19 Hz) with uncertain predictions. We also discovered that spatial prediction strengthens theta-alpha modulations at parietal-occipital areas, frontal theta phase and parietal-occipital alpha amplitude coupling, within frontal theta phase/ alpha amplitude coupling, and the phase alignments of low frequency (1.2-5.7 Hz) oscillations between trials at frontal and parietal-occipital areas. Notably, during the pre-target period, beta-modulated gamma oscillations in parietal-occipital areas predict response precision in spatially uncertain conditions, while frontal theta phase and parietal-occipital alpha amplitude coupling predict response precision in spatially certain conditions. Overall, our results suggest that different levels of spatial certainty lead to distinct preparations for sampling unpredictable targets. Specifically, we found that certain spatial cues promote more robust communication between different brain areas (theta-alpha coupling) and override the phasic contributions of a natural filtering mechanism (i.e.,beta-gamma coupling) within the early visual cortex during perception. In conclusion, our study supports the notion that the speed of periodic sampling in perception depends on the task at hand, indicating that neural rhythms serve as an adaptive resource allocation mechanism in the brain and highlighting the critical role of spatial prediction in attentional sampling rhythms. |
