Subjects: Psychology >> Developmental Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Since the introduction of the time-frequency analysis technique into the field of EEG data in the 1980’s, researchers can excavate non-phase locked components in EEG signals, overcoming the previous shortcomings of traditional ERP methods. In the field of psychology, the two most commonly used time-frequency analysis methods are wavelet transform and Hilbert transform. Power, phase locking index (PLI), and coherence are three important indices of time-frequency analysis. Power in different frequency band is typically considered to reflect different mental processes. For example, α power is frequently related to selective attention, while γ energy is often associated with feature binding. Researchers use PLI to investigate the mechanism generated by an ERP component. Coherence indicates the exchange of information between long-distance brain regions and cognitive control of higher-level brain regions in the low-level brain regions, which show different patterns in various complex cognitive tasks.
Subjects: Psychology >> Developmental Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Feature-based attention (FBA) is the ability that observers can direct their attention to a specific feature dimension or value. In the attentional focus, FBA can modulate the response of neurons in visual cortex: it selectively increases the responses of neurons encoding attended features while suppresses the responses of neurons encoding distracting features. Many studies found that this attentional modulation can spread outside the focus of attention, but the underlying mechanism of the global modulation of FBA (enhancement or suppression) is still controversial. The global enhancement mechanism and the global suppression mechanism are different in time courses and may play distinctive roles in visual information processing. Compared to the global enhancement mechanism, the global suppression mechanism seems more likely to be influenced by experimental designs and parameters. Future studies are needed to investigate under what conditions the global suppression mechanism takes effect and to further disassociate these two global mechanisms in the process of feature-based attention.
Subjects: Psychology >> Developmental Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Human perception to near-threshold visual stimuli is not always reliable. To investigate variability of visual perception and its neural mechanism, some researchers focus on the influences of prestimulus ongoing alpha oscillations (8~13 Hz) on visual perception. Recently, studies found that decrease of prestimulus alpha power associated with improvement of observers’ detection rate, but no such effect on perception accuracy was found. In addition, phase of prestimulus alpha was reported to predict whether an observer can detect the following visual stimulus or not. Thus, power of prestimulus alpha is considered to reflect the excitability of visual cortex; decrease of alpha power indicates increase of cortical excitability, which results in higher detection rate of near-threshold stimuli. Nevertheless, phase of prestimulus alpha might play a role in regulating the time of excitation and inhibition of the cortex, and the different brain states (excitation or inhibition) at stimulus onset would lead to different perceptions of the stimulus.
Subjects: Psychology >> Social Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Behavioral oscillations are periodic changes of behavioral performance which result from rhythmic mental processes. Through behavioral methods that have high temporal resolutions, prior studies have provided a unique perspective to investigate the temporal dynamics of visual attention. Phenomena of behavioral oscillations were observed in many types of attentional tasks. There was much evidence supporting that attentional sampling showed periodic changes mainly at two different rhythms: α (8~13 Hz) band which reflects attentional suppression and θ (4~8 Hz) band which reflects attentional shift. These results help revealing the temporal dynamics of attention and provide a new approach for the controversy between serial- and parallel-search theories of attention. Some potential factors, including task difficulty and cue validity, were found to be able to influence the rhythmic characteristics of behavioral oscillations. Behavioral oscillations showed consistent rhythms with neural oscillations in some attentional tasks, suggesting that they might involve similar mental processes. To systematically reveal the temporal dynamics of attention, future studies are needed to investigate the specific patterns of behavioral oscillations under various attentional control processes, as well as in multimodal attentional tasks.
Subjects: Psychology >> Social Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Selective attention modulates multiple stages of visual processing, and nearly all the attentional modulations are affected by normal aging. Studies about the influence of aging on early stages of attentional processing can greatly help to understand the mechanism of cognitive aging. However, the related studies are insufficient and sometimes exhibit inconsistent results. Till now, there is still lack of reviews focusing the aging mechanism of early visual attention from the perspective of time course.This paper systematically reviews the ERP (event-related potential) studies investigating the aging effect on both pre-stimulus anticipatory attention and sensory stages of attentional processing (less than 200ms post-stimulus). Current evidence shows that: (1) early attentional effects reflected by many ERP components (e.g., ADAN and EDAN reflecting anticipatory attention, N1 reflecting early spatial attention, SP and SN reflecting early feature attention) are delayed in older adults compared to young adults; (2) the amplitudes of early attentional effects showed diverse age-related patterns in different ERP components : while some components (e.g., ADAN, EDAN, and P1 reflecting early spatial attention) appear to be resistant to aging, some other components (e.g., alpha power lateralization reflecting anticipatory attention, N1 reflecting early spatial attention, and SN reflecting early feature attention) seem to be influenced easily by aging, albeit some inconsistent results (e.g., the age-related spatial attention effect on N1 amplitudes is found to be enhanced, preserved, or declined in different studies); (3) while target facilitation reflected by some ERP components (e.g., SP reflecting early feature attention, P1 and N1 reflecting early object attention) is retained in healthy older adults, there is an age-related decline in distractor suppression. Regarding to the diverse and inconsistent findings about how normal aging affects early attentional effects in ERP amplitudes, there might be multiple reasons. On one hand, it might be due to different task demands and/or different attentional processes (distractor suppression vs. target facilitation) engaged in different studies: (1) different task demands will confuse the observation of, even exert distinct influences on different stages of early attention in healthy older adults; (2) target facilitation and distractor suppression might be two distinguished age-related attentional processes, with distractor suppression more sensitive to normal aging. On the other hand, it might be ascribable to some confounding factors, such as signal-to-noise ratio and individual differences of the elderly across studies: (1) the low signal-to-noise ratio in s aging-related ERP studies might lead to unstable and unconvincing results; (2) the range of age and cognitive function of the elderly samples are different across studies, which might also leads to inconsistent results. Future research should control the confounding factors to obtain stable and comparable results, such as ensuring sufficient trials and/or matching the task demands between the elderly and young. To further understand the aging mechanism, future research can also manipulate these factors to explore their specific effects on early stages of attention, such as providing a neutral condition to separate target facilitation and distractor suppression processes.
Subjects: Psychology >> Social Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： It is generally considered that the human brain will generate distinct neural representations corresponding to different mental processes. Exploring the differences of neural representations under various mental activities is one of the core issues in cognitive neuroscience. During recent decades, researchers have used different neuroimaging techniques to record brain activities involved in complex cognitive processes from the perspective of temporal or spatial measurement. Among these techniques, the non-invasive EEG/MEG with temporal resolution of millisecond has become a popular one to study the time courses of various cognitive activities. Due to the characteristics of EEG/MEG data (e.g., low S/N), in order to obtain relatively reliable results, traditional EEG/MEG studies mainly focused on the neural responses after group averaging, paying less attention to individual differences. Such method assumes that, for each subject, the amplitudes and directions of ERPs/ERMFs and their topographic maps in a specific time window of interest exhibit a consistent pattern under an experimental condition. In the case of poor consistency, the neural responses across subjects may cancel each other to a great extent after group averaging, which makes it difficult to get a reasonable interpretation. In recent years, researchers have introduced two techniques commonly used in fMRI studies, classification algorithms in machine learning (i.e., classification-based decoding) and representation similarity analysis, into the EEG/MEG data analysis. These two new techniques can overcome the shortcomings of traditional EEG/MEG data analysis based on averaging of voltage/magnetic flux density waveforms by taking individual differences into account, which could be used to reveal the coding of neural representation at individual level and provide a new idea to explore how the brain encodes specific neural representations dynamically. In the study of ERPs/ERMFs, classification-based decoding and representation similarity analysis can be used to explore not only the neural mechanisms that show consistent patterns along time among individuals, but also those that are significantly different across individuals but keep stable for a given individual. Thus, these two techniques are able to reveal specific neural representation patterns and even identify "brain fingerprints" at individual levels. Based on different methodological theories, these two techniques provide novel ways for EEG/MEG studies to compare representational differences of cognitive processes across time windows, tasks, modalities, and groups. Firstly, we systematically introduced the principles and operational processes of classification-based decoding and representation similarity analysis, together with a comparison with those traditional analysis methods of EEG/MEG. Then, the EEG/MEG studies to date using these two techniques are reviewed. Finally, some possible future research directions with regard to these two techniques are proposed.
Subjects: Psychology >> Cognitive Psychology submitted time 2022-07-10
Abstract：探究不同心智活动下的神经表征差异，是认知神经科学关注的核心问题之一。早期的脑电/脑磁分析方法主要关注组平均后的神经响应水平，这要求在关注的时间进程上，各个被试在相同刺激条件下事件相关电位/事件相关磁场的振幅大小和方向、以及地形图分布和极性均要有较高的一致性。近些年来，研究者们将功能性磁共振成像研究中常用到的两种技术机器学习中的分类算法(即基于分类的解码)和表征相似性分析引入到了脑电/脑磁数据分析中。这两种新技术可以克服传统脑电/脑磁数据基于具体电压/磁感应强度波形平均分析的缺点，具有在个体水平上探究神经表征编码的特点，为人们探究大脑在不同时间进程上如何对特定的神经表征信息进行动态编码提供了新的思路。两种技术基于不同的方法学原理来抽提个体间一致的脑认知加工机制，还为脑电/脑磁研究开展跨时域、跨任务、跨模态、跨群体比较不同认知过程中的表征差异提供了更多新颖的途径。我们首先通过与传统的脑电/脑磁分析方法进行比较，系统性介绍了基于分类的解码和表征相似性分析的原理和操作流程，之后对两种方法的应用场景进行了梳理，并在最后对未来可供研究的方向提出了我们的见解。
Peer Review Status:
Awaiting Review
Subjects: Psychology >> Cognitive Psychology Subjects: Psychology >> Developmental Psychology submitted time 2022-06-13
Abstract：
Selective attention modulates multiple stages of visual processing, and nearly all the attentional modulations are affected by normal aging. Studies about the influence of aging on early stages of attentional processing can greatly help to understand the mechanism of cognitive aging. This paper systematically reviews the ERP (event-related potential) studies investigating the aging effect on both pre-stimulus anticipatory attention and sensory stages of attentional processing (less than 200ms post-stimulus). Current evidence shows that: (1) early attentional effects reflected by many ERP components (e.g., ADAN and EDAN reflecting anticipatory attention, N1 reflecting early spatial attention, SP and SN reflecting early feature attention) are delayed in older adults compared to young adults; (2) the amplitudes of early attentional effects showed diverse age-related patterns in different ERP components: while some components (e.g., ADAN, EDAN, and P1 reflecting early spatial attention) appear to be resistant to aging, some other components (e.g., alpha power lateralization reflecting anticipatory attention, N1 reflecting early spatial attention, and SN reflecting early feature attention) seem to be influenced easily by aging, albeit some inconsistent results; (3) while target facilitation reflected by some ERP components (e.g., SP reflecting early feature attention, P1 and N1 reflecting early object attention) is retained in healthy older adults, there is an age-related decline in distractor suppression. Regarding to the diverse and inconsistent findings about how normal aging affects early attentional effects in ERP amplitudes, it might be due to task demands, different attentional processes (distractor suppression vs. target facilitation) engaged in different studies, and/or individual differences in older adults across studies. Future research should control these confounding factors to obtain stable and comparable results, and manipulate these factors to explore their specific effects on early stages of attention to further understand the aging mechanism.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Cognitive Psychology submitted time 2020-10-23
Abstract： Behavioral oscillations are periodic changes of behavioral performance which result from rhythmic mental processes. Through behavioral methods that have high temporal resolutions, prior studies have provided a unique perspective to investigate the temporal dynamics of visual attention. Phenomena of behavioral oscillations were observed in many types of attentional tasks. There was much evidence supporting that attentional sampling showed periodic changes mainly at two different rhythms: α (8-13 Hz) band which reflects attentional suppression and θ (4-8 Hz) band which reflects attentional shift. These results help revealing the temporal dynamics of attention and provide a new approach for the controversy between serial- and parallel-search theories of attention. Some potential factors, including task difficulty and cue validity, were found to be able to influence the rhythmic characteristics of behavioral oscillations. Behavioral oscillations showed consistent rhythms with neural oscillations in some attentional tasks, suggesting that they might involve similar mental processes. To systematically reveal the temporal dynamics of attention, future studies are needed to investigate the specific patterns of behavioral oscillations under various attentional control processes, as well as in multimodal attentional tasks. "
Peer Review Status:Awaiting Review
Subjects: Psychology >> Cognitive Psychology submitted time 2020-01-14
Abstract： Human perception to near-threshold visual stimuli is not always reliable. To investigate variability of visual perception and its neural mechanism, some researchers focus on the influences of prestimulus ongoing alpha oscillations (8~13 Hz) on visual perception. Recently, studies found that decrease of prestimulus alpha power associated with improvement of observers’ detection rate, but no such effect on perception accuracy was found. In addition, phase of prestimulus alpha was reported to predict whether an observer can detect the following visual stimulus or not. Thus, power of prestimulus alpha is considered to reflect the excitability of visual cortex; decrease of alpha power indicates increase of cortical excitability, which results in higher detection rate of near-threshold stimuli. Nevertheless, phase of prestimulus alpha might play a role in regulating the time of excitation and inhibition of the cortex, and the different brain states (excitation or inhibition) at stimulus onset would lead to different perceptions of the stimulus.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Cognitive Psychology submitted time 2020-01-08
Abstract： Feature-based attention (FBA) is the ability that observers can direct their attention to a specific feature dimension or value. In the attentional focus, FBA can modulate the response of neurons in visual cortex: it selectively increases the responses of neurons encoding attended features while suppresses the responses of neurons encoding distracting features. Many studies found that this attentional modulation can spread outside the focus of attention, but the underlying mechanism of the global modulation of FBA (enhancement or suppression) is still controversial. The global enhancement mechanism and the global suppression mechanism are different in time courses and may play distinctive roles in visual information processing. Compared to the global enhancement mechanism, the global suppression mechanism seems more likely to be influenced by experimental designs and parameters. Future studies are needed to investigate under what conditions the global suppression mechanism takes effect and to further disassociate these two global mechanisms in the process of feature-based attention.
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