EEG and fMRI agree: Mental arithmetic is the easiest form of imagery to detect

fMRI and EEG during mental imagery provide alternative methods of detecting awareness in patients with disorders of consciousness (DOC) without reliance on behaviour. Because using fMRI in patients with DOC is difficult, studies increasingly employ EEG. However, there has been no verification that these modalities provide converging information at the individual subject level. The present study examined simultaneous EEG and fMRI in healthy volunteers during six mental imagery tasks to determine whether one mental imagery task generates more robust activation across subjects; whether activation can be predicted from familiarity with the imagined activity; and whether EEG and fMRI converge upon the same conclusions about individual imagery performance. Mental arithmetic generated the most robust activation in the majority of subjects for both EEG and fMRI, and level of activation could not be predicted from familiarity, with either modality. We conclude that overall, EEG and fMRI agree regarding individual mental imagery performance.     

基于fNIRS的运动执行与运动想象脑激活模式比较

使用《运动想象问卷−修订版》筛选出的30名被试(男女各半), 采用功能性近红外光谱成像技术(fNIRS)监测被试在执行实际举哑铃(男生, 4磅和8磅; 女生, 2磅和4磅)任务和想象举同等重量哑铃任务时, 其大脑皮层氧合血红蛋白浓度的变化。结果发现：男女被试在运动执行与运动想象任务下都激活了主运动皮层; 且运动执行的大脑激活水平高于运动想象。在执行实际运动任务时, 运动强度显著影响大脑皮层血氧浓度的变化, 表现出左半球偏侧化优势; 在执行想象运动任务时, 运动强度没有影响大脑皮层血氧浓度的变化, 且无偏侧化现象。     

Bridging the intention–behavior gap: Inducing implementation intentions through persuasive appeals

The potential of using implementation intentions—action plans that link a critical situational cue to a specific goal-directed behavior—to bridge the intention–behavior gap in consumer behavior has been limited by the practice of using explicit instructions to induce the construct. In two studies, we therefore tested the effectiveness of an indirect, persuasive strategy that benefits from the positive consequences of implementation intentions by ‘mimicking’ their underlying psychological processes. Experiment 1 showed that a strategy presenting vivid information on critical cues and appropriate behavioral responses affected mental imagery. Experiment 2 demonstrated that this strategy affected actual purchase behavior.     

视觉表象生成系统及其影响因素

视觉表象是在记忆基础上产生的类似知觉的信息表征, 也是人们在日常生活中不可或缺的心理活动之一。本综述介绍了该领域中比较有影响力的表象计算理论模型, 并进一步归纳了视觉表象生成系统的成分及其对应的神经基础。分析结果强调了初级视觉皮层作为“视觉缓冲器”是生成表象的主要机能结构, 以“视觉缓冲器”为基础的表象生成系统的机能受多重因素影响。本综述有助于对视觉表象生成系统形成全面的认识, 促进视觉表象实质的进一步研究。     

Internal imagery training in active high jumpers

The main purpose of this study was to examine whether the use of internal imagery would affect high jumping performance for active high jumping athletes. Over a period of six weeks, a group of active high jumpers were trained with an internal imagery program for a total of 72 minutes. This group was compared to a control group consisting of active high jumpers that only maintained their regular work-outs during the same time period. Four variables were measured; jumping height, number of failed attempts, take-off angle, and bar clearance. There was a significant improvement on bar clearance for the group that trained imagery (p < 0.05) but not for the control group. No other differences were found. The results suggest that internal imagery training may be used to improve a component of a complex motor skill. Possible explanations and future recommendations are discussed.     

Patterns of Adolescent Depression to Age 20: The Role of Maternal Depression and Youth Interpersonal Dysfunction

Considerable research has focused on youth depression, but further information is needed to characterize different patterns of onset and recurrence during adolescence. Four outcome groups by age 20 were defined (early onset-recurrent, early-onset-desisting, later-onset, never depressed) and compared on three variables predictive of youth depression: gender, maternal depression, and interpersonal functioning. Further, it was hypothesized that the association between maternal depression and youth depression between 15 and 20 is mediated by early-onset depression and interpersonal dysfunction by age 15. Eight hundred sixteen community youth selected for depression risk by history (or absence) of maternal depression were interviewed at age 15, and 699 were included in the 5-year follow-up. Controlling for gender, early onset and interpersonal dysfunction mediated the link between maternal depression and late adolescent major depression. Different patterns for males and females were observed. For males maternal depression’s effect was mediated by early onset but not interpersonal difficulties, while for females maternal depression’s effect was mediated by interpersonal difficulties but not early onset. Maternal depression did not predict first onset of major depression after age 15. The results suggest the need for targeting the impact of maternal depression’s gender-specific effects on early youth outcomes, and also highlight the different patterns of major depression in youth and their likely implications for future course of depression.

Prospective and positive mental imagery deficits in dysphoria

We know less about positive mental imagery than we do about negative mental imagery in depression. This study examined the relationship between depressed mood and the subjective experience of emotion in imagined events; specifically, prospective imagery, and imagery in response to emotionally ambiguous stimuli. One hundred and twenty-six undergraduates completed measures of depression, imagery vividness for future events, and a homograph interpretation task in which they generated images and subsequently rated image pleasantness and vividness. As predicted, compared to low dysphoria, high dysphoria was associated with poorer ability to vividly imagine positive (but not negative) future events. These findings were augmented by the observation that high dysphorics provided lower pleasantness ratings of images generated in response to homographs they interpreted as positive. We suggest that an imbalance in the inability to vividly imagine positive but not negative future events may curtail the ability of high dysphorics to be optimistic. High dysphoric individuals are further disadvantaged: even when they interpret ambiguity positively, the resulting images they generate are associated with less positive affect. Therapeutic strategies that address both such positive-specific imagery biases hold promise for depression treatment innovation.     

A computational model of spatial visualization capacity

Visualizing spatial material is a cornerstone of human problem solving, but human visualization capacity is sharply limited. To investigate the sources of this limit, we developed a new task to measure visualization accuracy for verbally-described spatial paths (similar to street directions), and implemented a computational process model to perform it. In this model, developed within the Adaptive Control of Thought-Rational (ACT-R) architecture, visualization capacity is limited by three mechanisms. Two of these (associative interference and decay) are longstanding characteristics of ACT-R’s declarative memory. A third (spatial interference) is a new mechanism motivated by spatial proximity effects in our data. We tested the model in two experiments, one with parameter-value fitting, and a replication without further fitting. Correspondence between model and data was close in both experiments, suggesting that the model may be useful for understanding why visualizing new, complex spatial material is so difficult.