关于上下视野不对称性的研究

该研究就国内外对上下视野不对称性的研究成果做了详细的阐述,主要包括上下视野的定义、上下视野不对称性的行为和神经机制方面的研究成果及当前所面临的问题,并在文章的最后提出自己的观点。     

European starlings are capable of discriminating subtle size asymmetries in paired stimuli

Small deviations from bilateral symmetry (fluctuating asymmetries) are cues to fitness differences in some animals. Therefore, researchers have considered whether animals use these small asymmetries as visual cues to determine appropriate behavioral responses (e.g., mate preferences). However, there have been few systematic studies of animals' abilities to visually discriminate such minor asymmetries. If the asymmetries cannot be discriminated, fluctuating asymmetry can not be a visual cue. Here, we report an investigation of European starlings' (Sturnus vulgaris) abilities to discriminate small size asymmetries. We trained starlings, through operant conditioning in a free-flight aviary, to discriminate achromatic, symmetric paired stimuli from size-matched asymmetric stimuli. By starting the learning process with a large asymmetry and progressing through sequential trials of decreasing asymmetry, we elucidated a behavioral limit to asymmetry discrimination. We found that starlings are capable of discriminating a 10% size asymmetry. There was weaker evidence for discrimination of 5% asymmetry but no evidence for signal discrimination at 2.5% size asymmetry. This level of asymmetry discrimination suggests that many size asymmetry cues in nature can be discriminated by birds. At each level of asymmetry discrimination, we also tested whether starlings could generalize their learned symmetry preference to unreinforced novel images. Consistent with previous findings, we found that starlings could generalize their symmetry preferences.     

Disorders in planning and strategy application in frontal lobe lesion patients

The aim of this study was to investigate deficits in planning ability using an adapted version of the Modified Six Elements Test, from the Behavioral Assessment of the Dysexecutive Syndrome—BADS [Wilson, B. A., Alderman, N., Burgess, P. W., Emslie, H., & Evans, J. J. (1996). Behavioural Assessment of the Dysexecutive Syndrome (BADS). Bury St Edmunds, U.K.: Thames Valley Test Company. Trans. Ricardo O Souza, Sergio L Schmidt. Rio de Janeiro: Cognição]. Subjects were left- and right-frontal lobe lesion patients. Other measures of executive dysfunctions used were verbal fluency, the Wisconsin Card Sorting Test, and the Trail Making Test. These other instruments were sensitive to detect executive deficits in the left frontal lobe lesion group, except the Wisconsin Card Sorting Test, which showed impairment only for the frontal lobe lesion group as a whole. The Modified Six Elements Test detected planning disorders in left frontal lobe lesion patients. The deficit of these patients was due to a greater likelihood to break the rules of the task, that is, in plan-following processes, rather than in planning the strategic approach to solve it.     

Frontal and parietal EEG asymmetries interact to predict attentional bias to threat

Frontal and parietal electroencephalographic (EEG) asymmetries mark vulnerability to depression and anxiety. Drawing on cognitive theories of vulnerability, we hypothesise that cortical asymmetries predict attention to threat. Participants completed a dot-probe task in which bilateral face displays were followed by lateralised targets at either short (300 ms) or long (1050 ms) SOA. We also measured N2pc to face onset as an index of early attentional capture. At long SOA only, frontal and parietal asymmetry interacted to predict attentional bias to angry faces. Those with leftward frontal asymmetry showed no attentional bias. Among those with rightward frontal asymmetry those with low right parietal activity showed vigilance for threat, and those with high right parietal activity showed avoidance. Asymmetry was not related to the N2pc or to attentional bias at the short SOA. Findings suggest that trait asymmetries reflect function in a fronto-parietal network that controls attention to threat.     

Visual asymmetry revisited: Mind wandering preferentially disrupts processing in the left visual field

An emerging theory proposes that visual attention operates in parallel at two distinct time scales – a shorter one (<1 s) associated with moment-to-moment orienting of selective visuospatial attention, and a longer one (>10 s) associated with more global aspects of attention-to-task. Given their parallel nature, here we examined whether these comparatively slower fluctuations in task-related attention show the same visual field asymmetry – namely, a right visual field bias – as often reported for selective visual–spatial attention. Participants performed a target detection task at fixation while event-related potentials (ERP) time-locked to task-irrelevant visual probes presented in the left and right visual fields were recorded. At random intervals, participants were asked to report whether they were “on-task” or “mind wandering”. Our results demonstrated that sensory attenuation during periods of “mind wandering” relative to “on-task”, as measured by the visual P1 ERP component at electrodes sites contralateral to the stimulus, was only observed for probes presented in the left visual field. In contrast, the magnitude of sensory gain in the right visual field was insensitive to whether participants were “on-task” or “mind wandering”. Taken together, our results support the notion that task-related attention at longer time scales and spatial attention at shorter time scales affect the same underlying mechanism in visual cortex.     

Reduced asymmetry in motor skill learning in left-handed compared to right-handed individuals

Hemispheric specialization for motor control influences how individuals perform and adapt to goal-directed movements. In contrast to adaptation, motor skill learning involves a process wherein one learns to synthesize novel movement capabilities in absence of perturbation such that they are performed with greater accuracy, consistency and efficiency. Here, we investigated manual asymmetry in acquisition and retention of a complex motor skill that requires speed and accuracy for optimal performance in right-handed and left-handed individuals. We further determined if degree of handedness influences motor skill learning. Ten right-handed (RH) and 10 left-handed (LH) adults practiced two distinct motor skills with their dominant or nondominant arms during separate sessions two–four weeks apart. Learning was quantified by changes in the speed–accuracy tradeoff function measured at baseline and one-day retention. Manual asymmetry was evident in the RH group but not the LH group. RH group demonstrated significantly greater skill improvement for their dominant-right hand than their nondominant-left hand. In contrast, for the LH group, both dominant and nondominant hands demonstrated comparable learning. Less strongly-LH individuals (lower EHI scores) exhibited more learning of their dominant hand. These results suggest that while hemispheric specialization influences motor skill learning, these effects may be influenced by handedness.     

面孔吸引力和配偶价值:进化心理学视角

面孔吸引力是对个体容貌的审美评价。根据进化心理学的观点,面孔吸引力是配偶价值的线索。这一假设是进化心理学视角下的面孔吸引力研究的前提所在。本文就涉及这一核心假设的研究进行梳理,重点关注影响面孔吸引力的形态特征与配偶价值的关系。这些形态特征包括面孔的性别二态性特征,面孔的波动性不对称特征以及面孔的肥胖特征。     

A four‐disc version of the Tower of London for clinical use

Three studies are reported on the development of a four‐disc version of the Tower of London test of planning ability. The first (n = 138) involved the selection of items based on rational and empirical criteria to provide a short test of graded difficulty suitable for use with children and clinical populations. The second study (n = 480) checked the properties of the 10‐item test on a new sample and in addition examined the internal consistency and factor structure of the test. The third study (n = 61) examined the test – retest reliability of the test over a period of 1 month. The difficulty level of the test remained relatively stable from sample to sample and was sensitive to linear trend in performance from age 5 years up to 30 years. Total score did not reflect the action of a single underlying construct but rather appeared to index a number of factors. Scores were reasonably stable over the 1‐month period studied, at least for the children's sample employed. The four‐disc version is a promising method of assessing planning in children and adolescents in clinical situations.     

A forced-attention dichotic listening fMRI study on 113 subjects

We report fMRI and behavioral data from 113 subjects on attention and cognitive control using a variant of the classic dichotic listening paradigm with pairwise presentations of consonant-vowel syllables. The syllable stimuli were presented in a block-design while subjects were in the MR scanner. The subjects were instructed to pay attention to and report either the left or right ear stimulus. The hypothesis was that paying attention to the left ear stimulus (FL condition) induces a cognitive conflict, requiring cognitive control processes, not seen when paying attention to the right ear stimulus (FR condition), due to the perceptual salience of the right ear stimulus in a dichotic situation. The FL condition resulted in distinct activations in the left inferior prefrontal gyrus and caudate nucleus, while the right inferior frontal gyrus and caudate were activated in both the FL and FR conditions, and in a non-instructed (NF) baseline condition.     

Speech presentation cues moderate frontal EEG asymmetry in socially withdrawn young adults

Socially withdrawn individuals display solitary behavior across wide contexts with both unfamiliar and familiar peers. This tendency to withdraw may be driven by either past or anticipated negative social encounters. In addition, socially withdrawn individuals often exhibit right frontal electroencephalogram (EEG) asymmetry at baseline and when under stress. In the current study we examined shifts in frontal EEG activity in young adults (N=41) at baseline, as they viewed either an anxiety-provoking or a benign speech video, and as they subsequently prepared for their own speech. Results indicated that right frontal EEG activity increased, relative to the left, only for socially withdrawn participants exposed to the anxious video. These results suggest that contextual affective cues may prime an individual's response to stress, particularly if they illustrate or substantiate an anticipated negative event.