Deficit in selective and divided attention associated with cholinergic basal forebrain immunotoxic lesion produced by 192-saporin; motoric/sensory deficit associated with Purkinje cell immunotoxic lesion produced by OX7-saporin

The immunotoxin 192-saporin, infused intracerebroventricularly into rats, destroys cholinergic neurons in the basal forebrain nuclei. Doses required for complete cholinergic loss also kill some Purkinje cells. The immunotoxin OX7-saporin, when infused intraventricularly into rats, destroys Purkinje cells in a pattern similar to that produced by 192-saporin, without affecting cholinergic neurons. Thus, we used OX7-saporin to distinguish behavioral effects of 192-saporin due to cerebellar damage versus those due to cholinergic cell loss. Three doses of 192-saporin (1.6, 2.6, and 3.3 micrograms/rat) were chosen along with a dose of OX7-saporin (2.0 micrograms/rat) that produced Purkinje loss equivalent to the two highest doses of 192-saporin. Groups of Fischer-344 rats were trained in the multiple choice reaction time task and retested with more complex tasks after lesioning. They were also tested in the water maze, passive avoidance, acoustic startle, and open field. The OX7-saporin group exhibited changes in many tests suggesting hypermotility and sensory deficits. The 192-saporin groups differed from the OX7-saporin group when they displayed deficits in multiple choice reaction time tasks in which novel challenges were introduced, including sessions with a noise distractor, shortened and lengthened intertrial intervals, and use of nine instead of five sources of light stimulus. The 192-saporin groups showed no impairment in the other tasks. The cholinergic basal forebrain lesion may mask some of the effects of cerebellar damage up to a threshold after which effects of Purkinje cell loss predominate when 192-saporin is administered intraventricularly.     

Recognition Memory for Faces: Reliability and Validity of the Warrington Recognition Memory Test (RMT) in a Neurological Sample

In response to critiques regarding the psychometric limitations of the Warrington Recognition Memory Test for faces (RMT-F), the current study was conducted to examine the test-retest reliability and validity of the measure in a neurological sample. Forty adult outpatients, ages 35–81, were administered the RMT-F as part of their diagnostic exam. A second evaluation was conducted after an average interval of 7 months (range = 2–20 months). Results yielded a Pearson reliability coefficient of 0.81 (p < .001), indicating a clinically satisfactory index of stability. Correlations with other measures were conducted to examine convergent and divergent validity. Results indicate that the facial component of the RMT has adequate reliability for patients with established neurological disease, shows moderate correlations with other measures of complex visuospatial function, and shows no significant correlation with measures of verbal reasoning, visual problem-solving, or verbal fluency. These findings provide additional support for the clinical efficacy of this instrument for use in a diverse neurological patient sample.     

Qualitative analyses of critical aspects of adaptation to the visually left-right reversed world

In this article, mechanisms of perceptual adaptation to the transposed world are analyzed based on introspective and behavioral performance data gathered during an extended period of wearing left-right reversing goggles. Three aspects central to this study were the mental map of the living space surrounding the subject, body image (both seen and felt), and the sensorimotor coordination system, which reflects the relationship between the subject and surroundings. These were investigated through map-drawing tests, self-representation tests when postures other than face forward were adopted, and after effects observed immediately after removal of the reversing goggles. It was concluded that the main course of the perceptual adaptation to the visually left-right reversed world consists of double reversals of the mental map and body image as well as the establishment of a new sensorimotor coordination system. In sharp contrast to the proprioceptive-change hypothesis, the importance of the visual nature of the body image was emphasized.     

Infant responses to adult happy and sad vocal and facial expressions during face-to-face interactions

We examined 5-month-olds’ responses to adult facial versus vocal displays of happy and sad expressions during face-to-face social interactions in three experiments. Infants interacted with adults in either happy-sad-happy or happy-happy-happy sequences. Across experiments, either facial expressions were present while presence/absence of vocal expressions was manipulated or visual access to facial expressions was blocked but vocal expressions were present throughout. Both visual attention and infant affect were recorded. Although infants looked more when vocal expressions were present, they smiled significantly more to happy than to sad facial expressions regardless of presence or absence of the voice. In contrast, infants showed no evidence of differential responding to voices when faces were obscured; their smiling and visual attention simply declined over time. These results extend findings from non-social contexts to social interactions and also indicate that infants may require facial expressions to be present to discriminate among adult vocal expressions of affect.     

Learning to Make Selection and Detection Decisions: The Roles of Base Rate and Feedback

The effects of type of feedback and base rate on threshold learning in a multiple‐cue decision task were examined. In most such decision experiments, participants receive feedback after every trial (full feedback), and a single base rate (usually 0.5) is used. Our experiment explored conditional feedback (feedback only after positive decisions) representing common selection and detection tasks (such as hiring), where the decision maker receives no feedback unless the decision is positive (e.g., hire the applicant). We used three base rates (0.2, 0.5, and 0.8). As expected, performance was best in full feedback, but after 300 learning trials, the difference was small. Conditional feedback generally resulted in fewer positive decisions than full feedback, but this difference was not found in the low (0.2) base rate condition. There were interactions between base rates and types of feedback. Results provide partial support for the constructivist encoding hypothesis of Elwin and colleagues. Simulation results suggest that our results may reflect overconfidence when feedback is not given. With respect to rate of learning, when the base rate was 0.2, conditional feedback participants reached approximately the same selection rate but did so more slowly than the full feedback participants. Partial feedback participants learned slower and appeared to be still learning after 500 trials. When the base rate was 0.5 or 0.8, partial feedback was nearly as good as full feedback, but conditional feedback resulted in a systematically lower rate of positive decisions. Copyright © 2011 John Wiley & Sons, Ltd.     

视觉刺激探测的警觉性注意特征初探

采用"预警提示-目标探测"范式,对视觉刺激探测的警觉性注意特征进行初步探索。实验一表明,随着预备到目标刺激的时间间隔(interstimulus interval,ISI)变化,固定位置上探测目标刺激的速度也随之变化,并且对大概率刺激的探测更快,表现出了警觉性注意的稳定性和选择性特征。实验二进一步考察了目标刺激在不同ISI和不同空间位置的情况,除发现与实验一相似的结果以外,被试探测目标刺激的速度随注意视角增大而下降,表现出了警觉性注意的集中性特征。     

远、近空间内注意加工的分离

临床证据发现空间忽视症病人对于近处和远处空间内的注意加工存在差异,表现为空间忽视只发生于近处空间或只发生于远处空间,提示近处空间与远处空间在脑内可能是分别表征的。对健康成人的研究也发现了与之类似的近处空间和远处空间注意的分离现象,即在近处空间表现出左偏的伪忽视现象,在远处空间表现出左偏减弱或者右偏的趋势。本文综述了远、近空间内注意加工分离的实验证据以及采用线段二分任务这一主要的研究范式相关的实验结果,并且着重指出了远、近空间的划分不是绝对的,而是动态可变的研究证据。最后,指出了将来的研究需要深入考察空间参照系统在远、近空间知觉中的作用,以及关注社会交互情境下的远、近空间距离认知的动态变化。     

The Role of Executive Control of Attention and Selective Encoding for Preschoolers' Learning

Selectivity in encoding, aspects of attentional control and their contribution to learning performance were explored in a sample of preschoolers. While the children are performing a learning task, their encoding of relevant and attention towards irrelevant information was recorded through an eye‐tracking device. Recognition of target items was used as measure of learning outcome, and individual differences in resistance to interference and inhibition of attention to task‐irrelevant stimuli (i.e. distractibility) were used as measures of executive control of attention. Results indicated well‐developed selectivity during encoding in young children. Recognition performance was related to selective encoding and aspects of attentional control, explaining individual differences in learning. Copyright © 2011 John Wiley & Sons, Ltd.     

Acquisition of social referencing via discrimination training in infants

This experiment investigated social referencing as a form of discriminative learning in which maternal facial expressions signaled the consequences of the infant's behavior in an ambiguous context. Eleven 4- and 5-month-old infants and their mothers participated in a discrimination-training procedure using an ABAB design. Different consequences followed infants' reaching toward an unfamiliar object depending on the particular maternal facial expression. During the training phases, a joyful facial expression signaled positive reinforcement for the infant reaching for an ambiguous object, whereas a fearful expression signaled aversive stimulation for the same response. Baseline and extinction conditions were implemented as controls. Mothers' expressions acquired control over infants' approach behavior for all participants. All participants ceased to show discriminated responding during the extinction phase. The results suggest that 4- and 5-month-old infants can learn social referencing via discrimination training.