Insights into a molecular switch that gates sensory neuron synapses during habituation in Aplysia

This review focuses on synaptic depression at sensory neuron-to-motor neuron synapses in the defensive withdrawal circuit of Aplysia as a model system for analysis of molecular mechanisms of sensory gating and habituation. We address the following topics:1. Of various possible mechanisms that might underlie depression at these sensory neuron-to-motor neuron synapses in Aplysia, historically the most widely-accepted explanation has been depletion of the readily releasable pool of vesicles. Depletion is also believed to account for synaptic depression at long interstimulus intervals in a variety of other systems.2. Multiple lines of evidence now indicate that vesicle depletion is not an important contributing mechanism to synaptic depression at Aplysia sensory neuron-to-motor neuron synapses. More generally, it appears that vesicle depletion does not contribute substantially to depression that occurs with those stimulus patterns that are typically used in studying behavioral habituation.3. Recent evidence suggests that at these sensory neuron-to-motor neuron synapses in Aplysia, synaptic depression is mediated by an activity-dependent, but release-independent, switching of individual release sites to a silent state. This switching off of release sites is initiated by Ca²⁺ influx during individual action potentials. We discuss signaling proteins that may be regulated by Ca²⁺ during the silencing of release sites that underlies synaptic depression.4. Bursts of 2–4 action potentials in presynaptic sensory neurons in Aplysia prevent the switching off of release sites via a mechanism called “burst-dependent protection” from synaptic depression.5. This molecular switch may explain the sensory gating that allows animals to discriminate which stimuli are innocuous and appropriate to ignore and which stimuli are more important and should continue to elicit responses.     

Costs and benefits of cultural value mismatch in the globalising era: A commentary on the special issue “cross-cultural value mismatch: A by-product of migration and population diversity around the world” (IJP,December, 2018)

In this commentary, the author first seeks to counterbalance the current focus on the cost of cultural value mismatch by calling attention to ample evidence in the literature that value mismatch can produce cultural adaptation and resilience in the long run, besides promoting cultural innovations and individual creativity. Second, we propose three factors that differentiate the benefits from the costs of cultural value mismatch. Personal orientation towards integrating heritage and host culture, accurate perception of cultural value differences, and supportive multicultural environments are associated with benefits. In contrast, dichotomous orientation towards one or the other culture, exaggeration of value differences between heritage and host culture, and assimilationist social environments are associated with costs. Third, our analysis of the decoupling between cultural values and ecological niches in the special issue led to observation of bidirectionality in cultural value mismatch: Whereas most articles in the Special Issue focus on the cross-cultural value mismatch that occurs when people move from a more rural, low-resource, less technological ecology into a more urban, high-resource, more technological ecology, we were able to document the effects of value mismatch when movement occurs in the opposite direction.     

A Review of Sensory Imagery for Consumer Psychology

This review of mental imagery research has the core objective of fostering more research on the topic of sensory imagery. The review is organized around a conceptual framework highlighting (a) how mental imagery is formed, (b) the elicitation and elaboration of mental imagery, (c) the multi-modal nature of sensory imagery, and (d) the consumer behavior consequences of mental imagery. This conceptual framework provides many new lenses through which researchers can view prior findings, and thereby motivates innovative new research ideas. Future research directions are provided in each section of the review, with additional unexplored opportunities presented in a final section.     

Symmetry perception in the blind

Bilateral mirror symmetry, especially vertical symmetry, is a powerful phenomenon in spatial organization of visual shapes. However, the causes of vertical symmetry salience in visual perception are not completely clear. Here we investigated whether the perceptual salience of vertical symmetry depends on visual experience by testing a group of congenitally blind individuals in a memory task in which either horizontal or vertical symmetry was used as an incidental feature. Both blind and sighted subjects remembered more accurately configurations that were symmetrical compared to those that were not. Critically, whereas sighted subjects displayed a higher level of facilitation by vertical than horizontal symmetry, no such difference was found in the blind. This suggests that the perceptual salience of the vertical dimension is visually based.     

家庭第一代大学生的心理挑战及其解析——基于文化不匹配理论的视角

家庭第一代大学生在大学校园的学习和生活中都面临着一定的挑战。以往文献表明家庭第一代大学生表现出了明显的心理适应水平低, 学校参与度不高以及学业表现不足。文化不匹配理论从大学生的文化自我模式与高校文化规范之间关系出发, 解释了家庭第一代大学生在大学生活中的适应与学业成就等方面的不利处境。以文化不匹配理论为基础, 对家庭第一代大学生所面临的心理行为挑战及其干预实践进行了系统的回顾。未来的研究可以关注人格因素对文化不匹配的调节作用, 也可以探讨教育多样化在推进教育公平过程中的角色以及我国家庭第一代大学生的独特心理特征等内容。     

Infant long-term memory for associations formed during mere exposure

We previously found that young infants spontaneously associate stimuli that they merely see together. Using a sensory preconditioning paradigm with 6- and 9-month-olds, we asked how long such associations remain latent before being forgotten and what exposure conditions affect their persistence. Groups were preexposed to two puppets for 1 h/day for 2 days, 1 h on 1 day, or 1 h on 1 day in two sessions; 1-27 days later, target actions were modeled on one puppet, and infants were tested with the other puppet 1 day later. The longest delay after which infants imitated the actions on the other puppet defined how long they remembered the association. The data revealed that the preexposure regimen determined retention. Regardless of exposure time, both ages remembered the association longer after two sessions, and younger infants remembered longer than older infants - for 4 weeks - after two 30-min sessions on 1 day.     

Attention and suppression affect tactile perception in reach-to-grasp movements

Reaching with the hand is characterized by a decrease in sensitivity to tactile stimuli presented to the moving hand. Here, we investigated whether tactile suppression can be canceled by attentional orienting. In a first experiment, participants performed a dual-task involving a goal-directed movement paired with the speeded detection of a tactile pulse. The pulse was either delivered to the moving or stationary hand, during movement preparation, execution, or the post-movement phase. Furthermore, stimulation was delivered with equal probability to either hand, or with a higher probability to either the moving or resting hand. The results highlighted faster RTs under conditions of higher probability of stimulation delivery to both moving and resting hands, thus indicating an attentional effect. For the motor preparation period, RTs were faster only at the resting hand under conditions where tactile stimulation was more likely to be delivered there. In a second experiment, a non-speeded perceptual task was used as a secondary task and tactile discrimination thresholds were recorded. Tactile stimulation was delivered concomitantly at both index fingers either in the movement preparation period (both before and after the selection of the movement effector had taken place), in the motor execution period, or, in a control condition, in the time-window of motor execution, but the movement of the hand was restrained. In the preparation period, tactile thresholds were comparable for the two timings of stimulation delivery; i.e., before and after the selection of the movement effector had taken place. These results therefore suggest that shortly prior to, and during, the execution of goal-directed movements, a combined facilitatory and inhibitory influence acts on tactile perception.     

Similarity and categorization: from vision to touch

Even though human perceptual development relies on combining multiple modalities, most categorization studies so far have focused on the visual modality. To better understand the mechanisms underlying multisensory categorization, we analyzed visual and haptic perceptual spaces and compared them with human categorization behavior. As stimuli we used a three-dimensional object space of complex, parametrically-defined objects. First, we gathered similarity ratings for all objects and analyzed the perceptual spaces of both modalities using multidimensional scaling analysis. Next, we performed three different categorization tasks which are representative of every-day learning scenarios: in a fully unconstrained task, objects were freely categorized, in a semi-constrained task, exactly three groups had to be created, whereas in a constrained task, participants received three prototype objects and had to assign all other objects accordingly. We found that the haptic modality was on par with the visual modality both in recovering the topology of the physical space and in solving the categorization tasks. We also found that within-category similarity was consistently higher than across-category similarity for all categorization tasks and thus show how perceptual spaces based on similarity can explain visual and haptic object categorization. Our results suggest that both modalities employ similar processes in forming categories of complex objects.     

Descartes' Causal Principle and the Case of Body-to-Mind Causation1

It is a common view that Descartes' causal principle is to be understood in light of a similarity condition that accounts for how finite causes (as opposed, or in addition, to God) contribute to an explanation of their effects. This paper challenges this common view and offers a sui generis reading of Descartes' views on causation that has also the advantage of solving the two exegetical issues of whether Descartes thought of the body-to-mind relation in occasionalist or causal terms and of whether Descartes regarded sensory ideas innate or caused by bodies.