Learning under stress: A role for the neural cell adhesion molecule NCAM

Stress is known to be a potent modulator of brain function and cognition. While prolonged and/or excessive stress generally exerts negative effects on learning and memory processes, acute stress can have differential effects on memory function depending on a number of factors (such as stress duration, stress intensity, timing and the source of the stress, as well as the learning type under study). Here, we have focused on the effects of ‘acute’ stress, and examined the literature attending to whether the “source of stress” is ‘intrinsic’ (i.e., when stress is originated by the cognitive task) or ‘extrinsic’ (i.e., when stress is induced by elements not related to the cognitive task). We have questioned here whether the neural cell adhesion molecule of the immunoglobulin superfamily (NCAM) contributes to the neurobiological mechanisms that translate the effects of these two different stress sources into the different behavioral and cognitive outcomes. NCAM is a cell adhesion macromolecule known to play a critical role in development and plasticity of the nervous system. NCAM and its post-translational modified form PSA-NCAM are critically involved in mechanisms of learning and memory and their expression levels are known to be highly susceptible to modulation by stress. Whereas available data are insufficient to conclude as to whether NCAM mediates extrinsic stress effects on learning and memory processes, we present systematic evidence supporting a key mediating role for both NCAM and PSA-NCAM in the facilitation of memory consolidation induced by intrinsic stress. Furthermore, NCAM is suggested to participate in some of the bidirectional effects of stress on memory processes, with its enhanced synaptic expression involved in facilitating stress actions while its reduced expression being related to impairing effects of stress on memory function.     

Investigating emotional contagion in dogs (<Emphasis Type="Italic">Canis familiaris</Emphasis>) to emotional sounds of humans and conspecifics

Emotional contagion, a basic component of empathy defined as emotional state-matching between individuals, has previously been shown in dogs even upon solely hearing negative emotional sounds of humans or conspecifics. The current investigation further sheds light on this phenomenon by directly contrasting emotional sounds of both species (humans and dogs) as well as opposed valences (positive and negative) to gain insights into intra- and interspecies empathy as well as differences between positively and negatively valenced sounds. Different types of sounds were played back to measure the influence of three dimensions on the dogs’ behavioural response. We found that dogs behaved differently after hearing non-emotional sounds of their environment compared to emotional sounds of humans and conspecifics (“Emotionality” dimension), but the subjects responded similarly to human and conspecific sounds (“Species” dimension). However, dogs expressed more freezing behaviour after conspecific sounds, independent of the valence. Comparing positively with negatively valenced sounds of both species (“Valence” dimension), we found that, independent of the species from which the sound originated, dogs expressed more behavioural indicators for arousal and negatively valenced states after hearing negative emotional sounds. This response pattern indicates emotional state-matching or emotional contagion for negative sounds of humans and conspecifics. It furthermore indicates that dogs recognized the different valences of the emotional sounds, which is a promising finding for future studies on empathy for positive emotional states in dogs.     

The efficacy of the Microsoft Kinect<Superscript>TM</Superscript> to assess human bimanual coordination

The Microsoft Kinect has been used in studies examining posture and gait. Despite the advantages of portability and low cost, this device has not been used to assess interlimb coordination. Fundamental insights into movement control, variability, health, and functional status can be gained by examining coordination patterns. In this study, we investigated the efficacy of the Microsoft Kinect to capture bimanual coordination relative to a research-grade motion capture system. Twenty-four healthy adults performed coordinated hand movements in two patterns (in-phase and antiphase) at eight movement frequencies (1.00–3.33 Hz). Continuous relative phase (CRP) and discrete relative phase (DRP) were used to quantify the means (mCRP and mDRP) and variability (sdCRP and sdDRP) of coordination patterns. Between-device agreement was assessed using Bland–Altman bias with 95 % limits of agreement, concordance correlation coefficients (absolute agreement), and Pearson correlation coefficients (relative agreement). Modest-to-excellent relative and absolute agreements were found for mCRP in all conditions. However, mDRP showed poor agreement for the in-phase pattern at low frequencies, due to large between-device differences in a subset of participants. By contrast, poor absolute agreement was observed for both sdCRP and sdDRP, while relative agreement ranged from poor to excellent. Overall, the Kinect captures the macroscopic patterns of bimanual coordination better than coordination variability.     

Do capuchin monkeys use weight to select hammer tools?

The extent to which tool-using animals take into account the properties of the tool is little explored. The use of percussors to crack open encapsulated fruit is a complex form of tool use, the choice of an adequate tool being a critical aspect in success. Several properties (e.g., material, resistance, friability, shape and weight) affect the suitability of an object to open a hard-shelled nut, with weight being amongst the most important factors. In general, heavier tools require fewer strikes to crack open a nut.     

Inferential reasoning by exclusion in pigeons, dogs, and humans

The ability to reason by exclusion (which is defined as the selection of the correct alternative by logically excluding other potential alternatives; Call in Anim Cogn 9:393–403 2006) is well established in humans. Several studies have found it to be present in some nonhuman species as well, whereas it seems to be somewhat limited or even absent in others. As inconsistent methodology might have contributed to the revealed inter-species differences, we examined reasoning by exclusion in pigeons (n = 6), dogs (n = 6), students (n = 6), and children (n = 8) under almost equal experimental conditions. After being trained in a computer-controlled two-choice procedure to discriminate between four positive (S+) and four negative (S−) photographs, the subjects were tested with displays consisting of one S− and one of four novel stimuli (S′). One pigeon, half of the dogs and almost all humans preferred S′ over S−, thereby choosing either by novelty, or by avoiding S− without acquiring any knowledge about S′, or by inferring positive class membership of S′ by excluding S−. To decide among these strategies the subjects that showed a preference for S′ were then tested with displays consisting of one of the S′ and one of four novel stimuli (S′′). Although the pigeon preferentially chose the S′′ and by novelty, dogs and humans maintained their preference for S′, thereby showing evidence of reasoning by exclusion. Taken together, the results of the present study suggest that none of the pigeons, but half of the dogs and almost all humans inferred positive class membership of S′ by logically excluding S−. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

The Effectiveness of Cognitive Processing Therapy for PTSD With Refugees in a Community Setting

Opinions vary on the generalizability of empirically supported treatments to diverse populations in naturalistic settings and on the relative merits of delivering treatments through interpreters. The authors present statistical analyses of outcome data from a community mental health program that served foreign-born refugees resettled in the U.S. The program used a manualized, empirically supported treatment, Cognitive Processing Therapy, to address symptoms of PTSD in this population. Participants received psychological treatment in native languages either with a therapist who spoke their language or with a therapist who used an interpreter. Results demonstrated that treatment of PTSD was highly effective whether delivered directly or through an interpreter.     

Gaze following in the red-footed tortoise (Geochelone carbonaria)

Gaze following refers to the ability of an animal to orient its gaze direction to that of another organism. Such a behavior may be adaptive as it alerts the observer to important objects in the environment such as food or predators. This behavior has been shown in mammals and birds, but the evolutionary history and the distribution of this behavior throughout the animal kingdom remain unclear. Here, we show that a reptile, the red-footed tortoise (Geochelone carbonaria), is able to follow the gaze of a conspecific in a lookup task. Controls revealed that neither the mere presence of a conspecific nor the presentation of a light stimulus (without a demonstrator present) controlled the tortoises’ behavior. The findings indicate that the ability to follow gaze may be found in mammals, birds and reptiles and could have evolved before the amniotic line diverged, or may result from a general ability to learn.     

Embodied numerosity: Implicit hand-based representations influence symbolic number processing across cultures

In recent years, a strong functional relationship between finger counting and number processing has been suggested. Developmental studies have shown specific effects of the structure of the individual finger counting system on arithmetic abilities. Moreover, the orientation of the mental quantity representation (“number line”) seems to be influenced by finger counting habits. However, it is unclear whether the structure of finger counting systems still influences symbolic number processing in educated adults.In the present transcultural study, we pursued this question by examining finger-based sub-base-five effects in an Arabic number comparison task with three different groups of participants (German deaf signers, German and Chinese hearing adults). We observed sub-base-five effects in all groups, but particularly so for both German groups who use an explicit sub-base-five system in their finger counting habits. It is concluded that bodily experiences – namely finger counting – influence the structure of the abstract mental number representations even in adults. Thus, the present findings support the general idea that even seemingly abstract cognition may at least partially be rooted in our bodily experiences.