Survival with an asymmetrical brain: advantages and disadvantages of cerebral lateralization

Recent evidence in natural and semi-natural settings has revealed a variety of left-right perceptual asymmetries among vertebrates. These include preferential use of the left or right visual hemifield during activities such as searching for food, agonistic responses, or escape from predators in animals as different as fish, amphibians, reptiles, birds, and mammals. There are obvious disadvantages in showing such directional asymmetries because relevant stimuli may be located to the animal's left or right at random; there is no a priori association between the meaning of a stimulus (e.g., its being a predator or a food item) and its being located to the animal's left or right. Moreover, other organisms (e.g., predators) could exploit the predictability of behavior that arises from population-level lateral biases. It might be argued that lateralization of function enhances cognitive capacity and efficiency of the brain, thus counteracting the ecological disadvantages of lateral biases in behavior. However, such an increase in brain efficiency could be obtained by each individual being lateralized without any need to align the direction of the asymmetry in the majority of the individuals of the population. Here we argue that the alignment of the direction of behavioral asymmetries at the population level arises as an "evolutionarily stable strategy" under "social" pressures occurring when individually asymmetrical organisms must coordinate their behavior with the behavior of other asymmetrical organisms of the same or different species.     

Time ordering in frontal lobe patients: a stochastic model approach

Frontal lobe patients reproduced a sequence of capital letters or abstract shapes. Immediate and delayed reproduction trials allowed the analysis of short- and long-term memory for time order by means of suitable Markov chain stochastic models. Patients were as proficient as healthy subjects on the immediate reproduction trial, thus showing spared encoding and short-term memory. They failed, instead, on the delayed trials with capital letters, but not with random shapes, suggesting that their long-term memory impairment did not depend on primary deficits for ordering, but on inability to benefit from the organisational strategies that improve the retention and retrieval in normal subjects.     

Intermittent exposure to social defeat and open-field test in rats: acute and long-term effects on ECG,body temperature and physical activity

This study investigated the effects of exposure to an intermittent homotypic stressor on: (i) habituation of acute autonomic responsivity (i.e. cardiac sympathovagal balance and susceptibility to arrhythmias), and (ii) circadian rhythmicity of heart rate, body temperature, and physical activity. After implantation of a transmitter for the radiotelemetric recording of electrocardiogram (ECG), body temperature and physical activity, adult male rats (Rattus norvegicus, Wild Type Groningen strain) were repeatedly exposed (10 consecutive times, on alternate days) to either a social stressor (defeat by a con-specific, n = 15) or an open-field, control challenge (transfer to a new cage; n = 8). ECGs, body temperature and physical activity were continuously recorded in baseline, test and recovery periods (each lasting 15 min), at the 1st and 10th episodes of both defeat and open-field challenge. The circadian rhythms of heart rate, body temperature and physical activity were monitored before (5 days), during (16 days) and after (21 days) the intermittent stress protocol. This study indicates that there is no clear habituation of either acute cardiac autonomic responsivity (as estimated by means of time-domain indexes of heart rate variability) or arrhythmia occurrence to a brief, intermittent, homotypic challenge, regardless of the nature of the stressor (social or non-social). On the other hand, rats exposed to social challenge also failed to show adaptation of acute temperature and activity stress responsiveness, whereas rats facing open-field challenge developed habituation of activity and sensitization of temperature responses. Repeated social challenge produced remarkable reductions of the heart rate circadian rhythm amplitude (this effect being significantly greater than that produced by intermittent open-field), but only minor changes in the daily rhythms of body temperature and physical activity.     

Naïve chicks do not prefer objects with stable body orientation,though they may prefer behavioural variability

Animal Cognition - Domestic chicks (Gallus gallus domesticus) have been widely used as a model to study the motion cues that allow visually naïve organisms to detect animate agents shortly...     

Psychological distance and reaction time in a Stroop task

Several sources of interference may simultaneously affect the onset of the well-known “Stroop effect.” Among them is the semantic component, which is reflected in the gradient or semantic effect. This effect consists of an increase in the amount of interference as the semantic distance between the word and the color concept decreases. Shepard (Science 237:1317–1323, 1987) relates psychological space, measured through multidimensional scaling, to mean response times. The present investigation aims to study the function relating the semantic gradient with the psychological distance between the word and the color in a Stroop task. After measuring the gradient, we obtained the subjective rating of the degree of dissimilarity of the gradient words with the concept of “color.” In our work, we show that the amount of interference in a Stroop task increases when the semantic distance from the word to the color concept decreases, and it does so exponentially. We replicated the study with different stimuli to test the robustness of the results.     

Epistemic Operators in Dependence Logic

The properties of the ${\forall^{1}}$ quantifier defined by Kontinen and Väänänen in [13] are studied, and its definition is generalized to that of a family of quantifiers ${\forall^{n}}$ . Furthermore, some epistemic operators δ ⁿ for Dependence Logic are also introduced, and the relationship between these ${\forall^{n}}$ quantifiers and the δ ⁿ operators are investigated. The Game Theoretic Semantics for Dependence Logic and the corresponding Ehrenfeucht- Fraissé game are then adapted to these new connectives. Finally, it is proved that the ${\forall^{1}}$ quantifier is not uniformly definable in Dependence Logic, thus answering a question posed by Kontinen and Väänänen in the above mentioned paper.     

Stress‐related exhaustion disorder – clinical manifestation of burnout? A review of assessment methods,sleep impairments,cognitive disturbances,and neuro‐biological and physiological changes in clinical burnout

The aim of this paper was to provide an overview of the literature on clinically significant burnout, focusing on its assessment, associations with sleep disturbances, cognitive impairments, as well as neurobiological and physiological correlates. Fifty‐nine English language articles and six book chapters were included. The results indicate that exhaustion disorder (ED), as described in the Swedish version of the International Classification of Diseases, seems to be the most valid clinical equivalent of burnout. The data supports the notion that sleep impairments are causative and maintaining factors for this condition. Patients with clinical burnout/ED suffer from cognitive impairments in the areas of memory and executive functioning. The studies on neuro‐biological mechanisms have reported functional uncoupling of networks relating the limbic system to the pre‐frontal cortex, and decreased volumes of structures within the basal ganglia. Although there is a growing body of literature on the physiological correlates of clinical burnout/ED, there is to date no biomarker for this condition. More studies on the role of sleep disturbances, cognitive impairments, and neurobiological and physiological correlates in clinical burnout/ED are warranted.     

At the root of the left–right asymmetries in spatial–numerical processing: From domestic chicks to human subjects

In this review, we discuss evidence showing that birds (Gallus gallus and Nucifraga columbiana) represent numerical magnitudes as being oriented from left to right. Subjects, trained to identify a target element (i.e. the 4th) in a series of sagittally oriented identical elements, when required to generalise on an identical series oriented spatially from left to right, correctly identified the target element “counting” from the left of the array. Moreover, chicks, when presented with sets of 5 vs. 10 or 6 vs. 9 imprinting objects, which were made to disappear one at a time behind one of two identical screens, spontaneously inspected the screen which occluded the larger set. Interestingly, chicks scored a higher percentage of correct choices when the larger of the two sets was on their right side. Similarities with the phenomenon of the spatially oriented (left to right) number line in humans are discussed. Animal models promise a fresh approach to the understanding of developmental mechanisms underlying the expression of knowledge, offering attractive arguments for doubting the uniqueness of human numerical cognition.     

Dual commitment profiles and job satisfaction among temporary agency workers

Temporary agency workers (TAWs) are an ever-increasing type of employees which establish a double work relationship with both the agency and the client organization. Within this context, the concept of dual commitment has received considerable attention in the last years. The present contribution integrates dual commitment line of research with the one adopting a person-centered approach to the study of commitment configurations, to investigate commitment profiles on a large sample of TAWs. According to Sinclair et al.'s framework, we aimed to identify TAWs' commitment profiles based on their levels of dual affective commitment (to the agency and to the client organization) and on their general continuance commitment and to investigate differences in job satisfaction among profiles. Latent profile analyses on 7225 TAWs revealed 5 distinct profiles, namely Dually Free Agents, Dually Involved, Dually Allied, (Unilaterally) Client Allied and (Unilaterally) Agency Invested. The Dually Involved profile, followed by the Dually Allied profile, had the highest level of job satisfaction, whereas the Dually Free Agent profile and the (Unilaterally) Agency Invested had the lowest. Furthermore, the (Unilaterally) Client Allied group had a higher level of job satisfaction as compared to the (Unilaterally) Agency Invested profile. Implications are discussed.     

Normal body scheme and absent phantom limb experience in amputees while dreaming

While dreaming amputees often experience a normal body image and the phantom limb may not be present. However, dreaming experiences in amputees have mainly been collected by questionnaires. We analysed the dream reports of amputated patients with phantom limb collected after awakening from REM sleep during overnight videopolysomnography (VPSG). Six amputated patients underwent overnight VPSG study. Patients were awakened during REM sleep and asked to report their dreams. Three patients were able to deliver an account of a dream. In all dreaming recalls, patients reported that the amputated limbs were intact and completely functional and they no longer experienced phantom limb sensations. Phantom limb experiences, that during wake result from a conflict between a pre-existing body scheme and the sensory information on the missing limb, were suppressed during sleep in our patients in favour of the image of an intact body accessed during dream.