Intelligence and neural efficiency: The influence of task content and sex on the brain–IQ relationship

In studying physiological correlates of human intelligence, new brain imaging techniques like positron emission tomography (PET) and electroencephalography (EEG) mapping methods focus on the level and topographical distribution of cortical activation. Actually, there is strong empirical evidence that more intelligent individuals display a more focused cortical activation during cognitive performance resulting in lower total brain activation than in less intelligent individuals (i.e., neural efficiency hypothesis). Former studies have used only single, homogeneous tasks and most of the studies have been performed using males. Therefore, here the influence of different task content and of sex on the relationship between intelligence and cortical activation has been tested. In a sample of 26 males and 25 females, we administered verbal, numerical, and figural versions of a well-known elementary cognitive task, the so-called Posner task. Our results suggest a comparatively low cortical activation in brighter as compared to less intelligent individuals but this expected neural efficiency pattern interacted with sex and task content: In the verbal Posner task, the females were more likely to produce cortical activation patterns in line with the neural efficiency hypothesis, whereas in the figural task, primarily the males displayed the expected inverse relationship between IQ and cortical activation.     

Catastrophic associations predict level of change in anxiety sensitivity in response to cognitive-behavioural treatment for panic

The aim of the present study was to elucidate one of the factors that might be responsible for the maintenance of panic patients' harmful beliefs about anxiety. Specifically, it was hypothesized that harmful beliefs about anxiety, i.e. anxiety sensitivity, is maintained in panic patients by automatic activation of idiographic catastrophic cognitions. To test this prediction, panic patients participated in a one-session cognitive-behavioural treatment of 4-8h to reduce anxiety sensitivity. The strength of automatic catastrophic cognitions in response to idiographic anxiety symptoms, measured with a modified semantic priming task, as well as the strength of the consciously accessible catastrophic meaning of these symptoms were assessed before treatment. In accordance with the hypothesis, stronger automatic catastrophic cognitions predicted a smaller reduction of anxiety sensitivity independently of the strength of conscious catastrophic cognitions. Moreover, in a first exploration, the strength of catastrophic associations was also shown to have an incremental predictive value for change in anxiety sensitivity beyond that of a number of demographic, clinical, treatment and assessment variables. The theoretical and clinical implications are discussed.     

Anger and asymmetrical frontal cortical activity: Evidence for an anger–withdrawal relationship

Anger has been associated with relative left frontal cortical activity, reflecting its approach (vs. withdrawal) motivational tendency. However, there may be contexts in which anger is associated with withdrawal motivation and, hence, relative right frontal cortical activity. Based on past research, we hypothesised that for some individuals, interracial interactions may be one such context, as societal pressure to be politically correct dictates that anger should not be expressed. Thus, in the context of an interracial interaction, the experience of anger may coincide with a desire to withdraw from the situation. Cortical activity was measured while White participants anticipated an interracial interaction. Consistent with expectations, self-reported anger was associated with relative right frontal cortical activity. In general, the motivational correlates of anger may be partially determined by the specific attributes of the person and the social context in which anger occurs.     

Differential time course of implicit and explicit cueing by colour and orientation in visual search

Using a cued conjunction search task, Anderson, Heinke, and Humphreys (2010) demonstrated larger effects from cueing target colour than from cueing target orientation. In this study, we separated the implicit (nonexpectation-dependent) and explicit (expectation-dependent) effects of orientation and colour visual cues. In Experiment 1, we replicated the original findings for short cue durations (100–200 ms), demonstrating that cues matching the physical property of the target on 80% of trials exert a rapid effect on search. These early cueing effects on reaction times were supported by evidence of guidance from cues on early eye movements. Experiment 2 introduced a feature to the cue that randomly matched the colour or orientation of the target. When cue orientation was predictive, there were strong implicit effects based on whether the colour of the cue and target matched. When cue colour was predictive, there were only weak effects from the cue's orientation. Implicit effects from cue colour remained when orientation-predictive cues were used and colour was unlikely to predict the target (Experiment 3). The data suggest that strong effects of colour cueing result from a combination of implicit and explicit processes, whereas effects from orientation cues are largely limited to the explicit guidance of visual search.     

Monkeys perform as well as apes and humans in a size discrimination task

Whether the cognitive competences of monkeys and apes are rather similar or whether the larger-brained apes outperform monkeys in cognitive experiments is a highly debated topic. Direct comparative analyses are therefore essential to examine similarities and differences among species. We here compared six primate species, including humans, chimpanzees, bonobos, gorillas (great apes), olive baboons, and long-tailed macaques (Old World monkeys) in a task on fine-grained size discrimination. Except for gorillas, subjects of all taxa (i.e. humans, apes, and monkeys) were able to discriminate three-dimensional cubes with a volume difference of only 10 % (i.e. cubes of 50 and 48 mm side length) and performed only slightly worse when the cubes were presented successively. The minimal size discriminated declined further with increasing time delay between presentations of the cubes, highlighting the difficulty to memorize exact size differences. The results suggest that differences in brain size, as a proxy for general cognitive abilities, did not account for variation in performance, but that differential socio-ecological pressures may better explain species differences. Our study highlights the fact that differences in cognitive abilities do not always map neatly onto phylogenetic relationships and that in a number of cognitive experiments monkeys do not fare significantly worse than apes, casting doubt on the assumption that larger brains per se confer an advantage in such kinds of tests.     

Epigenetic programming of the HPA axis: early life decides

Stress during early life can impact the developing brain and increase vulnerability to mood disorders later in life. Here, we argue that epigenetic mechanisms can mediate the gene-environment dialogue in early life and give rise to persistent epigenetic programming of adult physiology eventually resulting in disease. Early life stress in mice leads to epigenetic marking of the arginine vasopressin (AVP) gene underpinning sustained expression and increased hypothalamic-pituitary-adrenal axis activity. This epigenetic memory is laid down in the parvocellular neurons of the paraventricular nucleus and involves Ca(2+)/calmodulin kinase-mediated phosphorylation of the methyl-CpG binding domain protein MeCP2 leading to dissociation from its DNA-binding site and derepression of the AVP gene. The reduced occupancy of MeCP2 during this early stage of life facilitates the development of hypomethylation at the AVP enhancer, which sustains derepression throughout later life and thereby serves to hardwire early life experiences. The sequential order of these events may represent a critical time window for the preventive therapy of severe trauma.     

Bridging the gap between physiology and behavior: evidence from the sSoTS model of human visual attention

We present the case for a role of biologically plausible neural network modeling in bridging the gap between physiology and behavior. We argue that spiking-level networks can allow "vertical" translation between physiological properties of neural systems and emergent "whole-system" performance-enabling psychological results to be simulated from implemented networks and also inferences to be made from simulations concerning processing at a neural level. These models also emphasize particular factors (e.g., the dynamics of performance in relation to real-time neuronal processing) that are not highlighted in other approaches and that can be tested empirically. We illustrate our argument from neural-level models that select stimuli by biased competition. We show that a model with biased competition dynamics can simulate data ranging from physiological studies of single-cell activity (Study 1) to whole-system behavior in human visual search (Study 2), while also capturing effects at an intermediate level, including performance breakdown after neural lesion (Study 3) and data from brain imaging (Study 4). We also show that, at each level of analysis, novel predictions can be derived from the biologically plausible parameters adopted, which we proceed to test (Study 5). We argue that, at least for studying the dynamics of visual attention, the approach productively links single-cell to psychological data.     

Where and how does grammatically geared processing take place-and why is Broca's area often involved. A coordinated fMRI/ERBP study of language processing

We address the possibility of combining the results from hemodynamic and electrophysiological methods for the study of cognitive processing of language. The hemodynamic method we use is Event-Related fMRI, and the electrophysiological method measures Event-Related Band Power (ERBP) of the EEG signal. The experimental technique allows us to approach the relation between cortical structure and cognitive function in a sophisticated way. In particular, we can formulate original working hypotheses about the language-induced changes in the ongoing brain dynamics. We show, on the basis of electrophysiological data collected in an experiment on language production, that synchronized cortical networks code cognitive processes induced by language in form of power modulations of specific frequency bands. The hemodynamic (fMRI) data collected in the same task point to the existence of a central processor for the phrase structure assignment. We conceptualize such a central processor as a frequency scanner, a cortical device designed to pick up synchronized brain activity over a specific range of frequencies. We discuss the experimental designs which result from this set of hypotheses and show their relevance for the models of language processing.