Large-scale neural network for sentence processing

Our model of sentence comprehension includes at least grammatical processes important for structure-building, and executive resources such as working memory that support these grammatical processes. We hypothesized that a core network of brain regions supports grammatical processes, and that additional brain regions are activated depending on the working memory demands associated with processing a particular grammatical feature. We used functional magnetic resonance imaging (fMRI) to test this hypothesis by comparing cortical activation patterns during coherence judgments of sentences with three different syntactic features. We found activation of the ventral portion of left inferior frontal cortex during judgments of violations of each grammatical feature. Increased recruitment of the dorsal portion of left inferior frontal cortex was seen during judgments of violations of specific grammatical features that appear to involve a more prominent working memory component. Left posterolateral temporal cortex and anterior cingulate were also implicated in judging some of the grammatical features. Our observations are consistent with a large-scale neural network for sentence processing that includes a core set of regions for detecting and repairing several different kinds of grammatical features, and additional regions that appear to participate depending on the working memory demands associated with processing a particular grammatical feature.     

Don't Make Me Angry! A Psychophysiological Examination of the Anger–Performance Relationship in Intermediate and Elite Fencers

We aimed to identify the effect of state-anger on precision, speed, and power components of performance during fencing attacks. We conducted a laboratory-based, single-case research experiment to test the fine motor task performance of two experienced and two elite-level fencers under two emotional states: anger and emotion-neutral. We assessed anger via psychophysiological and self-report measures, and we induced anger via a brief imagery intervention. Through the use of an innovative design, which included multiple measures of change, we showed that anger had a consistent negative effect on precision but an inconsistent relationship with response time and muscle activity. The current research design and protocol offer a novel and in-depth method for examining the specific relationships between affective states, emotions, and the complexities that underpin performance. The specific effects of anger on performance were multifarious, complex, and inconsistent. Nonetheless, the results tend to indicate that anger facilitates reaction time and debilitates performance, and these effects were clearer for the most elite performers. The effects of anger on performance are clearly complex, so it would be rather premature to make any suggestions for future practice at this point. Nonetheless, the clearer findings with the elite fencers indicate that researchers will likely yield the most fruitful insights by examining the effects of emotion of performance in elite performers.     

Properties of intention: component structure and consequences for behavior,information processing,and resistance

Three studies tested the impact of properties of behavioral intention on intention–behavior consistency, information processing, and resistance. Principal components analysis showed that properties of intention formed distinct factors. Study 1 demonstrated that temporal stability, but not the other intention attributes, moderated intention–behavior consistency. Study 2 found that greater stability of intention was associated with improved memory performance. In Study 3, participants were confronted with a rating scale manipulation designed to alter their intention scores. Findings showed that stable intentions were able to withstand attack. Overall, the present research findings suggest that different properties of intention are not simply manifestations of a single underlying construct (“intention strength”), and that temporal stability exhibits superior resistance and impact compared to other intention attributes.     

Movement Related EMGs Become More Variable During Learning of Fast Accurate Movements

Human subjects performed simple flexion and extension movements about the elbow in a visual step-tracking paradigm. Movements were self-terminated. Subjects were instructed to increase movement velocity while maintaining end-point accuracy during practice. The effects of practice on the pattern and variability of EMG activity of the biceps and triceps muscles were studied. Initial movements were performed using reciprocal phasic activation of agonist and antagonist muscles as indicated by surface EMGs. With practice, increases in movement speed were associated with larger agonist and antagonist bursts and an earlier onset of the antagonist burst. Decreased duration of the premovement antagonist silence was also observed during practice.

Decreases in variability of movements during practice were not accompanied by equivalent decreases in variability of the associated EMGs. Surprisingly, both agonist and antagonist EMGs were more variable in faster, practiced movements. The combined agonist-antagonist EMG variability depended on both movement speed and trajectory variability. Lower variability in movements in the presence of greater variability in the related EMGs occurred because of linked variations in agonist and antagonist muscle activities. Variations in the first agonist burst were often compensated for by associated variations in the antagonist and late agonist bursts. These linked variations maintained the limb trajectory relatively constant in spite of large variations in the first agonist burst. Modifications to impulse-variability models are therefore needed to explain compensations for variability in accelerative impulses (produced by the first agonist burst) by linked variations in impulses for deceleration (produced by the antagonist and late agonist bursts).     

Conceptual fallacies in subjective probability

Subjective probability considered as a logic of partial belief succumbs to three fundamental fallacies. These concern the representation of preference via expectation, the measurability of partial belief, and the normalization of belief.     

The impact of bundle comparisons on bundle preference

The bundling literature largely holds that a person's reaction to a given product bundle depends only on the characteristics of the products contained in the bundle. This paper, instead, proposes that people evaluate bundles in reference to other bundles that they have seen. Prior research indicates that people are sensitive to a bundle's “attribute inventory” or the aggregate level of comparable attributes possessed by its constituent products. We show that when people evaluate a bundle, they compare the attribute inventories that it offers to those offered by other bundles that they have seen. The resulting compositional comparisons can occur without changes to the products that comprise the target and contextual bundles, vary by attribute comparability and attentional focus, and coexist with (and at times reverse the effects of) well‐established product‐specific context effects, which are determined solely by the products and their attributes.     

Preservation of long-term memory and synaptic plasticity despite short-term impairments in the Tc1 mouse model of Down syndrome

Down syndrome (DS) is a genetic disorder arising from the presence of a third copy of the human chromosome 21 (Hsa21). Recently, O’Doherty and colleagues in an earlier study generated a new genetic mouse model of DS (Tc1) that carries an almost complete Hsa21. Since DS is the most common genetic cause of mental retardation, we have undertaken a detailed analysis of cognitive function and synaptic plasticity in Tc1 mice. Here we show that Tc1 mice have impaired spatial working memory (WM) but spared long-term spatial reference memory (RM) in the Morris watermaze. Similarly, Tc1 mice are selectively impaired in short-term memory (STM) but have intact long-term memory (LTM) in the novel object recognition task. The pattern of impaired STM and normal LTM is paralleled by a corresponding phenotype in long-term potentiation (LTP). Freely-moving Tc1 mice exhibit reduced LTP 1 h after induction but normal maintenance over days in the dentate gyrus of the hippocampal formation. Biochemical analysis revealed a reduction in membrane surface expression of the AMPAR (α-amino-3-hydroxy-5-methyl-4-propionic acid receptor) subunit GluR1 in the hippocampus of Tc1 mice, suggesting a potential mechanism for the impairment in early LTP. Our observations also provide further evidence that STM and LTM for hippocampus-dependent tasks are subserved by parallel processing streams.