Neural Correlates of Hand–Object Congruency Effects during Action Planning

Selecting hand actions to manipulate an object is affected both by perceptual factors and by action goals. Affordances may contribute to “stimulus–response” congruency effects driven by habitual actions to an object. In previous studies, we have demonstrated an influence of the congruency between hand and object orientations on response times when reaching to turn an object, such as a cup. In this study, we investigated how the representation of hand postures triggered by planning to turn a cup was influenced by this congruency effect, in an fMRI scanning environment. Healthy participants were asked to reach and turn a real cup that was placed in front of them either in an upright orientation or upside–down. They were instructed to use a hand orientation that was either congruent or incongruent with the cup orientation. As expected, the motor responses were faster when the hand and cup orientations were congruent. There was increased activity in a network of brain regions involving object-directed actions during action planning, which included bilateral primary and extrastriate visual, medial, and superior temporal areas, as well as superior parietal, primary motor, and premotor areas in the left hemisphere. Specific activation of the dorsal premotor cortex was associated with hand–object orientation congruency during planning and prior to any action taking place. Activity in that area and its connectivity with the lateral occipito-temporal cortex increased when planning incongruent (goal-directed) actions. The increased activity in premotor areas in trials where the orientation of the hand was incongruent to that of the object suggests a role in eliciting competing representations specified by hand postures in lateral occipito-temporal cortex.

Automatic effects of covert practice

Automatic behaviour is supposedly underlain by the unintentional retrieval of processing episodes, which are stored during the repeated overt practice of a task or activity. In the present study, we investigated whether covertly practicing a task (e.g., repeatedly imagining responding to a stimulus) also leads to the storage of processing episodes and thus to automatic behaviour. Participants first either responded overtly or covertly to stimuli according to a first categorization task in a practice phase. We then measured the presence of automatic response-congruency effects in a subsequent test phase that involved a different categorization task but the same stimuli and responses. Our results indicate that covert practice can lead to a response-congruency effect. We conclude that covert practice can lead to automatic behaviour and discuss the different components of covert practice, such as motor imagery, visual imagery, and inner speech, that contribute to the formation of processing episodes in memory.

Anticipatory Defocusing of Attention and Contextual Response Priming but No Role of Aesthetic Appreciation in Simple Symmetry Judgments when Switching between Tasks

Visual attention can be adjusted to task requirements. We asked participants to switch between judging the symmetry of vertically presented three-letter strings and identifying the central stimulus (i.e., Eriksen task) to investigate anticipatory adjustment of attention. Our experiments provide evidence for anticipatory adjustment of visual attention, depending on the cued task (i.e., focusing and defocusing of attention after the Eriksen task cue and after the symmetry task cue, respectively). Although, symmetry judgments were, overall, considerably slower than the identification of the central letter, the effects of response congruency between tasks were comparable in the two tasks, which suggested strong response priming from concurrent symmetry judgment in Eriksen task trials. Symmetry judgment performance was best for homogeneous letter strings (e.g., HHH), worst for strings that were symmetrical and inhomogeneous (e.g., XHX), and intermediate for asymmetrical strings (e.g., HHX). The difficulty of categorizing symmetrical-inhomogeneous items markedly deviated from the aesthetic ratings of the stimuli, displaying a pronounced preference for symmetrical strings, but only little difference among the symmetrical items, and might be accounted by conflict with response priming based on inhomogeneity detection. Although our study provides little evidence for an effect of aesthetic appreciation in simple symmetry judgments, it demonstrates the strong role of contextual dependencies.

The effect of aging on response congruency in task switching: A meta-analysis

Response congruency effects in task switching are the observed slowing of response times for incongruent targets which afford more than one response (depending on task) in comparison to congruent stimuli that afford just one response regardless of the task. These effects are thought to reflect increased ambiguity during response selection for incongruent stimuli. The present study presents a meta-analysis of 27 conditions (from 16 separate studies) whose designs allowed investigation of age-related differences in response-congruency effects. Multilevel modelling of Brinley plots and state–trace plots showed no age-related effect on response congruency beyond that which can be explained by general age-related slowing. The results add to the growing body of evidence of no age-related decline in measures of attention and executive functioning.

Bilingualism enhances attentional control in non-verbal conflict tasks – evidence from ex-Gaussian analyses

Bilinguals have been found to possess cognitive advantages. But the nature of this advantage is unclear. While some evidence suggests that bilinguals have developed enhanced inhibitory control abilities, other evidence suggests that they possess enhanced attentional control abilities. In the current study, English monolingual and English–Chinese bilingual young adults were tested in three non-verbal conflict tasks (Flanker task, Spatial Stroop task and Simon task). Ex-Gaussian analyses were utilized to inspect response time distributions. The two participant groups showed comparable effects of stimulus-response congruency on the Gaussian part of response distributions (μ), but different effects on the distribution tails (τ), with reduced tails for bilingual speakers particularly in the more demanding incongruent condition. These results suggest that bilingual advantage emerges from better sustained attention and attentional monitoring rather than inhibition. We also discuss the usefulness of ex-Gaussian analyses.

Simultaneous fMRI and eye gaze recordings during prolonged natural stimulation - a studyforrest extension

Here we present an update of the studyforrest (http://studyforrest.org) dataset that complements the previously released functional magnetic resonance imaging (fMRI) data for natural language processing with a new two-hour 3Tesla fMRI acquisition while 15 of the original participants were shown an audio-visual version of the stimulus motion picture. We demonstrate with two validation analyses that these new data support modeling specific properties of the complex natural stimulus, as well as a substantial within-subject BOLD response congruency in brain areas related to the processing of auditory inputs, speech, and narrative when compared to the existing fMRI data for audio-only stimulation. In addition, we provide participants’ eye gaze location as recorded simultaneously with fMRI, and an additional sample of 15 control participants whose eye gaze trajectories for the entire movie were recorded in a lab setting — to enable studies on attentional processes and comparative investigations on the potential impact of the stimulation setting on these processes.