Cling together, swing together? Assessing indirect retrieval of stimulus-response bindings for associated stimuli.

When a stimulus is paired with a response, a stimulus-response (SR) binding (or event file) is formed. Subsequent stimulus repetition retrieves the SR binding from memory, which facilitates (impedes) performance when the same (a different) response is required. We aimed to explore whether indirect retrieval of SR bindings by a newly learnt associated stimulus is possible. Participants first went through a learning task to acquire novel stimulus-stimulus associations. The same stimulus pairs were then presented in a prime-probe task to assess direct and indirect retrieval effects. Participants responded by classifying word color in prime and probe trials. Probe words were either identical to prime words (test for direct retrieval) or corresponded to the associated stimulus (test for indirect retrieval) or were unrelated words (baseline). Independently of word relation, response relation (repetition vs. change) across prime and probe trials was manipulated. In two highly powered preregistered studies (total N = 260) using different types of stimulus associations, we obtained evidence for direct retrieval due to identical word repetition in the probe. Crucially, evidence for indirect retrieval upon presentation of an associated probe word was absent. Controlling for memory of each stimulus-stimulus association did not alter the findings. Our results show that indirect retrieval through newly acquired associations does not occur at the level of SR bindings, at least not for recently acquired stimulus-stimulus associations. Our study illustrates the scope of binding principles and highlights boundary conditions for the stimulus properties that can elicit automatic response retrieval.

What is behind partial repetition costs? Event-files do not fully occupy bound feature codes.

Feature binding accounts state that features of perceived and produced events are bound into event-files. Performance while responding to an event is impaired when some, as opposed to all or none, of this event's features already belong to a previous event-file. While these partial repetition costs are generally considered to be indicators of feature binding, their cause is still unclear. Possibly, features are fully occupied when bound in an event-file and must be unbound in a time-consuming process before they can enter a novel event-file. In this study, we tested this code occupation account. Participants responded to the font color (target) of a word (distractor) by pressing one of three keys (response) while ignoring the word meaning. We measured partial repetition costs from prime to probe while introducing an intermediate trial. We compared sequences in which this intermediate trial did not repeat any prime features and sequences in which it repeated either the prime response or distractor. Partial repetition costs occurred in the probe, even when one (vs. none) of the prime features repeated in the intermediate trial, although significantly reduced. Thus, single bindings do not fully occupy feature codes. By ruling out a possible mechanism behind partial repetition costs, the present study contributes to the further specification of feature binding accounts.

Beyond Left and Right: Binding and Retrieval of Spatial and Temporal Features of Planned Actions.

There is evidence that planning an action relies on binding codes of the relevant features of that action into an action plan. Such binding is indicated by the observation that planning a novel action is impaired if it shares some but not all features with another action that is held in memory for later execution. Most previous studies have focused on the binding of the spatial features left and right, which are particularly salient but not the only features of intentional body movements. In a series of four online experiments, we tested whether evidence for the binding of other (non)spatial features could also be found. Taken together, we indeed obtained evidence for the binding of temporal (short and long) and vertical (top and bottom) features, in addition to the commonly studied horizontal features (left and right). Yet, clear binding effects were mainly restricted to action features that remained uncertain up to the point the respective action had to be planned. These observations have important theoretical and methodical implications for the future studies of feature binding in action planning.

Task relevance determines binding of effect features in action planning.

Action planning can be construed as the temporary binding of features of perceptual action effects. While previous research demonstrated binding for task-relevant, body-related effect features, the role of task-irrelevant or environment-related effect features in action planning is less clear. Here, we studied whether task-relevance or body-relatedness determines feature binding in action planning. Participants planned an action A, but before executing it initiated an intermediate action B. Each action relied on a body-related effect feature (index vs. middle finger movement) and an environment-related effect feature (cursor movement towards vs. away from a reference object). In Experiments 1 and 2, both effects were task-relevant. Performance in action B suffered from partial feature overlap with action A compared to full feature repetition or alternation, which is in line with binding of both features while planning action A. Importantly, this cost disappeared when all features were available but only body-related features were task-relevant (Experiment 3). When only the environment-related effect of action A was known in advance, action B benefitted when it aimed at the same (vs. a different) environment-related effect (Experiment 4). Consequently, the present results support the idea that task relevance determines whether binding of body-related and environment-related effect features takes place while the pre-activation of environment-related features without binding them primes feature-overlapping actions.

Cerebral microbleeds are associated with cognitive decline early after ischemic stroke.

BACKGROUND AND PURPOSE: The present study aimed to investigate whether cerebral microbleeds (CMB) are associated with vascular cognitive decline (VCD) already in the early course after ischemic stroke, and-if so-whether distinct cognitive domains are affected more preferentially by CMB. METHODS: In a prospective cohort study, cognitive performance was examined in 33 stroke patients showing ≥ 1 CMB on MRI. Matched for age, gender, clinical and radiological characteristics, 33 stroke survivors without CMB served as a control group. Neuropsychological testing was performed in both groups six months after the index event using the Consortium to Establish a Registry for Alzheimer's Disease (CERAD)-plus test battery. RESULTS: CMB-positive stroke patients showed more severe cognitive decline in mini mental state test compared to the control group (p = 0.024). Regarding the episodic memory, CMB-positive patients reached lower scores in Word-List-Learning- (p = 0.009) and the Word-List-Recognition-test (p = 0.006), whereas the findings in Word-List-Recall-test were similar in both groups. While semantic fluency is not more affected in CMB-positive than in CMB-negative patients, those with CMB reveal a significantly impaired phonemic fluency (p = 0.007). Concerning the visuospatial abilities, stroke patients with CMB showed restricted recall of recently learned visual information. Only slight differences between both groups were found in any test investigating the participants' executive functions. CONCLUSION: Cognitive abilities are more severely impaired in CMB-positive stroke patients compared to CMB-free controls, whereby memory-associated functions are most affected. CMB might be associated with post-stroke cognitive decline, particularly with impaired memory and phonemic fluency.