TMS-induced Neural Noise in Sensory Cortex Interferes with Short-term Memory Storage in Prefrontal Cortex

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.\u27s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature

TMS-induced Neural Noise in Sensory Cortex Interferes with Short-term Memory Storage in Prefrontal Cortex

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.\u27s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature

Mechanisms of Interference in Vibrotactile Working Memory

In previous studies of interference in vibrotactile working memory, subjects were presented with an interfering distractor stimulus during the delay period between the target and probe stimuli in a delayed match-to-sample task. The accuracy of same/different decisions indicated feature overwriting was the mechanism of interference. However, the distractor was presented late in the delay period, and the distractor may have interfered with the decision-making process, rather than the maintenance of stored information. The present study varies the timing of distractor onset, (either early, in the middle, or late in the delay period), and demonstrates both overwriting and non-overwriting forms of interference

The effects of freedom of choice in action selection on perceived mental effort and the sense of agency

The Publisher's final version can be found by following the DOI link.Previous research showed that increasing the number of action alternatives enhances the sense of agency (SoA). Here, we investigated whether choice space could affect subjective judgments of mental effort experienced during action selection and examined the link between subjective effort and the SoA. Participants performed freely selected (among two, three, or four options) and instructed actions that produced pleasant or unpleasant tones. We obtained action-effect interval estimates to quantify intentional binding – the perceived interval compression between actions and outcomes and feeling of control (FoC) ratings. Additionally, participants re- ported the degree of mental effort they experienced during action selection. We found that both binding and FoC were systematically enhanced with increasing choice-level. Outcome valence did not influence binding, while FoC was stronger for pleasant than unpleasant outcomes. Finally, freely chosen actions were associated with low subjective effort and slow responses (i.e., higher reaction times), and instructed actions were associated with high effort and fast responses. Although the conditions that yielded the greatest and least subjective effort also yielded the greatest and least binding and FoC, there was no significant correlation between subjective effort and SoA measures. Overall, our results raise interesting questions about how agency may be influenced by response selection demands (i.e., indexed by speed of responding) and subjective mental effort. Our work also highlights the importance of understanding how subjective mental effort and response speed are related to popular notions of fluency in response selection

Effects of free choice and outcome valence on the sense of agency: evidence from measures of intentional binding and feelings of control

The Publisher's final version can be found by following the DOI link.Everyday actions can be characterized by whether they are freely chosen or commanded by external stimuli, and whether they produce pleasant or unpleasant outcomes. To assess how these aspects of actions affect the sense of agency, we asked participants to perform freely selected or instructed key presses which could produce pleasant or unpleasant chords. We obtained estimates of the key press–chord intervals and ratings of the feeling of control (FoC) over the outcomes. Interval estimates were used to assess intentional binding—the perceived tempo- ral attraction between actions and their outcomes. Results showed stronger binding and higher FoC ratings in the free compared to instructed condition. Additionally, FoC was stronger for pleasant compared to unpleasant outcomes, and for pleasant outcomes that were produced by freely selected compared to instructed actions. These results highlight the importance of free choice and outcome valence on the SoA. They also reveal how freedom of action selection and pleas- antness of action-outcomes can interact to affect the FoC

Effects of free choice and outcome valence on the sense of agency: evidence from measures of intentional binding and feelings of control

Barlas Z, Hockley WE, Obhi SS. Effects of free choice and outcome valence on the sense of agency: evidence from measures of intentional binding and feelings of control. Experimental Brain Research. 2018;236(1):129-139

The effects of context in item-based directed forgetting: Evidence for “one-shot” context storage

The effects of context on item-based directed forgetting were assessed. Study words were presented against different background pictures and were followed by a cue to remember (R) or forget (F) the target item. The effects of incidental and intentional encoding of context on recognition of the study words were examined in Experiments 1 and 2. Recognition memory for the picture contexts was assessed in Experiments 3a and 3b. Recognition was greater for R-cued compared to F-cued targets, demonstrating an effect of directed forgetting. In contrast, no directed forgetting effect was seen for the background pictures. An effect of context-dependent recognition was seen in Experiments 1 and 2, such that the hit rate and the false-alarm rate were greater for items tested in an old compared to a novel context. An effect of context-dependent discrimination was also observed in Experiment 2 as the hit rate was greater for targets shown in their same old study context compared to a different old context. The effects of context and directed forgetting did not interact. The results are consistent with Malmberg and Shiffrin’s (Journal of Experimental Psychology: Learning, Memory, and Cognition, 31, 322–336, 2005) “one-shot” context storage hypothesis that assumes that a fixed amount of context is stored in the first 1 to 2 s of the presentation of the study item. The effects of context are independent of item-based directed forgetting because context is encoded prior to the R or F cue, and the differential processing of target information that gives rise to the directed forgetting effect occurs after the cue