What are the neurophysiological correlates of paired associative stimulation (PAS) in inducing plastic changes in human motor cortex (M1)? Here, Arrigoni and colleagues (2024) will apply transcranial magnetic stimulation (TMS) to left M1 paired with electrical stimulation of the right median nerve at an ISI of 25 ms or 10 ms to induce long-term potentiation (LTP) or long-term depression (LTD), respectively. Arrigoni and colleagues (2024) will determine if these stimulation pairings effect cortical excitability using motor-evoked potentials (MEPs) and TMS-evoked potentials (TEPs). Specifically, they hypothesize PASLTP will increase the peak-to-peak amplitude of MEPs, whereas PASLTD will decrease the amplitude, replicating previous work. They will then extend these previous findings by examining TEPs. The authors anticipate modulation of the P30 and P60, which are TEPs thought to reflect local cortical excitability. They plan to account for the MEP reafference which may also mediate the P60 amplitude by stimulating at sub- and supra- motor threshold. Further, they hypothesize an increase of the N100, a marker of inhibitory processing mediated by GABA, by PASLTD. Finally, the authors will also examine the impact of cortical excitability over time to determine the duration of the PAS effects.   

 

This detailed examination of TEPs following PAS stimulation will determine which TEPs could be used as biomarkers with the induction of LTP and LTD through stimulation. The authors have built in an MEP replication for the PAS stimulation, supporting previous literature and acting as a positive control.  

 

The Stage 1 manuscript was evaluated by three expert reviewers across two rounds. Following in-depth review and responses from the authors, the recommender determined that Stage 1 criteria was met and awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/detjc (under temporary private embargo)
 
Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA. 
 
List of eligible PCI RR-friendly journals:

 

References
 
1. Arrigoni, E., Bolognini, N., Pisoni, A. & Guidali, G. (2024). Neurophysiological correlates of plasticity induced by paired associative stimulation (PAS) targeting the motor cortex: a TMS-EEG registered report. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/detjc

Vocal sounds, including both speech and non-speech sounds, have been found to activate the Superior Temporal Sulci and Gyri in comparison to non-vocal sounds. These regions, termed Temporal Voice Areas (TVAs), are considered to be involved in early voice processing and therefore critical for social interaction. TVA activation has been examined in Autism Spectrum Disorder (ASD) to determine if the characteristic difficulties in social communication and interaction are linked to an impaired early voice processing. Using functional magnetic resonance imaging (fMRI), one study found typical brain activation in TVAs for 15 out of 16 autistic participants (Schelinski et al., 2016), whereas another found atypical activation in 4 out of 5 autistic participants (Gervais et al., 2004).

 

Here, the inconsistencies in the previous literature propel Gautier et al. (2023) to examine brain activation of TVAs with a larger sample size (26 ASD and 26 non-ASD participants). Gautier et al. (2023) will present vocal sounds and non-vocal sounds to both groups of participants during fMRI and predict that fewer participants in the ASD group will show a preferential response to voices in TVAs compared to the non-ASD group. These results would suggest that symptoms of ASD interfere with early stages of social interaction, at the level of voice processing.

 

This Stage 1 manuscript was evaluated in an initial round by the co-recommenders and another two rounds of in-depth review by two expert reviewers. With these revisions, the recommenders judged that the manuscript met the Stage 1 criteria and awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/538m4
 
Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI RR-friendly journals:

 

 

References
 
1. Gautier, R., Houy-Durand, E., Barantin, L., Briend, F. & Latinus, M. (2023). Cortical voice processing in Autism Spectrum Disorder. In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/538m4

Visual symmetry is critical to our interaction with our environment so that when detected, symmetry automatically produces a neural marker in the form of an Event Related Potential (ERP) called Sustained Posterior Negativity (SPN). However, when symmetry is presented to the visual system slanted away from the viewer, there is a reduction in SPN, termed a perspective cost. 

 

Considering ​objects are rarely presented front-on (or frontoparallel) in our natural environment, Karakashevska et al., (2023) plan to examine the extent of the perspective cost with the addition of visual cues to facilitate extraretinal representation of the visual symmetry. The authors will record electroencephalography (EEG) from 120 participants while they perform a luminance task on symmetrical and asymmetrical stimuli. The authors hypothesize perspective cost will be reduced by three perspective cues: 1) monocular viewing, when cue conflict caused by binocular viewing is eliminated, 2) a static frame surrounding the symmetrical stimulus, adding a depth cue, and 3) a moving frame, assisting 3D perception prior to the symmetry onset. If the SPN is equivalent during frontoparallel and slanted presentation in a cue condition, the authors will conclude extraretinal representation can be automatic when sufficient visual cues are available. The proposed experiment is powered to detect a relatively small difference between perspective cue conditions. This will solidify fundamental research on visual symmetry processing and will further our understanding of object perception and recognition. 

 

The Stage 1 manuscript was evaluated over three rounds by four expert reviewers. Following in-depth review and responses from the authors, the recommenders have determined that Stage 1 criteria was met and have awarded in-principle acceptance (IPA). 

URL to the preregistered Stage 1 protocol: https://osf.io/yzsq5
 
Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI-RR-friendly journals:
 

• Advances in Cognitive Psychology
• Brain and Neuroscience Advances
• Cortex
• F1000Research
• Imaging Neuroscience
• In&Vertebrates
• NeuroImage: Reports
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Studia Psychologica
• Swiss Psychology Open

 
References
 
1. Karakashevska, E., Bertamini, M. & Makin, A. D. J. (2023). Putting things into perspective: Which visual cues facilitate automatic extraretinal symmetry representation? [Stage 1 Registered Report]. In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/yzsq5