Biology subjects

Korka, B.

Publications and source records attributed to Korka, B..

2 recordsLinked to original sources

bioRxiv2025

Flexibility and Neural Correlates of Action-Sound Predictions

To interact efficiently with our environment, our brain predicts the sensory effects of our actions and compares them with the actual outcomes. This allows us to adapt our actions when predictions and sensory outcomes mismatch. While this process is generally well understood for action-sound predictions, it is an open question how flexibly these predictions can adapt in frequently changing environments, as they occur in real life. To investigate the flexibility of top-down predictions, we asked participants (N = 41) to press one of two buttons, a left-hand and a right-hand button, and switch hands autonomously. One button frequently produced a sound (80%) and rarely no sound. The other button frequently generated no sound (80%) and rarely produced a sound. In a third, separate condition, each button produced a sound in 50% of the trials. Unexpected sounds and unexpected sound omissions elicited a series of error-related brain responses in the electroencephalogram (EEG) at different levels of auditory processing, including a mismatch negativity (MMN) and the P3 complex for unexpected sounds, and the oN1, oN2, and oP3 complex for unexpected omissions. Moreover, unexpected sounds elicited an equivalent MMN--regardless of whether silence was expected (80%) or no reliable expectation was possible (50%), while later P3 components showed different amplitudes. Our results demonstrate flexible action-sound predictions at sensory and higher cortical levels. Furthermore, they indicate that predicted silence does not have an explicit sensory representation at lower levels but emerges at later stages, when higher-level information has been integrated.

neuroscience↗

bioRxiv2025

Post-movement beta rebound reflects strategic re-aiming during motor adaptation, but not re-aiming accuracy

Motor adaptation results from several interacting learning mechanisms, including learning via cognitive strategies and implicit adaptation. While strategy-based and implicit learning can be dissociated at a behavioural level, their underlying systems-level physiology is poorly understood. A neural signal that undergoes pronounced changes during motor adaptation is the post-movement beta-rebound (PMBR). However, it is unclear how these changes relate to the specific learning mechanisms that contribute to motor adaptation. We measured electroencephalography (EEG) while healthy participants (N=27) performed reaching movements towards a target. In most trials, a cursor showed the veridical position of the unseen hand, however, for some reaches, the direction of the cursor was rotated relative to the position of the hand. Participants were informed that, once a rotation occurred, it could persist for a single trial (1x condition), or for two consecutive trial (2x condition). In the 2x condition, participants could therefore redirect the rotated cursor through the target in the second rotated trial by re-aiming, while they had to continue aiming at the target in the 1x condition. We observed a stronger decrease of PMBR following the first rotated reach in the 2x condition, compared to the 1x condition, despite similar kinematics. This corroborates our previous results that PMBR reflects strategic re-aiming (Korka et al., 2023). However, when we collapsed data from the two studies (total N=53), we found that the degree to which the PMBR decreases does not predict re-aiming accuracy. We discuss the role of PMBR in motor adaptation, including implications for clinical disorders.

neuroscience↗