Biology subjects

Betka, S. J. A.

Publications and source records attributed to Betka, S. J. A..

3 recordsLinked to original sources

bioRxiv2024

Motor Equivalence in Motor Awareness

Motor awareness (MA) describes the level of conscious access we have to the details of our movements and as such is critical to the feeling of control we maintain over our actions (sense of agency). Although our movements rely on specific sensorimotor transformations as well as distinct reference frames for the active body part, or effector, numerous studies report spatiotemporal thresholds of MA that are comparable across different effectors and tasks as well as supramodal. However, this has not been tested directly and there is currently no direct empirical support for effector-independent MA nor a description of a potentially shared underlying mechanisms. We therefore designed a goal-directed reaching paradigm that participants performed once with their upper-limbs, using a joystick, and once with their full body, by leaning and thereby displacing their center-of-mass. We assessed both MA and corrective movements for sensorimotor mismatches by providing either veridical feedback or introducing random spatial deviations. We hypothesized that changes in motor compensation and awareness, across effectors, with and without a concurrent cognitive load, would follow the same pattern of behavior if they relied on a shared underlying mechanism. Our results lend support for such an effector-independent mechanism, as we observed that MA was comparable across effectors: i) in un-deviated control trials with and without cognitive load, ii) in converging trials where the direction of the deviation corresponded to the direction of the target location, and iii) based on strongly correlated psychometric MA thresholds across effectors. At the same time, data from diverging trials, where the direction of the deviation opposed the direction of the target location, indicate that in case of conflicting information and increased kinematic task demands MA draws on effector-specific sensorimotor information, corresponding to performance differences between hand and full body movements observed in baseline blind-reaching versus visually guided reaching. Overall, our findings provide a direct link between low-level sensorimotor transformations and abstract motor representations and their role in MA, consolidating a gap in conceptual frameworks of the sense of agency.

animal behavior and cognition↗

bioRxiv2021

Relationship between systolic blood pressure and decision-making during emotional processing

ObjectiveEmotional states are expressed in body and mind through subjective experience of physiological changes. In previous work, subliminal priming of anger prior to lexical decisions increased systolic blood pressure (SBP). This increase predicted the slowing of response times (RT), suggesting that baroreflex-related autonomic changes and their interoceptive (feedback) representations, influence cognition. Alexithymia is a subclinical affective dysfunction characterized by difficulty in identifying emotions. Atypical autonomic and interoceptive profiles are observed in alexithymia. Therefore, we sought to identify mechanisms through which SBP fluctuations during emotional processing might influence decision-making, including whether alexithymia contributes to this relationship. MethodsThirty-two male participants performed an affect priming paradigm and completed the Toronto Alexithymia Scale. Emotional faces were briefly presented (20ms) prior a short-term memory task. RT, accuracy and SBP were recorded on a trial-by-trial basis. Generalized mixed-effects linear models were used to evaluate the impact of emotion, physiological changes, alexithymia score, and their interactions, on performances. ResultsA main effect of emotion was observed on accuracy. Participants were more accurate on trials with anger primes, compared to neutral priming. Greater accuracy was related to increased SBP. An interaction between SBP and emotion was observed on RT: Increased SBP was associated with RT prolongation in the anger priming condition, yet this relationship was absent under the sadness priming. Alexithymia did not significantly moderate the above relationships. ConclusionsOur data suggest that peripheral autonomic responses during affective challenges guide cognitive processes. We discuss our findings in the theoretical framework proposed by Lacey and Lacey (1970).

neuroscience↗

bioRxiv2021

Oxytocin reduces interoceptive influences on empathy-for-pain in the anterior insula

Empathy-for-pain states are underpinned by interoception, i.e the central representation of internal states. Cardiac signals occur in a phasic manner; baroreceptor discharges at systole communicate the heartbeats strength. These signals modulate pain and emotion processing. We tested whether these phasic interoceptive signals modulate empathy-for-pain. As oxytocin (OT) enhances empathy and modulates interoceptive signals precision, we also tested if OT administration impacts empathy-for-pain via interoceptive mechanisms. Male subjects (N=32) attended three sessions to perform psychometric tests and an fMRI empathy-for-pain task, after intranasal administration of OT or placebo (40IU). Pictures of hands in painful or non-painful context were presented at systole or diastole. Effects of drug, emotion and cardiac timing on behaviour and brain activity was tested using general and mixed-effects linear models. Across conditions, activation was observed within regions implicated in pain and empathy-for-pain, with insula activation greater in the right than left hemisphere. OT administration, compared to placebo, attenuated the reactivity of some regions, including anterior cingulate cortex, but presentation of stimuli at systole blocked the OT attenuating effect. Our data suggest that OT alters the processing of motivationally-salient social cues, interacting with interoceptive signals. Our findings may inform targeted use of OT in psychiatric conditions linked to aberrant interoceptive processing.

neuroscience↗