Biology subjects

Zaaimi, B.

Publications and source records attributed to Zaaimi, B..

3 recordsLinked to original sources

bioRxiv2025

Breathing-Driven Modulation of Reticulospinal Tract Activity

The reticulospinal tract (RST) plays a pivotal role in motor control, especially during recovery after neurological injuries such as stroke and spinal cord injury (SCI). Understanding how RST activity is modulated offers valuable insights into improving motor function recovery. Recent studies have demonstrated that breathing rhythms influence brain activity. This study explores how respiratory rhythms modulate RST excitability during motor tasks, using the StartReact paradigm to examine reaction times (RTs) across visual (VRT), visual-auditory (VART), and visual-auditory startling (VSRT) conditions. We measured RTs in three muscles (first dorsal interosseous, flexor digitorum superficialis, and biceps) in healthy adult participants (n=13, both sexes) performing multi-joint movements. RTs were longest in the VRT condition and significantly decreased when auditory stimuli were added (VART), with further reductions observed in the VSRT condition. Additionally, respiratory phase transitions, particularly from inspiration to expiration (IE), significantly influenced RTs, with the shortest RTs observed during these transitions in the VSRT condition. These findings suggest that RST excitability is dynamically modulated by respiratory rhythms. This modulation of the RST by respiratory phase transitions could inform future neurorehabilitation strategies, such as respiratory-phase-aligned stimulation, to enhance motor recovery following corticospinal lesions. Ultimately, this approach may optimize the timing of interventions, improving outcomes in conditions such as stroke and SCI. Significance StatementBrainstem pathways play a crucial role in motor recovery after stroke, and understanding how these pathways change during recovery is key to optimizing their participation in rehabilitation. This study demonstrates how respiratory rhythms influence these brainstem pathways. Using the StartReact paradigm, we show that muscle response times are faster when transitioning from inspiration to expiration. These findings suggest that the bodys natural breathing rhythms can enhance motor output by activating these pathways. This could inform innovative rehabilitation strategies, such as aligning interventions with specific respiratory phases, to improve motor recovery in stroke and spinal cord injury. Our research highlights the potential for personalized therapies that harness the bodys intrinsic rhythms to optimize recovery.

neuroscience↗

bioRxiv2025

Boosting Motor Cortex Plasticity through Respiratory Phase-Triggered Paired Associative Stimulation

Paired Associative Stimulation (PAS) has shown promise in promoting motor cortex plasticity by using transcranial magnetic stimulation (TMS) paired with peripheral nerve stimulation. However, the effectiveness of PAS is often limited by its short-lived potentiation effects. Recent research indicates that respiratory rhythms can influence cortical excitability, suggesting a potential method to enhance PAS efficacy. This study investigated the impact of synchronizing PAS with respiratory phase transitions - specifically, the transition from inspiration to expiration (I-E) and expiration to inspiration (E-I) - on motor cortical plasticity. We conducted experiments with 18 healthy volunteers (13 females, 5 males) aged 21-45 years, assessing motor-evoked potentials (MEPs) elicited by TMS applied to the left motor cortex. Participants underwent PAS sessions where paired stimuli were delivered either at I-E or E-I transitions, or at random intervals. MEPs were recorded at baseline, immediately post-PAS, and at 10, 20, and 30 minutes post-stimulation. Results showed that PAS triggered at the I-E transition significantly increased MEP amplitudes, with significant differences in MEP amplitudes at 20 minutes post-PAS between the I-E and the other conditions. This highlights the benefit of timing PAS with the I-E transition for enhanced motor cortical plasticity. These findings underscore the potential of integrating respiratory rhythms into neuromodulation techniques to improve therapeutic outcomes. Synchronizing PAS with natural respiratory phases may enhance motor recovery strategies and offers a refined approach for therapeutic interventions. This approach could be particularly relevant for stroke rehabilitation, where enhancing motor cortical plasticity is crucial for recovery. Significance StatementThis study demonstrates that syncing brain stimulation with breathing patterns can enhance motor learning. By coordinating Paired Associative Stimulation (PAS)--a technique that stimulates sensory and motor inputs--with specific phases of the breathing cycle, we observed stronger responses in the motor cortex. This approach not only improves our understanding of brain adaptability but also offers a new way to fine-tune therapeutic techniques. For stroke patients, where regaining motor function is critical, integrating natural body rhythms into treatment could lead to more effective and personalized rehabilitation strategies.

neuroscience↗

bioRxiv2024

Brain-responsive music enables non-invasive, targeted and unobtrusive neurostimulation

ObjectiveWe are developing a new closed-loop brain stimulation method by embedding, within music, auditory elements that respond to the listeners brain activity. Here we show that this brain-responsive music has systematic and targeted effects on neural oscillations implicated in a variety of neurological and mental health disorders. ApproachWe recorded magnetoencephalogram (MEG) or electroencephalogram (EEG) signals from participants as they listened to music synthesized by commercial audio software. Brain signals were bandpass filtered, phase-shifted and used to control the timbre and/or timing of notes within the music. Main resultsListening to brain-responsive music induced peaks and troughs in spectral power at frequencies that depended systematically on the phase-shift applied to the brain signal. Phase-dependent modulation was greatest at the centre frequency of the filter. As a result, by calibrating these parameters we could achieve selective enhancement or suppression of either theta (5 Hz) or alpha (10 Hz) oscillations. Moreover, by chosing different sensor locations we could target power modulation to either frontal or temporal cortex. The phase-dependent power modulation observed with brain-responsive music was significantly attenuated when participants listened to identical music as a conventional, open-loop stimulus. Finally, we demonstrate that brain activity could be modulated by more complex compositions combining a variety of brain-responsive musical elements controlled by a wireless, wearable EEG headband suitable for home use. SignificanceBrain-responsive music provides an unobtrusive and targeted method of modulating neural oscillations in the listeners brain, and may enable both creative and therapeutic applications of Brain Computer Interface technologies.

neuroscience↗