Search results for "aivokuori"

Corticokinematic coherence is stronger to regular than irregular proprioceptive stimulation of the hand

2021

Funding Information: This study was supported by the Academy of Finland “Brain changes across the life-span” profiling funding to University of Jyva€skyla€. H. Piitulainen was supported by Academy of Finland (Grants 296240, 326988, 307250, and 327288) and Jane and Aatos Erkko Foundation. Publisher Copyright: © 2021 the American Physiological Society. Proprioceptive afference can be investigated using corticokinematic coherence (CKC), which indicates coupling between limb kinematics and cortical activity. CKC has been quantified using proprioceptive stimulation (movement actuators) with fixed interstimulus interval (ISI). However, it is unclear how regularity of the stimulus sequence (jitter…

CMC is more than a measure of corticospinal tract integrity in acute stroke patients

2021

In healthy subjects, motor cortex activity and electromyographic (EMG) signals from contracting contralateral muscle show coherence in the beta (15-30 Hz) range. Corticomuscular coherence (CMC) is considered a sign of functional coupling between muscle and brain. Based on prior studies, CMC is altered in stroke, but functional significance of this finding has remained unclear. Here, we examined CMC in acute stroke patients and correlated the results with clinical outcome measures and corticospinal tract (CST) integrity estimated with diffusion tensor imaging (DTI). During isometric contraction of the extensor carpi radialis muscle, EMG and magnetoencephalographic oscillatory signals were re…

Entrainment and its perturbation in the auditory cortex of the rat : phase and frequency modulations

2010

Tutkimuksen tavoitteena oli luoda oskillatorista tahdistamista rotan kuuloaivokuorella sekä valikoivasti häiritä sitä. Tahdistamista ei ole juuri lainkaan tutkittu aiemmin, joten tutkimuksessa yritettiin löytää uutta tietoa käyttäen ainutlaatuista kokeellista asetelmaa. Viisitoista rottaa nukutettiin uretaanilla ja niiltä mitattiin paikallisia kenttäpotentiaaleja (local field potentials,LFPs) kovakalvon päälle sijoitetun solun ulkopuolisen mikroelektrodin avulla. Neljässä pääkokeessa luotiin 2,5 Hz tahdistamista yhdeksän ärsykkeen äänijonoilla, missä tahdistamisäänen taajuus oli 4000 Hz ja häiritsevän äänen taajuus oli 4500 Hz. Häirintä oli aina kahdeksannessa äänessä, jonka vaihetta ja/tai…

Modulation of plasticity of the soleus area of the motor cortex using paired associative stimulation

2015

Paired associative stimulation (PAS) repeatedly combines single somatosensory nerve stimuli with single transcranial magnetic stimuli to induce bidirectional changes in the excitability of the cortical projections to the target muscle. PAS and motor training have been shown to share common neural mechanisms, suggesting that PAS tests functionally relevant neuronal circuits. While PAS has been used extensively to target the hand area of the motor cortex, few studies have targeted the leg area of the motor cortex. The optimal interstimulus inter- val (ISI) to induce plasticity in the cortical projections to lower limbs is still not well established. Thus, the first purpose of this thesis was …

Acoustic, neural, and perceptual correlates of polyphonic timbre

2012

Load-dependent alpha suppression is related to working memory capacity for numbers

2022

Alpha suppression is proposed to reflect a surge in cortical excitability to enhance stimulus processing in working memory. The attenuated state of alpha might reflect the prioritisation of behaviourally relevant information, making it a proxy for working memory functioning. Despite the growing interest in utilising the advancement of brain-based measures to evaluate individuals’ cognitive processes, there was a lack of consistent evidence on the relationship between alpha suppression and working memory performance. To investigate whether interindividual differences in alpha suppression might be related to variability in working memory capacity, we recorded participants’ electroencephalogra…

Motor action execution in reaction-time movements : Magnetoencephalographic study

2019

OBJECTIVE: Reaction-time movements are internally planned in the brain. Presumably, proactive control in reaction-time movements appears as an inhibitory phase preceding movement execution. We identified the brain activity of reaction-time movements in close proximity to movement onset and compared it with similar self-paced voluntary movements without external command. DESIGN: We recorded 18 healthy participants performing reaction-time and self-paced fast index finger abductions with 306-sensor magnetoencephalography and electromyography. Reaction-time movements were performed as responses to cutaneous electrical stimulation delivered on the hand radial nerve area. Motor field and movemen…