Search results for "cortex"
showing 10 items of 1827 documents
Motor Cortex Function in Fibromyalgia: A Study by Functional Near-Infrared Spectroscopy
2019
Previous studies indicated changes of motor cortex excitability in fibromyalgia (FM) patients and the positive results of transcranial stimulation techniques. The present study aimed to explore the metabolism of motor cortex in FM patients, in resting state and during slow and fast finger tapping, using functional Near-Infrared Spectroscopy (fNIRS), an optical method which detects in real time the metabolism changes in the cortical tissue. We studied 24 FM patients and 24 healthy subjects. We found a significant slowness of motor speed in FM patients compared to controls. During resting state and slow movement conditions, the metabolism of the motor areas was similar between groups. The oxy…
Adaptive Whisking in Mice
2021
Rodents generate rhythmic whisking movements to explore their environment. Whisking trajectories, for one, appear as a fixed pattern of whisk cycles at 5-10 Hz driven by a brain stem central pattern generator. In contrast, whisking behavior is thought to be versatile and adaptable to behavioral goals. To begin to systematically investigate such behavioral adaptation, we established a whisking task, in which mice altered the trajectories of whisking in a goal-oriented fashion to gain rewards. Mice were trained to set the whisker to a defined starting position and generate a protraction movement across a virtual target (no touch-related tactile feedback). By ramping up target distance based o…
Impaired glutamatergic neurotransmission in migraine with aura? Evidence by an input-output curves transcranial magnetic stimulation study.
2011
Objective: An imbalance between activity of inhibitory and facilitatory intracortical circuits could play a central role in migraine etiology. We used input-output curves to achieve further information about intracortical excitability of motor cortex in migraine with aura. METHODS: Input-output curves were measured in the right abductor pollicis brevis muscle at rest in 12 patients suffering from migraine with aura and 8 healthy subjects. Stimuli were delivered at intensity ranging from 100% to 160% of resting motor threshold with 10-second inter-stimulus intervals. Seven patients were studied before and during treatment with levetiracetam. RESULTS: Results showed a greater motor-evoked pot…
It's Sad but I Like It The Neural Dissociation Between Musical Emotions and Liking in Experts and Laypersons
2016
Emotion-related areas of the brain, such as the medial frontal cortices, amygdala, and striatum, are activated during listening to sad or happy music as well as during listening to pleasurable music. Indeed, in music, like in other arts, sad and happy emotions might co-exist and be distinct from emotions of pleasure or enjoyment. Here we aimed at discerning the neural correlates of sadness or happiness in music as opposed those related to musical enjoyment. We further investigated whether musical expertise modulates the neural activity during affective listening of music. To these aims, 13 musicians and 16 non-musicians brought to the lab their most liked and disliked musical pieces with a …
Spoken-Word Segmentation and Dyslexia
2002
We used magnetoencephalography to elucidate the cortical activation associated with the segmentation of spoken words in nonreading-impaired and dyslexic adults. The subjects listened to binaurally presented sentences where the sentence-ending words were either semantically appropriate or inappropriate to the preceding sentence context. Half of the inappropriate final words shared two or three initial phonemes with the highly expected semantically appropriate words. Two temporally and functionally distinct response patterns were detected in the superior temporal lobe. The first response peaked at approximately 100 msec in the supratemporal plane and showed no sensitivity to the semantic appr…
Bilateral activations in operculo‐insular area show temporal dissociation after peripheral electrical stimulation in healthy adults
2018
Interhemispheric transfer is necessary for sensory integration and coordination of body sides. We studied how somatosensory input from one body side may reach both body sides. First, we investigated with 17 healthy adults in which uni‐ and bilateral brain areas were involved in consecutive stages of automatic sensory processing of non‐nociceptive peripheral stimulation. Somatosensory evoked fields (SEFs) to electrical stimulation were recorded with 306‐channel magnetoencephalography in two conditions. First, SEFs were registered following sensory radial nerve (RN) stimulation to dorsal surface of the right hand and second, following median nerve (MN) stimulation at the right wrist. Cortical…
Audiovisual processing of Chinese characters elicits suppression and congruency effects in MEG
2019
Learning to associate written letters/characters with speech sounds is crucial for reading acquisition. Most previous studies have focused on audiovisual integration in alphabetic languages. Less is known about logographic languages such as Chinese characters, which map onto mostly syllable-based morphemes in the spoken language. Here we investigated how long-term exposure to native language affects the underlying neural mechanisms of audiovisual integration in a logographic language using magnetoencephalography (MEG). MEG sensor and source data from 12 adult native Chinese speakers and a control group of 13 adult Finnish speakers were analyzed for audiovisual suppression (bimodal responses…
More comprehensive proprioceptive stimulation of the hand amplifies its cortical processing
2021
Corticokinematic coherence (CKC) quantifies the phase coupling between limb kinematics and cortical neurophysiological signals reflecting proprioceptive feedback to the primary sensorimotor (SM1) cortex. We studied whether the CKC strength or cortical source location differs between proprioceptive stimulation (i.e., actuator-evoked movements) of right-hand digits (index, middle, ring, and little). Twenty-one volunteers participated in magnetoencephalography measurements during which three conditions were tested: 1) simultaneous stimulation of all four fingers at the same frequency, 2) stimulation of each finger separately at the same frequency, and 3) simultaneous stimulation of the fingers…
Neural generators of the frequency-following response elicited to stimuli of low and high frequency: A magnetoencephalographic (MEG) study.
2021
The frequency-following response (FFR) to periodic complex sounds has gained recent interest in auditory cognitive neuroscience as it captures with great fidelity the tracking accuracy of the periodic sound features in the ascending auditory system. Seminal studies suggested the FFR as a correlate of subcortical sound encoding, yet recent studies aiming to locate its sources challenged this assumption, demonstrating that FFR receives some contribution from the auditory cortex. Based on frequency-specific phase-locking capabilities along the auditory hierarchy, we hypothesized that FFRs to higher frequencies would receive less cortical contribution than those to lower frequencies, hence supp…
Analysis of Somatosensory Cortical Responses to Different Electrotactile Stimulations as a Method Towards an Objective Definition of Artificial Senso…
2022
Sensory feedback is a critical component in many human-machine interfaces (e.g., bionic limbs) to provide missing sensations. Specifically, electrotactile stimulation is a popular feedback modality able to evoke configurable sensations by modulating pulse amplitude, duration, and frequency of the applied stimuli. However, these sensations coded by electrotactile parameters are thus far predominantly determined by subjective user reports, which leads to heterogeneous and unstable feedback delivery. Thus, a more objective understanding of the impact that different stimulation parameters induce in the brain, is needed. Analysis of cortical responses to electrotactile afference might be an effe…