MEG lab




Neuromagnetic studies of musical training effects on auditory-motor functions
Bernhard Ross, Fujioka Takako, Ween Jon, Alain Claude, Stuss Donald

By providing music-supported training to stroke rehabilitation treatment, we shall reproduce and evaluate behavioural improvements. We will examine changes in cortical and muscle activities and integrity of motions before, throughout, and after the training. These physiological and behavioural data will tell how much the music-supported training can benefit motor rehabilitation. At the same time we shall examine healthy age-matched subjects for potential benefits in cognitive and motor functions. We use MEG recording when the subjects perform simple auditory or motor tasks which will be overlayed on an individual’s MRI (listening or tapping to auditory beats, or passively perceiving somatosensory stimulation). The physiological indices (evoked responses and accompanying oscillatory activities) are usually sensitive to yield differences within subject across multiple measurements, thus suitable for assessing training-induced changes.

Magnetoencephalography as a possible diagnostic tool for traumatic brain injury: Cortical oscillations during retrieval from working memory
Bernhard Ross

Mild head injury, concussion or ‘mild traumatic brain injury’ is an important public health concern with an estimated annual incident rate of 150, 000 cases in Canada. About 15-30% of mild traumatic brain injury cases will have persistent physical, emotional, and cognitive symptoms, referred to as ‘postconcussion symptoms’ over months and years following the injury. The analysis of electromagnetic neural activity is a sensitive tool, which can reveal abnormal brain function. My novel approach is to the analyse specific brain activity related to cognitive processing, which may be impaired after mild traumatic brain injury.

Improved characterization of human somatosensory cortex using simultaneous vibro-tactile stimulation of multiple digits
Bernhard Ross, Shahab Jamali Gharetape

Tactile sensation is encoded in the primary somatosensory cortex in topographical maps accordingly to the body surface. This topographical representation can be modified as the result of training and experience. This brain plasticity results from newly expressed or strengthened synaptic connections. The effect can be measured in humans noninvasively using magnetoencephalography (MEG) as increased activation, or larger activated area on the cortical surface. Brain plasticity is an important factor for successful recovery from a stroke. We shall develop a new method for objectively monitoring of plastic reorganization in somatosensory cortex by measuring the size of the somatotopic hand area as indicated by the distance between finger representation.

Auditory cortex activation indicating audiovisual integration during listening and reading the speakers lips
Bernhard Ross, Hao Luo

Simultaneous use of visual and auditory information when listening and seeing the speaker’s lips results in better speech understanding than listening alone. Both normal-hearing and hearing impaired listeners benefit from lipreading. Training lipreading potentially facilitates compensatory mechanisms to overcome communication deficits, which especially the elderly population experiences in noisy environments. However, the neurobiological basis of lipreading is widely unknown. Therefore, we shall investigate the effects of lipreading on auditory evoked and oscillatory cortical activity. We shall record brain activity with whole head magnetoencephalography (MEG) and localize underlying sources in auditory, visual, and multi-sensory cortices. Source activity in those identified areas will be analyzed with respect to various stimulus conditions This method will serve as an objective tool for assessing functional changes during audiovisual training and thus should help to develop efficient training programs. Moreover, we shall gain the basic knowledge about human cross-modal sensory processing.

Functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) in human somatosensory cortex
Michael Marxen, Tara Dawon, Tim Bardouille, Bernhard Ross, Fred Tam, Simon Graham

Motivation: Stroke is one of the most significant causes of impaired brain function. Non-invasive imaging techniques allow the mapping of brain activity in space and time with great potential for a better understanding of normal brain functions and their impairments. However, all non-invasive techniques image brain activity indirectly. Functional magnetic resonance imaging (fMRI) is sensitive to changes in blood flow and oxygenation following neuronal activation. Magnetoencephalography (MEG), in comparison, measures the very small magnetic fields outside of the skull generated by neuronal activity. Both fMRI and MEG will be used in conjunction in this study to develop models of neuronal activity within the brain consistent with the spatiotemporal signals obtained with both modalities.

Neuroimaging studies of auditory perception and attention
Sylvain Moreno, Ellen Bialystok Claude Alain

Bilinguals have been shown to perform better than monolinguals in executive function tasks involving conflict (for a review, see Bialystok, 2001). These findings have been attributed to bilinguals’ need to switch constantly between their two languages and inhibit interference from the other language. Frequent recruitment of these processes forces bilinguals to develop executive function skills differently than monolinguals. Research with children has shown that bilinguals performed better than monolinguals in executive function tasks (Bialystok et al, 2004; 2005). Our project is to test children who were either English monolingual or English bilingual while they performed a control task.

Scientists

Scientific Associates

  • Dr. Takako Fujioka

Programmer/Physicist

  • Fan Dong

Research Assistants

  • Panteha Razavi

Recent Graduates and Students

  • Shahab Jamali Gharetape
  • Becca Charron
  • Michelle Nurwandi
  • Jessica Thompson
  • Antoine Shahin
  • Tim Bardouille
  • Dr. Hao Luo