Characterizing Brain Cortical Plasticity and Network Dynamics Across the Age-Span in Health and Disease with TMS-EEG and TMS-fMRI

Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA.
Brain Topography (Impact Factor: 3.47). 08/2011; 24(3-4):302-15. DOI: 10.1007/s10548-011-0196-8
Source: PubMed


Brain plasticity can be conceptualized as nature's invention to overcome limitations of the genome and adapt to a rapidly changing environment. As such, plasticity is an intrinsic property of the brain across the lifespan. However, mechanisms of plasticity may vary with age. The combination of transcranial magnetic stimulation (TMS) with electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) enables clinicians and researchers to directly study local and network cortical plasticity, in humans in vivo, and characterize their changes across the age-span. Parallel, translational studies in animals can provide mechanistic insights. Here, we argue that, for each individual, the efficiency of neuronal plasticity declines throughout the age-span and may do so more or less prominently depending on variable 'starting-points' and different 'slopes of change' defined by genetic, biological, and environmental factors. Furthermore, aberrant, excessive, insufficient, or mistimed plasticity may represent the proximal pathogenic cause of neurodevelopmental and neurodegenerative disorders such as autism spectrum disorders or Alzheimer's disease.

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    • "During the training, Growing When Required networks (Marsland et al., 2002) dynamically change their topological structure through competitive Hebbian learning (Martinetz, 1993) to incrementally match the input space. The learning process is built upon input-driven synaptic plasticity (Pascual-Leone et al., 2011) and habituation (Thompson and Spencer, 1966). Clustered neuronal activation trajectories from the parallel pathways are subsequently integrated to generate prototype neurons representing action dynamics in the joint pose-motion domain, resembling the neural integration of multi-cue action features in the visual cortex (Beauchamp et al., 2003). "
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