Modulating brain networks to promote brain health and recovery from brain injury.


December 15, 2015 - 12:00pm
NW 243
About the Speaker
Alvaro Pascual-Leone (BIDMC)

The brain changes across the lifespan. This life-long brain plasticity can be conceptualized as nature’s invention to overcome limitations of the genome and adapt to a rapidly changing environment. The human brain is made up of neurones, highly sophisticated and stable cellular structures. However, neurones are engaged in dynamically changing networks that provide a most energy efficient, spatially compact, and precise means to process input signals and generate adaptable responses to a changing environment. Plasticity is an intrinsic property of such networks. However, mechanisms of plasticity and the resulting brain dynamics vary across individuals and are modified by genetic predispositions, environmental influences, life experiences and even age.
Innovative experimental paradigms can assess cortical plasticity in humans, in vivo, across the lifespan. Ultimately, changes in brain plasticity and dynamics may proof maladaptive and lead to disease. Aberrant, excessive or insufficient, or mistimed plasticity may represent the proximal pathogenic cause of neurodevelopmental and neurodegenerative disorders such as autism spectrum disorders, schizophrenia, or Alzheimer’s disease. On the other hand, optimizing activity within and across brain networks can promote brain health, sustain cognitive function and well-being across the life-span, and leverage the impact of brain function on overall health (salutogenesis).
Following a brain insult (e.g. following a stroke or traumatic brain injury), or as a consequence of the alteration of function in a specific brain region (for example due to a sustained change in afferent input or efferent demand), the affected neural network adapts fluidly. This neural plasticity can confer no perceptible change in the behavioral output of the brain, lead to changes demonstrated only under special testing conditions, or cause behavioral changes that may constitute symptoms of disease or represent paradoxical functional facilitations. A consequence of such a formulation is the notion that the manifestations of focal brain dysfunction are ultimately defined by brain plasticity. Thus, disability after a brain insult, is the consequence of plasticity, just as through plasticity it might be possible to recover from the functional consequences of a brain insult.
The challenge in interventional cognitive neuroscience and rehabilitation is to guide the plastic changes across the lifespan, or following a brain insult, in order to promote the best functional outcome for a given individual. This requires modulation of neural networks. The challenge is to learn enough about the mechanisms of plasticity and the nature of dynamics of neural networks to be able to suppress changes that may lead to undesirable behaviors while accelerating or enhancing those that result in a behavioral benefit for the patient. Neurostimulation, including non-invasive brain stimulation techniques, provide an opportunity to modulate plastic brain networks in a controlled and specific manner, and a growing body of evidence supports its utility in promoting recovery of function after a brain injury.

Supported by grants from the National Institutes of Health, the Sidney-Baer Foundation, and Harvard Catalyst.