Brain Mapping

Quite simply, brain mapping is identifying which parts of the brain relate to which parts of the body. All our functioning is controlled by the brain. Neuroscientists are able to map tiny parts of the brain to the activities performed in the body.

A similar concept is the simple map of a foot that is used in reflexology. This maps parts of the foot to different body organs. A reflexologist then "works" the foot to effect change in the organse.

Another way to think of it is to think of how a globe provides a spatial representation of the Earth, showing the continents, mountain ranges and oceans. You can use this as a parallel for how a brain map provides a similar representation of the brain and its relationship to the body.

The outcome is also a thorough picture of the brain's structure. A complete structural map of the brain shows all regions of the brain including functional lobes, specialized centers, neuronal bundles connecting brain parts, neuron circuits, single neurons, neuronal junctions and even parts of a neuron.

Techniques

All neuroimaging techniques can be considered part of brain mapping. While other brain imaging techniques measure properties such as cerebral blood flow, metabolism or structural integrity; QEEG measures electrical activity of the brain. Brain mapping can be conceived as a higher form of neuroimaging, producing brain images supplemented by the result of additional data processing or analysis. It provides complex analysis of brainwave characteristics as symmetry, phase, coherence, amplitude, power and dominant frequency.

The techniques used are constantly evolving. The purpose and goal is to advance the understanding of the relationship between structure and function in the human brain. Researchers in this field look forward to gaining knowledge of the physical processes that underlie human sensation, attention awareness and cognition. These results are instantly applicable to surgical intervention, to the design of medical interventions and to the treatment of psychological and psychiatric disorders.

Brain mapping also looks from the outside in by examining how the environment changes the brain's structure and how physical changes occur in the brain through the learning and aging processes. It also looks at reasons for what goes wrong in the brain during mental illnesses and other brain diseases.

The tools used to take images of the brain include computer axial tomography (CAT) scan, structural magnetic resonance imaging (MRI) and diffusion tensor-MRI (DTI) images.

Brain activity is examined through:

• electroencephalography - indicating locations that are electrically active in the brain
• positron emission tomography (PET) that takes images of radioactive markers in the brain
• functional MRI (fMRI) that shows images of brain activity
• pharmacological functional MRI (phMRI) that shows brain activity during drug administration
• transcranial magnetic stimulation (TMS) that non-invasively stimulates parts of the brain to trigger certain behaviors.

Relevance to Stroke

Brain mapping helps us to understand the impact of stroke - by understanding where the stroke has damaged the brain, we can understand the physical and neuropsychological changes that may occur. But this is more supportive evidence for what is often observable anyway.

Research has shown that the map created is only correct at a point in time. Our brains are constantly changing - evolving and reorganizing as we learn new things, experience new things and focus on particular items. So, it's not just in response to injury that the brain changes.

Most importantly, brain mapping has allowed researchers to find evidence of brain plasticity. This is where the brain adapts around the injury. And, for a stroke patient, the hope from this is directed brain plasticity - where a therapist (or even the patient) can focus on specific activities with directed attention to force the brain to change and to improve the patient's capabilities.