Neuropsychology & the Localization of Function of the Brain
The sciences of psychology and sociology are sometimes held separate from the “hard” sciences such as biology and physics because describing behavior tends to have more subjective elements. Neuropsychologists bridge the gap between psychology and biology by studying the relationships between brain structures and activity and human thoughts and behaviors. The link between our organ of cognition -- the brain -- and our thoughts has been an object of interest since ancient times, but only recently have we had the technology to draw concrete conclusions about links between brain areas and brain functions.
1 The Science of Neuropsychology
The roots of neuropsychology go back to ancient societies that practiced trephination, or drilling holes in the skull, possibly to relieve pressure caused by injuries and possibly as a treatment for mental illness. The ancient Greeks hypothesized on the functions of the brain, although their understanding of neurophysiology was rudimentary. It wasn’t until the 1800s that distinct functions were localized to regions of the brain. Specifically, a region on the frontal lobe known as Broca’s area was found to control language expression. Modern brain imaging allows increasing refinement in relating function and structure.
2 Studying the Functions of Brain Regions
One way to study the functions of areas of the brain is to study the dysfunction that results from brain injuries. When a physical injury or stroke affects a relatively small section of the brain, the resulting changes in cognitive function or behavior in that individual can illuminate the function of that section of brain.
Healthy and even exceptional people also contribute to neuropsychology by participating in studies using magnetic resonance imaging, positron emission tomography and other technologies that allow researchers to visualize a brain while it is in the process of thinking or feeling. A notable example is the imaging studies on meditating Buddhist monks that showed differences in the blood flow to different areas of the brain in long-term meditators.
3 Examples of Localization of Function
You can overlay a model of the brain with a patchwork of functional areas that control aspects of our interactions with the world. The brain is divided into lobes, and each lobe contains areas associated with different functions. The frontal lobe holds areas responsible for reasoning, emotions and emotional control and voluntary movements. The parietal lobe holds your ability to touch and place yourself in space. The temporal lobe holds your memories, hearing and ability to understand language.
4 Neuropsychology Limitations
Localizing brain functions to specific brain areas provides a biological basis for many behaviors, both typical and atypical, but the areas of the brain are not strictly partitioned. People who suffer brain injuries can recover function as other areas of their brain take over the function of the injured part. From the perspective of neuropsychology, a complex mental or emotional process cannot be completely isolated to a single region of the brain and the specific pathways used can vary from individual to individual.