Cognition Neuroimaging
Neuro imaging in many respects revolutionized the study of cognitive neuroscience, the discipline that attempts to determine the neural mechanisms underlying cognitive processes. Early studies of Brain-behavior relationships relied on a precise neurological exam in the basis for hypothesizing the site of brain damage that was responsible for a given behavioral syndrome. The advent of structural brain imaging, first with computerized tomography and later with magnetic resonance imaging, paved the way for more precise anatomical localization of the cognitive deficits that manifest after brain injury. Functional neuroimaging, broadly defined as techniques that provide measures of brain activity, further increased our ability to study the neural basis of behavior. Functional MR (fMRI), in particular is an extremely powerful technique that afford excellent spatial and temporal resolution and has quickly become the most prominent tool in cognitive neuroscience.
Psychiatric disorders are common throughout the world and are a leading cause of disability. There is a growing appreciation of the importance of connectivity to brain function. Disruption of this connectivity can result in brain dysfunction manifested in impaired cognitive functioning and development of clinical symptoms. White matter forms the basis of anatomical connectivity. Diffusion Tensor Imaging is a useful tool for examining and quantifying white matter microstructure. Clinical research studies in alcoholism, HIV-1 infection, geriatric depression and schizophrenia using DTI have revealed abnormalities in white matter microstructure. The use of complementary imaging methods may be helpful in further characterizing these abnormalities. Other psychiatric disorders may also have white matter involvement amenable to study with DTI. Advanced in acquisition and analysis methods will be necessary to further advance work in this field.
Functional neuroimaging can identify brain areas which respond atypically to cognitive challenges, and functional magnetic resonance imaging (fMRI) is now widely used to investigate the neuronal basis of cognitive deficits in depression. Some studies have focused on cognitive challenges based on classic neuropsychological domains (e.g., executive function, memory). Others have explored cognitive mechanisms of emotional disturbance (e.g., negative bias, response to failure).
The field of neuroimaging, using fMRI, has reached a high level of maturity and methodological sophistication. Neuroimaging now attracts interest not only from cognitive neuroscientists but also from a wide array of fields that lay outside those that might be thought to be concerned about the brain. Consequently, we have witnessed the emergence of a strong symbiosis between functional neuoroimaging and a range of other disciplines, in many instances constituting unlikely bedfellows, including genetics, economics, and aesthetics to name a few. functional imaging realized what was never previously possible: namely, a characterization of the functional anatomy of the intact brain without the confound of pathology and the likely consequential plastic reorganization in response to disease or developmental abnormalities. So, functional neuroimaging highlighted that even simple tasks engaged more widespread areas of the brain than would have been assumed from the lesion-deficit approach. This has led to a richer conceptualization of how brain function underpins cognition not only in terms of functional differentiation (localization) but also in terms of functional integration (distributed function).
For neuroimaging, the key variables are those proposed to mediate this transformation, an example being a prediction error signal underpinning reward-based or punishment-based learning. These variables are then correlated against fMRI data to determine brain regions manifesting a response profile consistent with the model variables. The key advantage of these model-based approaches derives from the fact that they address how a particular cognitive process is implemented in a specific brain area as opposed to identifying the location of its instantiation.
The dominant position of functional neuroimaging in systems neuroscience is unlikely to change in the immediate future. This reflects not only the absence of any emerging competition to existing technologies but also the necessity for system level descriptions of cognitive processing, no matter how one conceives of how the brain works. However, an increasing discourse between imaging neuroscience and experts from disciplines such as computational and theoretical neuroscience, as well as those working at the level of microcircuitry, seems inevitable. The largely untapped potential of functional neuroimaging to provide a richer characterization of aberrant processes in psychiatric disorders is likely to be of increasing importance.
What is an example of cognitive neuroscience? A recent prize-winning experiment explored the role of dopamine, a neurotransmitter associated with feelings of satisfaction, brain function, and decision making. Decision-making is an example of a biological process that influences cognitive processes.
What can Cognitive neuroscientists examine the brain with? The three brain-imaging techniques most commonly applied to development in normal children are event-related potentials (ERPs), functional magnetic resonance imaging (fMRI), and near infrared spectroscopy (NIRS).
Why is cognitive neuroscience useful? One of the major aims of cognitive neuroscience is to identify the neural deficiencies that mark various psychiatry and neurodegenerative disorders. From this information it becomes potentially possible to identify methods of combating such deficiencies.
