Looking inside the living human brain
What is neuroimaging?
Neuroimaging comprises a variety of techniques, designed to visualize and study a large range of properties of the brain, with a view to gaining a better understanding of this extremely complex organ. One of these imaging techniques is magnetic resonance imaging (MRI), which has become popular owing to its non-invasive nature and high spatial resolution. In the MRI scanner, all hydrogen nuclei (from water and fat) align with the scanner’s strong magnetic field. Transient distortion of this alignment by radiowaves and the subsequent realignment of the nuclei to the imposed magnetic field creates local variations in the magnetic field and this is monitored by receiver coils. The ensuing data allow to determine precise 3D-location of all events and can be visualized (the “image”).
Currently, MRI is the primary (cognitive) neuroscience tool for recording brain function. Another non-invasive technique on offer at the Spinoza Centre is electroencephalography (EEG). This technique is already well-established and complements the spatial resolution of MRI by enabling the tracking of brain activation at the millisecond timescale. This is accomplished by recording the small changes in the electric field around the head caused by predominantly cortical neuronal activity. EEG and functional MRI can be performed concurrently to their mutual benefit.
MRI is invaluable when it comes to non-invasive diagnostic purposes in general and for brain research particular. In addition to its value for clinical diagnostics, MRI is ideally suited for real-time monitoring of ongoing brain activity. Until the advent of MRI, human brain research was a difficult area, but today we can investigate both the healthy and the diseased living brain in unprecedented detail while the subject being examined is awake and conscious while subjected a choice of behavioural and pharmacological challenges.
Neuroimaging is presently undergoing a rapid expansion of data collection protocols and analysis methods through the concerted effort of basic and clinical neuroscientists, psychologists and MR physicists. Capturing causal relationships between brain activity and behaviour in health and disease will help to bridge the translational gap between basic and clinical neuroscience. These insights will be instrumental in designing and validating novel therapeutic approaches and will provide therapeutic biomarkers as local brain responses precede established clinical diagnostic changes. Accordingly, new approaches are available for medication choice and dosage optimization in those areas where treatment start and observable therapeutic benefits are weeks or months apart, or even longer.