This seminar will offer a basic account of event-related potentials for those who have little familiarity with them. It will cover how the ERP is obtained from the EEG, the assumptions underlying its derivation, and the problems involved in its extraction, but will presume a reasonable understanding of the EEG and how it derives from the electrical potentials of neurones. The seminar will review the major ERP components, their scalp distribution and the psychological functions they index, and provide a discussion of a number of the issues and techniques related to component identification from the ERP waveform. Issues and techniques relating to localising ERP components in the brain are also addressed.
The brain is an information processing machine adjusting itself to the environment. Information processing can be defined as reducing uncertainty. It has been suggested that the brain developed from an evolutionary point of view once living creatures started moving around in a changing and thus uncertain environment.
Considerable evidence exists to suggest that a variety if not all cortical systems can undergo some type of plastic reorganisation. Modulation of afferent input (sensory deprivation or sensory increase) to the cortical areas represents at least one factor that determines the type of reorganisation observed. This innate plastic response is probably determined to a certain extent by the central integrative state of the neurons and glial components of the functional projection networks involved.
This presentation is a single case study involving the use of transcranial direct current stimulation (tDCS) in the treatment of neuropathic back pain, with symptoms described in the lumbar-sacral region of the spine and down the left leg. An examination of the literature indicated that 40-50 percent improvement in pain perception might follow anodal stimulation over the primary motor cortex (M1). Given the report of left leg symptoms, anodal stimulation was applied to the scalp over M1 on the left.
Many diseases have been linked to plastic changes and changes in activity and functional connectivity in the brain, which can be demonstrated by functional imaging, either using resting state imaging (EEG, MEG, fMRI), or by evoked activity. Many brain related diseases can therefore be seen as emerging properties of altered dynamically changing overlapping networks. Different neuromodulation techniques such as Transcranial Magnetic Stimulation (TMS) and transcranial Direct Current Stimulation (tDCS) have been used in an attempt to modify the abnormal activity and connectivity. Recently, also transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) have been introduced as neuromodulation tools, and LORETA neurofeedback is emerging as another non-invasive neuromodulation tool. Each of these neuromodulation techniques has a different proposed working mechanism which could provide help in selecting the right neuromodulation technique that best suits the pathology related functional imaging changes.