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.
The central integrative state (CIS) of a neuron is the total integrated input received by the neuron at any given moment and the probability that the neuron will produce an action potential based on the state of polarisation and the firing requirements of the neuron to produce an action potential at one or more of its axons.
In some instances neuro-plastic responses and the resultant changes in activity lead to asymmetric functional levels in cortical projection networks. At some point of asymmetrical dysfunction a critical level of imbalance of activity or arousal levels between one cortical hemisphere and the other can result in a functional disconnect syndrome. This presentation uses case studies to explore the processes of development and correction of neuro-plastic induced cortical asymmetry via peripheral and direct current stimulation.
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.
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.
The size and complexity of the nervous system makes it unlikely that changes in a single synapse result in significant changes in the behaviour of an interconnected neural network. Significant changes in neural network behaviour require changes in populations of synapses, defined as multiple synaptic modifications occurring simultaneously at multiple sites. The goal of the presentation is to present a neural network model of human cerebral ontogenesis and to use the model to explain the development of human EEG coherence over the postnatal period from 1.5 to 16 years of age.