Biomedical Engineering Reference
In-Depth Information
single or multiple modes of action covering most of the neurophysiologically
relevant pathways. This allows the comparison of the response of unknown
new substances to those of substances in the database. Substances with
uncertain modes of action can be identified and compounds classified
accordingly, providing information on the toxicity pathway through which
these compounds may act. Therefore, analysis of spike train data using pattern
recognition methods provides a rich description of a wide variety of parameters
for the purpose of high-content screening.
Finally, in addition to analysis of spatio-temporal aspects of network
activity, the individual waveforms of each action potential event can be
collected and analyzed for changes in amplitude and/or duration. Thus, MEAs
are high-content platforms that can provide detailed information regarding the
changes in function of networks of neurons exposed to test compounds. The
activity patterns in response to drugs or toxins are remarkably reproducible.
Future high-throughput, parallel and rapid physiological screening will
require large-scale platforms, served by liquid handling robots connected to
automated data acquisition and analysis systems. Such scaling can be achieved
by multiplying the number of recording modules or by expanding the number
of networks per module. Thousands of toxins and pharmacological substances
can be tested in parallel in a very short time. No other technology has the
potential to offer rapid collection of information on this scale.
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3.10.5 Microelectrode Arrays in Basic Neuroscience Research
We are still overwhelmed by the complexity of the human brain and elucidating
the disorders of the brain is a pressing issue due to the economic and social
consequences of degenerative disorders. It is known that conditions such as
Alzheimer's disease (AD) and epilepsy depend on the concerted activity of
neural networks. Use of cultures as surrogates for in vivo experiments relies on
the premise that the 'functional units' of the brain are distinct cellular popu-
lations; cultured networks of neurons can be considered the 'functional unit of
functional organization' in the brain. MEA technologies can facilitate the study
of brain disorders and pathologies.
3.10.5.1 Alzheimer's disease
Brain degeneration that leads to dementia is a heartbreaking process: patients
do not recognize their own children and they lose their identity. There is an
immense emotional and financial pressure on families and society. No objective
clinical detecting tests are available (only behavioral and cognitive scores) and
no cure for the disease. One form of dementia, Alzheimer's disease (AD) is a
progressive neurodegenerative disease characterized by the cerebral accumu-
lation of insoluble proteinaceous clusters of amyloid b-peptides (Ab), which
have been implicated in neuronal toxicity and deterioration. Consequently,
efforts to mitigate neurodegeneration have emphasized the reduction of Ab
aggregates.
