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Parallel Processing and Parallel Machines
Published in Hojjat Adeli, Parallel Processing in Computational Mechanics, 2020
Hojjat Adeli, Prasad R. Vishnubhotla
A study of the mechanics of mind reveals that the human brain is made of a large number of highly interconnected elements that send excitatory and inhibitory signals to each other (Blakemore, 1977). More specifically it is estimated that the human brain is made of 10–100 billion brain cells or neurons. Each neuron is capable of switching approximately a thousand times each second. In comparison, a large computer consists of about 1 m2 of silicon containing about a billion transistors. Each transistor is capable of switching thousands of times per second. At present enough knowledge is not available about the human brain, but the apparent similarities between the brain and modern computers have encouraged some researchers to choose the brain as their model of a “thinking machine” (Hillis, 1986).
Concepts in EMF Biointeraction
Published in Jitendra Behari, Radio Frequency and Microwave Effects on Biological Tissues, 2019
Communication between brain cells is mediated by a spectrum of chemical substances that excite and inhibit transaction and transmission of information between them. These substance acts by binding to their specific receptors on cell surfaces. This process is also sensitive to modulated microwave fields. Kolomytkin et al. (1994) studied specific receptor binding to rat brain synaptosomes of three neurotransmitters: gamma-aminobutyric acid (GABA), an inhibitory transmitter; and acetyl choline and glutamate, both excitatory. Microwave exposures used 880 MHz or 915 MHz fields at power densities from 10 to 1,500 µW/cm2. It was found that with incident field densities of 1.5 mW/cm2, binding were observed at 3, 5, 5 or 30 Hz. Conversely, with 16 pulse per second (pps) modulation induced a significant increase in glutamate receptor binding. For acetyl choline receptors, binding decreased by 25% at 16 Hz, with similar trends at higher and lower frequencies; that is, as a function of field intensity as low as 50 µW/cm2 at 16 Hz with 915 MHz fields.
Introduction
Published in Munsif Ali Jatoi, Nidal Kamel, Brain Source Localization Using EEG Signal Analysis, 2017
The electrical signals that are measured by neuroimaging techniques are produced as a result of bioelectromagnetism inside the brain. This electromagnetic field is produced by ion currents inside the brain. As described in the previous sections, neurons are brain cells that transmit/receive information. However, transmitting and receiving information is dependent on the rise/fall of electrical potentials at the cell membrane. Hence, this potential difference is responsible for the generation of currents flowing into and outside the neuron [40]. Therefore, the signals in the dendrites are termed as postsynaptic potentials (PSPs) and the signals emitted, moving along the axon, are said to be action potentials (APs). APs are the information transmitted by a nerve. APs are generated due to the exchange of ions across the neuron membrane and are a temporary change in membrane potential, which is transmitted along the axon. The lifetime of AP is 5–10 ms with amplitude of 70–100 mV. Figure 1.6 shows an illustration for APs [31].
Robot-assisted therapy for arm recovery for stroke patients: state of the art and clinical implication
Published in Expert Review of Medical Devices, 2020
Giovanni Morone, Ilaria Cocchi, Stefano Paolucci, Marco Iosa
Stroke causes the death of brain cells and consequently the loss of the abilities controlled by the interested area of the brain such as memory and muscle control. The World Stroke Organization has declared stroke an epidemic disease: 1 in 6 people worldwide will have a stroke in their lifetime; 15 million people worldwide suffer a stroke each year and 5.8 million people die from it. Moreover, stroke is a leading cause of long-term disability: the National Stroke Association reports that 10% of stroke survivors make an almost-complete recovery, while another 25% recover with only minor impairments. Therefore, an adequate and sudden recovery and rehabilitation from a stroke is fundamental, also using all the new available technologies.