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Principles of Color
Published in Terry A. Slocum, Robert B. McMaster, Fritz C. Kessler, Hugh H. Howard, Thematic Cartography and Geovisualization, 2022
Terry A. Slocum, Robert B. McMaster, Fritz C. Kessler, Hugh H. Howard
It is important to realize that the eye is part of the larger visual processing system shown in Figure 10.7. Note first that information leaving the eyes via the optic nerves crosses over at the optic chiasm; up to that point, information from each eye is separate, but pathways beyond this point contain information from both eyes. After passing through the optic chiasm, each pathway enters the lateral geniculate nucleus (LGN). Physiological experiments with animals reveal that opponent cells similar to those found within the retina are also found in the LGN (De Valois and Jacobs 1984). Interpretation of the visual information begins in the visual cortex, the first place where information from both eyes is handled.6 As with the LGN, our knowledge of processing in this area is largely a function of physiological experiments with animals. Probably the most significant of these is the work of David Hubel and Torsten Wiesel, who received the 1981 Nobel Prize for their efforts. They found three kinds of specialized cells in the visual cortex: simple cortical cells, which respond best to lines of particular orientation; complex cells, which respond to bars of particular orientation that move in a particular direction; and end-stopped cells, which respond to moving lines of a specific length or to moving corners or angles. Not only did Hubel and Wiesel discover these different kinds of cells, but they also mapped out where they occur within the visual cortex (Goldstein and Brockmole 2017).
Brain Imaging Data
Published in Atsushi Kawaguchi, Multivariate Analysis for Neuroimaging Data, 2021
Figure 2.2 is called task-related research, which is conducted with various stimuli and tasks, and conversely, resting state research, which is conducted in a resting state without any stimuli. In recent years, network analysis has been widely used to evaluate the functional connectivity between resting sites. Please refer to Chapter 5 for the analysis. The medial prefrontal cortex and the anterior cuneiform and posterior cingulate gyrus are a network of brain regions called the default mode network (DMN), and they are more active when the subject is awake but not doing anything (Raichle et al., 2001). This neural activity consumes 60–80% of the energy in the brain. However, on the other hand, the energy expenditure of neural activity is only 0.5–1.0% in the brain while performing some kind of task. The DMN has been studied in various psychiatric disorders as it is believed to be involved in internal thought processes and the control of external stimuli (Joo et al., 2016; Liu et al., 2017). In addition to the DMN, several other networks showing activity at rest have been identified and resting-state fMRI is thought to contain a lot of information about individual brain function. Tavor et al. (2016) showed that an individual’s functional connectivity pattern of resting fMRI can predict the pattern of fMRI activity while performing a task.
Analgesic, Anti-Inflammatory, Antipyretic, and Anesthetic Drugs: Dealing With Pain, Inflammation, and Fever
Published in Richard J. Sundberg, The Chemical Century, 2017
Exactly how anesthetics achieve their effect remains a mystery. Consciousness seems to involve coordinated function of specific parts of the brain, including the cerebral cortex, the thalamus, and the reticular network. With the volatile anesthetics these functions are gradually lost as the concentration of the anesthetic increases. One site of action of the general anesthetics is the GABAA receptor (see Sections 17.2 and 17.5). The volatile anesthetics activate inhibitory receptors and reduce neuronal activity. The effects may be specific to subsets of receptors. GABA receptors are also the site of action of propofol and etomidate. The most convincing evidence for involvement of GABA receptors is a series of specific mutations in the receptor that have pronounced effect on anesthetic potency.
Emerging photoelectric devices for neuromorphic vision applications: principles, developments, and outlooks
Published in Science and Technology of Advanced Materials, 2023
Yi Zhang, Zhuohui Huang, Jie Jiang
The formation of vision consists of two main parts: the retina perceives and preprocesses visual information, and the visual center of the cerebral cortex implements computing and memory for visual information. The two are connected through the optical nerve, as shown in Figure 2 [73]. The entire visual system is a neural network formed by neurons and synapses connections. A significant number of photoreceptor neurons, known as cone neurons and rod neurons, are laminarly distributed in the retina. They convert the incident light signals into neuroelectrical signals. These signals, which are pre-processed by the retina, are transmitted to the brain via the optical nerve [74,75]. Finally, they are further processed by the visual centers of the cerebral cortex to complete the recognition and memory functions. This forms images in the brain of what we see in the outside world. In the process of visual formation, the information transmission is mainly through the rapid release and reception of neurotransmitters in the synapses. It realizes the real-time imaging in the brain from external environment.
Study of Full-body Virtual Embodiment Using noninvasive Brain Stimulation and Imaging
Published in International Journal of Human–Computer Interaction, 2021
Human brain is a bilateral, mostly symmetrical structure with functionally distinct areas. Scalp EEG cannot be used to record arbitrary brain signals, but is limited mainly to recording of the signals from the youngest part of the brain, the cerebral cortex. This part of the brain is responsible for higher functions, such as those requiring cognitive activity (2000). Cortex forms the outer part of the human brain and is further divided into functionally specialized lobes; the frontal, parietal, occipital, and temporal lobes. Of interest for purposes of this study was mainly the sensorimotor cortex composed of somatosensory cortex (located in the parietal lobe; its function include perception of somatic inputs and multisensory integration) and the motor cortex (neighboring with the somatosensory cortex, but located in the frontal lobe; its main function concerns planning, programming, and executing motor actions). Small cortical area called the temporoparietal junction (TPJ) is of special interest as a large portion of multisensory integration and building of the unified self-image originates there (Arzy et al., 2006).
Compliant activity rather than difficulty accelerates thought probe responsiveness and inhibits deliberate mind wandering
Published in Behaviour & Information Technology, 2019
Benjamin R. Subhani, Oluwademilade I. Amos-Oluwole, Harry L. Claxton, Daisy C. Holmes, Carina E. I. Westling, Harry J. Witchel
The causes of mind wandering remain a hot topic of research that may relate to its substrates in the brain, including the default mode network and the executive network (Christoff et al. 2009). The default mode network is normally associated with resting wakefulness (as well as autobiographical thought) and includes the medial prefrontal cortex, the posterior cingulate, and the temporo-parietal junction. The executive network resides in the frontal cortex and is responsible for attention, inhibition, decision-making, judgement and planning. These two networks had been thought to act in opposition, but in mind wandering they are both active. Although many researchers search for the causes of mind wandering, MW may be the default state of the healthy waking brain (Killingsworth and Gilbert 2010), while attention and persistent, task-related thought may be the exceptional states.