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Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
From a functional point of view, the cerebral cortex can be divided into primary areas and association areas. The primary areas are those where sensory signals are first received by the cortex or from which output signals of the cortex directly emanate. Examples of primary sensory areas are the primary visual cortex in the occipital lobe (Figure 1.9), the primary auditory cortex in the temporal lobe, and the primary somatosensory cortex in the postcentral gyrus of the anterior portion of the parietal lobe (Figure 12.1). An example of a primary output area is the primary motor cortex in the precentral gyrus of the posterior portion of the frontal lobe, the primary motor cortex being separated from the primary somatosensory cortex by the central sulcus (Figure 12.1). The primary motor cortex is also referred to as the somatomotor cortex, M1, or Brodmann’s area 4. In contrast, association areas, which constitute a considerably larger area of the cortex, are those areas where signals from different sensory modalities are integrated, or areas associated with “higher mental functions”.
Central nervous system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Certain areas are identified with specific brain functions. The pre-central gyrus is known as the motor cortex and is the origin of all voluntary movements. The post-central gyrus is known as the sensory cortex and receives and appreciates all general sensations. Other important areas include the auditory area, which receives impulses from the auditory nerve and is situated in the cortex of the temporal lobe immediately below the lateral sulcus; the visual area, situated in the cortex of the occipital lobe and receives impulses via the optic chiasm; and the motor speech area (Broca’s area), which initiates tongue movements and is situated in the cortex of the frontal lobe just above the anterior end of the lateral sulcus. The sensory speech area that interprets the written and spoken word is situated in the lower part of the parietal cortex.
Mirror Neuron Based Alerts for Control Flight Into Terrain Avoidance
Published in Kay M. Stanney, Kelly S. Hale, Advances in Cognitive Engineering and Neuroergonomics, 2012
M. Causse, J. Phan, T. Ségonzac, F. Dehais
In this study, we introduced a new type of visual alert―which do not require semantic decoding of complex verbal information and do not introduce additional auditory alarm―specifically dedicated to activate the mirror neurons that appear to play a key role in both action understanding and imitation (Rizzolatti, 2004). Such motor neurons are known to fire either when a person acts or when a person observes the same action performed by another one. This type of alert can be a good candidate to inform the pilot of the action to perform, even if this latter is subjected to inattentional deafness or a high deleterious stress. Historically discovered in the rostral part of inferior area 6 (area F5) of the monkey (Rizzolatti, et al., 1990), there is growing evidence that these specialized neurons also exist in human (Rizzolatti, 2005). Functional imaging studies revealed activation in lower part of the precentral gyrus and of the pars opercularis of the inferior frontal during observation of actions made by another individual (Buccino, et al., 2001). The opercularis of the inferior frontal gyrus (basically corresponding to Broadman area 44) likely corresponds to the area F5 in monkey (Petrides & Pandya, 1994). The authors hypothesized that these regions support a mirror system dedicated to action observation/execution matching processes. More recently, a fMRI study of Chong et al. (2008) showed that the right inferior parietal lobe responds independently to specific actions regardless of whether they are observed or executed. Furthermore, magnetoencephalography (Hari et al. 1998) and EEG (Cochin et al. 1999) experiments revealed activation of motor cortex during observation of finger movement. More recently, an EEG experiment of Muthukumaraswamy (2004) showed suppression in the 8–13 Hz (mu) frequency band during the passive observation of object grip. Gastaut et al. (1954) showed that, at rest, sensorimotor neurons spontaneously fire in synchrony leading to large amplitude EEG oscillations in the mu frequency band. In addition, Gastaut et al. (1954) reported desynchronization of these rhythms―thereby decreasing the power of the mu-band EEG oscillations―not only when a subject performed an action, but also while the subjects observed an action executed by someone else. According to Muthukumaraswamy (2004), the mu reduction during the observation of an object grip movement indicates the existence of a brain structure that is functionally comparable to the monkey mirror neuron system. The activation of this hypothesized frontal mirror region in the human brain has also been observed using different modalities, for instance during the observation of static pictures (Johnson-Frey, et al., 2003) or robotic actions (Gazzola, Rizzolatti, Wicker, & Keysers, 2007; Oberman, McCleery, Ramachandran, & Pineda, 2007).
The effect of Tai Chi practice on brain white matter structure: a diffusion tensor magnetic resonance imaging study
Published in Research in Sports Medicine, 2019
Jian Yao, Qipeng Song, Kai Zhang, Youlian Hong, Weiping Li, Dewei Mao, Yan Cong, Jing Xian Li
Tai Chi practice has impact on brain volume has been reported by Mortimer and colleagues (2012). They found that a 40-week Tai Chi practice increased the whole brain volume of healthy elderly people. However, they did not report whether or not this change is associated with a specific area of the brain volume, such as the dispersion tension of the white matter fiber or the brain net. Later Wei and co-workers (Wei et al., 2013) quantified the difference in brain images between Tai Chi practitioners and control subjects based on cortical surface brain reconstruction (Wei et al., 2013). The authors found that Tai Chi practitioners showed significantly thicker cortex in precentral gyrus, insula sulcus, and middle frontal sulcus in the right hemisphere, and superior temporal gyrus, medial occipito-temporal sulcus, and lingual sulcus in the left hemisphere than the controls. Moreover, the thick cortex in the left medial occipito-temporal sulcus and lingual sulcus was associated with the high intensity of Tai Chi practice. One year later Wei and co-workers (Wei, Dong, Yang, Luo, & Zuo, 2014) reported that these Tai Chi experts had significantly greater and more experience-dependent functional homogeneity in the right post-central gyrus (PosCG) and less functional homogeneity in the left anterior cingulated cortex and right dorsal lateral prefrontal cortex than the controls. These findings provided neuro-imaging evidence that Tai Chi can improve the brain grey matter of old population. However, to the authors’ knowledge little is known about the impact of Tai Chi practice on the microstructure of brain white matter. Moreover, the association of experience and skill level of Tai Chi with white matter change remains unknown.
Louvain clustering integration within density-based graph classification (Louvain dbGC) in Schizophrenia
Published in IISE Transactions on Healthcare Systems Engineering, 2022
Mai Abdulla, Mohammad T. Khasawneh
Graph theoretical measures can quantify topological organization of a network. Thus, in the Louvain dbGC, measures that characterize global/nodal functional connectivity for the nBUD network and modular functional connectivity for the mBUD network were extracted. For the nBUD network, 14 global measures and 9 nodal measures were computed. The global measures refer to the global properties of a graph, and therefore consists of a single number for each graph. Nodal measures refer to properties of the nodes of a graph, and therefore consists of a single number for each node in the graph. The global measures used are average degree, radius, diameter, eccentricity, characteristic path length, characteristic path length within subgraphs, global efficiency, local efficiency, clustering, transitivity, modularity, assortativity, small-worldness and small-worldness within subgraphs. The nodal measures used are degree, eccentricity, triangle, path lengths, global efficiency nodes, local efficiency nodes, clustering nodes, between centrality, and closeness centrality. The modular measures that were extracted from the mBUD graph are within module degree z-score and participation. Modular measures asses one specific type of organization in a graph, and thus were combined with nodal and global measures of the nBUD graph to account for heterogeneous function based on the anatomy of different brain regions. It is important to note that modular measures are reported on a nodal level. In this study, the nodal measures were calculated for the bilateral precentral gyrus (PreCG L). The PreCG has shown abnormal connectivity patterns for schizophrenic patients (Mahdi, 2018), and thus was used in this study to help discriminate between patients and healthy controls. Table 3 shows some global and nodal measures for the nBUD and mBUD networks. For more information on graph measures, the reader is referred to Bickle (1920).
Transcranial direct current stimulation combined with peripheral stimulation in chronic pain: a systematic review and meta-analysis
Published in Expert Review of Medical Devices, 2023
Rayssa Maria Do Nascimento, Rafael Limeira Cavalcanti, Clécio Gabriel Souza, Gabriela Chaves, Liane Brito Macedo
The hypothesis that M1 anodal stimulation activates several circuits presented in the precentral gyrus responsible for connecting structures involved in the sensory and emotional processing of pain, such as thalamus, justifies its potential to reduce pain via inhibitory control of descendants pathways [48,49].