Physiology of the nervous system
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal in Principles of Physiology for the Anaesthetist, 2015
Sensory impulses project to the somatosensory cortex. The postcentral gyrus comprises the primary somatosensory cortex, which corresponds to Brodmann’s areas 3, 1 and 2. A smaller secondary somatosensory cortex lies along the lateral fissure. Within the primary somatosensory cortex, segregation of the body is maintained so that the face is located ventrally near the lateral fissure, upper limb continues medially and dorsally from the face region and extends to the convexity of the hemisphere and lower extremity projects on to the medial surface of the hemisphere (Figure 2.21). Those body surfaces with a higher density of sensory receptors are represented by larger areas in the cortex than those with a lower density of receptors.
The Central Nervous System Organization of Behavior
Rolland S. Parker in Concussive Brain Trauma, 2016
Proprioception refers to the sense of one’s own body and limbs without using vision: (1) stationary position of the limbs and (2) sense of limb movement (kinesthesia). Information needed for motion is received from muscles, joints, and tendons, somatosensory receptors (touch, pressure, vibration, skin stretch, texture), the vestibular system, distance receptors (vision and hearing), and pain. Axons ascending in the dorsal column from the sacral region are placed at the midline and are placed more laterally at higher levels. These divide into the medial gracile and lateral cuneate fascicles, which terminate in the medullary gracile and cuneate nuclei. Second-order neurons decussate to form the medial lemniscus, shifting laterally to terminate in the ventral posterior lateral nucleus of the thalamus. The proprioceptive and touch neurons project to the primary sensory cortex of the postcentral gyrus (Gardner et al., 2000).
Biological Basis of Behavior
Mohamed Ahmed Abd El-Hay in Understanding Psychology for Medicine and Nursing, 2019
The parietal lobe is located above the occipital lobe of the brain and behind the frontal lobe. The parietal lobe is divided into three parts: (1) the postcentral gyrus; (2) the superior parietal lobule; and (3) the inferior parietal lobule. The postcentral gyrus receives sensory input from the contralateral half of the body. The sequential representation is the same as in the primary motor area, with upside-down reversal of sensations: the head is represented in inferior parts of the gyrus and sensations from the lower extremities are represented in superior portions. The primary somatosensory cortex, located in the postcentral gyrus, integrates somesthetic stimuli for recognition and recall of form, texture, and weight. The primary somatosensory cortex on one side receives all the somatosensory input from the contralateral side of the body. Lesions of the postcentral gyrus can cause difficulty in recognizing objects by touch (astereognosis). The superior parietal lobule is regarded as an association cortex. The inferior parietal lobule (composed of the angular and supramarginal gyri) is a cortical region involved with the integration of multiple sensory signals (K. Rogers, 2011).
Altered spontaneous brain activities in maintenance hemodialysis patients with cognitive impairment and the construction of cognitive function prediction models
Published in Renal Failure, 2023
Qing Sun, Jiahui Zheng, Yutao Zhang, Xiangxiang Wu, Zhuqing Jiao, Lifang Xu, Haifeng Shi, Tongqiang Liu
Compared with HC, we found that MHD-CI patients had abnormal spontaneous brain activity in several brain regions. The frontal lobe and occipital lobe are part of the default mode network (DMN) and had connections with the medial temporal lobe system such as the hippocampus and parahippocampal gyrus [21,22], several rs-fMRI studies reported reduced spontaneous brain activity in the DMN in ESRD patients [5,10]. The enhanced spontaneous brain activity in the hippocampus and parahippocampal gyrus and caudate nucleus is thought to be a compensatory mechanism for impaired cognitive function in the brain. Continuous hyperfunction accelerates neurodegeneration and impaired cognitive function. The postcentral gyrus which is located in the parietal lobe of the cerebral cortex is part of the somatosensory-motor network; reduced spontaneous brain activity suggests abnormal somatosensory regulation. Notably, compared with the HC group, only mfALFF in the left medial superior frontal gyrus was decreased, and mALFF in the right hippocampus was elevated in the MHD-NCI group, while no significant abnormal spontaneous brain activity was seen in the remaining regions. These findings suggest that MHD-CI patients tend to have more severe neurophysiological alterations and compensatory effects. Therefore, we compared various brain areas and clinical indicators between the MHD-CI and MHD-NCI groups to identify the brain areas and risk factors associated with cognitive function.
Fluid–structure interaction analysis of cerebrospinal fluid with a comprehensive head model subject to a rapid acceleration and deceleration
Published in Brain Injury, 2018
Milan Toma, Paul D.H. Nguyen
Figure 10 shows the cortical areas affected by the SPH impulse intensity at the peak velocity. The diffuse pattern of SPH impulse intensity maxima may represent the cortical areas most affected by a concussion. Brodmann’s areas with at least 10% coverage of maximal SPH impulse intensity include 40 (10.1%), 4 (11.7%), 1, 2, 3 (15.3%) and 52 (21.7%). Brodmann area 40, the left supramarginal gyrus, receives input from multiple sensory modalities and supports complex linguistic processes. Lesions here may result Gerstmann syndrome and fluent aphasia, such as Wernicke’s aphasia. Brodmann area 4 is typically associated with motor functions but also plays a supportive role in sensory perception. Lesions in the primary motor cortex may result in paralysis and decreased somatic sensation. Brodmann areas 1, 2 and 3 comprise the postcentral gyrus in the parietal lobe and are primarily associated with somatosensory perception. Lesions in the postcentral gyrus may result in cortical sensory impairments, including loss of fine touch and proprioception. Brodmann area 52, the parainsular, is the smallest of the mentioned areas and has the high percentage of SPH impulse intensity maxima coverage. It joins the insula and the temporal lobe.
Neuroanatomical and behavioural factors associated with the effectiveness of two weekly sessions of prism adaptation in the treatment of unilateral neglect
Published in Neuropsychological Rehabilitation, 2020
Maria Gutierrez-Herrera, Simone Eger, Ingo Keller, Joachim Hermsdörfer, Styrmir Saevarsson
Based on the median splits calculated for the improvement in performance at follow-up session in the LM-M and in the cancellation tasks, patients were consistently classified into groups with higher vs lower levels of improvement. To identify the brain regions that were predominantly involved in patients showing a low prism-related improvement in motor-related tasks, we subtracted the superimposed lesions of patients with a higher level improvement (n = 7; Figure 8, bottom panel) from those of patients with a lower level of improvement (n = 7; Figure 8, top panel). As indicated in Figure 9, an extended area could be defined were lesions were 57% more common in patients showing a lower performance improvement in motor-related tasks. This area included the right inferior and middle temporal gyri, thalamus, angular, and supramarginal gyri, postcentral gyrus, fusiform gyrus, and hippocampus. As for the opposite subtraction, brain regions including the right superior temporal gyrus, temporal pole, heschl gyrus, and superior, middle, and inferior frontal gyri were damaged 57% more often in patients with better performance improvement in motor-related tasks. Additionally, a higher percentage of overlap was observed in the insula, the putamen, and the rolandic operculum (71%) (Figure 9).1
Related Knowledge Centers
- Brodmann Area
- Gyrus
- Neuroanatomy
- Parietal Lobe
- Somatosensory System
- Brain
- Primary Somatosensory Cortex
- Cortical Homunculus
- Thalamocortical Radiations
- Longitudinal Fissure