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Sensory System
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Sensory impulses project to the somatosensory cortex. The postcentral gyrus comprises the primary somatosensory cortex (S1), which corresponds to Brodmann's areas 3, 1 and 2. A smaller secondary somatosensory cortex (S2) lies along the lateral fissure. S1 has a somatotrophic representation (map of the body) called the sensory homunculus. Within the primary somatosensory cortex, segregation of the body is maintained so that the face is located ventrally near the lateral fissure, the upper limbs continue medially and dorsally from the face region and extend to the convexity of the hemisphere and lower extremity projects on to the medial surface of the hemisphere (Figure 8.7). The largest areas represent the face, hands and fingers where precise localization is important.
Imaging Pain in the Brain: The Role of the Cerebral Cortex in Pain Perception and Modulation
Published in Robert M. Bennett, The Clinical Neurobiology of Fibromyalgia and Myofascial Pain, 2020
M. Catherine Bushnell, Chantal Villemure, Irina Strigo, Gary H. Duncan
FIGURE 1. Functional and anatomical magnetic resonance imaging of a single subject exposed to a 46°C noxious heat stimulus on the left leg. Ten nine-sec noxious heat stimuli and 10 nine-sec neutral warm stimuli [36°C] were presented sequentially with nine-sec interstimulus intervals. The circled color-coded areas represent regions with significantly greater activation during the noxious heat than during the warm stimuli [Spearman's rank order correlation]. In this subject and others, there was significant pain-related activation in [1A] primary somatosensory cortex [S1J, [1B] secondary somatosensory cortex [S2], anterior insular cortex [IC], and cingulate cortex [ACC], Panels 1A and 1C show coronal slices [right side of brain depicted on right], and panel 1B shows a sagittal slice. Adapted from Bushnell et al. (9).
The cortical processing of pain
Published in Camille Chatelle, Steven Laureys, Assessing Pain and Communication in Disorders of Consciousness, 2015
The development of non-invasive functional neuroimaging techniques has prompted an unparalleled increase in studies investigating the neural basis of perception in humans. In the field of pain, a large number of studies using functional magnetic resonance imaging (fMRI), positron emission tomography (PET), magnetoencephalography (MEG), or electroencephalography (EEG) have shown that when a noxious sensory stimulus is applied to the human skin, it elicits neuronal activity within a vast network of brain regions, including the primary somatosensory cortex (S1), the secondary somatosensory cortex (S2), the insula, and the anterior portion of the cingulate cortex (ACC) (Apkarian, Bushnell, Treede, & Zubieta, 2005; Bushnell & Apkarian, 2006; Garcia-Larrea, Frot, & Valeriani, 2003; Peyron, Laurent, & Garcia-Larrea, 2000; Tracey & Mantyh, 2007).
Altered brain activity and functional connectivity in migraine without aura during and outside attack
Published in Neurological Research, 2023
Luping Zhang, Wenjing Yu, Zhengxiang Zhang, Maosheng Xu, Feng Cui, Wenwen Song, Zhijian Cao
Compared with HC, the MWoA-DI patients showed increased ALFF with peaks in the right rolandic operculum extending to the insular but decreased with peaks in the right cuneus and extent to the right calcarine gyrus. The rolandic operculum is part of the secondary somatosensory cortex (S2). The insula is a brain region that integrates sensory and affective information. The S2 and insula belong to the pain matrix and are involved in the perception and processing of pain. The S2 and insula are activated by noxious stimulation and code pain intensity [21–24]. These two regions may take part in defense and analgesic effects. S2 stimulation can cause impaired judgments of pain intensity and reduced perceived pain intensity [25]. In other words, increased pain thresholds produce analgesia. Activation of the insula is associated with the analgesic effect produced by acupuncture [26]. Taken together, our study showed that the rolandic operculum (S2) and insula were activated in MWoA-DI patients and may reflect the defense or self-protection during the pain-free phase. A related study also revealed an increase in ALFF in S2 and insula in MWoA-DI patients relative to HC, and these changes were thought to represent an adaptive response to repeated migraine attacks in these patients [27]. However, the ALFF value in the right rolandic operculum was negatively correlated with the disease duration in MWoA-DA patients. The correlation results suggest that this defense effect disappears during the attack and weakens with disease duration.
Visual attention affects late somatosensory processing in autism spectrum disorder
Published in International Journal of Neuroscience, 2022
Haruka Noda, Akiko Tokunaga, Akira Imamura, Goro Tanaka, Ryoichiro Iwanaga
P100 and N140 are considered indicators of late somatosensory processing. Also, the P100 response of SEPs is reflected in secondary somatosensory cortex (SII) activities [30, 31]. However, the source of N140 is debated; the contenders are the SII, inferior and superior parietal lobules, supplementary motor area, medial temporal area, anterior cingulate gyrus, and prefrontal cortex [18, 30–33]. These regions are related to attentional processing and sensorimotor integration [34–37]. In the current study, P100-N140 amplitudes during both ‘closed’ and ‘open’ conditions were higher than during ‘visual’ condition in the ASD group. These findings imply that higher order somatosensory processing, reflecting attentional function and sensorimotor integration, may be affected in individuals with ASD, irrespective of whether they receive visual information.
Preventing pediatric chronic postsurgical pain: Time for increased rigor
Published in Canadian Journal of Pain, 2022
Christine B. Sieberg, Keerthana Deepti Karunakaran, Barry Kussman, David Borsook
During surgery, general anesthetics produce a state of drug-induced unconsciousness but not analgesia. The exception is ketamine, which produces dose-related unconsciousness and analgesia. Analgesics are administered according to weight-based dosing in response to clinical (patient movement) and autonomic (blood pressure, heart rate, respiratory rate, sweating) activity, rather than with a objective marker of nociception directly from the central nervous system. The mechanism and intensity of analgesia will vary with the class of drug, dosage, and route of administration. With respect to pain perception, a preclinical fMRI study in macaques found that noxious stimuli resulted in activation of the secondary somatosensory cortex and insula under propofol or pentobarbital anesthesia, whereas no activation was observed with isoflurane anesthesia.40 In humans, ongoing nociceptive processing has been shown to occur in adolescent patients under balanced general anesthesia.41