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Effects of Essential Oils on Human Cognition
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Many odorants stimulate not only the olfactory system via the first cranial nerve (N. olfactorius) but also the trigeminal system via the fifth cranial nerve (N. trigeminus), which enervates the nasal mucosa. The trigeminal system is part of the body's somatosensory system and mediates mechanical- and temperature-related sensations, such as itching and burning or warmth and cooling sensations. Trigeminal information reaches the brain via the trigeminal ganglion and the ventral posterior nucleus of the thalamus. The primary cortical projection area of the somatosensory system is the contralateral postcentral gyrus of the parietal lobe (Zilles and Rehkämpfer 1998). The reticular formation in the brain stem is part of the reticular activating system (RAS) (Figure 12.2) and receives collaterals from the trigeminal system. Thus, trigeminal stimuli have direct effects on arousal. Utilizing this direct connection, highly potent trigeminal stimulants, such as ammonia and menthol, have been used in the past in smelling salts to awaken people who fainted.
Brain stimulation: new directions
Published in Alan Weiss, The Electroconvulsive Therapy Workbook, 2018
When the auditory canal is irrigated with cold water there is activation in the contralateral cortical and subcortical brain regions shown in functional brain imaging studies (Bottini et al., 1994; Ferre, Bottini and Haggard, 2012). It is thought that spatial and bodily representations are multisensory processes that form the somatosensory system, which overlaps with vestibular information from the balance organs in the inner ear (Bottini et al., 2013). CVS has been shown to have effects on a wide range of visual and cognitive phenomena as well as post-stroke conditions, mania and chronic pain states (Been et al., 2007). Left-cold CVS has been shown to affect the perception of distinct somatosensory modalities, with increased sensitivity to touch and reduced sensitivity to pain on both the ipsilateral and contralateral hands (Bottini et al., 2013).
Nervous System
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Mark T. Butt, Alys Bradley, Robert Sills
For the somatosensory system, multiple peripheral nerves should be examined. This examination should include longitudinal sections in paraffin (H&E staining suffices) and osmicated, resin-embedded, transverse sections. Osmicated sections can be embedded in paraffin (see Figure 22.6), but the level of detail is much less than that easily obtainable in a resin-embedded section. Resin sections provide greatly enhanced detail and are suitable for morphometric studies (counts and measurements of myelinated axons). Osmicated sections are the only means of assessing whether myelin sheaths are of the appropriate thickness (as compared to axon diameter) and greatly enhance differentiating regeneration from degeneration.
Mechanisms of action of vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) in pain: a narrative review
Published in Nutritional Neuroscience, 2023
A. M. Paez-Hurtado, C. A. Calderon-Ospina, M. O. Nava-Mesa
Pain is a serious and widespread public health problem affecting around 10%–20% of adults worldwide [1–5]. There are three different types of pain subcategorized according to their pathophysiological mechanisms by the International Association for the Study of Pain. Nociceptive pain is a pain sensation caused by ‘an actual or threatened damage to non-neural tissue and is due to activation of nociceptors’ [6]. Pain initiated or caused by a lesion or a disease of the somatosensory system is referred to as neuropathic pain. Nociplastic pain is defined as ‘pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain’ [6]. Inflammatory pain is a type of nociceptive pain which results from hypersensibility of nociceptors by inflammatory mediators [7].
Neuropathic ocular surface pain: Emerging drug targets and therapeutic implications
Published in Expert Opinion on Therapeutic Targets, 2022
Sneh Patel, Rhiya Mittal, Konstantinos D. Sarantopoulos, Anat Galor
However, crucial gaps in our current scientific understanding still exist. A major challenge that exists in the field currently is our reliance on clinical diagnosis for patients with signs of neuropathic ocular surface pain. While an array of high specificity/sensitivity in-clinic tools exist for nociceptive pain, this is in stark comparison to the paucity of available in-clinic testing which can help to precisely determine whether there is a dysfunction within the somatosensory system, and if so, where it exists in the body, as well as what might be the underlying mechanisms. This lack of diagnostic capability binds together researchers in the field as it forces reliance on clinical judgment, and thereby brings forth an important target in future research: improved diagnostic testing, which can in turn help us to identify which individuals may be more likely to benefit from specific mechanism-based therapies.
Hypnotic Automaticity in the Brain at Rest: An Arterial Spin Labelling Study
Published in International Journal of Clinical and Experimental Hypnosis, 2019
Pierre Rainville, Anouk Streff, Jen-I Chen, Bérengère Houzé, Carolane Desmarteaux, Mathieu Piché
The first brain imaging study examining more directly the brain correlates of hypnotic involuntariness showed robust parietal activity while subjects moved their arm in response to hypnotic suggestions that their arm would be moved passively (Blakemore, Oakley, & Frith, 2003). Importantly, the study included control passive and active movements in a nonhypnotic condition to allow comparing brain responses associated with normal sensory feedback alone (passive condition) and executive motor processes (active condition). In the normal passive condition, the afferent sensory signal conveyed through the somatosensory system activated the parietal cortex in the region of the inferior parietal lobule (parietal operculum/supramarginal gyrus). In the active condition, motor cortices were also activated to produce the motor command. In this condition, there was less parietal activity, consistent with the feedforward model of motor control (Wolpert & Ghahramani, 2000). Indeed, during voluntary actions, a motor command is sent to the motoneurons while a copy of this efferent signal is sent to sensory areas of the parietal cortex to monitor the correspondence between the sensory feedback and the expected effect of the action that was prescribed (i.e., prediction signal). Importantly, when the feedback matches the expectations, activity is reduced in the parietal cortex. However, when there is a mismatch (i.e., prediction error) or during passive movement (i.e., no prediction signal), the parietal cortex is strongly activated.