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Chemosensory Disorders and Nutrition
Published in Alan R. Hirsch, Nutrition and Sensation, 2023
Carl M. Wahlstrom, Alan R. Hirsch, Bradley W. Whitman
It should be noted that the entorhinal cortex is both a primary and a secondary olfactory cortical area. Efferent fibers project via the uncinate fasciculus to the hippocampus, the anterior insular cortex next to the gustatory cortical area, and the frontal cortex. This may explain why temporal lobe epilepsy, which involves the uncinate, often produces phantosmias of burning rubber, also known as “uncinate fits” (Acharya, Acharya, and Luders 1996).
Prefrontal Inhibitory Signaling in the Control of Social Behaviors
Published in Tian-Le Xu, Long-Jun Wu, Nonclassical Ion Channels in the Nervous System, 2021
Social interaction is a complex behavior that involves multiple neural processes, including sensory perception, motivation, learning and memory, reward-seeking, and motor generation. Not surprisingly, a variety of brain structures have been identified to participate in social behavior, such as the olfactory bulb (Sanchez-Andrade and Kendrick 2009; Montagrin et al. 2018), the amygdala (Adolphs 2010), the hippocampus (Montagrin et al. 2018), the paraventricular nucleus of hypothalamus (PVN) (Resendez et al. 2020; Tang et al. 2020; Hung et al. 2017), the cerebellum (Carta et al. 2019), the ventral tegmental area (VTA) (Gunaydin et al. 2014), the nucleus accumbens (NAc) (Dolen et al. 2013), and the mPFC (Ko 2017). Of these, the mPFC is a higher-order cortical area that constantly receives and processes incoming information from numerous upstream structures and transmits integrated output to down-stream brain structures for top-down behavioral control. Therefore, the mPFC represents an ideal hub to combine external social cues with animal’s internal states to produce proper output and thus generate appropriate social behavior.
Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Stimulation of the surface of the primary motor cortex, at a relatively low threshold, elicits movement of different parts of the body. Moving the site of stimulation laterally across the motor cortex reveals a somatotopic organization, the most medial part corresponding to the lowest extremities and the most lateral parts corresponding to the face and tongue (Figure 12.3). However, the distribution of various body parts over the primary motor cortex is not uniform, resulting in a caricature of a human figure referred to as the motor homunculus, or little person. A relatively large cortical area representation is associated with finer movements, which involve small motor units and hence a larger number of motor neurons that need to be controlled. This is the case, for example, with: The hand, including the four fingers and the opposable thumb, which underlies the amazing manual dexterity of humans.Facial muscles, conveying a variety of facial expressions, which is important for social interaction.The mouth and tongue, involved in vocalization.
Centella asiatica prevents D-galactose-Induced cognitive deficits, oxidative stress and neurodegeneration in the adult rat brain
Published in Drug and Chemical Toxicology, 2022
Zeba Firdaus, Neha Singh, Santosh Kumar Prajapati, Sairam Krishnamurthy, Tryambak Deo Singh
Light microscopic examination of H & E stained brain sections of the Control group revealed normal architecture of the cerebral cortex (Figure 4(A)) without any significant histopathological alterations. The D-gal group showed several histological changes in the cerebral cortex region (Figure 4(B)) as compared to the Control group. Pyramidal cells were highly affected; cells were shrunken, irregular in shape with a hyperchromatic nucleus, eosinophilic to vacuolated cytoplasm, and moderate gliosis was apparent. Granular cells showed indistinct cellular margins, nuclear karyorrhexis, and karyolysis with prominent pericellular edema. Prominent vacuolation in the neuropil was observed. Stroma adjacent to the affected neuronal cells showed marked pericellular and perivascular edema, karyorrhectic debris, and focal areas of gliosis. All of these findings indicate neurodegenerative changes in the cortical area. The D-gal + CAE group showed noticeably more normal histology in the cerebral cortex area (Figure 4(C)) when compared to the D-gal group. In the D-gal + CAE group, most neuronal cells were intact and appeared healthy. Cells rarely exhibited pericellular edema, nuclear pyknosis, neuronal degeneration, atrophy, or focal gliosis. Neuroglial cells appeared similar to the Control group except that a few were darkly stained. Small focal areas of neuropil vacuolations were seen (Figure 4(C)) but to a markedly lesser extent than in the D-gal group.
A review of the impact of hormone therapy on prefrontal structure and function at menopause
Published in Climacteric, 2021
The PFC is the part of the cerebral cortex covering the frontal lobe, which reaches its maximum volume in the human brain, where it occupies 30% of the total cortical area [31]. Over past decades, considerable efforts have been devoted to identifying the anatomy, cytoarchitecture and connectivity of this brain region using different approaches [32,33]. A wealth of anatomical studies of the PFC have identified multiple subdivisions at the functional, cytoarchitectonic and connectivity levels [34]. According to the widely used Brodmann’s cortical scheme (cytoarchitectonic map), the PFC traditionally comprises Brodmann areas (BAs) 8–14 and BAs 44–47 (Figure 1) [31]. A number of neuroimaging studies focus on functional localizations and divisions of the human PFC. There are variations in the subdivisions of the human PFC, but the dorsolateral, dorsomedial, ventromedial and orbital PFC are the most common functional divisions (Figure 1) [31]. The human dorsolateral PFC is often attributed to the lateral part of BAs 8, 9 and 46, and the human dorsomedial PFC includes portions of BAs 8, 9, 10, 24 and 32. In contrast, the ventromedial PFC and the orbitofrontal cortex (OFC) are usually attributed to the anatomical structures of BAs 47, 45 and 44 and BAs 10, 11 and 47, respectively.
Evaluation of Memory and Language Network in Children and Adolescents with Visual Impairment: A Combined Functional Connectivity and Voxel-based Morphometry Study
Published in Neuro-Ophthalmology, 2021
A Ankeeta, Rohit Saxena, S Senthil Kumaran, Sada Nand Dwivedi, Naranamangalam Raghunathan Jagannathan, Vaishna Narang
The role of the visual cortex while reading Braille words has been confirmed by neuroimaging techniques like functional neuroimaging, positron emission tomography (PET), and transcranial magnetic stimulation (TMS).6–10 In blind participants, the occipital cortex has been reported to process non-visual stimuli in the early years of blindness.11 During the Braille reading task, the primary visual cortex was found to be activated in late blind (LB), but not in early blind (EB) participants.12 Varying nature of utilisation and reorganisation of primary visual cortex in EB and LB participants suggests an alteration in dorsal and ventral perception pathways.7,13–16 Visual and somatosensory network involvement has been reported during language processing in blind population, but memory network performance during the encoding of language component is yet to be explored. Visual cortical area, language area, and the learning network may differ in children and adolescent participants, and may contribute to different levels of plasticity in EB and LB participants.17–19 Understanding the extent of neuro-plasticity associated with visual loss onset, neurobiology and cognition would help in developing a training pattern for better adaptation during early and late onset of blindness.