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Positron Emission Tomography and Neuropsychological Studies in Dementia
Published in Robert E. Becker, Ezio Giacobini, Alzheimer Disease, 2020
Randolph W. Parks, Robert E. Becker, Kathryn L. Dodrill, Bettina A. Bennett, David J. Crockett, Trevor A. Hurwitz, Patrick L. McGeer, Edith G. McGeer
Phelps et al. (1981) and Phelps, Kuhl & Mazziotta (1981) conducted a series of experiments in which volunteers were presented with increasingly complex stimuli varying from white light to a black and white checkerboard pattern. Stimulation with white light produced bilaterally twice as much metabolic activation in the primary visual cortex (Brodmann area 17) than did the associative visual cortex (Brodmann areas 18 and 19). The more complex stimulation of the black and white checkerboard pattern produced significantly more activation of the associative visual cortex than of the primary visual cortex although area 17 also showed increased stimulation when compared with white light stimulation.
Biological Basis of Behavior
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
The occipital cortex is the smallest of the four lobes of the brain. It is located posterior to the temporal lobe and parietal lobes. The occipital cortex is concerned with visual processing and is composed of primary visual cortex (Brodmann area 17), and secondary visual (association) cortex (Brodmann areas 18 and 19). It receives projections from the retina (via the thalamus) from where different groups of neurons separately encode different visual information, such as color, orientation, and motion. Two important pathways of information originate in the occipital lobes: the dorsal and ventral streams. The dorsal stream projects to the parietal lobes and processes where objects are located. The ventral stream projects to structures in the temporal lobes and processes what objects are.
Neuro-ophthalmology
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
The optic radiations connect the LGN to the occipital lobe. Superior optic radiations, representing the inferior visual field quadrants, pass through the parietal lobe and terminate at the primary visual cortex (also known as V1 or Brodmann area 17) in the occipital lobe, superior to the calcarine sulcus (cuneus gyrus). The inferior optic radiations (Meyer's loop), representing the superior visual field quadrants, pass through the temporal lobe and terminate at the primary visual cortex, inferior to the calcarine sulcus (lingual gyrus). The macula is represented posteriorly just lateral to the tip of the calcarine sulcus.
Intragastric quinine administration decreases hedonic eating in healthy women through peptide-mediated gut-brain signaling mechanisms
Published in Nutritional Neuroscience, 2019
Julie Iven, Jessica R. Biesiekierski, Dongxing Zhao, Eveline Deloose, Owen G. O’Daly, Inge Depoortere, Jan Tack, Lukas Van Oudenhove
Second-level (group level) analysis was performed by applying a one-way within-subject ANOVA on the 25 individual first-level contrast images, with the condition-by-time bin interaction effect being the main effect of interest. Voxel-level threshold was set at pFWE-corrected<0.05. Voxel-based analysis was performed within a single mask consisting of regions of interest (ROI) selected based on previous human functional neuroimaging studies on hedonic and homeostatic control of appetite and food intake.23,24 These ROIs are all anatomically defined atlas structures, including key homeostatic (medulla (NTS), hypothalamus) and hedonic (midbrain (VTA), dorsal (caudate, putamen) and ventral (nucleus accumbens) striatum, pallidum, pregenual anterior cingulate cortex, medial and lateral rectus of the OFC, amygdala, anterior insula) brain regions involved in the regulation of appetite and food intake.23,24 To investigate if changes are specific to our a priori ROI, the same second-level analysis was performed in a priori irrelevant regions, such as the occipital lobe (visual cortex, Brodmann Area 17, 18, and 19) and the primary motor cortex (Brodmann Area 4). For each time bin, contrast estimates reflecting the difference in brain response (relative to pre-infusion) between QHCl and placebo administration were extracted from the entire cluster (averaged across all voxels) in representative ROIs with the MarsBar toolbox for SPM12. These estimates were used to plot the time course of the differential effect of the intragastric infusions on the BOLD signal.
Altered Functional Connectivity of the Primary Visual Cortex in Adult Comitant Strabismus: A Resting-State Functional MRI Study
Published in Current Eye Research, 2019
Xiaohe Yan, Yun Wang, Lijuan Xu, Yong Liu, Shaojie Song, Kun Ding, Yuan Zhou, Tianzi Jiang, Xiaoming Lin
Comitant strabismus, which affects 1–4.2% of the population, is the most common type of strabismus and is characterized by an equal angle of ocular misalignment in all fields of gaze, regardless of which eye is used for fixation.1–3 Comitant strabismus presents with abnormal eye position and poor stereopsis. Although few studies have focused on brain changes in strabismic patients, several animal studies have revealed alterations in the function of the visual cortex and brain connections within and between brain regions. The number of binocular disparity-sensitive neurons in the primary visual cortex of strabismic animals is reduced, as has been shown in kittens and monkeys.4,5 Moreover, various areas [Brodmann area 17 (BA17) and BA18] of the visual cortex are differentially affected in strabismic cats: the layouts of functional maps in area 17 are affected by experience-dependent manipulations, while those in BA18 are not affected.6,7 In cats, the site of suppressive binocular interaction has been shown to most likely lie in the primary visual cortex and is mediated by γ-aminobutyric acid.8 Consistent with this result, reduced metabolic activity was observed in ipsilateral ocular dominance columns in strabismic monkeys.9
A review of magnetoencephalography use in pediatric epilepsy: an update on best practice
Published in Expert Review of Neurotherapeutics, 2021
Hiroshi Otsubo, Hiroshi Ogawa, Elizabeth Pang, Simeon M Wong, George M Ibrahim, Elysa Widjaja
Visual evoked potential stimulation typically consists of a binocular presentation of a reversing or alternating checkboard pattern in either the right or left hemi-field (see guidelines on Burgess et al. [92] for details). Binocular stimulation of each hemi–field leads to a dipolar localization in the contralateral occipital cortex, V1, or Brodmann Area 17 [121]. Checkerboard size and subtended visual field size are important as these affect the latency of VEF as decreasing checkerboard size increases VEF latency [122,123], and an optimal visual field size allows maximal stimulation of foveal receptors.