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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.
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Finally, the authors of the sixth text are inconsistent in this regard. On p. 301, 370, and 495, Crosby, Humphrey, and Lauer (1962) use the terms “inferior thalamic peduncle” and “inferior thalamic radiations” interchangeably. They do not define “posterior thalamic peduncle” and “posterior thalamic radiations” identically, however. They describe the former as interrelating “the occipital and the parietal regions of the cortex with the lateral thalamic nuclei, with the pulvinar, and with the superior colliculus” (p. 396). The latter, however, is described as connecting Brodmann areas 18 and 19—i.e., occipital cortex only—with not only the pulvinar and the superior colliculus, but also the pretectal nucleus, the ipsilateral red nucleus and substantia nigra, and the contralateral abducens nucleus (Table 2B on p. 397).
Neuroplasticity and rehabilitation therapy
Published in Mark J. Ashley, David A. Hovda, Traumatic Brain Injury, 2017
As these two pathways project to separate areas of the cerebral cortex, this helps explain the selective loss of some features of an object. As an example, object agnosia, the ability to name an object, is associated with Brodmann areas 18, 20, and 21 on the left temporal cortex, whereas color anomia, the ability to name a color, is associated with the speech zones or connections for Brodmann areas 18 and 37. The mechanism of the complete visual construct is pulled together by a yet unknown binding mechanism.
Effect of object substitution, spontaneous compensation and repetitive training on reaching movements in a patient with optic ataxia
Published in Neuropsychological Rehabilitation, 2020
Josselin Baumard, Frédérique Etcharry-Bouyx, Valérie Chauviré, Delphine Boussard, Mathieu Lesourd, Chrystelle Remigereau, Yves Rossetti, François Osiurak, Didier Le Gall
Figure 1 displays a timeline of the case study. M.B. was a 75 year-old, right-handed pensioner. His medical history included: Type 2 diabetes, high blood pressure, smoking, dyslipidemia, chronic renal failure treated by hemodialysis, and sleep apnea syndrome treated by positive pressure ventilation. In 2001, he sustained a first ischemic stroke which provoked lesions in the left middle cerebral artery territory. At that time, he recovered with little disability (see Figure 1). In 2014, M.B. suddenly became confused but he did not present any obvious language, motor or sensory deficits according to his wife. After three days, he eventually visited the emergency department. Brain imaging revealed large ischemic lesions in the left occipital, temporal and parietal lobes (Brodmann areas 18, 19, 21, 22, 37, 39, 40) but also in the cerebellum, the left caudate nucleus and the right thalamus (Figure 2).
Cortical Alterations by the Abnormal Visual Experience beyond the Critical Period: A Resting-state fMRI Study on Constant Exotropia
Published in Current Eye Research, 2019
Hongmei Shi, Yanming Wang, Xuemei Liu, Lin Xia, Yao Chen, Qinlin Lu, Benedictor Alexander Nguchu, Huijuan Wang, Bensheng Qiu, Xiaoxiao Wang, Lixia Feng
The lingual gyrus, located in Brodmann area 18 (BA18), is the major component of cortical visual area V2 and thus plays a prominent role in visual memory,26 vivid visual imagery,27 and different functions of vision. These functions include color motion,28 identification of facial expressions of emotions,29 and recognition of words.30 Being a primary component of the early visual cortex, V2 appears to be essential for conscious visual awareness.31 Besides, previous studies have already presented that right BA18, BA19, and BA732 are responsible for processing stereopsis. V2 is highly activated in patients with infantile exotropia, providing evidence that it is potentially involved in optical fusion.33 Huang et al.34 observed that patients with concomitant strabismus show increased ReHo values in the V2, which may compensate for the dysfunction of optical fusion. Moreover, Qian et al. found obvious activation in V2 in IXT35 and speculated that more activation was needed to keep the fixation on fusion images during performance in visual tasks. In the present study, we also found higher ReHo values in patients with XT than in HCs. Here, we speculate that the increased ReHo values in the V2 may reflect a functional compensation for binocular fusion dysfunction in XT, which is consistent with previous research results. Meanwhile, in our study, XT presents with severe stereopsis impairment; thus, we believe this is probably associated with the abnormalities of the right V2.
Characterizing changes in network connectivity following chronic head trauma in special forces military personnel: a combined resting-fMRI and DTI study
Published in Brain Injury, 2021
Allen A Champagne, Nicole S Coverdale, Andrew Ross, Christopher Murray, Isabelle Vallee, Douglas J Cook
Voxelwise analysis of distance-based functional connectivity between the groups revealed significant short- and long-FCS differences spread across the GM (Table 2; Figure 2a, 3a, 3c). Lower short-FCS in the CANSOF group was identified in a single cluster located around the right cuneus and Brodmann area 18 (Table 2; Figure 2a). Voxelwise analysis of the reconstructed WM tract associated with the short-FCS cluster (Figure 2b) did not show any group-based differences in FA or MD, following correction of multiple comparison (P > .05, corrected).