Occipital lobe morphological anatomy: anatomical and surgical aspects

Flores, Leandro Pretto

doi:10.1590/s0004-282x2002000400010

Cited by 34 publications

(23 citation statements)

References 5 publications

(10 reference statements)

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“…The visual cortex of individuals might vary up to 40% (Stensaas et al 1974, Flores 2002); hence, the area for electrode implantation will vary and in few patients the area available for the electrodes might be less than average. Also, few electrodes might fail during surgical procedure itself and few more during a long-term implantation.…”

Section: Introductionmentioning

confidence: 99%

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Srivastava

Troyk

Dagnelie³

2009

J. Neural Eng.

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In order to assess visual performance using a future cortical prosthesis device, the ability of normally sighted and low vision subjects to adapt to a dotted ‘phosphene’ image was studied. Similar studies have been conduced in the past and adaptation to phosphene maps has been shown but the phosphene maps used have been square or hexagonal in pattern. The phosphene map implemented for this testing is what is expected from a cortical implantation of the arrays of intracortical electrodes, generating multiple phosphenes. The dotted image created depends upon the surgical location of electrodes decided for implantation and the expected cortical response. The subjects under tests were required to perform tasks requiring visual inspection, eye–hand coordination and way finding. The subjects did not have any tactile feedback and the visual information provided was live dotted images captured by a camera on a head-mounted low vision enhancing system and processed through a filter generating images similar to the images we expect the blind persons to perceive. The images were locked to the subject’s gaze by means of video-based pupil tracking. In the detection and visual inspection task, the subject scanned a modified checkerboard and counted the number of square white fields on a square checkerboard, in the eye–hand coordination task, the subject placed black checkers on the white fields of the checkerboard, and in the way-finding task, the subjects maneuvered themselves through a virtual maze using a game controller. The accuracy and the time to complete the task were used as the measured outcome. As per the surgical studies by this research group, it might be possible to implant up to 650 electrodes; hence, 650 dots were used to create images and performance studied under 0% dropout (650 dots), 25% dropout (488 dots) and 50% dropout (325 dots) conditions. It was observed that all the subjects under test were able to learn the given tasks and showed improvement in performance with practice even with a dropout condition of 50% (325 dots). Hence, if a cortical prosthesis is implanted in human subjects, they might be able to perform similar tasks and with practice should be able to adapt to dotted images even with a low resolution of 325 dots of phosphene.

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Section: Introductionmentioning

confidence: 99%

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Srivastava

Troyk

Dagnelie³

2009

J. Neural Eng.

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“…Our results show that during both wakefulness and N1 sleep the occipital lobe presented a major predominance of the bands that are characteristic of these two sleep phases in the spider monkey. There is evidence that the primary responsibility for visual perception | 5 of 10 resides in the occipital lobe, which is associated with memory formation and visual processing (Flores, 2002;Rehman & Al Khalili, 2020); while the 1-3 Hz range is the delta band commonly related to sleep in primates (Cruz-Aguilar et al, 2015;Hsieh et al, 2008;Rechtschaffen & Kales, 1968). The common theta band range in rodents is 3-12 Hz.…”

Section: Discussionmentioning

confidence: 99%

Topographic distribution of the EEG ad hoc broad bands during sleep and wakefulness in the spider monkey (Ateles Geoffroyi)

Hernández‐Arteaga

Cruz‐Aguilar

Hernández‐González

et al. 2021

American J Primatol

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There is evidence that research on sleep among New World monkeys may provide important knowledge related to the evolution of sleep more broadly in the primate order. Digital electroencephalographic (EEG) analyses provide essential knowledge on sleep in the spider monkey. Recently, specific EEG bands related to sleep in these animals have been obtained using principal component analysis, but the exact spatio-temporal distribution of these EEG bands in this species has not yet been analyzed. This study determined the topographic distribution of the EEG spectral power of ad hoc broad bands during rapid eye movement sleep, nonrapid eye movement sleep, and wakefulness. Superficial EEG activity was obtained from the occipital, frontal, and central areas of six young adult male monkeys housed in a laboratory. During wakefulness, occipital areas showed high absolute power in the 1-3, 3-12, and 11-30 Hz ranges, while during nonrapid eye movement 1 sleep the highest absolute power was in the 13-30 Hz range. During nonrapid eye movement 3 sleep, frontal and central areas showed a high absolute power in the 18-19 Hz range. Finally, the right central area showed a high absolute power in the 20-30 Hz range during rapid eye movement sleep. This topographic distribution of EEG bands could represent the brain organization required for arousal and mnemonic processing during sleep in the spider monkey.

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“…As essential structures involved in auditory processing, including language, the STG and ITG are also associated with social cognition processes ( 71 , 72 ). The MOG, which is located in the occipital lobe, participates in visual processing ( 73 ). These increased FCs in thalamus nuclei to the auditory and visual cortex further support the disturbance of somatosensory processing and the motor/sensory cortex.…”

Section: Discussionmentioning

confidence: 99%

Enhanced Connectivity of Thalamo-Cortical Networks in First-Episode, Treatment-Naive Somatization Disorder

Zhao

Liu

et al. 2020

Front. Psychiatry

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Background Dysfunctions of the thalamus and its projections to cortical cortices have been implicated in patient with somatization disorder (SD). However, changes in the anatomical specificity of thalamo-cortical functional connectivity (FC) in SD remain unclear. Methods Resting-state fMRI scans were collected in 25 first-episode, drug-naive patients with SD, as well as 28 sex-, age-, and education-matched healthy controls. We parcellated the thalamus with seven predefined regions of interest (ROIs) and used them as seeds to map whole-brain FC. Correlation analysis was conducted in the patients. Results We found an increased pattern of thalamic ROI-cortex connectivity in patients with SD. Patients with SD demonstrated enhanced thalamic connectivity to the bilateral anterior/middle cingulum, motor/sensory cortex, visual cortex, and auditory cortex. A significantly negative correlation was found between the right occipital thalamic ROI to the anterior cingulum and EPQ extraversion scores ( r =0.404, p =0.045) after the Benjamini-Hochberg correction. Conclusions This study demonstrates that anatomical specificity of enhanced thalamo-cortical FCs exists in first-episode, drug-naive patients with SD. These findings further highlight the importance of the thalamic subregions in the pathophysiology of SD.

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Occipital lobe morphological anatomy: anatomical and surgical aspects

Cited by 34 publications

References 5 publications

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Detection, eye–hand coordination and virtual mobility performance in simulated vision for a cortical visual prosthesis device

Topographic distribution of the EEG ad hoc broad bands during sleep and wakefulness in the spider monkey (Ateles Geoffroyi)

Enhanced Connectivity of Thalamo-Cortical Networks in First-Episode, Treatment-Naive Somatization Disorder

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