Increases in dendritic length in occipital cortex after 4 days of differential housing in weanling rats

Stimulation of primary visual cortices has the potential to restore some degree of vision to blind individuals. Developing safe and reliable visual cortical prostheses requires assessment of the long-term stability, feasibility, and safety of generating stimulation-evoked perceptions.A NeuroPace responsive neurostimulation system was implanted in a blind individual with an 8-year history of bare light perception, and stimulation-evoked phosphenes were evaluated over 19 months (41 test sessions). Electrical stimulation was delivered via two four-contact subdural electrode strips implanted over the right medial occipital cortex. Current and charge thresholds for eliciting visual perception (phosphenes) were measured, as were the shape, size, location, and intensity of the phosphenes. Adverse events were also assessed.Stimulation of all contacts resulted in phosphene perception. Phosphenes appeared completely or partially in the left hemifield. Stimulation of the electrodes below the calcarine sulcus elicited phosphenes in the superior hemifield and vice versa. Changing the stimulation parameters of frequency, pulse width, and burst duration affected current thresholds for eliciting phosphenes, and increasing the amplitude or frequency of stimulation resulted in brighter perceptions. While stimulation thresholds decreased between an average of 5% and 12% after 19 months, spatial mapping of phosphenes remained consistent over time. Although no serious adverse events were observed, the subject experienced mild headaches and dizziness in three instances, symptoms that did not persist for more than a few hours and for which no clinical intervention was required.Using an off-the-shelf neurostimulator, the authors were able to reliably generate phosphenes in different areas of the visual field over 19 months with no serious adverse events, providing preliminary proof of feasibility and safety to proceed with visual epicortical prosthetic clinical trials. Moreover, they systematically explored the relationship between stimulation parameters and phosphene thresholds and discovered the direct relation of perception thresholds based on primary visual cortex (V1) neuronal population excitation thresholds.

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Faculty Opinions recommendation of Extrastriate body area in human occipital cortex responds to the performance of motor actions.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1019325.218482 ◽

2004 ◽

Author(s):

Kathleen Cullen

Keyword(s):

Occipital Cortex ◽

Body Area ◽

Extrastriate Body Area ◽

Motor Actions

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Perception of vision up to occipital cortex of brain.

10.35841/ophthalmology.1.1.20-39 ◽

2017 ◽

Vol 01 (01) ◽

Author(s):

Merab urushadze

Keyword(s):

Occipital Cortex

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The brain dynamics of architectural affordances during transition

Scientific Reports ◽

10.1038/s41598-021-82504-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zakaria Djebbara ◽

Lars Brorson Fich ◽

Klaus Gramann

Keyword(s):

Occipital Cortex ◽

The Body ◽

Brain Dynamics ◽

Alpha Band ◽

Time Frequency ◽

Posterior Cingulate ◽

Sensory Signals ◽

Event Related Desynchronization ◽

The Brain ◽

Attentional Mechanisms

AbstractAction is a medium of collecting sensory information about the environment, which in turn is shaped by architectural affordances. Affordances characterize the fit between the physical structure of the body and capacities for movement and interaction with the environment, thus relying on sensorimotor processes associated with exploring the surroundings. Central to sensorimotor brain dynamics, the attentional mechanisms directing the gating function of sensory signals share neuronal resources with motor-related processes necessary to inferring the external causes of sensory signals. Such a predictive coding approach suggests that sensorimotor dynamics are sensitive to architectural affordances that support or suppress specific kinds of actions for an individual. However, how architectural affordances relate to the attentional mechanisms underlying the gating function for sensory signals remains unknown. Here we demonstrate that event-related desynchronization of alpha-band oscillations in parieto-occipital and medio-temporal regions covary with the architectural affordances. Source-level time–frequency analysis of data recorded in a motor-priming Mobile Brain/Body Imaging experiment revealed strong event-related desynchronization of the alpha band to originate from the posterior cingulate complex, the parahippocampal region as well as the occipital cortex. Our results firstly contribute to the understanding of how the brain resolves architectural affordances relevant to behaviour. Second, our results indicate that the alpha-band originating from the occipital cortex and parahippocampal region covaries with the architectural affordances before participants interact with the environment, whereas during the interaction, the posterior cingulate cortex and motor areas dynamically reflect the affordable behaviour. We conclude that the sensorimotor dynamics reflect behaviour-relevant features in the designed environment.

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Central Noradrenergic Neurotransmission and Weight Loss 6 Months After Gastric Bypass Surgery in Patients with Severe Obesity

Obesity Surgery ◽

10.1007/s11695-021-05657-7 ◽

2021 ◽

Author(s):

J. Marvin Soeder ◽

Julia Luthardt ◽

Michael Rullmann ◽

Georg A. Becker ◽

Mohammed K. Hankir ◽

...

Keyword(s):

Weight Loss ◽

Gastric Bypass ◽

Severe Obesity ◽

Occipital Cortex ◽

Brain Regions ◽

General Tendency ◽

Strong Positive Correlation ◽

Reference Tissue ◽

Efficient Treatment ◽

Post Surgery

Abstract Purpose Roux-en-Y gastric bypass (RYGB) surgery is currently the most efficient treatment to achieve long-term weight loss in individuals with severe obesity. This is largely attributed to marked reductions in food intake mediated in part by changes in gut-brain communication. Here, we investigated for the first time whether weight loss after RYGB is associated with alterations in central noradrenaline (NA) neurotransmission. Materials and Methods We longitudinally studied 10 individuals with severe obesity (8 females; age 43.9 ± 13.1 years; body mass index (BMI) 46.5 ± 4.8 kg/m2) using (S,S)-[11C]O-methylreboxetine and positron emission tomography to estimate NA transporter (NAT) availability before and 6 months after surgery. NAT distribution volume ratios (DVR) were calculated by volume-of-interest analysis and the two-parameter multilinear reference tissue model (reference region: occipital cortex). Results The participants responded to RYGB surgery with a reduction in BMI of 12.0 ± 3.5 kg/m2 (p < 0.001) from baseline. This was paralleled by a significant reduction in DVR in the dorsolateral prefrontal cortex (pre-surgery 1.12 ± 0.04 vs. post-surgery 1.07 ± 0.04; p = 0.019) and a general tendency towards reduced DVR throughout the brain. Furthermore, we found a strong positive correlation between pre-surgery DVR in hypothalamus and the change in BMI (r = 0.78; p = 0.01). Conclusion Reductions in BMI after RYGB surgery are associated with NAT availability in brain regions responsible for decision-making and homeostasis. However, these results need further validation in larger cohorts, to assess whether brain NAT availability could prognosticate the outcome of RYGB on BMI. Graphical abstract

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Potential for imaging the high-affinity state of the 5-HT1B receptor: a comparison of three PET radioligands with differing intrinsic activity

EJNMMI Research ◽

10.1186/s13550-019-0570-1 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Anton Lindberg ◽

Ryosuke Arakawa ◽

Tsuyoshi Nogami ◽

Sangram Nag ◽

Magnus Schou ◽

...

Keyword(s):

Pet Imaging ◽

Specific Binding ◽

Occipital Cortex ◽

Intrinsic Activity ◽

High Affinity ◽

G Protein Coupled ◽

Dose Dependent ◽

The Brain ◽

Agonist Affinity States ◽

Different Doses

Abstract Background Over the last decade, a few radioligands have been developed for PET imaging of brain 5-HT1B receptors. The 5-HT1B receptor is a G-protein-coupled receptor (GPCR) that exists in two different agonist affinity states. An agonist ligand is expected to be more sensitive towards competition from another agonist, such as endogenous 5-HT, than an antagonist ligand. It is of interest to know whether the intrinsic activity of a PET radioligand for the 5-HT1B receptor impacts on its ability to detect changes in endogenous synaptic 5-HT density. Three high-affinity 11C-labeled 5-HT1B PET radioligands with differing intrinsic activity were applied to PET measurements in cynomolgus monkey to evaluate their sensitivity to be displaced within the brain by endogenous 5-HT. For these experiments, fenfluramine was pre-administered at two different doses (1.0 and 5.0 mg/kg, i.v.) to induce synaptic 5-HT release. Results A dose-dependent response to fenfluramine was detected for all three radioligands. At the highest dose of fenfluramine (5.0 mg/kg, i.v.), reductions in specific binding in the occipital cortex increased with radioligand agonist efficacy, reaching 61% for [11C]3. The most antagonistic radioligand showed the lowest reduction in specific binding. Conclusions Three 5-HT1B PET radioligands were identified with differing intrinsic activity that could be used in imaging high- and low-affinity states of 5-HT1B receptors using PET. From this limited study, radioligand sensitivity to endogenous 5-HT appears to depend on agonist efficacy. More extensive studies are required to substantiate this suggestion.

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Compound heterozygous variants in LAMC3 in association with posterior periventricular nodular heterotopia

BMC Medical Genomics ◽

10.1186/s12920-021-00911-4 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Carla De Angelis ◽

Alicia B. Byrne ◽

Rebecca Morrow ◽

Jinghua Feng ◽

Thuong Ha ◽

...

Keyword(s):

Cortical Development ◽

Occipital Cortex ◽

Compound Heterozygous ◽

Valuable Insight ◽

Periventricular Nodular Heterotopia ◽

Case Presentation ◽

Malformation Of Cortical Development ◽

Nodular Heterotopia ◽

Compound Heterozygous Variants ◽

Insight Into

Abstract Background Periventricular nodular heterotopia (PNH) is a malformation of cortical development characterized by nodules of abnormally migrated neurons. The cause of posteriorly placed PNH is not well characterised and we present a case that provides insights into the cause of posterior PNH. Case presentation We report a fetus with extensive posterior PNH in association with biallelic variants in LAMC3. LAMC3 mutations have previously been shown to cause polymicrogyria and pachygyria in the occipital cortex, but not PNH. The occipital location of PNH in our case and the proposed function of LAMC3 in cortical development suggest that the identified LAMC3 variants may be causal of PNH in this fetus. Conclusion We hypothesise that this finding extends the cortical phenotype associated with LAMC3 and provides valuable insight into genetic cause of posterior PNH.

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An analysis framework for the integration of broadband NIRS and EEG to assess neurovascular and neurometabolic coupling

Scientific Reports ◽

10.1038/s41598-021-83420-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

P. Pinti ◽

M. F. Siddiqui ◽

A. D. Levy ◽

E. J. H. Jones ◽

Ilias Tachtsidis

Keyword(s):

Infrared Spectroscopy ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Visual Stimulation ◽

Finite Impulse Response ◽

Occipital Cortex ◽

Integrated Analysis ◽

Impulse Response Functions ◽

Functional Near Infrared Spectroscopy ◽

Brain Functioning

AbstractWith the rapid growth of optical-based neuroimaging to explore human brain functioning, our research group has been developing broadband Near Infrared Spectroscopy (bNIRS) instruments, a technological extension to functional Near Infrared Spectroscopy (fNIRS). bNIRS has the unique capacity of monitoring brain haemodynamics/oxygenation (measuring oxygenated and deoxygenated haemoglobin), and metabolism (measuring the changes in the redox state of cytochrome-c-oxidase). When combined with electroencephalography (EEG), bNIRS provides a unique neuromonitoring platform to explore neurovascular coupling mechanisms. In this paper, we present a novel pipeline for the integrated analysis of bNIRS and EEG signals, and demonstrate its use on multi-channel bNIRS data recorded with concurrent EEG on healthy adults during a visual stimulation task. We introduce the use of the Finite Impulse Response functions within the General Linear Model for bNIRS and show its feasibility to statistically localize the haemodynamic and metabolic activity in the occipital cortex. Moreover, our results suggest that the fusion of haemodynamic and metabolic measures unveils additional information on brain functioning over haemodynamic imaging alone. The cross-correlation-based analysis of interrelationships between electrical (EEG) and haemodynamic/metabolic (bNIRS) activity revealed that the bNIRS metabolic signal offers a unique marker of brain activity, being more closely coupled to the neuronal EEG response.

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