Consistent and precise localization of brain activity in human primary visual cortex by MEG and fMRI

NeuroImage ◽  
2003 ◽  
Vol 18 (3) ◽  
pp. 595-609 ◽  
Author(s):  
F. Moradi ◽  
L.C. Liu ◽  
K. Cheng ◽  
R.A. Waggoner ◽  
K. Tanaka ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Brain Activity ◽  
Precise Localization

scholarly journals Retinotopic-like maps of spatial sound in primary ‘visual’ cortex of blind human echolocators

2019 ◽  
Vol 286 (1912) ◽  
pp. 20191910 ◽  
Author(s):  
Liam J. Norman ◽  
Lore Thaler
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Functional Organization ◽  
Brain Activity ◽  
Sensory Modality ◽  
Spatial Sound ◽  
Sensory Cortices ◽  
Spatial Locations ◽  
The Brain ◽  
Rule Out

The functional specializations of cortical sensory areas were traditionally viewed as being tied to specific modalities. A radically different emerging view is that the brain is organized by task rather than sensory modality, but it has not yet been shown that this applies to primary sensory cortices. Here, we report such evidence by showing that primary ‘visual’ cortex can be adapted to map spatial locations of sound in blind humans who regularly perceive space through sound echoes. Specifically, we objectively quantify the similarity between measured stimulus maps for sound eccentricity and predicted stimulus maps for visual eccentricity in primary ‘visual’ cortex (using a probabilistic atlas based on cortical anatomy) to find that stimulus maps for sound in expert echolocators are directly comparable to those for vision in sighted people. Furthermore, the degree of this similarity is positively related with echolocation ability. We also rule out explanations based on top-down modulation of brain activity—e.g. through imagery. This result is clear evidence that task-specific organization can extend even to primary sensory cortices, and in this way is pivotal in our reinterpretation of the functional organization of the human brain.

scholarly journals Synchronous SSVEP Data Acquisition System

2014 ◽  
Vol 14 (3) ◽  
Author(s):  
Sławomir Kotyra ◽  
Grzegorz M. Wójcik ◽  
Marcin Smolira
Keyword(s):  
Visual Cortex ◽  
Steady State ◽  
Data Acquisition ◽  
Primary Visual Cortex ◽  
Brain Activity ◽  
Data Acquisition System ◽  
Visually Evoked Potentials ◽  
Light Stimulation ◽  
Simple Method ◽  
Stimulation Of

AbstractSteady State Visually Evoked Potentials have been known for several decades and they appear in the primary visual cortex of brain as a result of light stimulation of the sense of sight. In this article a simple method for electroencephalographic data acquisition is presented. The system is based on the DSM-51 unit connected to goggles with blinking diodes and Mindset-1000 EEG amplifier with 16 channels. We present self-developed hardware and method of effective synchronization for the light stimulation and brain activity recording.

scholarly journals In vivo brain activity imaging of interactively locomoting mice

2017 ◽  
Author(s):  
Shigenori Inagaki ◽  
Masakazu Agetsuma ◽  
Shinya Ohara ◽  
Toshio Iijima ◽  
Tetsuichi Wazawa ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Brain Activity ◽  
Field Potential ◽  
Brain Functions ◽  
Wide Range ◽  
Novel Method ◽  
Freely Moving ◽  
Voltage Indicator

AbstractElectrophysiological field potential dynamics have been widely used to investigate brain functions and related psychiatric disorders. Conversely, however, various technical limitations of conventional recording methods have limited its applicability to freely moving subjects, especially when they are in a group and socially interacting with each other. Here, we propose a new method to overcome these technical limitations by introducing a bioluminescent voltage indicator called LOTUS-V. Using our simple and fiber-free recording method, named “SNIPA,” we succeeded in capturing brain activity in freely-locomotive mice, without the need for complicated instruments. This novel method further allowed us to simultaneously record from multiple independently-locomotive animals that were interacting with one another. Further, we successfully demonstrated that the primary visual cortex was activated during the interaction. This methodology will further facilitate a wide range of studies in neurobiology and psychiatry.

Sleep is more than rest for plasticity in the human cortex

SLEEP ◽  
2021 ◽  
Author(s):  
Christoph Nissen ◽  
Hannah Piosczyk ◽  
Johannes Holz ◽  
Jonathan G Maier ◽  
Lukas Frase ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Neural Plasticity ◽  
Discrimination Task ◽  
Cortical Plasticity ◽  
Brain Activity ◽  
Nrem Sleep ◽  
Human Cortex ◽  
Healthy Humans ◽  
Active Wakefulness

Abstract Sleep promotes adaptation of behavior and underlying neural plasticity in comparison to active wakefulness. However, the contribution of its two main characteristics, sleep-specific brain activity and reduced stimulus interference, remains unclear. We tested healthy humans on a texture discrimination task, a proxy for neural plasticity in primary visual cortex, in the morning and retested them in the afternoon after a period of daytime sleep, passive waking with maximally reduced interference, or active waking. Sleep restored performance in direct comparison to both passive and active waking, in which deterioration of performance across repeated within-day testing has been linked to synaptic saturation in the primary visual cortex. No difference between passive and active waking was observed. Control experiments indicated that deterioration across wakefulness was retinotopically specific to the trained visual field and not due to unspecific performance differences. The restorative effect of sleep correlated with time spent in NREM sleep and with electroencephalographic slow wave energy, which is thought to reflect renormalization of synaptic strength. The results indicate that sleep is more than a state of reduced stimulus interference, but that sleep-specific brain activity restores performance by actively refining cortical plasticity.

scholarly journals Cortical Oscillatory Dysrhythmias in Visual Snow Syndrome: A MEG Study

2021 ◽  
Author(s):  
Jenny L Hepschke ◽  
Robert A Seymour ◽  
Wei A He ◽  
Andrew Etchell ◽  
Paul F Sowman ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Brain Activity ◽  
Peak Frequency ◽  
Alpha Phase ◽  
Alpha Power ◽  
Gamma Peak ◽  
Gamma Power ◽  
Early Visual Cortex ◽  
Phase Amplitude

Visual Snow (VS) refers to the persistent visual experience of static in the whole visual field of both eyes. It is often reported by patients with migraine and co-occurs with conditions like tinnitus and tremor. The underlying pathophysiology of the condition is poorly understood. Previously we hypothesised, that VSS may be characterised by disruptions to rhythmical activity within the visual system. To test this, data from 18 patients diagnosed with visual snow syndrome (VSS), and 16 matched controls, were acquired using Magnetoencephalography (MEG). Participants were presented with visual grating stimuli, known to elicit decreases in alpha-band (8-13Hz) power and increases in gamma-band power (40-70Hz). Data were mapped to source-space using a beamformer. Across both groups, decreased alpha power and increased gamma power localised to early visual cortex. Data from primary visual cortex (V1) were compared between groups. No differences were found in either alpha or gamma peak frequency or the magnitude of alpha power, p>.05. However, compared with controls, our VSS cohort displayed significantly increased V1 gamma power, p=.035. This new electromagnetic finding concurs with previous fMRI and PET findings suggesting that in VSS, the visual cortex is hyper-excitable. The coupling of alpha-phase to gamma amplitude (i.e., phase-amplitude coupling, PAC) within V1 was also quantified. Compared with controls, the VSS group had significantly reduced alpha-gamma PAC, p<.05, indicating a potential excitation-inhibition imbalance in VSS, as well as a potential disruption to top-down 'noise-cancellation' mechanisms. Overall, these results suggest that rhythmical brain activity in primary visual cortex is both hyperexcitable and disorganised in VSS, consistent with visual snow being a condition of thalamocortical dysrhythmia.

scholarly journals Visual physiology of the Layer 4 cortical circuitin silico

2018 ◽  
Author(s):  
Anton Arkhipov ◽  
Nathan W. Gouwens ◽  
Yazan N. Billeh ◽  
Sergey Gratiy ◽  
Ramakrishnan Iyer ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Brain Activity ◽  
Visual Stimuli ◽  
Quantitative Agreement ◽  
In Vivo Experiments ◽  
Model And Simulation ◽  
Layer 4 ◽  
Detailed Circuit

ABSTRACTDespite advances in experimental techniques and accumulation of large datasets concerning the composition and properties of the cortex, quantitative modeling of cortical circuits under in-vivo-like conditions remains challenging. Here we report and publicly release a biophysically detailed circuit model of layer 4 in the mouse primary visual cortex, receiving thalamo-cortical visual inputs. The 45,000-neuron model was subjected to a battery of visual stimuli, and results were compared to published work and new in vivo experiments. Simulations reproduced a variety of observations, including effects of optogenetic perturbations. Critical to the agreement between responses in silico and in vivo were the rules of functional synaptic connectivity between neurons. Interestingly, after extreme simplification the model still performed satisfactorily on many measurements, although quantitative agreement with experiments suffered. These results emphasize the importance of functional rules of cortical wiring and enable a next generation of data-driven models of in vivo neural activity and computations.AUTHOR SUMMARYHow can we capture the incredible complexity of brain circuits in quantitative models, and what can such models teach us about mechanisms underlying brain activity? To answer these questions, we set out to build extensive, bio-realistic models of brain circuitry employing systematic datasets on brain structure and function. Here we report the first modeling results of this project, focusing on the layer 4 of the primary visual cortex (V1) of the mouse. Our simulations reproduced a variety of experimental observations in a large battery of visual stimuli. The results elucidated circuit mechanisms determining patters of neuronal activity in layer 4 – in particular, the roles of feedforward thalamic inputs and specific patterns of intracortical connectivity in producing tuning of neuronal responses to the orientation of motion. Simplification of neuronal models led to specific deficiencies in reproducing experimental data, giving insights into how biological details contribute to various aspects of brain activity. To enable future development of more sophisticated models, we make the software code, the model, and simulation results publicly available.

scholarly journals Altered Spontaneous Brain Activity of Children with Unilateral Amblyopia: A Resting State fMRI Study

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Peishan Dai ◽  
Jinlong Zhang ◽  
Jing Wu ◽  
Zailiang Chen ◽  
Beiji Zou ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Resting State ◽  
Function Analysis ◽  
Brain Activity ◽  
Brain Regions ◽  
Angular Gyrus ◽  
Spontaneous Brain Activity ◽  
Analysis Methods ◽  
Local Brain

Objective. This study is aimed at investigating differences in local brain activity and functional connectivity (FC) between children with unilateral amblyopia and healthy controls (HCs) by using resting state functional magnetic resonance imaging (rs-fMRI). Methods. Local activity and FC analysis methods were used to explore the altered spontaneous brain activity of children with unilateral amblyopia. Local brain function analysis methods included the amplitude of low-frequency fluctuation (ALFF). FC analysis methods consisted of the FC between the primary visual cortex (PVC-FC) and other brain regions and the FC network between regions of interest (ROIs-FC) selected by independent component analysis. Results. The ALFF in the bilateral frontal, temporal, and occipital lobes in the amblyopia group was lower than that in the HCs. The weakened PVC-FC was mainly concentrated in the frontal lobe and the angular gyrus. The ROIs-FC between the default mode network, salience network, and primary visual cortex network (PVCN) were significantly reduced, whereas the ROIs-FC between the PVCN and the high-level visual cortex network were significantly increased in amblyopia. Conclusions. Unilateral amblyopia may reduce local brain activity and FC in the dorsal and ventral visual pathways and affect the top-down attentional control. Amblyopia may also alter FC between brain functional networks. These findings may help understand the pathological mechanisms of children with amblyopia.

Neurofeedback Training of Gamma Oscillations in Monkey Primary Visual Cortex

2019 ◽  
Vol 29 (11) ◽  
pp. 4785-4802 ◽  
Author(s):  
L Chauvière ◽  
W Singer
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Stimulation ◽  
Brain Activity ◽  
Gamma Oscillations ◽  
Gamma Activity ◽  
Oscillatory Activity ◽  
Feedback Signal ◽  
Sensory Cortices ◽  
Distinct Frequency

Abstract In humans, neurofeedback (NFB) training has been used extensively and successfully to manipulate brain activity. Feedback signals were derived from EEG, fMRI, MEG, and intracranial recordings and modifications were obtained of the BOLD signal, of the power of oscillatory activity in distinct frequency bands and of single unit activity. The purpose of the present study was to examine whether neuronal activity could also be controlled by NFB in early sensory cortices whose activity is thought to be influenced mainly by sensory input rather than volitional control. We trained 2 macaque monkeys to enhance narrow band gamma oscillations in the primary visual cortex by providing them with an acoustic signal that reflected the power of gamma oscillations in a preselected band and rewarding increases of the feedback signal. Oscillations were assessed from local field potentials recorded with chronically implanted microelectrodes. Both monkeys succeeded to raise gamma activity in the absence of visual stimulation in the selected frequency band and at the site from which the NFB signal was derived. This suggests that top–down signals are not confined to just modulate stimulus induced responses but can actually drive or facilitate the gamma generating microcircuits even in a primary sensory area.

scholarly journals V1 encodes the perceived position of static but not moving objects

2021 ◽  
Author(s):  
Man-Ling Ho ◽  
D. Samuel Schwarzkopf
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Moving Objects ◽  
Brain Activity ◽  
Stimulus Position ◽  
Apparent Position ◽  
Lyer Illusion ◽  
Neural Signature ◽  
Per Se

Brain activity in retinotopic cortex reflects illusory changes in stimulus position. Is this neural signature a general code for apparent position? Here we show that responses in primary visual cortex (V1) are consistent with perception of the Muller-Lyer illusion; however, we found no such signature for another striking illusion, the curveball effect. This demonstrates that V1 does not encode apparent position per se.

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