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The laminar cortex model: a new continuum cortex model incorporating laminar architecture.

Du J, Vegh V, Reutens DC - PLoS Comput. Biol. (2012)

Bottom Line: The power spectra of LFPs were calculated and compared with existing empirical data.During simulated intermittent light stimulation, the LCM captured the fundamental as well as high order harmonics as previously reported.The power spectrum expected with a reduction in layer IV neurons, often observed with focal cortical dysplasias associated with epilepsy was also simulated.

View Article: PubMed Central - PubMed

Affiliation: The University of Queensland, Centre for Advanced Imaging, Brisbane, Queensland, Australia.

ABSTRACT
Local field potentials (LFPs) are widely used to study the function of local networks in the brain. They are also closely correlated with the blood-oxygen-level-dependent signal, the predominant contrast mechanism in functional magnetic resonance imaging. We developed a new laminar cortex model (LCM) to simulate the amplitude and frequency of LFPs. Our model combines the laminar architecture of the cerebral cortex and multiple continuum models to simulate the collective activity of cortical neurons. The five cortical layers (layer I, II/III, IV, V, and VI) are simulated as separate continuum models between which there are synaptic connections. The LCM was used to simulate the dynamics of the visual cortex under different conditions of visual stimulation. LFPs are reported for two kinds of visual stimulation: general visual stimulation and intermittent light stimulation. The power spectra of LFPs were calculated and compared with existing empirical data. The LCM was able to produce spontaneous LFPs exhibiting frequency-inverse (1/ƒ) power spectrum behaviour. Laminar profiles of current source density showed similarities to experimental data. General stimulation enhanced the oscillation of LFPs corresponding to gamma frequencies. During simulated intermittent light stimulation, the LCM captured the fundamental as well as high order harmonics as previously reported. The power spectrum expected with a reduction in layer IV neurons, often observed with focal cortical dysplasias associated with epilepsy was also simulated.

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The temporal variations and power spectrum of membrane potentials in cortical layers.Illustrated are (A) simulated field potentials of layer I, II/III, IV, V and VI, and (B) their corresponding power spectra for the general visual stimulation experiment, and (C) the average power spectra of LFPs in the gamma frequency (30–100 Hz, circles) and sub-gamma frequency (5–20 Hz, triangles) during spontaneous activity (black lines) and general stimulation (red lines). In (B) the black lines depict the resting state LFPs and red lines show the outcome of stimulation. The data are obtained using .
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pcbi-1002733-g005: The temporal variations and power spectrum of membrane potentials in cortical layers.Illustrated are (A) simulated field potentials of layer I, II/III, IV, V and VI, and (B) their corresponding power spectra for the general visual stimulation experiment, and (C) the average power spectra of LFPs in the gamma frequency (30–100 Hz, circles) and sub-gamma frequency (5–20 Hz, triangles) during spontaneous activity (black lines) and general stimulation (red lines). In (B) the black lines depict the resting state LFPs and red lines show the outcome of stimulation. The data are obtained using .

Mentions: Figure 5 shows the time courses of membrane potentials in a single run of the LCM. We found that in every cortical layer, membrane potentials oscillated with amplitudes of 0.05–0.2 mV; the amplitudes are much larger in layers IV and VI (around 0.1 mV) than in other layers (around 0.05 mV). During stimulation, the membrane potentials and its oscillation amplitudes increased in all layers except layer I. The power spectra in all layers, as provided in Figure 5, all showed inverse-square decreasing frequency background activities, which is observed experimentally [37]. Stimulation also increased high-frequency membrane potential oscillation of all deep layers.


The laminar cortex model: a new continuum cortex model incorporating laminar architecture.

Du J, Vegh V, Reutens DC - PLoS Comput. Biol. (2012)

The temporal variations and power spectrum of membrane potentials in cortical layers.Illustrated are (A) simulated field potentials of layer I, II/III, IV, V and VI, and (B) their corresponding power spectra for the general visual stimulation experiment, and (C) the average power spectra of LFPs in the gamma frequency (30–100 Hz, circles) and sub-gamma frequency (5–20 Hz, triangles) during spontaneous activity (black lines) and general stimulation (red lines). In (B) the black lines depict the resting state LFPs and red lines show the outcome of stimulation. The data are obtained using .
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475685&req=5

pcbi-1002733-g005: The temporal variations and power spectrum of membrane potentials in cortical layers.Illustrated are (A) simulated field potentials of layer I, II/III, IV, V and VI, and (B) their corresponding power spectra for the general visual stimulation experiment, and (C) the average power spectra of LFPs in the gamma frequency (30–100 Hz, circles) and sub-gamma frequency (5–20 Hz, triangles) during spontaneous activity (black lines) and general stimulation (red lines). In (B) the black lines depict the resting state LFPs and red lines show the outcome of stimulation. The data are obtained using .
Mentions: Figure 5 shows the time courses of membrane potentials in a single run of the LCM. We found that in every cortical layer, membrane potentials oscillated with amplitudes of 0.05–0.2 mV; the amplitudes are much larger in layers IV and VI (around 0.1 mV) than in other layers (around 0.05 mV). During stimulation, the membrane potentials and its oscillation amplitudes increased in all layers except layer I. The power spectra in all layers, as provided in Figure 5, all showed inverse-square decreasing frequency background activities, which is observed experimentally [37]. Stimulation also increased high-frequency membrane potential oscillation of all deep layers.

Bottom Line: The power spectra of LFPs were calculated and compared with existing empirical data.During simulated intermittent light stimulation, the LCM captured the fundamental as well as high order harmonics as previously reported.The power spectrum expected with a reduction in layer IV neurons, often observed with focal cortical dysplasias associated with epilepsy was also simulated.

View Article: PubMed Central - PubMed

Affiliation: The University of Queensland, Centre for Advanced Imaging, Brisbane, Queensland, Australia.

ABSTRACT
Local field potentials (LFPs) are widely used to study the function of local networks in the brain. They are also closely correlated with the blood-oxygen-level-dependent signal, the predominant contrast mechanism in functional magnetic resonance imaging. We developed a new laminar cortex model (LCM) to simulate the amplitude and frequency of LFPs. Our model combines the laminar architecture of the cerebral cortex and multiple continuum models to simulate the collective activity of cortical neurons. The five cortical layers (layer I, II/III, IV, V, and VI) are simulated as separate continuum models between which there are synaptic connections. The LCM was used to simulate the dynamics of the visual cortex under different conditions of visual stimulation. LFPs are reported for two kinds of visual stimulation: general visual stimulation and intermittent light stimulation. The power spectra of LFPs were calculated and compared with existing empirical data. The LCM was able to produce spontaneous LFPs exhibiting frequency-inverse (1/ƒ) power spectrum behaviour. Laminar profiles of current source density showed similarities to experimental data. General stimulation enhanced the oscillation of LFPs corresponding to gamma frequencies. During simulated intermittent light stimulation, the LCM captured the fundamental as well as high order harmonics as previously reported. The power spectrum expected with a reduction in layer IV neurons, often observed with focal cortical dysplasias associated with epilepsy was also simulated.

Show MeSH
Related in: MedlinePlus