Andrzej Foik | University of California, Irvine (original) (raw)
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Sorbonne Université, Université Pierre et Marie Curie & CNRS
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Papers by Andrzej Foik
Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2014, 2014
ABSTRACT Correlation methods were used to characterize the activity of single neurons and network... more ABSTRACT Correlation methods were used to characterize the activity of single neurons and network connections in three subcortical structures of the cat visual system. Autocorrelation analysis performed on spike trains of single cells recorded from the lateral geniculate and perigeniculate nuclei showed the presence of bursts of high-frequency oscillations ranging from 100 to 550 Hz in their spontaneous activity. Autocorrelation performed on spike trains of single cells recorded from the superior colliculus also revealed oscillations, but in the frequency range of 10 - 90 Hz, both in the spontaneous and visually evoked neuronal activity. The presence of oscillations was confirmed with spectral analysis and a shift predictor was used to distinguish between stimulus-locked and stimulus-independent oscillations in visually evoked activities. Additionally, a crosscorrelation analysis performed on two spike trains recorded from the same electrode or pairs of electrodes in the superior colliculus, revealed a common input from an external source and the presence of inhibitory interactions in the neuronal network.
PLoS ONE, 2014
Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the st... more Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the stimulus. In order to characterize the temporal frequency modulation in the cat's ascending tectofugal visual system, we recorded the activity of single neurons in the superior colliculus, the suprageniculate nucleus, and the anterior ectosylvian cortex during visual stimulation with drifting sine-wave gratings. In response to such stimuli, neurons in each structure showed an increase in firing rate and/or oscillatory modulated firing at the temporal frequency of the stimulus (phase sensitivity). To obtain a more complete characterization of the neural responses in spatiotemporal frequency domain, we analyzed the mean firing rate and the strength of the oscillatory modulations measured by the standardized Fourier component of the response at the temporal frequency of the stimulus. We show that the spatiotemporal stimulus parameters that elicit maximal oscillations often differ from those that elicit a maximal discharge rate. Furthermore, the temporal modulation and discharge-rate spectral receptive fields often do not overlap, suggesting that the detection range for visual stimuli provided jointly by modulated and unmodulated response components is larger than the range provided by a one response component.
Investigative ophthalmology & visual science, Jan 3, 2015
Purpose: Little is known about the physiological mechanisms underlying the reported therapeutic e... more Purpose: Little is known about the physiological mechanisms underlying the reported therapeutic effects of transorbital alternating current stimulation (ACS) in vision restoration, nor the origin of the recorded electrically evoked potentials (EEPs) during such stimulation. We examined the issue of EEP origin and electrode configuration for transorbital ACS and characterized the physiological responses to CS in different structures of the visual system. Methods: We recorded visual evoked potentials (VEPs) and EEPs from the rat retina, visual thalamus, tectum, and visual cortex. VEPs were evoked by light flashes and EEPs were evoked by electric stimuli delivered by two electrodes placed either together on the same eye or on the eyeball and in the neck. EEPs and VEPs were recorded before and after bilateral intraorbital injections of tetrodotoxin (TTX) that blocked retinal ganglion cell activity. Results: TTX abolished VEPs at all levels in the visual pathway, confirming successful bl...
Frontiers in Behavioral Neuroscience, 1970
Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2014, 2014
ABSTRACT Correlation methods were used to characterize the activity of single neurons and network... more ABSTRACT Correlation methods were used to characterize the activity of single neurons and network connections in three subcortical structures of the cat visual system. Autocorrelation analysis performed on spike trains of single cells recorded from the lateral geniculate and perigeniculate nuclei showed the presence of bursts of high-frequency oscillations ranging from 100 to 550 Hz in their spontaneous activity. Autocorrelation performed on spike trains of single cells recorded from the superior colliculus also revealed oscillations, but in the frequency range of 10 - 90 Hz, both in the spontaneous and visually evoked neuronal activity. The presence of oscillations was confirmed with spectral analysis and a shift predictor was used to distinguish between stimulus-locked and stimulus-independent oscillations in visually evoked activities. Additionally, a crosscorrelation analysis performed on two spike trains recorded from the same electrode or pairs of electrodes in the superior colliculus, revealed a common input from an external source and the presence of inhibitory interactions in the neuronal network.
PLoS ONE, 2014
Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the st... more Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the stimulus. In order to characterize the temporal frequency modulation in the cat's ascending tectofugal visual system, we recorded the activity of single neurons in the superior colliculus, the suprageniculate nucleus, and the anterior ectosylvian cortex during visual stimulation with drifting sine-wave gratings. In response to such stimuli, neurons in each structure showed an increase in firing rate and/or oscillatory modulated firing at the temporal frequency of the stimulus (phase sensitivity). To obtain a more complete characterization of the neural responses in spatiotemporal frequency domain, we analyzed the mean firing rate and the strength of the oscillatory modulations measured by the standardized Fourier component of the response at the temporal frequency of the stimulus. We show that the spatiotemporal stimulus parameters that elicit maximal oscillations often differ from those that elicit a maximal discharge rate. Furthermore, the temporal modulation and discharge-rate spectral receptive fields often do not overlap, suggesting that the detection range for visual stimuli provided jointly by modulated and unmodulated response components is larger than the range provided by a one response component.
Investigative ophthalmology & visual science, Jan 3, 2015
Purpose: Little is known about the physiological mechanisms underlying the reported therapeutic e... more Purpose: Little is known about the physiological mechanisms underlying the reported therapeutic effects of transorbital alternating current stimulation (ACS) in vision restoration, nor the origin of the recorded electrically evoked potentials (EEPs) during such stimulation. We examined the issue of EEP origin and electrode configuration for transorbital ACS and characterized the physiological responses to CS in different structures of the visual system. Methods: We recorded visual evoked potentials (VEPs) and EEPs from the rat retina, visual thalamus, tectum, and visual cortex. VEPs were evoked by light flashes and EEPs were evoked by electric stimuli delivered by two electrodes placed either together on the same eye or on the eyeball and in the neck. EEPs and VEPs were recorded before and after bilateral intraorbital injections of tetrodotoxin (TTX) that blocked retinal ganglion cell activity. Results: TTX abolished VEPs at all levels in the visual pathway, confirming successful bl...
Frontiers in Behavioral Neuroscience, 1970