Effects of norepinephrine on the activity of visual neurons in the superior colliculus of the hamster

1999 ◽  
Vol 16 (3) ◽  
pp. 541-555 ◽  
Author(s):  
YI ZHANG ◽  
RICHARD D. MOONEY ◽  
ROBERT W. RHOADES
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Superior Colliculus ◽  
Visual Stimulation ◽  
Optic Chiasm ◽  
Evoked Responses ◽  
Visual Responses ◽  
Signal To Noise ◽  
Direct Stimulation ◽  
Stimulation Of

Single-unit recording and micropressure ejection techniques were used to test the effects of norepinephrine (NE) on the responses of neurons in the superficial layers (the stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). Application of NE suppressed visually evoked responses by ≥30% in 75% of 40 neurons tested and produced ≥30% augmentation of responses in only 5%. The decrement in response strength was mimicked by application of the α2 adrenoceptor agonist, p-aminoclonidine, the nonspecific β agonist, isoproterenol, and the β1 agonist, dobutamine. These agents had similar effects on responses evoked by electrical stimulation of the optic chiasm and visual cortex. The α1 agonist, methoxamine, augmented the light-evoked responses of 53% of 49 SC cells by ≥30%, but had little effect on responses evoked by electrical stimulation of optic chiasm or visual cortex. The effects of adrenergic agonists upon the glutamate-evoked responses of SC cells that were synaptically “isolated” by concurrent application of Mg2+ were similar to those obtained during visual stimulation. Analysis of effects of NE on visually evoked and background activity indicated that application of this amine did not significantly enhance signal-to-noise ratios for most superficial layer SC neurons, and signal-to-noise ratios were in some cases reduced. These results indicate that NE acts primarily through α2 and β1 receptors to suppress the visual responses of SC neurons. Activation of either of these receptors reduces the responses of SC neurons to either of their two major visual inputs as well as to direct stimulation by glutamate, and it would thus appear that these effects are primarily postsynaptic.

Effects of angiotensin II on visual neurons in the superficial laminae of the hamster's superior colliculus

1994 ◽  
Vol 11 (6) ◽  
pp. 1163-1173 ◽  
Author(s):  
Richard D. Mooney ◽  
Yi Zhang ◽  
Robert W. Rhoades
Keyword(s):  
Electrical Stimulation ◽  
Angiotensin Ii ◽  
Superior Colliculus ◽  
Visual Stimulation ◽  
Optic Chiasm ◽  
Superficial Layer ◽  
Receptor Subtypes ◽  
Visual Responses ◽  
Visual Neurons ◽  
Stimulation Of

AbstractSuperficial layer superior colliculus (SC) neurons were recorded extracellularly with multibarreled recording/ejecting micropipettes. Angiotensin II was delivered via micropressure ejection during visual stimulation (n = 215 cells), or during electrical stimulation of either the optic chiasm (OX; n = 150 cells) or visual cortex (CTX; n = 42 cells). Application of angiotensin II decreased visual responses of SC cells to 43.8% ± 30.7% (mean ± S.D.) and reduced responses to electrical stimulation of the OX and CTX to 58.6% ± 34.1% and 43.8% ± 30.7% of control values, respectively. Angiotensin II enhanced responses by at least 30% in only 6 cells (1.5%). Of the 35 neurons tested with both OX and CTX stimulation, the correlation of evoked response suppression by angiotensin II was highly significant (r = 0.69; P < 0.001). This suggests that the suppressive effects of angiotensin II were common to both pathways. To test whether the inhibitory effects of angiotensin II were presynaptic or postsynaptic, Mg2+ ions were ejected iontophoretically to abolish synaptic responses, and the neurons were activated by iontophoresis of glutamate and then tested with angiotensin II. Angiotensin II reduced the glutamate-evoked responses to an average 29.1% ± 21.1% of control values (n = 9 cells). This suggests that the site of action of angiotensin II is most likely postsynaptic. To identify which receptors were involved in these effects, angiotensin II was ejected concurrently with the AT1 antagonist Losartan (DUP753) or with either of two AT2 antagonists, CGP42112A or PD123177. Losartan antagonized the action of angiotensin II in 65.6% of the cells tested (n = 99) and CGP42112A and PD123177 had antagonistic effects in 58% (n = 65) and 60% (n = 5), respectively. Both classes of antagonists were tested in 29 cells; and there was no significant correlation between their effectiveness. These results suggest that both AT1, and AT2 receptors may independently mediate the suppressive effects of angiotensin II, and that collicular neurons may have either or both receptor subtypes.

Effects of neurotensin on visual neurons in the superficial laminae of the hamster's superior colliculus

1996 ◽  
Vol 13 (2) ◽  
pp. 237-246 ◽  
Author(s):  
Yi Zhang ◽  
Richard D. ◽  
Carol A. Bennett-Clarke ◽  
Robert W. Rhoades
Keyword(s):  
Electrical Stimulation ◽  
Superior Colliculus ◽  
Visual Stimulation ◽  
Optic Chiasm ◽  
Superficial Layer ◽  
Visual Responses ◽  
Unit Recording ◽  
Visual Neurons ◽  
Standard Deviation Range ◽  
Stimulation Of

AbstractAutoradiography with 125I-neurotensin in normal and enucleated hamsters was used to define the distribution of receptors for this peptide in the superficial layers of the superior colliculus (SC). Neurotensin binding sites were densely distributed in the stratum griseum superficiale (SGS), and results from the enucleated animals indicated that they were not located on retinal axons. The effects of neurotensin on individual superficial layer cells were tested in single-unit recording experiments. Neurotensin was delivered via micropressure ejection during visual stimulation (n = 75 cells), or during electrical stimulation of either the optic chiasm (OX; n = 47 cells) or visual cortex (CTX; n = 29 cells). In comparison with control values, application of neurotensin decreased visual responses of all SC cells tested to 54.1 ± 34.9% (mean ± standard deviation; range of decrement 7.5 to 100%; nine cells showed no effect or an increase in visual activity, which for four of these was ≥30%). Neurotensin application also reduced responses to electrical stimulation of either OX or CTX, respectively, to 65.8 ± 36.5% of control values (range of decrement 2.6 to 97.4%; 12 neurons showed a weak increment ≤ 30%) and 68.0 ± 38.5% (range of decrement 3.3 to 100%; five cells showed no effect or an increment, in one case ≥ 30%). Of the 25 neurons tested with both OX and CTX stimulation, the correlation of evoked response suppression by neurotensin was highly significant (r = 0.70; P < 0.001). This suggests that the suppressive effects of neurotensin were common to both pathways. To test whether the inhibitory effects of neurotensin were presynaptic or postsynaptic, Mg2+ ions were ejected iontophoretically to abolish synaptic responses, and the neurons (n = 16) were activated by iontophoresis of glutamate and then tested with neurotensin. Neurotensin reduced the glutamate-evoked responses to an average 59.3 ± 37.9% of control values (range 2.3 to 92.5%; one cell showed an increment >30%). This result suggests that the site of action of neurotensin is most likely postsynaptic.

Corticogeniculate neurons, corticotectal neurons, and suspected interneurons in visual cortex of awake rabbits: receptive-field properties, axonal properties, and effects of EEG arousal

1987 ◽  
Vol 57 (4) ◽  
pp. 977-1001 ◽  
Author(s):  
H. A. Swadlow ◽  
T. G. Weyand
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Receptive Field ◽  
Receptive Fields ◽  
Spontaneous Firing ◽  
Visual Responses ◽  
Firing Rates ◽  
Axonal Conduction ◽  
Conduction Velocities ◽  
Stimulation Of

The intrinsic stability of the rabbit eye was exploited to enable receptive-field analysis of antidromically identified corticotectal (CT) neurons (n = 101) and corticogeniculate (CG) neurons (n = 124) in visual area I of awake rabbits. Eye position was monitored to within 1/5 degrees. We also studied the receptive-field properties of neurons synaptically activated via electrical stimulation of the dorsal lateral geniculate nucleus (LGNd). Whereas most CT neurons had either complex (59%) or motion/uniform (15%) receptive fields, we also found CT neurons with simple (9%) and concentric (4%) receptive fields. Most complex CT cells were broadly tuned to both stimulus orientation and velocity, but only 41% of these cells were directionally selective. We could elicit no visual responses from 6% of CT cells, and these cells had significantly lower conduction velocities than visually responsive CT cells. The median spontaneous firing rates for all classes of CT neurons were 4-8 spikes/s. CG neurons had primarily simple (60%) and concentric (9%) receptive fields, and none of these cells had complex receptive fields. CG simple cells were more narrowly tuned to both stimulus orientation and velocity than were complex CT cells, and most (85%) were directionally selective. Axonal conduction velocities of CG neurons (mean = 1.2 m/s) were much lower than those of CT neurons (mean = 6.4 m/s), and CG neurons that were visually unresponsive (23%) had lower axonal conduction velocities than did visually responsive CG neurons. Some visually unresponsive CG neurons (14%) responded with saccadic eye movements. The median spontaneous firing rates for all classes of CG neurons were less than 1 spike/s. All neurons synaptically activated via LGNd stimulation at latencies of less than 2.0 ms had receptive fields that were not orientation selective (89% motion/uniform, 11% concentric), whereas most cells with orientation-selective receptive fields had considerably longer synaptic latencies. Most short-latency motion/uniform neurons responded to electrical stimulation of the LGNd (and visual area II) with a high-frequency burst (500-900 Hz) of three or more spikes. Action potentials of these neurons were of short duration, thresholds of synaptic activation were low, and spontaneous firing rates were the highest seen in rabbit visual cortex. These properties are similar to those reported for interneurons in several regions in mammalian central nervous system. Nonvisual sensory stimuli that resulted in electroencephalographic arousal (hippocampal theta activity) had a profound effect on the visual responses of many visual cortical neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of serotonin on retinotectal-, corticotectal-, and glutamate-induced activity in the superior colliculus of the hamster

1993 ◽  
Vol 70 (2) ◽  
pp. 723-732 ◽  
Author(s):  
X. Huang ◽  
R. D. Mooney ◽  
R. W. Rhoades
Keyword(s):  
Superior Colliculus ◽  
Optic Chiasm ◽  
Superficial Layer ◽  
Response Suppression ◽  
Visual Response ◽  
Evoked Responses ◽  
Average Response ◽  
Visual Responses ◽  
Unit Recording ◽  
Visual Cortical

1. Single-unit recording and iontophoretic techniques were used to test the effects of serotonin (5-HT) on the responses of neurons in the superficial layers (the stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). 2. Iontophoresis of 5-HT produced a visual response suppression of 40% or greater in 78.1% (n = 50) of 64 neurons tested. 5-HT did not augment the visual responses of any of the cells tested. The average response suppression was 75.3 +/- 21.2% (mean +/- S.D.). 3. Iontophoresis of 5-HT had significantly different effects on activation of SC cells by optic chiasm (OX) and visual cortical (CTX) stimulation. Application of 5-HT suppressed the OX-evoked responses of 96.9% (n = 31) of the 32 SC cells tested by at least 40%, and the average response suppression for all 32 neurons tested was 87.1 +/- 22.5%. Application of 5-HT suppressed the responses of only 35.7% (n = 10) of the 28 cells tested with CTX stimulation by at least 40%. The average response suppression for all 28 cells was 35.3 +/- 38.8%. 4. The effects of 5-HT on the glutamate-evoked responses of SC cells that were synaptically "isolated" by concurrent application of Mg2+ were also evaluated. Application of 5-HT produced a response suppression > or = 40% in 29.7% (n = 19) of the 64 neurons tested under these conditions. The average response suppression for all of the cells tested was 28.4 +/- 35.7%. This effect of 5-HT was significantly weaker than that on visually evoked responses of these neurons. 5. The present results demonstrate that 5-HT markedly depresses the visual responses of most superficial layer SC neurons. They suggest further that much of this effect is mediated by presynaptic inhibition of retinotectal transmission.

scholarly journals Frontal Eye Field Neurons Orthodromically Activated From the Superior Colliculus

1998 ◽  
Vol 80 (6) ◽  
pp. 3331-3335 ◽  
Author(s):  
Marc A. Sommer ◽  
Robert H. Wurtz
Keyword(s):  
Electrical Stimulation ◽  
Superior Colliculus ◽  
Direct Evidence ◽  
Visual Stimulation ◽  
Saccadic Eye Movements ◽  
Frontal Eye Field ◽  
Anatomical Studies ◽  
Eye Field ◽  
To Receive ◽  
Stimulation Of

Sommer, Marc A. and Robert H. Wurtz. Frontal eye field neurons orthodromically activated from the superior colliculus. J. Neurophysiol. 80: 3331–3333, 1998. Anatomical studies have shown that the frontal eye field (FEF) and superior colliculus (SC) of monkeys are reciprocally connected, and a physiological study described the signals sent from the FEF to the SC. Nothing is known, however, about the signals sent from the SC to the FEF. We physiologically identified and characterized FEF neurons that are likely to receive input from the SC. Fifty-two FEF neurons were found that were orthodromically activated by electrical stimulation of the intermediate or deeper layers of the SC. All the neurons that we tested ( n = 34) discharged in response to visual stimulation. One-half also discharged when saccadic eye movements were made. This provides the first direct evidence that the ascending pathway from SC to FEF might carry visual- and saccade-related signals. Our findings support a hypothesis that the SC and the FEF interact bidirectionally during the events leading up to saccade generation.

scholarly journals Focal Electrical Stimulation of Cortical Functional Networks

2020 ◽  
Vol 30 (10) ◽  
pp. 5532-5543 ◽  
Author(s):  
Jia Ming Hu ◽  
Mei Zhen Qian ◽  
Hisashi Tanigawa ◽  
Xue Mei Song ◽  
Anna Wang Roe
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Functional Organization ◽  
Visual Stimulation ◽  
Prosthetic Design ◽  
Single Feature ◽  
Selective Targeting ◽  
Visual Cortical ◽  
The Brain ◽  
Stimulation Of

Abstract Traditional electrical stimulation of brain tissue typically affects relatively large volumes of tissue spanning multiple millimeters. This low spatial resolution stimulation results in nonspecific functional effects. In addition, a primary shortcoming of these designs was the failure to take advantage of inherent functional organization in the cerebral cortex. Here, we describe a new method to electrically stimulate the brain which achieves selective targeting of single feature-specific domains in visual cortex. We provide evidence that this paradigm achieves mesoscale, functional network-specificity, and intensity dependence in a way that mimics visual stimulation. Application of this approach to known feature domains (such as color, orientation, motion, and depth) in visual cortex may lead to important functional improvements in the specificity and sophistication of brain stimulation methods and has implications for visual cortical prosthetic design.

scholarly journals Decoding network-mediated retinal response to electrical stimulation: implications for fidelity of prosthetic vision

2020 ◽  
Author(s):  
Elton Ho ◽  
Alex Shmakov ◽  
Daniel Palanker
Keyword(s):  
Electrical Stimulation ◽  
Visual Stimulation ◽  
Ganglion Cells ◽  
Signal To Noise Ratio ◽  
Population Level ◽  
Sufficient Information ◽  
Visual Responses ◽  
Natural Vision ◽  
Retinal Response ◽  
Stimulation Of

AbstractObjectivePatients with the photovoltaic subretinal implant PRIMA demonstrated letter acuity by ~0.1 logMAR worse than the sampling limit for 100μm pixels (1.3 logMAR) and performed slower than healthy subjects, which exceeded the sampling limit at equivalently pixelated images by ~0.2 logMAR. To explore the underlying differences between the natural and prosthetic vision, we compare the fidelity of the retinal response to visual and subretinal electrical stimulation through single-cell modeling and ensemble decoding.ApproachResponses of the retinal ganglion cells (RGC) to optical or electrical (1mm diameter arrays, 75μm pixels) white noise stimulation in healthy and degenerate rat retinas were recorded via MEA. Each RGC was fit with linear-non-linear (LN) and convolutional neural network (CNN) models. To characterize RGC noise level, we compared statistics of the spike-triggered average (STA) in RGCs responding to electrical or visual stimulation of healthy and degenerate retinas. At the population level, we constructed a linear decoder to determine the certainty with which the ensemble of RGCs can support the N-way discrimination tasks.Main resultsAlthough LN and CNN models can match the natural visual responses pretty well (correlation ~0.6), they fit significantly worse to spike timings elicited by electrical stimulation of the healthy retina (correlation ~0.15). In the degenerate retina, response to electrical stimulation is equally bad. The signal-to-noise ratio of electrical STAs in degenerate retinas matched that of the natural responses when 78±6.5% of the spikes were replaced with random timing. However, the noise in RGC responses contributed minimally to errors in the ensemble decoding. The determining factor in accuracy of decoding was the number of responding cells. To compensate for fewer responding cells under electrical stimulation than in natural vision, larger number of presentations of the same stimulus are required to deliver sufficient information for image decoding.SignificanceSlower than natural pattern identification by patients with the PRIMA implant may be explained by the lower number of electrically activated cells than in natural vision, which is compensated by a larger number of the stimulus presentations.

Electrical stimulation of retinal neurons in epiretinal and subretinal configuration using a multicapacitor array

2012 ◽  
Vol 107 (10) ◽  
pp. 2742-2755 ◽  
Author(s):  
Max Eickenscheidt ◽  
Martin Jenkner ◽  
Roland Thewes ◽  
Peter Fromherz ◽  
Günther Zeck
Keyword(s):  
Electrical Stimulation ◽  
Ganglion Cells ◽  
Ex Vivo ◽  
Biophysical Model ◽  
Retinal Neurons ◽  
Direct Stimulation ◽  
Tungsten Electrode ◽  
Partial Restoration ◽  
Low Amplitude ◽  
Stimulation Of

Electrical stimulation of retinal neurons offers the possibility of partial restoration of visual function. Challenges in neuroprosthetic applications are the long-term stability of the metal-based devices and the physiological activation of retinal circuitry. In this study, we demonstrate electrical stimulation of different classes of retinal neurons with a multicapacitor array. The array—insulated by an inert oxide—allows for safe stimulation with monophasic anodal or cathodal current pulses of low amplitude. Ex vivo rabbit retinas were interfaced in either epiretinal or subretinal configuration to the multicapacitor array. The evoked activity was recorded from ganglion cells that respond to light increments by an extracellular tungsten electrode. First, a monophasic epiretinal cathodal or a subretinal anodal current pulse evokes a complex burst of action potentials in ganglion cells. The first action potential occurs within 1 ms and is attributed to direct stimulation. Within the next milliseconds additional spikes are evoked through bipolar cell or photoreceptor depolarization, as confirmed by pharmacological blockers. Second, monophasic epiretinal anodal or subretinal cathodal currents elicit spikes in ganglion cells by hyperpolarization of photoreceptor terminals. These stimuli mimic the photoreceptor response to light increments. Third, the stimulation symmetry between current polarities (anodal/cathodal) and retina-array configuration (epi/sub) is confirmed in an experiment in which stimuli presented at different positions reveal the center-surround organization of the ganglion cell. A simple biophysical model that relies on voltage changes of cell terminals in the transretinal electric field above the stimulation capacitor explains our results. This study provides a comprehensive guide for efficient stimulation of different retinal neuronal classes with low-amplitude capacitive currents.

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