Michael Ariel - Academia.edu (original) (raw)

Papers by Michael Ariel

Vision Research, Apr 1, 1997

Turtle eye movements were measured during full-field horizontal optokinetic stimulation under clo... more Turtle eye movements were measured during full-field horizontal optokinetic stimulation under closed and open loop conditions. Because these animals display unyoked slow-phase eye movement behavior, open loop stimulation could not be presented to a paralyzed eye, while monitoring the position of the contralateral eye. The turtle's optokinetic reflex loop was opened electronically by a continuous adjustment of the pattern's position that effectively canceled the effect of the movement of the recorded eye. The highest open loop gains (2-3) were observed at low speeds (<1 deg/see), demonstrating a more limited speed range and lower gain in turtle than in the mammalian optokinetic system. These results in the intact animal can be correlated with the visual response properties of the turtle's pretectum and accessory optic system recorded in vitro.

Journal of Neurophysiology, Feb 1, 2005

Responses of separate regions of rat cerebellar cortex (Cb) to inferior olive (IO) stimulation oc... more Responses of separate regions of rat cerebellar cortex (Cb) to inferior olive (IO) stimulation occur with the same latency despite large differences in climbing fiber (CF) lengths. Here, the olivocerebellar path of turtle was studied because its Cb is an unfoliated sheet on which measurements of latency and CF length can be made directly across its entire surface in vitro. During extracellular DC recordings at a given Cb position below the molecular layer, IO stimulation evoked a large negative field potential with a half-width duration of ϳ6.5 ms. On this response were smaller oscillations similar to complex spikes. The stimulating electrode was moved to map the IO and the CF path from the brain stem to the Cb. The contralateral brain stem region that evoked these responses was tightly circumscribed within the medulla, lateral and deep to the obex. This response remained when the brain stem was bathed in solutions that blocked synaptic transmission. The Cb response to IO stimulation had a peak latency of ϳ10 ms that was not dependent on the position of the recording electrode across the entire 8-mm rostrocaudal length of the Cb. However, for a constant Cb recording position, moving the stimulation across the midline to the ipsilateral brain stem and along the lateral wall of the fourth ventricle toward the peduncle did shorten the response latency. Therefore a synchronous Cb response to CF stimulation seems to be caused by changes in its conduction velocity within the entire cerebellar cortex but not within the brain stem.

Journal of Neurophysiology, May 1, 1991

1. The direct retinal input pathway to the basal optic nucleus (BON), the primary nucleus of the ... more 1. The direct retinal input pathway to the basal optic nucleus (BON), the primary nucleus of the turtle accessory optic system, was characterized physiologically. We tested the hypothesis that directional information encoded in retinal ganglion cells can influence the BON via a direct pathway. Using an in vitro whole-brain, eyes-attached preparation, we demonstrated the directness of this pathway by 1) antidromic activation of retinal ganglion cells from the contralateral BON and 2) orthodromic activation of the BON from the contralateral optic nerve. 2. Of 72 physiologically classified retinal ganglion cells, 9 could be antidromically activated from the contralateral BON with low current (less than 200 micro A). Eight of these cells were direction-sensitive (DS). The ninth cell did not respond to visual stimulus movement. The antidromic latencies ranged from 2.2 to 6.1 ms with a mean of 3.8 ms. These latencies were quite consistent for each cell, having an average SD of 0.08 ms. Moreover, consistent responses could always be recorded at stimulation rates up to 100 Hz. 3. With current stimulation of the contralateral optic nerve, the orthodromic conduction latency of 17 BON single units ranged from 2.5 to 6.6 ms with a mean of 4.6 ms. These latencies were more variable for an individual cell, having an average SD of 0.3 ms. Responses to individual current pulses could never be consistently evoked at stimulation rates greater than 40 Hz. 4. DS responses were recorded in BON single units after the removal of the dorsal midbrain, including the optic tectum and pretectum as well as the telencephalon. Three of these cells were activated orthodromically by current stimulation delivered to the contralateral optic nerve. Thus directional information reaches the BON via a direct projection from the contralateral retina. 5. Visual response properties of DS retinal ganglion cells were compared with those of BON cells to examine the transformations that take place in the brain stem. Applying a limaçon model to the responses of both DS retinal ganglion cells and BON cells revealed that both types of cells have very similar direction tuning. However, the distribution of maximally responsive directions in the retina may differ from that of the BON. 6. Because DS retinal ganglion cells project directly to the BON, and because BON cells lose their direction sensitivity after retinal application of GABA antagonists, we conclude that the BON receives essential directional information directly from DS retinal ganglion cells. This directional information in the BON may represent a retinal slip error signal necessary for retinal image stabilization.

Brain Research, Feb 1, 2004

Extracellular unit responses were recorded from the vestibular nucleus (VN) and medial longitudin... more Extracellular unit responses were recorded from the vestibular nucleus (VN) and medial longitudinal fasciculus during horizontal head rotation of an in vitro turtle brainstem in which the temporal bones remained attached. Units were characterized as type I or type II based on the responses to ipsiversive or contraversive rotation, respectively. Lidocaine injections (0.5-2 Al of 0.5%) into the root of the eighth cranial nerve within the cranium caused rapid effects on unit responses to head rotation. Responses of type I units were reduced by ipsilateral injection but enhanced following contralateral injection. On the other hand, type II units had their responses increased by ipsilateral injections yet decreased by contralateral injections. In approximately half of the type II cells, decrease of the contraversive response was accompanied by the appearance of latent ipsiversive activity. Our findings not only confirm that each eighth nerve has afferents that drive ipsiversive excitation of both vestibular nuclei but also suggest that both nerves compete to dominate a central neuron's vestibular response. These results may be inconsistent with the push-pull vestibular model in which each nerve drives the central neuron with a complementary response that enhances the vestibular output. An alternate model is described in which vestibular neurons receive bilateral excitation, and that excitatory input is antagonized by crossed inhibition during contraversive motion.

Journal of Neurophysiology, May 1, 1992

1. Eye movements were measured in three rhesus monkeys after monocular intravitreal injections of... more 1. Eye movements were measured in three rhesus monkeys after monocular intravitreal injections of picrotoxin, a gamma-aminobutyric acid (GABA) antagonist. The effects of this drug were tested when the animals were in a completely dark room, when they performed a smooth pursuit task, and when they viewed either a stationary pattern or a full-field optokinetic pattern rotating horizontally. 2. Between 15 and 20 min after the injection, a sustained conjugate spontaneous nystagmus developed in the dark, with the slow-phase movement in the temporal-to-nasal direction with respect to the injected eye. Peak slow-phase velocity ranged from 15 to 45 degrees/s. The nystagmus persisted for at least 1 h but stopped by the next day. 3. In a well-lit room, the nystagmus was completely suppressed, even during monocular viewing with the injected eye. When the lights were turned off, the slow-phase velocity of the spontaneous nystagmus slowly increased to a steady-state level within 70-120 s. 4. Horizontal smooth pursuit eye movements to a 1 degree target light moving in front of the animal +/- 20 degrees to either side of center of gaze at constant speeds were normal. Target speeds ranging from 15 to 60 degrees/s for both monocular and binocular viewing conditions were used. Binocular and monocular optokinetic nystagmus (OKN) to a full-field drum rotating at a constant velocity (5-90 degrees/s) were also normal. The initial pursuit and steady-state components of OKN were measured, as well as the velocity-storage component (optokinetic after nystagmus, OKAN).(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Neurophysiology, Sep 1, 1988

1. Eye movements of awake turtles were measured from both eyes simultaneously using two search-co... more 1. Eye movements of awake turtles were measured from both eyes simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was evoked by full field patterns moving horizontally at different stimulus velocities. Intravitreal injections of either bicuculline or 2-amino-4-phosphonobutyrate (APB) were then made into one eye, after which eye movements were again recorded under similar stimulus conditions. Several days later, eye movements were again recorded and recovery was observed. 2. The effects of these two synaptic drugs on the optokinetic responses of the injected eye were similar to those previously reported in turtles, rabbits, and decorticate cats. APB, which blocks the retinal ON pathways, completely blocked visually evoked responses to any stimulus direction or velocity presented to the injected eye. On the other hand, the uninjected eye was still responsive to optokinetic stimuli. This difference between the eyes is consistent with the nonconjugate nature of OKN in the turtle. 3. After bicuclline application, the injected eye displayed a spontaneous nystagmus with its slow phase in the temporal-to-nasal direction. The movements of the injected eye were independent of stimulus direction or a range of stimulus velocities. During that effect, the eye contralateral to the injection still responded to visual stimuli in a direction- and velocity-dependent manner. For example, if the uninjected eye was exposed to optokinetic stimuli moving temporal-to-nasal, both eyes would then move in their respective temporal-to-nasal directions. This nonconjugate ocular behavior is similar to that seen when each eye of a normal turtle was exposed to its temporal-to-nasal stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Visual Neuroscience, Jun 1, 1990

Extracellular recordings from single units in the dorsal terminal nucleus (DTN) of the cat access... more Extracellular recordings from single units in the dorsal terminal nucleus (DTN) of the cat accessory optic system (AOS) were made before and after intravitreal injections of the GABA antagonist bicuculline methiodide (BMI). Direction-selective responses of DTN cells elicited through the contralateral, injected eye were abolished 7-12 h following the injection. For the concentrations tested, direction-selective responses through the contralateral (injected) eye did not recover within 26 h. Direction-selective responses through stimulation of the ipsilateral (uninjected) eye were also dramatically depressed for 1-9 h after contralateral eye injections. However, direction-selective responses through the ipsilateral eye eventually returned and were often more vigorous in the final stages. BMI injections into the ipsilateral eye failed to block direction-selective responses through the ipsilateral eye. The effects of intravitreal BMI on contralateral eye responses imply that DTN units receive input from direction-selective retinal ganglion cells. In addition, these results suggest that direction-selective input to the DTN from the visual cortex is independent of the retinal pathway. Using pharmacological methods described here, for the first time direction-selective responses of AOS units driven through the ipsilateral eye can be experimentally isolated.

Visual Neuroscience, Jul 1, 1990

In order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the posit... more In order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the positions of each eye were recorded simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was strikingly unyoked in this animal such that one eye's slow-phase velocity was substantially independent of that of the other eye. On the other hand, the fast-phase motions of both eyes occurred more or less in synchrony.An eye's slow-phase gain is primarily dependent on the direction and velocity of the stimulus to that eye. Using monocular stimuli, the highest mean gain (0.54 ± 0.047; mean ± standard error of mean) occurred using temporal-to-nasal movement at 2.5 deg/s. The mean OKN gain for nasal-to-temporal movement was only 0.13 ± 0.015 at that velocity. Additionally, using the optimal monocular stimulus (temporal-to-nasal stimulation at 2.5 deg/s) only drove the occluded eye to move nasal-to-temporally at 0.085 deg/s, equivalent to a “gain” of only 0.034 ± 0.011.The binocular OKN gain during rotational stimuli was higher than monocular gain, especially during nasal-to-temporal movement at high velocities. Also the difference in slow-phase eye velocity between the two eyes was smaller during binocular rotational stimuli. In contrast, when each eye simultaneously viewed its temporal-to-nasal stimulus at an equal velocity, two behaviors were observed. Often, OKN alternated between an animal's left eye and right eye. Occasionally, both eyes moved at equal but opposite velocities.These behavioral data provide a quantitative baseline to interpret the properties of the retinal slip information in the turtle's accessory optic system. Those properties are similar to the behavior of the turtle in that both are tuned to direction and velocity independently for each eye (Rosenberg & Ariel, 1990).

PubMed, May 1, 1983

We tested the effects of 6-hydroxydopamine (6-OHDA) on two forms of visual deprivation--monocular... more We tested the effects of 6-hydroxydopamine (6-OHDA) on two forms of visual deprivation--monocular and directional deprivation. In normal kittens monocular deprivation leads to a change in the ocular dominance histogram recorded from the visual cortex, and directional deprivation leads to a change in the percentage of directionally sensitive cells responding to the appropriate direction of movement. 6-OHDA was infused into the occipital cortex prior to the peak of the critical period for the effects of visual deprivation. In agreement with the results of Kasamatsu et al. (Kasamatsu, T., and J. D. Pettigrew (1979) J. Comp. Neurol. 185: 139-162; Kasamatsu, T., J. D. Pettigrew, and M. Ary (1979) J. Comp. Neurol. 185: 163-182), suture of one eye (monocular deprivation) after the 6-OHDA treatment did not lead to a shift in ocular dominance in the area of striate cortex infused. Moreover, rearing kittens in an environment continually moving past them in one direction (directional deprivation) did not lead to a change in the percentage of cells preferring movement in that direction. In both rearing procedures the 6-OHDA did not make the cells in the cortex nonspecific, compared to cells recorded from the cortex of animals reared similarly but without infusion of 6-OHDA. Monocular and directional deprivation are forms of visual deprivation with different critical periods, probably involving different synapses. Therefore, the effect of 6-OHDA on visual deprivation is a general one, involving more than one kind of visual deprivation. In both cases 6-OHDA abolishes the plasticity of the visual cortex.

Brain Research, Dec 1, 2005

Recent physiological data have demonstrated that retinal slip, the sensory code of global visual ... more Recent physiological data have demonstrated that retinal slip, the sensory code of global visual pattern motion, results from complex interactions of excitatory and inhibitory visual inputs to neurons in the turtle's accessory optic system (the basal optic nucleus, BON) [M. Ariel, N. Kogo, Direction tuning of inhibitory inputs to the turtle accessory optic system, Journal of Neurophysiology 86 (2001) 2919-2930. [6], N. Kogo, T.X. Fan, M. Ariel, Synaptic pharmacology in the turtle accessory optic system, Experimental Brain Research 147 (2002) 464-472. [23]]. In the present study, the inhibitory neurotransmitter g-aminobutyric acid (GABA), its synthetic enzyme, glutamic acid decarboxylase (GAD-67) and its receptor subtypes GABA A and GABA B receptors were localized within the BON. GABA antibodies revealed cell bodies and processes, whereas antibodies against GAD revealed a moderate density of immunoreactive puncta throughout the BON. GAD in situ hybridization labeled BON cell bodies, indicating a possible source of inhibition intrinsic to the nucleus. Ultrastructural analysis revealed terminals positive for GAD that exhibit symmetric synaptic specializations, mainly at neuronal processes having small diameters. Neurons exhibiting immunoreactivity for GABA A receptors were diffusely labeled throughout the BON, with neuronal processes exhibiting more labeling than cell bodies. In contrast, GABA B-receptor-immunoreactive neurons exhibited strong labeling at the cell body and proximal neuronal processes. Both these receptor subtypes are functional, as evidenced by changes of visual responses of BON neurons during application to the brainstem of selective receptor agonists and antagonists. Therefore, GABA may be synthesized by BON neurons, released by terminals within its neuropil and stimulate both receptor subtypes, supporting its role in mediating visually evoked inhibition contributing to modulation of the retinal slip signals in the turtle accessory optic system.

bioRxiv (Cold Spring Harbor Laboratory), Jul 3, 2022

Brain Research, Mar 1, 1984

Threshold concentrations for u-glutamate, L-aspartate and their agonists, kainate, quisqualate an... more Threshold concentrations for u-glutamate, L-aspartate and their agonists, kainate, quisqualate and N-methyl-D.e-aspartate, were determined for horizontal cells of the intact carp retina and horizontal cells that were enzymatically isolated and maintained in culture. Our results indicate that uptake or other mechanisms decrease the apparent sensitivity of these cells in the intact retina to e-glutamate by 25-200 times. Our findings also suggest that e-glutamate is more likely a photoreceptor transmitter than u-aspartate.

Neuroscience, 1989

L-Aspartate, L-glutamate and D-aspartate, alone or in combination, were applied by superfusion or... more L-Aspartate, L-glutamate and D-aspartate, alone or in combination, were applied by superfusion or by atomization to the isolated carp retina while recording from cone horizontal cells. Each of these agents when applied alone depolarized horizontal cells and reduced the size of their light responses, an action which mimics the effect of the endogenous photoreceptor transmitter. Application of D-aspartate in conjunction with either of the L-amino acids potentiated the effects the L-amino acids so that the threshold concentration was reduced by about five-fold, compared to when the L-amino acids were applied alone. The potentiating effect of D-aspartate occurred with all types of cone horizontal cells--both L- and C-types. Furthermore, the potentiating effect of D-aspartate occurred not only in the dark but also in the presence of bright light background or Co2+ ions, conditions during which the release of photoreceptor transmitter is reduced or blocked. D-Aspartate also potentiated the depolarizing effects of the acidic amino acid cysteine sulfinate. The potentiating effect of D-aspartate can be attributed to its action as an amino acid uptake blocker in the outer retina. Thus, these findings, in themselves, cannot eliminate L-aspartate, L-glutamate or cysteine sulfinate as candidates for the carp cone transmitter. However, other evidence, previously reported, strongly suggests that L-glutamate and not L-aspartate is the cone transmitter.

Brain Research, Jul 1, 2007

In the intact vertebrate central nervous system, the quantal nature of synaptic transmission is d... more In the intact vertebrate central nervous system, the quantal nature of synaptic transmission is difficult to measure because the postsynaptic sites may be distributed along a tortuous dendritic tree that cannot be readily clamped spatially to a uniform potential. Titrating the intact brain&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s extracellular concentration of calcium ions is also challenging because of its strong buffering mechanisms. In this study, using a whole brain with eye attached preparation, quantal neurotransmission was examined in the turtle brainstem in vitro, by recording from accessory optic system neurons that receive direct input from visually responsive retinal ganglion cells. Unitary EPSPs, evoked by microstimulation of a single ganglion cell, were measured during whole cell current-clamp recordings. In this preparation, the neurons exhibit direction-selectivity, despite the hypoxic conditions. Bath application of cadmium to reduce calcium influx also reduced evoked EPSP amplitudes to that of the spontaneous synaptic events. Statistical analyses indicated that these evoked response amplitudes could be well fitted to a Poisson distribution for most brainstem neurons. Therefore, the spontaneous miniature excitatory synaptic events of approximately 1 mV, as also observed during spike blockade of the retina [Kogo, N., Ariel, M., 1997. Membrane properties and monosynaptic retinal excitation of neurons in the turtle accessory optic system. Journal of Neurophysiology 78, 614-627], are likely responses to the neurotransmitter of single vesicles release by retinal axon terminals.

PLOS ONE, Jul 8, 2015

Although musculoskeletal pain disorders are common clinically, the central processing of muscle p... more Although musculoskeletal pain disorders are common clinically, the central processing of muscle pain is little understood. The present study reports on central neurons activated by injections of algesic solutions into the gastrocnemius muscle of the rat, and their subsequent localization by c-Fos immunohistochemistry in the spinal cord and brainstem. An injection (300μl) of an algesic solution (6% hypertonic saline, pH 4.0 acetate buffer, or 0.05% capsaicin) was made into the gastrocnemius muscle and the distribution of immunolabeled neurons compared to that obtained after control injections of phosphate buffered saline [pH 7.0]. Most labeled neurons in the spinal cord were found in laminae IV-V, VI, VII and X, comparing favorably with other studies, with fewer labeled neurons in laminae I and II. This finding is consistent with the diffuse pain perception due to noxious stimuli to muscles mediated by sensory fibers to deep spinal neurons as compared to more restricted pain localization during noxious stimuli to skin mediated by sensory fibers to superficial laminae. Numerous neurons were immunolabeled in the brainstem, predominantly in the lateral reticular formation (LRF). Labeled neurons were found bilaterally in the caudalmost ventrolateral medulla, where neurons responsive to noxious stimulation of cutaneous and visceral structures lie. Immunolabeled neurons in the LRF continued rostrally and dorsally along the intermediate reticular nucleus in the medulla, including the subnucleus reticularis dorsalis caudally and the parvicellular reticular nucleus more rostrally, and through the pons medial and lateral to the motor trigeminal nucleus, including the subcoerulear network. Immunolabeled neurons, many of them catecholaminergic, were found bilaterally in the nucleus tractus solitarii, the gracile nucleus, the A1 area, the CVLM and RVLM, the superior salivatory nucleus, the nucleus locus coeruleus, the A5 area, and the nucleus raphe magnus in the pons. The external lateral and superior lateral subnuclei of the parabrachial nuclear complex were consistently labeled in experimental data, but they also were labeled in many control cases. The internal lateral subnucleus of the parabrachial complex was labeled moderately. Few immunolabeled neurons were found in the medial reticular formation, however, but the rostroventromedial medulla was labeled consistently. These data are

Journal of Neurophysiology, Nov 1, 1985

Synaptic drugs were superfused into turtle eyecup preparation while recording extracellularly fro... more Synaptic drugs were superfused into turtle eyecup preparation while recording extracellularly from directionally sensitive (DS) retinal ganglion cells. As in previous experiments in intact rabbit retina, both picrotoxin (a GABA antagonist) and physostigmine [an acetylcholine (ACh) potentiator] reduced or eliminated the directional selectivity of these cells. These drug effects occurred at micromolar concentrations and were long lasting. Superfusion of ACh caused excitation, and GABA caused inhibition of the spike activity of these DS cells. In some experiments, the ganglion cell was isolated from its presynaptic inputs by perfusing with a low-Ca2+/EGTA perfusate, which blocked synaptic transmission but did not suppress spike firing. During this synaptic block, ACh still caused spontaneous spike firing, and GABA was able to suppress the ACh-induced spike activity. Strychnine slightly increased the spontaneous activity of DS ganglion cells and reduced their response to light. Glycine and taurine were equally effective in totally suppressing spike activity, and strychnine blocked this inhibition by both agents. However, these inhibitory effects may be transynaptic because glycine did not suppress ACh-induced excitation during synaptic block. Superfusion of micromolar concentrations of methionine enkephalin and [D-Ala2]methionine enkephalinamide occasionally caused small increases in the light responses of DS cells, whereas naloxone, a broad-spectrum opiate antagonist, moderately decreased light responsiveness. Because naloxone had no effect on these cell&amp;amp;amp;amp;amp;#39;s directional tuning, the opiate system is probably not involved in the mechanism of directional sensitivity. Based on the effects of these transmitter candidates and their antagonists, a possible site fo DS subunits may be the ACh and GABA receptors on the membrane of DS ganglion cells. ACh provides light-evoked excitation that may, when potentiated by physostigmine, overcome asymmetric GABA inhibition. Although the role of glycine in directional sensitivity is small, it may be responsible for regulating presynaptic excitatory pathways leading to the DS ganglion cells.

The Journal of Physiology, Mar 1, 1982

With 14 text-figures

Journal of Neurophysiology, Aug 1, 1980