Chapter 19 Temporal covariance of postsynaptic membrane potential and synaptic input – role in synaptic efficacy in visual cortex

Friedlander, M. J.; Frégnac, Yves; Jp, Burke

doi:10.1016/s0079-6123(08)60370-2

Cited by 14 publications

(6 citation statements)

References 130 publications

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“…Regardless of the specific underlying mechanisms, our results are consistent with the well-accepted notion that the presence of correlated activities in both presynaptic and postsynaptic neurons, which occur as a result ofcorrelated visual inputs from both eyes, is necessary to maintain cortical binocularity (Rauschecker, 199 1;Friedlander et al, 1993). Suppression could disrupt the maintenance ofnormal ocular dominance by inhibiting or altering the neuronal firing patterns of one or both eyes' inputs, or directly affecting the activity of postsynaptic units and, thus, create a decorrelation of signals between the two eyes or between pre-and postsynaptic neurons (Movshon and Kiorpes, 1990).…”

Section: Suppressionsupporting

confidence: 89%

Binocular interactions in striate cortical neurons of cats reared with discordant visual inputs

et al. 1994

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The postnatal development of cortical binocularity is known to be adversely affected by early abnormal visual experience. However, little information exists on how the signals from the two eyes are combined in individual cortical neurons of animals reared with early discordant binocular visual experience. Since this is a fundamental issue in understanding visual cortical development, we used extracellular single-unit recording methods to study binocular integration in striate cortical neurons of strabismic cats. Specifically, we measured the sensitivity of individual cells to the relative interocular spatial phase of dichoptically presented drifting sinusoidal gratings (i.e., to binocular retinal image disparity). Clear alterations in ocular dominance were observed in all strabismic subjects. Nevertheless, the majority of cortical neurons exhibited some form of binocular interactions when both eyes were stimulated together. The most prominent aspect of cortical physiology in the strabismic animals was the relatively high prevalence of suppressive binocular interactions. Suppression was most frequently found in kittens reared with 2 weeks of early optical dissociation and among adult cats that received 2 weeks of early optical dissociation and a prolonged recovery period. However, substantial excitatory binocular interactions were also maintained in these animals. With an extended period of interocular misalignment (3 or 8 months), all forms of binocular interactions, excitatory and suppressive, were drastically reduced and a greater number of neurons were truly monocular. Although the reduction in the strength of binocular interactions occurred in all units irrespective of their monocular spatial properties, the effect was more pronounced among those units tuned to higher spatial frequencies and this spatial-frequency-dependent effect was larger in the subjects receiving longer periods of binocular dissociation. The results suggest that the "breakdown" of cortical binocular properties in strabismic subjects is not an all-or-none process, and that suppressive binocular interactions may be closely associated with the abnormal binocular interactions exhibited by strabismic humans. Furthermore, our findings are consistent with the notion that cortical disparity-detecting mechanisms are spatial-frequency dependent and, thus, can be selectively altered depending on an animal's early visual experience.

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Section: Suppressionsupporting

confidence: 89%

Binocular interactions in striate cortical neurons of cats reared with discordant visual inputs

et al. 1994

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“…There is an overwhelming amount of circumstantial evidence for Hebbian synapses of some kind in the visual cortex (reviewed by Constantine-Paton et al 1990, Rauschecker 1991, Friedlander et al 1993. There is a small amount of direct evidence (Frégnac et al 1988, Greuel et al 1988 showing that stimulation of afferent pathways to a cell in combination with depolarization of the cell will lead to strengthening of the effects of afferent stimulation alone.…”

Section: Hebb Synapsesmentioning

confidence: 99%

The development of topography in the visual cortex: a review of models

Swindale

1996

Network: Computation in Neural Systems

257

165

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The repetitive stochastic patterns of eye dominance and orientation preference found in the mammalian visual cortex have attracted much attention from theoretical neurobiologists during the last two decades. Reasons for this include the visually intriguing nature of the patterns and the fact that many aspects of their development seem likely to be dependent upon both spontaneous and visually driven patterns of neural activity. Understanding these processes holds out the promise that general theories of learning and memory may be derived from those found to be applicable to the visual cortex. It has turned out, in fact, that remarkably simple models, based on Hebbian synaptic plasticity, intracortical interactions and competitive interactions between cells and growing axons, have been able to explain much of the phenomenology. This article reviews the models of topographic organization in the visual cortex in a roughly historical sequence, beginning with von der Malsburg's paper 1973 paper in Kybernetik on self-organization of orientation selectivity. The principles on which each of the models is based are explained, and the plausibility of each model and the extent to which it is able to account for the relevant experimental data are evaluated. Attention is drawn to the underlying similarities and differences between the models and suggestions are made for future directions in research.

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“…Additional results support the hypothesis that the postsynaptic membrane potential regulates the direction of synaptic gain changes. In slice preparations of kitten and adult guinea pig visual cortex, the same postsynaptic potential was either potentiated or depressed by pairing white matter stimulation with hyperpolarizing or depolarizing pulses to the postsynaptic cell (Friedlander et al, 1993;Fregnac et al, 1994). Using, different stimulation parameters, Hirsch & Gilbert (1993) have also demonstrated long-term modifications of synaptic efficacy in slices of cat visual cortex.…”

Section: Introductionmentioning

confidence: 99%

“…The synaptic modification rules proposed in the BCM model have been used to explain the results of many normal rearing and classical deprivation studies (Clothiaux et al, 1991;Law et al, 1994), and are also supported by a host of experimental evidence in kitten, rat, and guinea pig visual cortex (Bear et al, 1987;Greuel et al, 1988;Reiter & Stryker, 1988;Fregnac et al, 1988Fregnac et al, , 1992Artola et al, 1990;Friedlander et al, 1993;Shulz et al, 1993;Fregnac et al, 1994;Bear, 1995;Kirkwood, 1996) and in rat hippocampus (Dudek & Bear, 1992). In in vivo studies from Fregnac's group (Fregnac et al, 1988(Fregnac et al, , 1992, a differential pairing procedure was used to impose temporal correlations between visual afferent activity and postsynaptic firing induced iontophoretically.…”

Section: Introductionmentioning

confidence: 99%

Plasticity of neuronal response properties in adult cat striate cortex

McLean

Palmer

1998

Vis Neurosci

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We have utilized an associative conditioning paradigm to induce changes in the receptive field (RF) properties of neurons in the adult cat striate cortex. During conditioning, the presentation of particular visual stimuli were repeatedly paired with the iontophoretic application of either GABA or glutamate to control postsynaptic firing rates. Similar paradigms have been used in kitten visual cortex to alter RF properties (Fregnac et al., 1988, 1992; Greuel et al., 1988; Shulz & Fregnac, 1992). Roughly half of the cells that were subjected to conditioning with stimuli differing in orientation were found to have orientation tuning curves that were significantly altered. In general, the modification in orientation tuning was not accompanied by a shift in preferred orientation, but rather, responsiveness to stimuli at or near the positively reinforced orientation was increased relative to controls, and responsiveness to stimuli at or near the negatively reinforced orientation was decreased relative to controls. A similar proportion of cells that were subjected to conditioning with stimuli differing in spatial phase were found to have spatial-phase tuning curves that were significantly modified. Conditioning stimuli typically differed by 90 deg in spatial phase, but modifications in spatial-phase angle were generally 30-40 deg. An interesting phenomenon we encountered was that during conditioning, cells often developed a modulated response to counterphased grating stimuli presented at the null spatial phase. We present an example of a simple cell for which the shift in preferred spatial phase measured with counterphased grating stimuli was comparable to the shift in spatial phase computed from a one-dimensional Gabor fit of the space-time RF profile. One of ten cells tested had a significant change in direction selectivity following associative conditioning. The specific and predictable modifications of RF properties induced by our associative conditioning procedure demonstrate the ability of mature visual cortical neurons to alter their integrative properties. Our results lend further support to models of synaptic plasticity where temporal correlations between presynaptic and postsynaptic activity levels control the efficiency of transmission at existing synapses, and to the idea that the mature visual cortex is, in some sense, dynamically organized.

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Chapter 19 Temporal covariance of postsynaptic membrane potential and synaptic input – role in synaptic efficacy in visual cortex

Cited by 14 publications

References 130 publications

Binocular interactions in striate cortical neurons of cats reared with discordant visual inputs

Binocular interactions in striate cortical neurons of cats reared with discordant visual inputs

The development of topography in the visual cortex: a review of models

Plasticity of neuronal response properties in adult cat striate cortex

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