Changes In Receptive Field Properties Research Articles

Dual-Component Structural Plasticity Mediated by αCaMKII Autophosphorylation on Basal Dendrites of Cortical Layer 2/3 Neurones.

Sensory cortex exhibits receptive field plasticity throughout life in response to changes in sensory experience and offers the experimental possibility of aligning functional changes in receptive field properties with underpinning structural changes in synapses. We looked at the effects on structural plasticity of two different patterns of whisker deprivation in male and female mice: chessboard deprivation, which causes functional plasticity; and all deprived, which does not. Using 2-photon microscopy and chronic imaging through a cranial window over the barrel cortex, we found that layer 2/3 neurones exhibit robust structural plasticity, but only in response to whisker deprivation patterns that cause functional plasticity. Chessboard pattern deprivation caused dual-component plasticity in layer 2/3 by (1) increasing production of new spines that subsequently persisted for weeks and (2) enlarging spine head sizes in the preexisting stable spine population. Structural plasticity occurred on basal dendrites, but not apical dendrites. Both components of plasticity were absent in αCaMKII-T286A mutants that lack LTP and experience-dependent potentiation in barrel cortex, implying that αCaMKII autophosphorylation is not only important for stabilization and enlargement of spines, but also for new spine production. These studies therefore reveal the relationship between spared whisker potentiation in layer 2/3 neurones and the form and mechanisms of structural plasticity processes that underlie them.SIGNIFICANCE STATEMENT This study provides a missing link in a chain of reasoning that connects LTP to experience-dependent functional plasticity in vivo We found that increases in dendritic spine formation and spine enlargement (both of which are characteristic of LTP) only occurred in barrel cortex during sensory deprivation that produced potentiation of sensory responses. Furthermore, the dendritic spine plasticity did not occur during sensory deprivation in mice lacking LTP and experience-dependent potentiation (αCaMKII autophosphorylation mutants). We also found that the dual-component dendritic spine plasticity only occurred on basal dendrites and not on apical dendrites, thereby resolving a paradox in the literature suggesting that layer 2/3 neurones lack structural plasticity in response to sensory deprivation.

Nerve injury induces a new profile of tactile and mechanical nociceptor input from undamaged peripheral afferents

Chronic pain after nerve injury is often accompanied by hypersensitivity to mechanical stimuli, yet whether this reflects altered input, altered processing, or both remains unclear. Spinal nerve ligation or transection results in hypersensitivity to mechanical stimuli in skin innervated by adjacent dorsal root ganglia, but no previous study has quantified the changes in receptive field properties of these neurons in vivo. To address this, we recorded intracellularly from L4 dorsal root ganglion neurons of anesthetized young adult rats, 1 wk after L5 partial spinal nerve ligation (pSNL) or sham surgery. One week after pSNL, hindpaw mechanical withdrawal threshold in awake, freely behaving animals was decreased in the L4 distribution on the nerve-injured side compared with sham controls. Electrophysiology revealed that high-threshold mechanoreceptive cells of A-fiber conduction velocity in L4 were sensitized, with a seven-fold reduction in mechanical threshold, a seven-fold increase in receptive field area, and doubling of maximum instantaneous frequency in response to peripheral stimuli, accompanied by reductions in after-hyperpolarization amplitude and duration. Only a reduction in mechanical threshold (minimum von Frey hair producing neuronal activity) was observed in C-fiber conduction velocity high-threshold mechanoreceptive cells. In contrast, low-threshold mechanoreceptive cells were desensitized, with a 13-fold increase in mechanical threshold, a 60% reduction in receptive field area, and a 40% reduction in instantaneous frequency to stimulation. No spontaneous activity was observed in L4 ganglia, and the likelihood of recording from neurons without a mechanical receptive field was increased after pSNL. These data suggest massively altered input from undamaged sensory afferents innervating areas of hypersensitivity after nerve injury, with reduced tactile and increased nociceptive afferent response. These findings differ importantly from previous preclinical studies, but are consistent with clinical findings in most patients with chronic neuropathic pain.

Sparse Coding Can Predict Primary Visual Cortex Receptive Field Changes Induced by Abnormal Visual Input

Receptive fields acquired through unsupervised learning of sparse representations of natural scenes have similar properties to primary visual cortex (V1) simple cell receptive fields. However, what drives in vivo development of receptive fields remains controversial. The strongest evidence for the importance of sensory experience in visual development comes from receptive field changes in animals reared with abnormal visual input. However, most sparse coding accounts have considered only normal visual input and the development of monocular receptive fields. Here, we applied three sparse coding models to binocular receptive field development across six abnormal rearing conditions. In every condition, the changes in receptive field properties previously observed experimentally were matched to a similar and highly faithful degree by all the models, suggesting that early sensory development can indeed be understood in terms of an impetus towards sparsity. As previously predicted in the literature, we found that asymmetries in inter-ocular correlation across orientations lead to orientation-specific binocular receptive fields. Finally we used our models to design a novel stimulus that, if present during rearing, is predicted by the sparsity principle to lead robustly to radically abnormal receptive fields.

Adaptation-Dependent Synchronous Activity Contributes to Receptive Field Size Change of Bullfrog Retinal Ganglion Cell

Nearby retinal ganglion cells of similar functional subtype have a tendency to discharge spikes in synchrony. The synchronized activity is involved in encoding some aspects of visual input. On the other hand, neurons always continuously adjust their activities in adaptation to some features of visual stimulation, including mean ambient light, contrast level, etc. Previous studies on adaptation were primarily focused on single neuronal activity, however, it is also intriguing to investigate the adaptation process in population neuronal activities. In the present study, by using multi-electrode recording system, we simultaneously recorded spike discharges from a group of dimming detectors (OFF-sustained type ganglion cells) in bullfrog retina. The changes in receptive field properties and synchronization strength during contrast adaptation were analyzed. It was found that, when perfused using normal Ringer's solution, single neuronal receptive field size was reduced during contrast adaptation, which was accompanied by weakening in synchronization strength between adjacent neurons' activities. When dopamine (1 µM) was applied, the adaptation-related receptive field area shrinkage and synchronization weakening were both eliminated. The activation of D1 receptor was involved in the adaptation-related modulation of synchronization and receptive field. Our results thus suggest that the size of single neuron's receptive field is positively related to the strength of its synchronized activity with its neighboring neurons, and the dopaminergic pathway is responsible for the modulation of receptive field property and synchronous activity of the ganglion cells during the adaptation process.

The influence of behavioral context on sensory encoding

The properties of sensory neurons are not fixed, but change dynamically according to the task being performed [1]. While there has been a huge experimental effort put into characterizing these effects, a clear understanding of why they occur is lacking. A large body of research focuses on the idea that the visual system learns a probabilistic model of natural image statistics. Typically, the goal of the visual system is seen as inferring the hidden causes underlying a given sensory input [2]. While this framework is successful in helping to understand the properties of neurons in the early sensory cortex, it presents a passive view of learning: the sensory representation is optimized independently of behavioral demands. We propose an alternative normative framework for modeling visual processing, with the representation optimized adaptively in order to facilitate interaction with the environment [3,4]. This framework is used to ask the following questions: (1) under what conditions should behavioral context influence the responses of sensory neurons; (2) what are the expected changes in receptive field properties? We simulate a visual detection task where an agent is presented with stimuli at various locations, and has to report whether or not a stimulus is present at a single task-relevant location. Stimuli are represented by binary latent variables (each variable corresponding to a different spatial location), which combine linearly to produce the sensory input. The task is thus to infer the state of a single task-relevant latent variable based on the sensory input: correct responses result in an immediate reward. In performing the task, the agent is assumed to follow a strategy whereby they parameterize the expected value of state-response pairs using a probabilistic model describing how sensory data are generated from hidden causes (‘sensory encoding’), and a utility function describing the expected reward for different responses, given the hidden state (‘reward encoding’). The parameters of the model and of the utility function are learned simultaneously to fit both the distribution of inputs, and ‘desired' responses in the task (estimated using the received reward). When there were no limitations on what could be learned, we found that the task had no influence on the learned model. Therefore, we hypothesized that task-dependent changes in sensory encoding occur due to a computational resource limitation, when there is a compromise between explaining all the sensory inputs, and enabling good task performance. Specifically, we considered the case where there are fewer hidden units in the learned model than in the true model generating the data. In this condition, we found that the task strongly affected the learned model, with basic functions corresponding to task-relevant hidden units achieving the closest fit to the true model. Significantly, task-relevant hidden units showed increased activation in response to preferred stimuli, compared to task-irrelevant hidden units (due to the reduction in uncertainty associated with learning a better model), analogous to the experimental effects of attention, found in low to mid-level areas of the visual cortex [1]. Finally, we tested the ability of the model to account for other observed effects of attention, such as multiplicative scaling of neuronal tuning curves, biased competition and modulation of centre-surround interactions [1].

A Re-Examination of Hebbian-Covariance Rules and Spike Timing-Dependent Plasticity in Cat Visual Cortex in vivo

Spike timing-dependent plasticity (STDP) is considered as an ubiquitous rule for associative plasticity in cortical networks in vitro. However, limited supporting evidence for its functional role has been provided in vivo. In particular, there are very few studies demonstrating the co-occurrence of synaptic efficiency changes and alteration of sensory responses in adult cortex during Hebbian or STDP protocols. We addressed this issue by reviewing and comparing the functional effects of two types of cellular conditioning in cat visual cortex. The first one, referred to as the “covariance” protocol, obeys a generalized Hebbian framework, by imposing, for different stimuli, supervised positive and negative changes in covariance between postsynaptic and presynaptic activity rates. The second protocol, based on intracellular recordings, replicated in vivo variants of the theta-burst paradigm (TBS), proven successful in inducing long-term potentiation in vitro. Since it was shown to impose a precise correlation delay between the electrically activated thalamic input and the TBS-induced postsynaptic spike, this protocol can be seen as a probe of causal (“pre-before-post”) STDP. By choosing a thalamic region where the visual field representation was in retinotopic overlap with the intracellularly recorded cortical receptive field as the afferent site for supervised electrical stimulation, this protocol allowed to look for possible correlates between STDP and functional reorganization of the conditioned cortical receptive field. The rate-based “covariance protocol” induced significant and large amplitude changes in receptive field properties, in both kitten and adult V1 cortex. The TBS STDP-like protocol produced in the adult significant changes in the synaptic gain of the electrically activated thalamic pathway, but the statistical significance of the functional correlates was detectable mostly at the population level. Comparison of our observations with the literature leads us to re-examine the experimental status of spike timing-dependent potentiation in adult cortex. We propose the existence of a correlation-based threshold in vivo, limiting the expression of STDP-induced changes outside the critical period, and which accounts for the stability of synaptic weights during sensory cortical processing in the absence of attention or reward-gated supervision.

Stability of Thalamocortical Synaptic Transmission across Awake Brain States

Sensory cortical neurons are highly sensitive to brain state, with many neurons showing changes in spatial and/or temporal response properties and some neurons becoming virtually unresponsive when subjects are not alert. Although some of these changes are undoubtedly attributable to state-related filtering at the thalamic level, another likely source of such effects is the thalamocortical (TC) synapse, where activation of nicotinic receptors on TC terminals have been shown to enhance synaptic transmission in vitro. However, monosynaptic TC synaptic transmission has not been directly examined during different states of alertness. Here, in awake rabbits that shifted between alert and non-alert EEG states, we examined the monosynaptic TC responses and short-term synaptic dynamics generated by spontaneous impulses of single visual and somatosensory TC neurons. We did this using spike-triggered current source-density analysis, an approach that enables assessment of monosynaptic extracellular currents generated in different cortical layers by impulses of single TC afferents. Spontaneous firing rates of TC neurons were higher, and burst rates were much lower in the alert state. However, we found no state-related changes in the amplitude of monosynaptic TC responses when TC spikes with similar preceding interspike interval were compared. Moreover, the relationship between the preceding interspike interval of the TC spike and postsynaptic response amplitude was not influenced by state. These data indicate that TC synaptic transmission and dynamics are highly conserved across different states of alertness and that observed state-related changes in receptive field properties that occur at the cortical level result from other mechanisms.

Gustatory sweating: Frey syndrome

Sensory cortex exhibits receptive field plasticity throughout life in response to changes in sensory experience and offers the experimental possibility of aligning functional changes in receptive field properties with underpinning structural changes in synapses. We looked at the effects on structural plasticity of two different patterns of whisker deprivation in male and female mice: chessboard deprivation, which causes functional plasticity; and all deprived, which does not. Using 2-photon microscopy and chronic imaging through a cranial window over the barrel cortex, we found that layer 2/3 neurones exhibit robust structural plasticity, but only in response to whisker deprivation patterns that cause functional plasticity. Chessboard pattern deprivation caused dual-component plasticity in layer 2/3 by (1) increasing production of new spines that subsequently persisted for weeks and (2) enlarging spine head sizes in the preexisting stable spine population. Structural plasticity occurred on basal dendrites, but not apical dendrites. Both components of plasticity were absent in α<i>CaMKII-T286A</i> mutants that lack LTP and experience-dependent potentiation in barrel cortex, implying that αCaMKII autophosphorylation is not only important for stabilization and enlargement of spines, but also for new spine production. These studies therefore reveal the relationship between spared whisker potentiation in layer 2/3 neurones and the form and mechanisms of structural plasticity processes that underlie them. <b>SIGNIFICANCE STATEMENT</b> This study provides a missing link in a chain of reasoning that connects LTP to experience-dependent functional plasticity <i>in vivo</i>. We found that increases in dendritic spine formation and spine enlargement (both of which are characteristic of LTP) only occurred in barrel cortex during sensory deprivation that produced potentiation of sensory responses. Furthermore, the dendritic spine plasticity did not occur during sensory deprivation in mice lacking LTP and experience-dependent potentiation (αCaMKII autophosphorylation mutants). We also found that the dual-component dendritic spine plasticity only occurred on basal dendrites and not on apical dendrites, thereby resolving a paradox in the literature suggesting that layer 2/3 neurones lack structural plasticity in response to sensory deprivation.

A psychophysical correlate of contrast dependent changes in receptive field properties

Recent physiological investigations have demonstrated that a neuron's area of spatial summation can vary depending on stimulus contrast. Specifically, when the same stimulus is presented to a neuron at a low contrast, the area of summation (or neuron's receptive field) can increase by at least a factor of two, compared to that estimated with a high contrast stimulus. We sought to examine this phenomenon psychophysically by using an orientation discrimination task carried out in the presence of contextual stimuli. We have found previously that orientation discrimination thresholds for a sine-wave grating are elevated by the presence of a surround pattern of similar orientation (with an offset) and spatial frequency. However, when these patterns were separated by a gap of mean luminance exceeding roughly 1 deg, thresholds dropped to the level measured using the center pattern alone. Here, we examined the surround pattern's effect on orientation thresholds as a function of the contrast of the center and surround. We find that when both are presented at a low contrast, the detrimental influence of the surround on orientation thresholds is maintained over larger gap separations. We also find that the spatial frequency and orientation selectivity of the surround's masking effect on orientation thresholds is broader at low contrast than at high contrast. Although the results support the idea of a spatial reorganization of the mechanisms involved in the task at low contrast, these changes are insufficient, in and of themselves, to account for the data. We suggest that additional influences possibly reflecting image segmentation also affect performance.

Activity-dependent regulation of receptive field properties of cat area 17 by supervised Hebbian learning

Most algorithms currently used to model synaptic plasticity in self-organizing cortical networks suppose that the change in synaptic efficacy is governed by the same structuring factor, i.e., the temporal correlation of activity between pre- and postsynaptic neurons. Functional predictions generated by such algorithms have been tested electrophysiologically in the visual cortex of anesthetized and paralyzed cats. Supervised learning procedures were applied at the cellular level to change receptive field (RF) properties during the time of recording of an individual functionally identified cell. The protocols were devised as cellular analogs of the plasticity of RF properties, which is normally expressed during a critical period of postnatal development. We summarize here evidence demonstrating that changes in covariance between afferent input and postsynaptic response imposed during extracellular and intracellular conditioning can acutely induce selective long-lasting up- and down-regulations of visual responses. The functional properties that could be modified in 40% of cells submitted to differential pairing protocols include ocular dominance, orientation selectivity and orientation preference, interocular orientation disparity, and the relative dominance of ON and OFF responses. Since changes in RF properties can be induced in the adult as well, our findings also suggest that similar activity-dependent processes may occur during development and during active phases of learning under the supervision of behavioral attention or contextual signals. Such potential for plasticity in primary visual cortical neurons suggests the existence of a hidden connectivity expressing a wider functional competence than the one revealed at the spiking level. In particular, in the spatial domain the sensory synaptic integration field is larger than the classical discharge field. It can be shaped by supervised learning and its subthreshold extent can be unmasked by the pharmacological blockade of intracortical inhibition.

Immediate thalamic sensory plasticity depends on corticothalamic feedback.

Multiple neuron ensemble recordings were obtained simultaneously from both the primary somatosensory (SI) cortex and the ventroposterior medial thalamus (VPM) before and during the combined administration of reversible inactivation of the SI cortex and a reversible subcutaneous block of peripheral trigeminal nerve fibers. This procedure was performed to quantify the contribution of descending corticofugal projections on (i) the normal organization of thalamic somatosensory receptive fields and (ii) the thalamic somatosensory plastic reorganization that immediately follows a peripheral deafferentation. Reversible inactivation of SI cortex resulted in immediate changes in receptive field properties throughout the VPM. Cortical inactivation also significantly reduced but did not completely eliminate the occurrence of VPM receptive field reorganization resulting from the reversible peripheral deafferentation. This result suggests that the thalamic plasticity that is seen immediately after a peripheral deafferentation is dependent upon both descending corticofugal projections and ascending trigeminothalamic projections.

Adaptive changes in the somatotopic properties of individual thalamic neurons immediately following microlesions in connected regions of the nucleus cuneatus.

We examined the ability of thalamic neurons in the ventrobasal complex to show adaptive changes in receptive field properties following the loss of projections from the nucleus cuneatus. Thalamic responses to air jet stimulation were tested at multiple peripheral sites before and after making discrete microlesions in topographically-matched regions of the nucleus cuneatus. Prior to making a lesion, crosscorrelation analysis and orthodromic microstimulation were used to confirm the source of cuneate neurons projecting to the thalamic recording site. A total of 69 thalamic neurons were recorded from 29 rats. Following placement of a microlesion (100-200 microns diameter) in the nucleus cuneatus, 34 thalamic neurons did not show significant changes in stimulus-induced responses, possibly because the lesion was too small or because critical sites in the receptive field were not tested. The remaining 35 neurons were affected by cuneate microlesions, but the change in responsiveness varied according to stimulation site. When the most responsive site in the receptive field was examined, 24 neurons exhibited significant decreases and three neurons showed significant increases in responsiveness. Cuneate microlesions produced decreases at moderately responsive sites, but the reduction in response magnitude was smaller than at the most responsive site. When responses near the receptive field boundary were examined, 11 neurons displayed significant increases and only four neurons showed significant decreases. For two neurons without well-defined receptive field boundaries, cuneate microlesions caused new excitatory responses to emerge from sites that had formerly caused a slight inhibition of spontaneous activity. In all cases of increased responsiveness, the changes appeared on only one side of a neuron's receptive field. This asymmetry may account for the fact that the probability of detecting receptive field expansion increased from 27% (six of 22 experiments) to 71% (five of seven experiments) when the number of stimulation sites located throughout the receptive field was increased. These results indicate that the receptive field structure of individual neurons shows adaptive properties immediately after loss of the predominant ascending inputs.

Long-term changes in synaptic strength along specific intrinsic pathways in the cat visual cortex.

1. The dense system of horizontal connections that arise and course within the striate cortex are thought to inform single cells about stimuli arising in disparate points in visual space and to modulate responses evoked from within the receptive field. To learn whether or not the strength of the horizontal connections could vary over the long term, and if such changes could affect the integration of vertical, interlaminar inputs, we have recorded intracellularly from the superficial layers in slices of the adult cat's visual cortex. 2. The monosynaptic EPSP evoked by stimulating horizontal fibres showed long-term facilitation in twelve of the twenty cells that were conditioned by repetitively pairing synaptic responses with depolarizing pulses of current; the maximum increase observed was 200%. Strong inhibition present in the postsynaptic response usually indicated that facilitation would not occur. 3. In instances where horizontal input evoked both mono- and polysynaptic EPSPs, both early and late events showed facilitation, with the most dramatic enhancement contributed by the polysynaptic components. 4. For the twenty-eight cells whose responses to stimulation of interlaminar as well as horizontal pathways were assessed, all were found to receive non-overlapping inputs from each source. Conditioning produced long-term changes in the strength of the interlaminar inputs. 5. Changes in synaptic strength were usually confined to the conditioned pathway, though in four out of twenty-six times we observed heterosynaptic facilitation of polysynaptic EPSPs. 6. The conditioning protocol led to lasting depression rather than facilitation in three out of eleven instances; the reduction was only observed in the multisynaptic components. 7. We suggest that the synaptic changes observed here may be related to certain dynamic changes in receptive field properties that have been characterized in vivo.

Long-term expansion and sensitization of mechanosensory receptive fields in Aplysia support an activity-dependent model of whole-cell sensory plasticity

Long-term changes in peripheral receptive field properties of mechanosensory/nociceptive neurons were investigated 1-3 weeks after noxious stimulation. Noxious stimuli consisted of a deep penetrating cut through the middle of the tail, strong electric shock applied to the tail surface, or a combination of deep and superficial tail stimulation. Action potentials evoked in the tail were monitored with intracellular electrodes in central somata of tail sensory neurons. Three long-term changes in receptive field properties were produced in the region of noxious stimulation: (1) mechanosensory thresholds decreased, (2) receptive field areas increased, and (3) the percentage of cells showing receptive field extension across the tail midline increased. Sizes and shapes of individual receptive fields did not vary during extensive testing of tails perfused with artificial seawater or during testing in cobalt solutions that block synaptic transmission. This stability of receptive field geometry, coupled with the observation that increased peripheral excitability in these cells does not increase receptive field size, suggests that long-term receptive field alterations involve growth of peripheral sensory processes. A model is proposed in which the signaling strength of the entire sensory cell increases in response to trauma of its receptive field. In this model long-term enhancement of central and peripheral sensory responsiveness is selectively triggered by activity dependent extrinsic modulation of the centrally located soma, which accelerates synthesis of growth-associated proteins used in collateral and regenerative sprouting of traumatized peripheral processes.

Long-term recordings and receptive field measurements from single units of the visual cortex of awake unrestrained kittens

A method is described which allows simultaneous recording of the activity of several neurons in the visual cortex of awake unrestrained kittens for a period sufficiently long to follow experience-dependent changes in receptive field properties. The electrodes consisted of 25 μ m thick Teflon-coated platinum-iridium wires whose tips were tapered and coated with platinum black. They were implanted individually into the striate cortex and fixed with tissue glue to the pia mater. The other end of the electrodes was connected to a 21-pin plug and fixed to the skull in a way which allowed the wires to follow freely any movements of the brain. With this arrangement single and multi unit activity could be recorded from up to 10 sites over several weeks. In fortuitous cases the activity of a single cell could be followed over several days. The receptive field properties of these neurons were determined in awake animals by computing response histograms to moving gratings that covered the whole visual field and whose orientation could be changed in small steps. Comparison with receptive field properties that were determined for the same neurons after the kittens had been lightly anesthetized, revealed that this method allowed reliable determination of the eye preference of the neurons as well as of their orientation and direction selectivity. Since this method allowed repeated non-invasive measurements of neuronal response properties in only lightly restrained kittens, it was possible to study, in individual units, the nature and time course of changes in receptive field properties such as result from monocular deprivation and reverse occlusion.

Unilateral visual cortex deafferentation induces changes in receptive field properties of cortical cells in the intact hemisphere of normal and of monocularly deprived cats

Receptive field properties and the selectivity of cortical cells to visual stimulation were studied in the visual cortices (the boundary between areas 17 and 18) of both hemispheres following unilateral deafferentation in normal and in early monocularly deprived cats. Almost no visual activity was encountered in the deafferented hemisphere and a considerable diminution in visual responsiveness was found in the intact hemisphere of all experimental cats. Responsiveness had increased with recovery time; unresponsive cells had consisted 44.6% of the cells in the intact hemisphere of the acute, 34.7% in the 3-month chronic and 14.5% in the normal cats. Disregarding the bias due to an early monocular deprivation, the ocular dominance distribution of the cells in the intact hemispheres of these cats was unaffected. Selectivity was markedly reduced in the intact hemisphere of the deafferented cats as expressed mainly in the increased orientation tuning range and in the proportion of orientation-selective cells. The proportion of these cells was 45.5% in the deafferented cats, 38.6% in the deafferented monocularly deprived cats, 65.3% in the monocularly deprived and 81.9% in the normal control cats. A similar trend, although less prominent, was found in respect to the proportion of direction-selective cells. The size of receptive fields was only slightly affected in the deafferented deprived cats. Receptive fields were considerably larger in size (length) in the deafferented cats in comparison to their respective normal and monocularly deprived controls. It is concluded that the absence of visual input from the deafferented hemisphere is bidirectionally affecting the corpus callosum. This is mainly reflected in the reduction in the excitability level of the cells in the intact hemisphere, which results in modification of the selectivity of the cells to orientation and direction of movement of the visual stimuli.

Receptive-field properties of different classes of neurons in visual cortex of normal and dark-reared cats.

ArticlesReceptive-field properties of different classes of neurons in visual cortex of normal and dark-reared catsA. G. Leventhal, and H. V. HirschA. G. Leventhal, and H. V. HirschPublished Online:01 Apr 1980https://doi.org/10.1152/jn.1980.43.4.1111MoreSectionsPDF (4 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByDecoding the orientation of contrast edges from MEG evoked and induced responsesNeuroImage, Vol. 180Orientation anisotropies in human primary visual cortex depend on contrastNeuroImage, Vol. 119Visual experience promotes the isotropic representation of orientation preference3 May 2004 | Visual Neuroscience, Vol. 21, No. 01Visual cortex is rescued from the effects of dark rearing by overexpression of BDNF26 September 2003 | Proceedings of the National Academy of Sciences, Vol. 100, No. 21Oblique Effect: A Neural Basis in the Visual CortexBaowang Li, Matthew R. Peterson, and Ralph D. Freeman1 July 2003 | Journal of Neurophysiology, Vol. 90, No. 1Degradation of stimulus selectivity of visual cortical cells in senescent rhesus monkeys1 April 2000 | Nature Neuroscience, Vol. 3, No. 4The nature and origin of orientation specificity in neurons of the visual pathwaysProgress in Neurobiology, Vol. 43, No. 4-5Simulation of visual cortex development under lid-suture conditions: enhancement of response specificity by a reverse-Hebb rule in the absence of spatially patterned inputBiological Cybernetics, Vol. 70, No. 4Effect of the richness of the environment on neurons in cat visual cortex. I. Receptive field propertiesDevelopmental Brain Research, Vol. 53, No. 1Consequences of visual deprivation in the absence of binocular competitive mechanisms in Siamese cat area 17Developmental Brain Research, Vol. 50, No. 1Unilateral visual cortex deafferentation induces changes in receptive field properties of cortical cells in the intact hemisphere of normal and of monocularly deprived catsDevelopmental Brain Research, Vol. 33, No. 2Physiological segregation of geniculo-cortical afferents in the visual cortex of dark-reared catsBrain Research, Vol. 362, No. 2Synapse elimination in the developing visual cortex: a morphometric analysis in normal and dark-reared catsDevelopmental Brain Research, Vol. 22, No. 1Ocular dominance of cortical cells in cats dark-reared into maturity after short postnatal monocular deprivationExperimental Neurology, Vol. 85, No. 3Survival of early monocular deprivation effects in cortical cells of kittens following prolonged dark rearingDevelopmental Brain Research, Vol. 16, No. 1Synaptic characteristics of identified pyramidal and multipolar non-pyramidal neurons in the visual cortex of young and adult rabbits. A quantitative Golgi-electron microscope studyNeuroscience, Vol. 12, No. 4Human orientation discrimination tested with long stimuliVision Research, Vol. 24, No. 2Behavioral and physiological effects of monocular deprivation: A comparison of rearing with diffusion and occlusionBrain Research, Vol. 280, No. 1Receptive field characteristics of neurones in striate cortex of newborn lambs and adult sheepNeuroscience, Vol. 10, No. 2Meridional variations in the line orientation discrimination of the catBehavioural Brain Research, Vol. 9, No. 2Prolonged sensitivity to monocular deprivation in dark-reared cats: Effects of age and visual exposureDevelopmental Brain Research, Vol. 8, No. 2-3Effects of monocular deprivation upon the binocularity of cells in area 18 of cat visual cortexDevelopmental Brain Research, Vol. 8, No. 1Frequency specific effects of stroboscopic rearing in the visual cortex of the rabbitDevelopmental Brain Research, Vol. 7, No. 2-3An oblique effect of spatial summationVision Research, Vol. 23, No. 6Chronic intraventricular administration of lysergic acid diethylamide (LSD) affects the sensitivity of cortical cells to monocular deprivationBrain Research, Vol. 250, No. 2Principal components analysis of cells in cat visual cortexBrain Research, Vol. 251, No. 1Plasticity in the kitten's visual cortex: effects of the suppression of visual experience upon the orientational properties of visual cortical cellsDevelopmental Brain Research, Vol. 4, No. 4The Oblique Effects of Pattern and Flicker Sensitivity: Implications for Mixed Physiological Input25 June 2016 | Perception, Vol. 11, No. 4Meridional Differences in Temporal Resolution25 June 2016 | Perception, Vol. 11, No. 1Comparison of the effects of dark rearing and binocular suture on development and plasticity of cat visual cortexBrain Research, Vol. 220, No. 2The critical period for alteration in cortical binocularity resulting from divergent and convergent strabismusDevelopmental Brain Research, Vol. 2, No. 2The effects of dark-rearing on the development and plasticity of the lateral geniculate nucleusDevelopmental Brain Research, Vol. 1, No. 3The influence of eccentricity on receptive field types and orientation selectivity in areas 17 and 18 of the catBrain Research, Vol. 208, No. 1 More from this issue > Volume 43Issue 4April 1980Pages 1111-1132 Copyright & PermissionsCopyright © 1980 the American Physiological Societyhttps://doi.org/10.1152/jn.1980.43.4.1111PubMed7359177History Published online 1 April 1980 Published in print 1 April 1980 Metrics

Restoration of visual cortical plasticity by local microperfusion of norepinephrine

Using a newly developed technique of continuous microperfusion, we obtained further evidence in support of our hypothesis that the neocortical catecholamines (CAs), particularly norepinephrine (NE), are responsible for a high level of cortical plasticity. We used the visual cortical changes in ocular dominance which follow a brief monocular deprivation as a simple and reliable index of cortical plasticity. Local perfusion of kitten visual cortex with 1 mg/ml (4.0 mM) 6-hydroxydopamine (6-OHDA) prevented the effects of monocular deprivation in kittens, thus replicating the results we had obtained using intraventricular injections (Kasamatsu and Pettigrew, '76b, '79). Locally perfused NE at a concentration of of 10(-2) mg/ml (48.6 micron) restored visual cortical plasticity in animals which were no longer susceptible to brief monocular lid-suture. These numbers refer to the concentration of solutions in the cannula/minipump system. The effective concentrations at the site of recording (about 2 mm away) are probably much lower than these. This effect of NE perfusion was seen both in kittens which had received prior 6-OHDA treatment as well as in older animals which had outgrown the susceptible period. In the kittens we obtained as a nearly complete shift in ocular dominance toward the open eye and in the older animals a decrease in binocularity was obtained. The changes were found only in the local region of visual cortex perfused with either NE or 6-OHDA, while nearby cortical regions in the same animals were unaffected. There were no obvious changes in receptive field properties of individual neurons other than ocularity, and externally perfused NE did not itself reduce binocularity in normal animals: the effects of NE described about only occurred when the animal's visual experience was simultaneously altered. These results support the view that NE plays an important role in cortical plasticity.