Structural basis of cortical synchronization. I. Three types of interhemispheric coupling

1995 ◽  
Vol 74 (6) ◽  
pp. 2379-2400 ◽  
Author(s):  
L. G. Nowak ◽  
M. H. Munk ◽  
J. I. Nelson ◽  
A. C. James ◽  
J. Bullier
Keyword(s):  
Time Course ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Structural Basis ◽  
Encounter Rate ◽  
Visual Responses ◽  
Different Types ◽  
Temporal Coupling ◽  
Areas 17 And 18 ◽  
Oscillatory Coupling

1. Single-unit and multiunit activities were recorded at the area 17-18 border of each cortical hemisphere in paralyzed cats anesthetized with nitrous oxide supplemented with halothane. Cross-correlation histograms (CCHs) were computed between 86 pairs of single units and 99 pairs of multiunit activities. Visually evoked peaks in the CCHs were removed by subtracting the shift predictor. 2. Three types of CCH peaks were observed: T peaks with narrow widths (4-28 ms), C peaks with intermediate widths (30-100 ms), and H peaks with large widths (100-1,000 ms). Oscillatory coupling was observed rarely. This tripartite distribution of CCH peaks is similar to that reported in an earlier study on the temporal coupling between areas 17 and 18. Different types of peaks occurred in isolation or in combination. Combination of different peak types was more often observed in multiunit recordings. 3. CCH peaks of all types were usually centered, meaning that units in opposite hemispheres tend to synchronize their discharges. 4. T peaks were observed almost exclusively for units with overlapping receptive fields and preferentially for units with similar optimal orientations. No dependence on receptive field position or optimal orientation was observed for the encounter rate of C and H peaks. 5. A new method, called the peristimulus CCH, was developed to study the time course of the temporal coupling. This showed that H peaks can occur during visual stimulation and that their time course follows that of the visual responses of the coupled neurons. 6. Using one single bar or two simultaneously presented light bars as stimuli, we studied the effect of visual stimulation on the strength of H coupling. This showed that H coupling observed under stimulation with a single moving light bar can be completely abolished, with little change in visual responses, when the stimulus is changed to two noncoherently moving bars. This was related to a strong decrease of the H peaks in the autocorrelograms. 7. These results demonstrate that T, C, and H peaks constitute, together with high-frequency oscillations, universal forms of temporal coupling between neurons located in different cortical areas. The following paper reports on the effects of cortical lesions on the encounter rate and strength of these different types of coupling.

Visual responses of pulvinar and collicular neurons during eye movements of awake, trained macaques

1991 ◽  
Vol 66 (2) ◽  
pp. 485-496 ◽  
Author(s):  
D. L. Robinson ◽  
J. W. McClurkin ◽  
C. Kertzman ◽  
S. E. Petersen
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Visual Responses ◽  
Stimulus Motion ◽  
Stimulus Movement ◽  
Pursuit Eye Movements ◽  
Extraretinal Signal ◽  
Wide Range

1. We recorded from single neurons in awake, trained rhesus monkeys in a lighted environment and compared responses to stimulus movement during periods of fixation with those to motion caused by saccadic or pursuit eye movements. Neurons in the inferior pulvinar (PI), lateral pulvinar (PL), and superior colliculus were tested. 2. Cells in PI and PL respond to stimulus movement over a wide range of speeds. Some of these cells do not respond to comparable stimulus motion, or discharge only weakly, when it is generated by saccadic or pursuit eye movements. Other neurons respond equivalently to both types of motion. Cells in the superficial layers of the superior colliculus have similar properties to those in PI and PL. 3. When tested in the dark to reduce visual stimulation from the background, cells in PI and PL still do not respond to motion generated by eye movements. Some of these cells have a suppression of activity after saccadic eye movements made in total darkness. These data suggest that an extraretinal signal suppresses responses to visual stimuli during eye movements. 4. The suppression of responses to stimuli during eye movements is not an absolute effect. Images brighter than 2.0 log units above background illumination evoke responses from cells in PI and PL. The suppression appears stronger in the superior colliculus than in PI and PL. 5. These experiments demonstrate that many cells in PI and PL have a suppression of their responses to stimuli that cross their receptive fields during eye movements. These cells are probably suppressed by an extraretinal signal. Comparable effects are present in the superficial layers of the superior colliculus. These properties in PI and PL may reflect the function of the ascending tectopulvinar system.

scholarly journals Eye-centered visual receptive fields in the ventral intraparietal area

2014 ◽  
Vol 112 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Xiaodong Chen ◽  
Gregory C. DeAngelis ◽  
Dora E. Angelaki
Keyword(s):  
Optic Flow ◽  
Reference Frames ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Large Field ◽  
Visual Responses ◽  
Full Field ◽  
Spatial Reference Frames ◽  
Visual Receptive Fields ◽  
Ventral Intraparietal Area

The ventral intraparietal area (VIP) processes multisensory visual, vestibular, tactile, and auditory signals in diverse reference frames. We recently reported that visual heading signals in VIP are represented in an approximately eye-centered reference frame when measured using large-field optic flow stimuli. No VIP neuron was found to have head-centered visual heading tuning, and only a small proportion of cells had reference frames that were intermediate between eye- and head-centered. In contrast, previous studies using moving bar stimuli have reported that visual receptive fields (RFs) in VIP are head-centered for a substantial proportion of neurons. To examine whether these differences in previous findings might be due to the neuronal property examined (heading tuning vs. RF measurements) or the type of visual stimulus used (full-field optic flow vs. a single moving bar), we have quantitatively mapped visual RFs of VIP neurons using a large-field, multipatch, random-dot motion stimulus. By varying eye position relative to the head, we tested whether visual RFs in VIP are represented in head- or eye-centered reference frames. We found that the vast majority of VIP neurons have eye-centered RFs with only a single neuron classified as head-centered and a small minority classified as intermediate between eye- and head-centered. Our findings suggest that the spatial reference frames of visual responses in VIP may depend on the visual stimulation conditions used to measure RFs and might also be influenced by how attention is allocated during stimulus presentation.

Postcritical-period reversal of effects of monocular deprivation on striate cortex cells in the cat

1976 ◽  
Vol 39 (3) ◽  
pp. 501-511 ◽  
Author(s):  
K. E. Kratz ◽  
P. D. Spear
Keyword(s):  
Critical Period ◽  
Time Course ◽  
Striate Cortex ◽  
Visual Stimulation ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Monocular Deprivation ◽  
Unit Recording ◽  
Functional Connections ◽  
Stimulation Of

1. The possibility that effects of monocular deprivation on cat striate cortex could be reversed after the developmental critical period by removal of the normal eye was investigated. In addition, the time course of any postcriticalperiod reversal was studied. Single-unit recording was conducted in the striate cortex of kittens anesthetized with nitrous oxide.2. Six control kittens were raised with monocular lid suture until they were 4-8 mo old (group MD). In agreement with previous investigators, from 0-10% of the striate cortex cells could be driven by visual stimulation of the deprived eye in these kittens.3. Eleven kittens were raised with monocular lid suture until they were 4-5 mo old, at which time the normal eye was enucleated. In five of these (group MD-DE-immediate), recording was conducted in striate cortex on the day of the enucleation. In these animals, 29-39% of the striate cortex cells could be driven by the deprived eye. In four kittens (group MD-DE-3 mo), the deprived eye remained closed for an additional 3 mo before recording was conducted. In these animals, 17-45% of the striate cortex cells could be driven by the deprived eye. In two kittens (group MD-DE greater than 12 mo), the deprived eye remained closed for 14-15 mo after the normal eye was enucleated. In these kittens, 26-40% of the striate cortex cells could be driven by the deprived eye. Thus, removal of the normal eye after the critical period in monocularly drprived kittens results in a rapid increase in the percent of striate cortex cells that can be driven by visual stimulation of the deprived eye, and there is no further increase in responsiveness over a period of more than a year.4. The receptive-field properties of the cells which responded to the deprived eye following enucleation of the normal eye were usually abnormal; 61% of them had nonspecific receptive fields, 39% of the responsive cells were direction selective, and only 12% were both direction and orientation selective.5. The increase in responsive cells was observed in the striate cortex of both hemispheres. However, the increase was greater in the hemisphere contralateral to the deprived eye. The responsive cells tended to occur in clusters of two to four adjacent cells separated by regions containing nonresponsive cells. These clusters were not related to the horizontal cortical layers; however, they may be related to the ocular dominance columns in striate cortex.6. Several mechanisms were considered for the present findings, including neuronal sprouting, denervation supersensitivity, and release from inhibition. It was suggested that the increased responsiveness to the deprived eye was probably not the result of rapid sprouting in the 4- to 5-mo-old kittens. If this is so, then the results indicate that functional connections from the deprived layers of the DLG to the striate cortex remain following rearing with monocular deprivation...

Serial and parallel processing of tactual information in somatosensory cortex of rhesus monkeys

1992 ◽  
Vol 68 (2) ◽  
pp. 518-527 ◽  
Author(s):  
T. P. Pons ◽  
P. E. Garraghty ◽  
M. Mishkin
Keyword(s):  
Substantial Reduction ◽  
Receptive Fields ◽  
Somatosensory System ◽  
Encounter Rate ◽  
Specific Information ◽  
Tactile Information ◽  
Cortical Areas ◽  
Area 3A ◽  
Area 3B ◽  
Made In

1. Selective ablations of the hand representations in postcentral cortical areas 3a, 3b, 1, and 2 were made in different combinations to determine each area's contribution to the responsivity and modality properties of neurons in the hand representation in SII. 2. Ablations that left intact only the postcentral areas that process predominantly cutaneous inputs (i.e., areas 3b and 1) yielded SII recording sites responsive to cutaneous stimulation and none driven exclusively by high-intensity or "deep" stimulation. Conversely, ablations that left intact only the postcentral areas that process predominantly deep receptor inputs (i.e., areas 3a and 2) yielded mostly SII recording sites that responded exclusively to deep stimulation. 3. Ablations that left intact only area 3a or only area 2 yielded substantial and roughly equal reductions in the number of deep receptive fields in SII. By contrast, ablations that left intact only area 3b or only area 1 yielded unequal reductions in the number of cutaneous receptive fields in SII: a small reduction when area 3b alone was intact but a somewhat larger one when only area 1 was intact. 4. Finally, when the hand representation in area 3b was ablated, leaving areas 3a, 1, and 2 fully intact, there was again a substantial reduction in the encounter rate of cutaneous receptive fields. 5. The partial ablations often led to unresponsive sites in the SII hand representation. In SII representations other than of the hand no such unresponsive sites were found and there were no substantial changes in the ratio of cutaneous to deep receptive fields, indicating that the foregoing results were not due to long-lasting postsurgical depression or effects of anesthesia. 6. The findings indicate that modality-specific information is relayed from postcentral cortical areas to SII along parallel channels, with cutaneous inputs transmitted via areas 3b and 1, and deep inputs via areas 3a and 2. Further, area 3b provides the major source of cutaneous input to SII, directly and perhaps also via area 1. 7. The results are in line with accumulating anatomic and electrophysiologic evidence pointing to an evolutionary shift in the organization of the somatosensory system from the general mammalian plan, in which tactile information is processed in parallel in SI and SII, to a new organization in higher primates in which the processing of tactile information proceeds serially from SI to SII. The presumed functional advantages of this evolutionary shift are unknown.

Area MT Neurons Respond to Visual Motion Distant From Their Receptive Fields

2005 ◽  
Vol 94 (6) ◽  
pp. 4156-4167 ◽  
Author(s):  
Daniel Zaksas ◽  
Tatiana Pasternak
Keyword(s):  
Time Course ◽  
Visual Motion ◽  
Cognitive Task ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Task Demands ◽  
Visual Signals ◽  
Area Mt ◽  
Mt Neurons ◽  
Stimulus Offset

Neurons in cortical area MT have localized receptive fields (RF) representing the contralateral hemifield and play an important role in processing visual motion. We recorded the activity of these neurons during a behavioral task in which two monkeys were required to discriminate and remember visual motion presented in the ipsilateral hemifield. During the task, the monkeys viewed two stimuli, sample and test, separated by a brief delay and reported whether they contained motion in the same or in opposite directions. Fifty to 70% of MT neurons were activated by the motion stimuli presented in the ipsilateral hemifield at locations far removed from their classical receptive fields. These responses were in the form of excitation or suppression and were delayed relative to conventional MT responses. Both excitatory and suppressive responses were direction selective, but the nature and the time course of their directionality differed from the conventional excitatory responses recorded with stimuli in the RF. Direction selectivity of the excitatory remote response was transient and early, whereas the suppressive response developed later and persisted after stimulus offset. The presence or absence of these unusual responses on error trials, as well as their magnitude, was affected by the behavioral significance of stimuli used in the task. We hypothesize that these responses represent top-down signals from brain region(s) accessing information about stimuli in the entire visual field and about the behavioral state of the animal. The recruitment of neurons in the opposite hemisphere during processing of behaviorally relevant visual signals reveals a mechanism by which sensory processing can be affected by cognitive task demands.

Temporal Dynamics of Shape Analysis in Macaque Visual Area V2

2004 ◽  
Vol 92 (5) ◽  
pp. 3030-3042 ◽  
Author(s):  
Jay Hegdé ◽  
David C. Van Essen
Keyword(s):  
Cortical Neurons ◽  
Time Course ◽  
Temporal Dynamics ◽  
Visual Stimulation ◽  
Signal To Noise Ratio ◽  
Stimulus Onset ◽  
Visual Area ◽  
Response Modulation ◽  
Population Response ◽  
Area V2

The firing rate of visual cortical neurons typically changes substantially during a sustained visual stimulus. To assess whether, and to what extent, the information about shape conveyed by neurons in visual area V2 changes over the course of the response, we recorded the responses of V2 neurons in awake, fixating monkeys while presenting a diverse set of static shape stimuli within the classical receptive field. We analyzed the time course of various measures of responsiveness and stimulus-related response modulation at the level of individual cells and of the population. For a majority of V2 cells, the response modulation was maximal during the initial transient response (40–80 ms after stimulus onset). During the same period, the population response was relatively correlated, in that V2 cells tended to respond similarly to specific subsets of stimuli. Over the ensuing 80–100 ms, the signal-to-noise ratio of individual cells generally declined, but to a lesser degree than the evoked-response rate during the corresponding time bins, and the response profiles became decorrelated for many individual cells. Concomitantly, the population response became substantially decorrelated. Our results indicate that the information about stimulus shape evolves dynamically and relatively rapidly in V2 during static visual stimulation in ways that may contribute to form discrimination.

Directional selectivity and spatiotemporal structure of receptive fields of simple cells in cat striate cortex

1991 ◽  
Vol 66 (2) ◽  
pp. 505-529 ◽  
Author(s):  
R. C. Reid ◽  
R. E. Soodak ◽  
R. M. Shapley
Keyword(s):  
Time Course ◽  
Linear Prediction ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Quantitative Measure ◽  
Direction Selectivity ◽  
Simple Cells ◽  
Preferred Direction ◽  
Orientation Contrast ◽  
Cat Striate Cortex

1. Simple cells in cat striate cortex were studied with a number of stimulation paradigms to explore the extent to which linear mechanisms determine direction selectivity. For each paradigm, our aim was to predict the selectivity for the direction of moving stimuli given only the responses to stationary stimuli. We have found that the prediction robustly determines the direction and magnitude of the preferred response but overestimates the nonpreferred response. 2. The main paradigm consisted of comparing the responses of simple cells to contrast reversal sinusoidal gratings with their responses to drifting gratings (of the same orientation, contrast, and spatial and temporal frequencies) in both directions of motion. Although it is known that simple cells display spatiotemporally inseparable responses to contrast reversal gratings, this spatiotemporal inseparability is demonstrated here to predict a certain amount of direction selectivity under the assumption that simple cells sum their inputs linearly. 3. The linear prediction of the directional index (DI), a quantitative measure of the degree of direction selectivity, was compared with the measured DI obtained from the responses to drifting gratings. The median value of the ratio of the two was 0.30, indicating that there is a significant nonlinear component to direction selectivity. 4. The absolute magnitudes of the responses to gratings moving in both directions of motion were compared with the linear predictions as well. Whereas the preferred direction response showed only a slight amount of facilitation compared with the linear prediction, there was a significant amount of nonlinear suppression in the nonpreferred direction. 5. Spatiotemporal inseparability was demonstrated also with stationary temporally modulated bars. The time course of response to these bars was different for different positions in the receptive field. The degree of spatiotemporal inseparability measured with sinusoidally modulated bars agreed quantitatively with that measured in experiments with stationary gratings. 6. A linear prediction of the responses to drifting luminance borders was compared with the actual responses. As with the grating experiments, the prediction was qualitatively accurate, giving the correct preferred direction but underestimating the magnitude of direction selectivity observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Receptive Field Size and Response Latency Are Correlated Within the Cat Visual Thalamus

2005 ◽  
Vol 93 (6) ◽  
pp. 3537-3547 ◽  
Author(s):  
Chong Weng ◽  
Chun-I Yeh ◽  
Carl R. Stoelzel ◽  
Jose-Manuel Alonso
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Response Latency ◽  
Time Course ◽  
Frequency Tuning ◽  
Receptive Fields ◽  
Cortical Cell ◽  
Field Size ◽  
Receptive Field Size ◽  
Spatial Frequency Tuning

Each point in visual space is encoded at the level of the thalamus by a group of neighboring cells with overlapping receptive fields. Here we show that the receptive fields of these cells differ in size and response latency but not at random. We have found that in the cat lateral geniculate nucleus (LGN) the receptive field size and response latency of neighboring neurons are significantly correlated: the larger the receptive field, the faster the response to visual stimuli. This correlation is widespread in LGN. It is found in groups of cells belonging to the same type (e.g., Y cells), and of different types (i.e., X and Y), within a specific layer or across different layers. These results indicate that the inputs from the multiple geniculate afferents that converge onto a cortical cell (approximately 30) are likely to arrive in a sequence determined by the receptive field size of the geniculate afferents. Recent studies have shown that the peak of the spatial frequency tuning of a cortical cell shifts toward higher frequencies as the response progresses in time. Our results are consistent with the idea that these shifts in spatial frequency tuning arise from differences in the response time course of the thalamic inputs.

Neuronal activity related to visually guided saccades in the frontal eye fields of rhesus monkeys: comparison with supplementary eye fields

1991 ◽  
Vol 66 (2) ◽  
pp. 559-579 ◽  
Author(s):  
J. D. Schall
Keyword(s):  
Rhesus Monkeys ◽  
Time Course ◽  
Receptive Fields ◽  
Peak Level ◽  
Frontal Eye Fields ◽  
Visually Guided ◽  
Visual Cells ◽  
Preparatory Set ◽  
Functional Classes ◽  
Supplementary Eye Fields

1. The purpose of this study was to analyze the response properties of neurons in the frontal eye fields (FEF) of rhesus monkeys (Macaca mulatta) and to compare and contrast the various functional classes with those recorded in the supplementary eye fields (SEF) of the same animals performing the same go/no-go visual tracking task. Three hundred ten cells recorded in FEF provided the data for this investigation. 2. Visual cells in FEF responded to the stimuli that guided the eye movements. The visual cells in FEF responded with a slightly shorter latency and were more consistent and phasic in their activation than their counterparts in SEF. The receptive fields tended to emphasize the contralateral hemifield to the same extent as those observed in SEF visual cells. 3. Preparatory set cells began to discharge after the presentation of the target and ceased firing before the saccade, after the go/no-go cue was given. These neurons comprised a smaller proportion in FEF than in SEF. In contrast to their counterparts in SEF, the preparatory set cells in FEF did not respond preferentially in relation to contralateral movements, even though most responded preferentially for movements in one particular direction. The time course of the discharge of the FEF set cells was similar to that of their SEF counterparts, except that they reached their peak level of activation sooner. The few preparatory set cells in FEF tested with both auditory and visual stimuli tended to respond preferentially to the visual targets, whereas, in contrast, most set cells in SEF were bimodal. 4. Sensory-movement cells represented the largest population of cells recorded in FEF, responding in relation to both the presentation of the targets and the execution of the saccade. Although some of these sensory-movement cells resembled their counterparts in SEF by exhibiting a sustained elevation of activity, most of the FEF sensory-movement cells gave two discrete bursts, one after the presentation of the target and another before and during the saccade. Like their counterparts in SEF, the sensory-movement cells tended to be tuned for saccades into the contralateral hemifield, but this tendency was more pronounced in FEF than in SEF. The FEF sensory-movement cells discharged more briskly, with a shorter latency relative to the presentation of the target, than their counterparts in SEF. In addition, the FEF sensory-movement neurons reached their peak activation sooner than SEF sensory-movement neurons. Most FEF sensory-movement cells exhibited different patterns of activation in response to visual and auditory targets.(ABSTRACT TRUNCATED AT 400 WORDS)

Receptive-field properties and neuronal connectivity in striate and parastriate cortex of contour-deprived cats

1976 ◽  
Vol 39 (3) ◽  
pp. 613-630 ◽  
Author(s):  
W. Singer ◽  
F. Tretter
Keyword(s):  
Electrical Stimulation ◽  
Receptive Field ◽  
Visual Experience ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Connectivity Pattern ◽  
Area 18 ◽  
Efferent Connections ◽  
Receptive Field Properties ◽  
Areas 17 And 18

An attempt was made to relate the alterations of cortical receptive fields as they result from binocular visual deprivation to changes in afferent, intrinsic, and efferent connections of the striate and parastriate cortex. The experiments were performed in cats aged at least 1 jr with their eyelids sutured closed from birth.The results of the receptive-field analysis in A17 confirmed the reduction of light-responsive cells, the occasional incongruity of receptive-field properties in the two eyes, and to some extent also the loss of orientation and direction selectivity as reported previously. Other properties common to numerous deprived receptive fields were the lack of sharp inhibitory sidebands and the sometimes exceedingly large size of the receptive fields. Qualitatively as well as quantitatively, similar alterations were observed in area 18. A rather high percentage of cells in both areas had, however, preserved at least some orientation preference, and a few receptive fields had tuning properties comparable to those in normal cats. The ability of area 18 cells in normal cats to respond to much higher stimulus velocities than area 17 cells was not influenced by deprivation.The results obtained with electrical stimulation suggest two main deprivation effects: 1) A marked decrease in the safety factor of retinothalamic and thalamocortical transmission. 2) A clear decrease in efficiency of intracortical inhibition. But the electrical stimulation data also show that none of the basic principles of afferent, intrinsic, and efferent connectivity is lost or changed by deprivation. The conduction velocities in the subcortical afferents and the differentiation of the afferents to areas 17 and 18 into slow- and fast-conducting projection systems remain unaltered. Intrinsic excitatory connections remain functional; this is also true for the disynaptic inhibitory pathways activated preferentially by the fast-conducting thalamocortical projection. The laminar distribution of cells with monosynaptic versus polsynaptic excitatory connections is similar to that in normal cats. Neurons with corticofugal axons remain functionally connected and show the same connectivity pattern as those in normal cats. The nonspecific activation system from the mesencephalic reticular formation also remains functioning both at the thalamic and the cortical level.We conclude from these and several other observations that most, if not all, afferent, intrinsic, and efferent connections of areas 17 and 18 are specified from birth and depend only little on visual experience. This predetermined structural plan, however, allows for some freedom in the domain of orientation tuning, binocular correspondence, and retinotopy which is specified only when visual experience is possible.

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