Eye Position Compensation Improves Estimates of Response Magnitude and Receptive Field Geometry in Alert Monkeys

2007 ◽  
Vol 97 (5) ◽  
pp. 3439-3448 ◽  
Author(s):  
Yamei Tang ◽  
Alan Saul ◽  
Moshe Gur ◽  
Stephanie Goei ◽  
Elsie Wong ◽  
...  
Keyword(s):  
Eye Movements ◽  
Receptive Field ◽  
Receptive Fields ◽  
Eye Position ◽  
Stimulus Position ◽  
Fixational Eye Movements ◽  
Field Geometry ◽  
Receptive Field Subregions ◽  
Movement Compensation ◽  
Definition Of

Studies of visual function in behaving subjects require that stimuli be positioned reliably on the retina in the presence of eye movements. Fixational eye movements scatter stimuli about the retina, inflating estimates of receptive field dimensions, reducing estimates of peak responses, and blurring maps of receptive field subregions. Scleral search coils are frequently used to measure eye position, but their utility for correcting the effects of fixational eye movements on receptive field maps has been questioned. Using eye coils sutured to the sclera and preamplifiers configured to minimize cable artifacts, we reexamined this issue in two rhesus monkeys. During repeated fixation trials, the eye position signal was used to adjust the stimulus position, compensating for eye movements and correcting the stimulus position to place it at the desired location on the retina. Estimates of response magnitudes and receptive field characteristics in V1 and in LGN were obtained in both compensated and uncompensated conditions. Receptive fields were narrower, with steeper borders, and response amplitudes were higher when eye movement compensation was used. In sum, compensating for eye movements facilitated more precise definition of the receptive field. We also monitored horizontal vergence over long sequences of fixation trials and found the variability to be low, as expected for this precise behavior. Our results imply that eye coil signals can be highly accurate and useful for optimizing visual physiology when rigorous precautions are observed.

scholarly journals Measuring V1 Receptive Fields Despite Eye Movements in Awake Monkeys

2003 ◽  
Vol 90 (2) ◽  
pp. 946-960 ◽  
Author(s):  
Jenny C. A. Read ◽  
Bruce G. Cumming
Keyword(s):  
Eye Movements ◽  
Receptive Field ◽  
Time Course ◽  
Receptive Fields ◽  
Field Measurements ◽  
Field Structure ◽  
Eye Position ◽  
Stimulus Position ◽  
Fixational Eye Movements ◽  
The Difference

One difficulty with measuring receptive fields in the awake monkey is that even well-trained animals make small eye movements during fixation. These complicate the measurement of receptive fields by blurring out the region where a response is observed, causing underestimates of the ability of individual neurons to signal changes in stimulus position. In simple cells, this blurring may severely disrupt estimates of receptive field structure. An accurate measurement of eye movements would allow correction of this blurring. Scleral search coils have been used to provide such measurements, although little is known about their accuracy. We have devised a range of approaches to address this issue: implanting two coils into a single eye, exploiting the small size of V1 receptive fields and developing maximum-likelihood fitting techniques to extract receptive field parameters in the presence of eye movements. All our investigations lead to the same conclusion: our scleral search coils (which were not sutured to the globe) are subject to an error of approximately the same magnitude as the small eye movements which occur during fixation: SD ∼ 0.1°. This error is large enough to explain the SD of measured vergence in the absence of any real changes in vergence state. This, and a variety of other arguments, indicate that the real variation in vergence is much smaller than coil measurements suggest. These results suggest that monkeys, like humans, maintain very stable vergence. The error has a slower time course than fixational eye movements so that search coils report the difference in eye position between two consecutive trials more accurately than the eye position itself on either trial. Receptive field estimates are unlikely to be improved by assuming the coil record is veridical and correcting for eye position accordingly. However, receptive field parameters can reliably be determined by a fitting technique that allows for eye movements. It is possible that suturing coils to the globe reduces the artifacts, but no method has been available to demonstrate this. These receptive field measurements provide a general means by which the reliability of eye-position measurements can be assessed.

scholarly journals Rhythmic neural spiking and attentional sampling arising from cortical receptive field interactions

2018 ◽  
Author(s):  
Ricardo Kienitz ◽  
Joscha T. Schmiedt ◽  
Katharine A. Shapcott ◽  
Kleopatra Kouroupaki ◽  
Richard C. Saunders ◽  
...  
Keyword(s):  
Eye Movements ◽  
Receptive Field ◽  
Spatial Attention ◽  
Receptive Fields ◽  
Reaction Times ◽  
List Type ◽  
Attention Task ◽  
Area V4 ◽  
Fixational Eye Movements ◽  
Visual Cortical Area

SummaryGrowing evidence suggests that distributed spatial attention may invoke theta (3-9 Hz) rhythmic sampling processes. The neuronal basis of such attentional sampling is however not fully understood. Here we show using array recordings in visual cortical area V4 of two awake macaques that presenting separate visual stimuli to the excitatory center and suppressive surround of neuronal receptive fields elicits rhythmic multi-unit activity (MUA) at 3-6 Hz. This neuronal rhythm did not depend on small fixational eye movements. In the context of a distributed spatial attention task, during which the monkeys detected a spatially and temporally uncertain target, reaction times (RT) exhibited similar rhythmic fluctuations. RTs were fast or slow depending on the target occurrence during high or low MUA, resulting in rhythmic MUA-RT cross-correlations at at theta frequencies. These findings suggest that theta-rhythmic neuronal activity arises from competitive receptive field interactions and that this rhythm may subserve attentional sampling.HighlightsCenter-surround interactions induce theta-rhythmic MUA of visual cortex neuronsThe MUA rhythm does not depend on small fixational eye movementsReaction time fluctuations lock to the neuronal rhythm under distributed attention

A model of the dynamics of retinal activity during natural visual fixation

2007 ◽  
Vol 24 (2) ◽  
pp. 217-230 ◽  
Author(s):  
GAËLLE DESBORDES ◽  
MICHELE RUCCI
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Visual Fixation ◽  
Natural Scenes ◽  
M Cells ◽  
Retinal Activity ◽  
Cell Responses ◽  
Fixational Eye Movements

During visual fixation, small eye movements keep the retinal image continuously in motion. It is known that neurons in the visual system are sensitive to the spatiotemporal modulations of luminance resulting from this motion. In this study, we examined the influence of fixational eye movements on the statistics of neural activity in the macaque's retina during the brief intersaccadic periods of natural visual fixation. The responses of parvocellular (P) and magnocellular (M) ganglion cells in different regions of the visual field were modeled while their receptive fields scanned natural images following recorded traces of eye movements. Immediately after the onset of fixation, wide ensembles of coactive ganglion cells extended over several degrees of visual angle, both in the central and peripheral regions of the visual field. Following this initial pattern of activity, the covariance between the responses of pairs of P and M cells and the correlation between the responses of pairs of M cells dropped drastically during the course of fixation. Cell responses were completely uncorrelated by the end of a typical 300-ms fixation. This dynamic spatial decorrelation of retinal activity is a robust phenomenon independent of the specifics of the model. We show that it originates from the interaction of three factors: the statistics of natural scenes, the small amplitudes of fixational eye movements, and the temporal sensitivities of ganglion cells. These results support the hypothesis that fixational eye movements, by shaping the statistics of retinal activity, are an integral component of early visual representations.

scholarly journals Microsaccade characterization using the continuous wavelet transform and principal component analysis

2010 ◽  
Vol 3 (5) ◽  
Author(s):  
Mario Bettenbühl ◽  
Claudia Paladini ◽  
Konstantin Mergenthaler ◽  
Reinhold Kliegl ◽  
Ralf Engbert ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Wavelet Transform ◽  
Eye Movements ◽  
Continuous Wavelet Transform ◽  
Principal Component ◽  
Real Data ◽  
Component Analysis ◽  
Continuous Wavelet ◽  
Fixational Eye Movements ◽  
Definition Of

During visual fixation on a target, humans perform miniature (or fixational) eye movements consisting of three components, i.e., tremor, drift, and microsaccades. Microsaccades are high velocity components with small amplitudes within fixational eye movements. However, microsaccade shapes and statistical properties vary between individual observers. Here we show that microsaccades can be formally represented with two significant shapes which we identfied using the mathematical definition of singularities for the detection of the former in real data with the continuous wavelet transform. For character-ization and model selection, we carried out a principal component analysis, which identified a step shape with an overshoot as first and a bump which regulates the overshoot as second component. We conclude that microsaccades are singular events with an overshoot component which can be detected by the continuous wavelet transform.

scholarly journals Beyond the labeled line: variation in visual reference frames from intraparietal cortex to frontal eye fields and the superior colliculus

2017 ◽  
Author(s):  
V. C. Caruso ◽  
D. S. Pages ◽  
M. A. Sommer ◽  
J. M. Groh
Keyword(s):  
Receptive Field ◽  
Superior Colliculus ◽  
Reference Frames ◽  
Receptive Fields ◽  
Visual Signals ◽  
Eye Position ◽  
Frontal Eye Fields ◽  
Response Patterns ◽  
The Stability ◽  
Retinal Information

ABSTRACTWe accurately perceive the visual scene despite moving our eyes ~3 times per second, an ability that requires incorporation of eye position and retinal information. We assessed how this neural computation unfolds across three interconnected structures: frontal eye fields (FEF), intraparietal cortex (LIP/MIP), and the superior colliculus (SC). Single unit activity was assessed in head-restrained monkeys performing visually-guided saccades from different initial fixations. As previously shown, the receptive fields of most LIP/MIP neurons shifted to novel positions on the retina for each eye position, and these locations were not clearly related to each other in either eye- or head-centered coordinates (hybrid coordinates). In contrast, the receptive fields of most SC neurons were stable in eye-centered coordinates. In FEF, visual signals were intermediate between those patterns: around 60% were eye-centered, whereas the remainder showed changes in receptive field location, boundaries, or responsiveness that rendered the response patterns hybrid or occasionally head-centered. These results suggest that FEF may act as a transitional step in an evolution of coordinates between LIP/MIP and SC. The persistence across cortical areas of hybrid representations that do not provide unequivocal location labels in a consistent reference frame has implications for how these representations must be read-out.New & NoteworthyHow we perceive the world as stable using mobile retinas is poorly understood. We compared the stability of visual receptive fields across different fixation positions in three visuomotor regions. Irregular changes in receptive field position were ubiquitous in intraparietal cortex, evident but less common in the frontal eye fields, and negligible in the superior colliculus (SC), where receptive fields shifted reliably across fixations. Only the SC provides a stable labelled-line code for stimuli across saccades.

Abnormal fixational eye movements in strabismus

2017 ◽  
Vol 102 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Fatema F Ghasia ◽  
Jorge Otero-Millan ◽  
Aasef G Shaikh
Keyword(s):  
Eye Movements ◽  
Large Angle ◽  
Fine Tuning ◽  
Eye Position ◽  
Visually Guided ◽  
Binocular Fusion ◽  
The Gaze ◽  
Fixational Eye Movements ◽  
The Stability ◽  
Fixational Saccades

IntroductionFixational saccades are miniature eye movements that constantly change the gaze during attempted visual fixation. Visually guided saccades and fixational saccades represent an oculomotor continuum and are produced by common neural machinery. Patients with strabismus have disconjugate binocular horizontal saccades. We examined the stability and variability of eye position during fixation in patients with strabismus and correlated the severity of fixational instability with strabismus angle and binocular vision.MethodsEye movements were measured in 13 patients with strabismus and 16 controls during fixation and visually guided saccades under monocular viewing conditions. Fixational saccades and intersaccadic drifts were analysed in the viewing and non-viewing eye of patients with strabismus and controls.ResultsWe found an increase in fixational instability in patients with strabismus compared with controls. We also found an increase in the disconjugacy of fixational saccades and intrasaccadic ocular drift in patients with strabismus compared with controls. The disconjugacy was worse in patients with large-angle strabismus and absent stereopsis. There was an increase in eye position variance during drifts in patients with strabismus. Our findings suggest that both fixational saccades and intersaccadic drifts are abnormal and likely contribute to the fixational instability in patients with strabismus.DiscussionFixational instability could be a useful tool for mass screenings of children to diagnose strabismus in the absence of amblyopia and latent nystagmus. The increased disconjugacy of fixational eye movements and visually guided saccades in patients with strabismus reflects the disruption of the fine-tuning of the motor and visual systems responsible for achieving binocular fusion in these patients.

Visual and presaccadic neuronal activity in thalamic internal medullary lamina of cat: a study of targeting

1977 ◽  
Vol 40 (1) ◽  
pp. 156-173 ◽  
Author(s):  
M. Schlag-Rey ◽  
J. Schlag
Keyword(s):  
Eye Movements ◽  
Receptive Field ◽  
Eye Movement ◽  
Receptive Fields ◽  
Stimulus Presentation ◽  
Visual Responses ◽  
Stimulus Movement ◽  
The Gaze ◽  
Double Activation ◽  
Alert Cats

1. Visual responses and eye movement-related activities were studied in single neurons of the thalamic internal medullary lamina (IML) of alert cats. The animals faced a tangent screen on which stationary or moving spots of light were presented. Of 95 units, 26% discharged in relation to photic stimuli but not eye movement, 6% in relation to eye movement but not photic stimuli, and 68% in relation to both. These units were intermixed in the same region. 2. Visual responses varied from transient to sustained. IML units were not found particularly sensitive to stimulus movement when the eyes were fixed. Strong and consistent responses could be elicited by extremely dim and weakly contrasted stationary stimuli (e.g.) 3.4 mcd/m2, 2.6% of illumination background) binocularly viewed. Receptive fields (from 250 to 800 deg2) were determined, in absence of eye movements, by computing the position of effective stimuli relative to the point of fixation of the gaze. An area of greatest responsiveness in the receptive field of most units could be detected on the basis of either higher probability of response, minimum latency, greater number of spikes in initial transient burst, or stronger sustained activity. Whole fields or their areas of greatest responsiveness were located on the side toward which saccades were accompanied by increased firing of the unit. 3. On trials in which a delay occurred between stimulus presentation and the cat's targeting saccade, the majority of the units studied changed their activity twice: after the stimulus and before the eye movement. In 16 units, the presaccadic activation occurred only with targeting, not with spontaneous saccades. 4. These results suggest that cells in the IML region of the cat play a significant role in the control of visually elicited eye movements. The resemblance of these cells to the monkey's tectual cells is discussed and hypotheses are proposed a) to relate the receptive field characteristics to the targeting operation, and b) to account for the double activation--sensory and motor--of many IML cells.

scholarly journals Beyond Fixation: detailed characterization of neural selectivity in free-viewing primates

2021 ◽  
Author(s):  
Jacob L Yates ◽  
Shanna H Coop ◽  
Gabriel H Sarch ◽  
Ruei-Jr Wu ◽  
Daniel A Butts ◽  
...  
Keyword(s):  
Eye Movements ◽  
Receptive Fields ◽  
Natural Behavior ◽  
Visual Neurons ◽  
Trained Subjects ◽  
V1 Neurons ◽  
Fixational Eye Movements ◽  
Neural Selectivity

Virtually all vision studies use a fixation point to stabilize gaze, rendering stimuli on video screens fixed to retinal coordinates. This approach requires trained subjects, is limited by the accuracy of fixational eye movements, and ignores the role of eye movements in shaping visual input. To overcome these limitations, we developed a suite of hardware and software tools to study vision during natural behavior in untrained subjects. We show this approach recovers receptive fields and tuning properties of visual neurons from multiple cortical areas of marmoset monkeys. Combined with high-precision eye-tracking, it achieves sufficient resolution to recover the receptive fields of foveal V1 neurons. These findings demonstrate the power of this approach for characterizing neural response while simultaneously studying the dynamics of natural behavior.

Finger movement responses of cutaneous mechanoreceptors in the dorsal skin of the human hand

1991 ◽  
Vol 65 (3) ◽  
pp. 657-670 ◽  
Author(s):  
B. B. Edin ◽  
J. H. Abbs
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Sampling Bias ◽  
Human Hand ◽  
Joint Movement ◽  
Dorsal Skin ◽  
Cutaneous Mechanoreceptors ◽  
Graded Responses ◽  
Finger Flexion ◽  
Definition Of

1. The movement sensitivity of dorsal skin mechanoreceptors in the human hand was studied by the use of single afferent recording techniques. 2. Units were classified as slowly (SA) and fast adapting (FA) and further characterized by thresholds to vertical indentation and by receptive-field sizes. Whereas SA units were evenly distributed within the supply area of the superficial branch of the radial nerve. FA units were usually situated near joints. 3. The proportion of different receptor types (32% SAI, 32% SAII, 28% FAI, 8% FAII; n = 107) compared favorably with previous electrophysiological and anatomic data, arguing for minimal sampling bias. The majority of the skin mechanoreceptive units were SA, largely due to a relative scarcity of FAII [Pacinian corpuscles (PC)] units. 4. A large majority (92%) of the afferents responded to active hand or finger movements. Responses in all unit types were consistent with observed movement-induced deformations of their receptive fields. 5. FAI units responded bidirectionally, albeit usually with somewhat higher discharge frequencies for finger flexion, which in most cases were associated with skin stretch. FAI units showed meager responses to remote stimuli, typically responding to one or, at the most, two adjacent joints. 6. SA units typically showed simple directional responses to joint movements with an increased discharge during flexion and a reduced discharge during extension. Joint movement that influenced the skin within the receptive field of SA units elicited graded responses even if the field, as assessed by perpendicular indentations, was minute. This finding suggests that definition of cutaneous receptive fields by classical perpendicular indentations may be inappropriate for the receptors in the hairy, nonglabrous skin. 7. The interpretation of the data from these recordings suggests that cutaneous mechanoreceptors in the dorsal skin can provide the CNS with detailed kinematic information, at least for movements of the hand.

scholarly journals Beyond the labeled line: variation in visual reference frames from intraparietal cortex to frontal eye fields and the superior colliculus

2018 ◽  
Vol 119 (4) ◽  
pp. 1411-1421 ◽  
Author(s):  
Valeria C. Caruso ◽  
Daniel S. Pages ◽  
Marc A. Sommer ◽  
Jennifer M. Groh
Keyword(s):  
Receptive Field ◽  
Superior Colliculus ◽  
Reference Frames ◽  
Receptive Fields ◽  
Visual Signals ◽  
Eye Position ◽  
Frontal Eye Fields ◽  
Response Patterns ◽  
The Stability ◽  
Retinal Information

We accurately perceive the visual scene despite moving our eyes ~3 times per second, an ability that requires incorporation of eye position and retinal information. In this study, we assessed how this neural computation unfolds across three interconnected structures: frontal eye fields (FEF), intraparietal cortex (LIP/MIP), and the superior colliculus (SC). Single-unit activity was assessed in head-restrained monkeys performing visually guided saccades from different initial fixations. As previously shown, the receptive fields of most LIP/MIP neurons shifted to novel positions on the retina for each eye position, and these locations were not clearly related to each other in either eye- or head-centered coordinates (defined as hybrid coordinates). In contrast, the receptive fields of most SC neurons were stable in eye-centered coordinates. In FEF, visual signals were intermediate between those patterns: around 60% were eye-centered, whereas the remainder showed changes in receptive field location, boundaries, or responsiveness that rendered the response patterns hybrid or occasionally head-centered. These results suggest that FEF may act as a transitional step in an evolution of coordinates between LIP/MIP and SC. The persistence across cortical areas of mixed representations that do not provide unequivocal location labels in a consistent reference frame has implications for how these representations must be read out. NEW & NOTEWORTHY How we perceive the world as stable using mobile retinas is poorly understood. We compared the stability of visual receptive fields across different fixation positions in three visuomotor regions. Irregular changes in receptive field position were ubiquitous in intraparietal cortex, evident but less common in the frontal eye fields, and negligible in the superior colliculus (SC), where receptive fields shifted reliably across fixations. Only the SC provides a stable labeled-line code for stimuli across saccades.

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