Precise Alignment of Micromachined Electrode Arrays With V1 Functional Maps

2007 ◽  
Vol 97 (5) ◽  
pp. 3781-3789 ◽  
Author(s):  
Ian Nauhaus ◽  
Dario L. Ringach
Keyword(s):  
Receptive Field ◽  
Electrode Array ◽  
Theoretical Models ◽  
Orientation Tuning ◽  
Feedback Signal ◽  
Electrode Arrays ◽  
Tuning Curves ◽  
Alignment Procedure ◽  
Receptive Field Properties ◽  
Orientation Maps

Recent theoretical models of primary visual cortex predict a relationship between receptive field properties and the location of the neuron within the orientation maps. Testing these predictions requires the development of new methods that allow the recording of single units at various locations across the orientation map. Here we present a novel technique for the precise alignment of functional maps and array recordings. Our strategy consists of first measuring the orientation maps in V1 using intrinsic optical imaging. A micromachined electrode array is subsequently implanted in the same patch of cortex for electrophysiological recordings, including the measurement of orientation tuning curves. The location of the array within the map is obtained by finding the position that maximizes the agreement between the preferred orientations measured electrically and optically. Experimental results of the alignment procedure from two implementations in monkey V1 are presented. The estimated accuracy of the procedure is evaluated using computer simulations. The methodology should prove useful in studying how signals from the local neighborhood of a neuron, thought to provide a dominant feedback signal, shape the receptive field properties in V1.

Effects of Biased AC Electroosmotic Micro-Pumping on Symmetric and Asymmetric Electrode Arrays

2012 ◽  
Author(s):  
Nazmul Islam
Keyword(s):  
Electrode Array ◽  
Theoretical Models ◽  
Electrode Arrays ◽  
Flow Measurements ◽  
Flow Rates ◽  
Forward Flow ◽  
Electrically Conducting ◽  
Array Configuration ◽  
Mems Fabrication ◽  
Dc Bias

This paper presents an analysis and experiment results that were conducted to assess the effect of combining an AC signal with a DC bias when generating the electric field on electrode arrays needed to impart electroosmosis within a microchannel. The analysis was done using COMSOL 3.5a in which currently available theoretical models for EO flows were embedded in the software and solved numerically. The simulation evaluate the effects of channel geometry, frequency of excitation, electrode array geometry, and AC signal with a DC bias on the flow imparted on an electrically conducting fluid. For the AC driven flow, the simulation results indicate the existence of an optimized frequency of excitation and an optimum geometry that lead to the maximum net forward flow of the pump. No relevant net flows were generated with the symmetric electrode arrays with a constant magnitude of AC voltage applied to both electrodes. However, superimposing a DC signal over the AC signal on the same symmetric electrode array lead to a noticeable net forward flow of 18.70 μL/min. On the other hand asymmetric electrode pattern can generate flow in both cases and can improve the microflow inside the micro-channel. Experimental flow measurements were performed on several electrode array configurations manufactured using typical MEMS fabrication techniques. The experimental results are in good agreement with the simulation data. They confirm that using an asymmetric electrode array excited by an AC signal with a DC bias leads to a significant improvement in flow rates in comparison to the flow rates obtained in an asymmetric electrode array configuration excited just with an AC signal.

Receptive field properties of neurons in area V3 of macaque monkey extrastriate cortex

1987 ◽  
Vol 57 (4) ◽  
pp. 889-920 ◽  
Author(s):  
D. J. Felleman ◽  
D. C. Van Essen
Keyword(s):  
Receptive Field ◽  
Binocular Disparity ◽  
Visual Fields ◽  
Direction Selectivity ◽  
Extrastriate Cortex ◽  
Thin Strip ◽  
Stimulus Motion ◽  
Form Analysis ◽  
Tuning Curves ◽  
Receptive Field Properties

Receptive field properties of 147 neurons histologically verified to be located in area V3 were investigated during semichronic recording from paralyzed anesthetized macaque monkeys. Quantitative analyses were made of neuron selectivities for direction, orientation, speed, binocular disparity, and color. The majority of neurons in V3 (76%) were strongly orientation selective; 40% demonstrated strong direction selectivity. Most cells were tuned for stimulus speed and almost half showed optimum responses at 16 degrees/s. The distribution of optimum speeds ranged primarily from 4 to 32 degrees/s. Several cells in V3 displayed multi-peaked orientation- and/or direction-tuning curves. These cells had two or more narrowly tuned peaks that were not co-axial. In some ways, they resemble higher-order hypercomplex cells of cat area 19 and may subserve a higher level of form or motion analysis than is seen at antecedent visual areas. Roughly half (45%) of the cells were selective for binocular disparity. Approximately half of these were tuned excitatory in that they showed weak responses when tested through either eye alone, but showed strong binocular facilitation centered on the fixation plane. The other disparity-selective cells were tuned inhibitory or asymmetric in their responses in front and behind the fixation plane. Contrary to previous reports, approximately 20% of the neurons in V3 were color selective in terms of showing a severalfold greater response to the best monochromatic wavelength compared with the worst. Color-tuning curves of the subset of color selective cells had, on average, a full bandwidth at half maximum response of 80-100 nm. A comparison of the receptive field properties of neurons in V3 to those in other areas of visual cortex suggests that V3, like MT, is well suited for the analysis of several aspects of stimulus motion. V3 may also be involved in some aspects of form analysis, particularly at low contrast levels. Comparison with area VP, a thin strip of cortex anterior to ventral V2, which was previously considered part of V3, indicates that direction selectivity is much more prevalent in V3 than in VP. Conversely, color-selective cells are the majority in VP but a minority in V3. This suggests that visual information is processed differently in the upper and lower visual fields.

Development of spatial receptive-field organization and orientation selectivity in kitten striate cortex

1985 ◽  
Vol 53 (5) ◽  
pp. 1158-1178 ◽  
Author(s):  
B. O. Braastad ◽  
P. Heggelund
Keyword(s):  
Receptive Field ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Orientation Selectivity ◽  
Half Width ◽  
Orientation Tuning ◽  
Maximal Response ◽  
Tuning Curves ◽  
Field Organization ◽  
Receptive Field Organization

The functional organization of the receptive field of neurons in striate cortex of kittens from 8 days to 3 mo of age was studied by extracellular recordings. A quantitative dual-stimulus technique was used, which allowed for analysis of both enhancement and suppression zones in the receptive field. Furthermore the development of orientation selectivity was studied quantitatively in the same cells. Already in the youngest kittens the receptive fields were spatially organized like adult fields, with a central zone and adjacent flanks that responded in opposite manner to the light stimulus. The relative suppression in the subzones was as strong as in adult cells. Both simple and complex cells were found from 8 days. The receptive fields were like magnified adult fields. The width of the dominant discharge-field zone and the distance between the positions giving maximum discharge and maximum suppression decreased with age in the same proportions. The decrease could be explained by a corresponding decrease of the receptive-field-center size of retinal ganglion cells. Forty percent of the cells were orientation selective before 2 wk, and the fraction increased to 94% at 4 wk. Cells whose responses could be attenuated to at least half of the maximal response by changes of slit orientation were termed orientation selective. The half-width of the orientation-tuning curves narrowed during the first 5 wk, and this change was most marked in simple cells. The ability of the cells to discriminate between orientations in statistical terms was weak in the youngest kittens due to a large response variability, and showed a more pronounced development than the half-width did. The orientation-tuning curves were fitted by an exponential function, which showed the shape to be adultlike in all age groups. Two kittens were dark reared until recording at 1 mo of age. The spatial receptive-field organization and the orientation selectivity in these kittens were similar to normal-reared kittens at 1 mo. The responsivity of the cells of the dark-reared kittens was lower, and the latency before firing was longer than in the normal-reared kittens of the same age, and these response properties were more similar to those in 1- to 2-wk-old normal kittens. Our results indicate that the spatial organization of the receptive field is innate in most cells and that visual experience is unnecessary for the organization to be maintained and for the receptive-field width to mature during the first month postnatally.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Local Signals From Beyond the Receptive Fields of Striate Cortical Neurons

2003 ◽  
Vol 90 (2) ◽  
pp. 822-831 ◽  
Author(s):  
James R. Müller ◽  
Andrew B. Metha ◽  
John Krauskopf ◽  
Peter Lennie
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Striate Cortex ◽  
Image Representation ◽  
Receptive Fields ◽  
Preferred Orientation ◽  
Orientation Tuning ◽  
Stimulus Space ◽  
Tuning Curves ◽  
Complex Cells

We examined in anesthetized macaque how the responses of a striate cortical neuron to patterns inside the receptive field were altered by surrounding patterns outside it. The changes in a neuron's response brought about by a surround are immediate and transient: they arise with the same latency as the response to a stimulus within the receptive field (this argues for a source locally in striate cortex) and become less effective as soon as 27 ms later. Surround signals appeared to exert their influence through divisive interaction (normalization) with those arising in the receptive field. Surrounding patterns presented at orientations slightly oblique to the preferred orientation consistently deformed orientation tuning curves of complex (but not simple) cells, repelling the preferred orientation but without decreasing the discriminability of the preferred grating and ones at slightly oblique orientations. By reducing responsivity and changing the tuning of complex cells locally in stimulus space, surrounding patterns reduce the correlations among responses of neurons to a particular stimulus, thus reducing the redundancy of image representation.

Quantitative studies of single-cell properties in monkey striate cortex. IV. Corticotectal cells

1976 ◽  
Vol 39 (6) ◽  
pp. 1352-1361 ◽  
Author(s):  
B. L. Finlay ◽  
P. H. Schiller ◽  
S. F. Volman
Keyword(s):  
Receptive Field ◽  
Superior Colliculus ◽  
Striate Cortex ◽  
Receptive Fields ◽  
Orientation Tuning ◽  
Antidromic Activation ◽  
Cortical Input ◽  
Quantitative Studies ◽  
Receptive Field Properties ◽  
Deep Layers

1. The receptive-field properties of corticotectal cells in the monkey's striate cortex were studied using stationary and moving stimuli. These cells were identified by antidromic activation from the superior colliculus. 2. Corticotectal cells form a relatively homogeneous group. They are found primarily in layers 5 and 6. These cells can usually be classified as CX-type cells but show broader orientation tuning, larger receptive fields, higher spontaneous activity, and greater binocular activation than CX-type cells do in general. A third of the corticotectal cells were direction selective. 3. These results suggest that the cortical input to the superior colliculus is not directly responsible for the receptive-field properties of collicular cells. We propose that this input has a gating function in contributing to the control of the downflow of excitation from the superficial to the deep layers of the colliculus.

Effects of selective pressure block of Y-type optic nerve fibers on the receptive-field properties of neurons in the striate cortex of the cat

1992 ◽  
Vol 9 (1) ◽  
pp. 47-64 ◽  
Author(s):  
W. Burke ◽  
B. Dreher ◽  
A. Michalski ◽  
B. G. Cleland ◽  
M. H. Rowe
Keyword(s):  
Optic Nerve ◽  
Receptive Field ◽  
Striate Cortex ◽  
Direction Selectivity ◽  
Nerve Fibers ◽  
Orientation Tuning ◽  
Area 17 ◽  
Single Neurons ◽  
Receptive Field Properties ◽  
Velocity Sensitivity

AbstractIn an aseptic operation under surgical anesthesia, one optic nerve of a cat was exposed and subjected to pressure by means of a special cuff. The conduction of impulses through the pressurized region was monitored by means of electrodes which remained in the animal after the operation. The pressure was adjusted to selectively eliminate conduction in the largest fibers (Y-type) but not in the medium-size fibers (X-type). The conduction block is probably due to a demyelination and remains complete for about 3 weeks. Within 2 weeks after the pressure-block operation, recordings were made from single neurons in the striate cortex (area 17, area VI) of the cat anesthetized with N2O/O2 mixture supplemented by continuous intravenous infusion of barbiturate. Neurons were activated visually via the normal eye and via the eye with the pressure-blocked optic nerve (“Y-blocked eye”). Several properties of the receptive fields of single neurons in area 17 such as S (simple) or C (complex) type of receptive-field organization, size of discharge fields, orientation tuning, direction-selectivity indices, and end-zone inhibition appear to be unaffected by removal of the Y-type input. On the other hand, the peak discharge rates to stimuli presented via the Y-blocked eye were significantly lower than those to stimuli presented via the normal eye. As a result, the eye-dominance histogram was shifted markedly towards the normal eye implying that there is a significant excitatory Y-type input to area 17. In a substantial proportion of area 17 neurons, this input converges onto the cells which receive also non-Y-type inputs. In one respect, velocity sensitivity, removal of the Y input had a weak but significant effect. In particular, C (but not S) cells when activated via the normal eye responded optimally at slightly higher stimulus velocities than when activated via the Y-blocked eye. These results suggest that the Y input makes a distinct contribution to velocity sensitivity in area 17 but only in C-type neurons. Overall, our results lead us to the conclusion that the Y-type input to the striate cortex of the cat makes a significant contribution to the strength of the excitatory response of many neurons in this area. However, the contributions of Y-type input to the mechanism(s) underlying many of the receptive-field properties of neurons in this area are not distinguishable from those of the non-Y-type visual inputs.

Depth perception and cortical physiology in normal and innate microstrabismic cats

1991 ◽  
Vol 6 (1) ◽  
pp. 25-41 ◽  
Author(s):  
C. Distler ◽  
K.-P. Hoffmann
Keyword(s):  
Receptive Field ◽  
Depth Perception ◽  
Cortical Neurons ◽  
Oblique Effect ◽  
Orientation Tuning ◽  
Maximal Response ◽  
Horizontal Distance ◽  
Area 17 ◽  
Receptive Field Properties ◽  
Stimulation Of

AbstractEvidence is presented that innate microstrabismus and abnormal cortical visual receptive-field properties can occur also in cats without any apparent involvement of the Siamese or albino genetic abnormalities in their visual system. A possible cause for microstrabismus in these cats may be sought in an abnormally large horizontal distance between blind spot and area centralis indicated by a temporal displacement of the most central receptive fields on both retinae.Depth perception was found to be impaired in cats with innate microstrabismus. Behavioral measurements using a Y-maze revealed in four such cats that the performance in recognizing the nearer of two random-dot patterns did not improve when they were allowed to use both eyes instead of only one. The ability of microstrabismic cats to perceive depth under binocular viewing conditions only corresponded to the monocular performance of five normal cats.Electrophysiological recordings were performed in the visual cortex (areas 17 and 18) of four awake cats, two normal, and two innate microstrabismic animals. Ocular dominance and orientation tuning of single neurons in area 17 and 18 were analyzed quantitatively.The percentage of neurons in area 17 and 18 which could be activated through either eye was significantly reduced to 49.7% in the microstrabismic animals when compared to the normal cats (74.8%). “True binocular cells,” which can only be activated by simultaneous stimulation of both eyes, were significantly less frequent (1.6%) in microstrabismic cats than in normal animals (10.4%). However, subthreshold binocular interactions were identical in both groups of animals. In the strabismic animals, long-term binocular stimulation of monocular neurons did not give a clear indication of alternating use of one or the other eye.The range of stimulus orientations leading to discharge rates above 50% of the maximal response, i.e. the half-width of the orientation tuning curves, was the same in the two groups of cats. However, orientation sensitivity, i.e. the alternation in discharge rate per degree change in stimulus orientation, was higher in cortical cells of normal cats than in those of microstrabismic cats.In normal and microstrabismic cats, no clear sign of an “oblique effect,” i.e. the preference of cortical neurons for vertical and horizontal orientations compared to oblique orientations, could be found neither in the incidence of cells with horizontal or vertical preferred orientation nor in the sharpness of orientation tuning and sensitivity of these neurons.In summary, the receptive-field properties reported here for awake innate microstrabismic cats are similar to those reported in the literature for anesthetized cats with varying degrees of albinism and for cats with artificial symmetrical strabismus surgically induced by sectioning the equivalent extraocular muscles in both eyes. Our innate microstrabismic cats may provide, however, an animal model for investigating the etiology of one form of naturally occurring strabismus.

scholarly journals Visual receptive field properties of cells in the optic tectum of the archer fish

2013 ◽  
Vol 110 (3) ◽  
pp. 748-759 ◽  
Author(s):  
Mor Ben-Tov ◽  
Ivgeny Kopilevich ◽  
Opher Donchin ◽  
Ohad Ben-Shahar ◽  
Chen Giladi ◽  
...  
Keyword(s):  
Receptive Field ◽  
Visual System ◽  
Optic Tectum ◽  
Functional Organization ◽  
Single Cells ◽  
Temporal Frequency ◽  
Fundamental Aspect ◽  
Orientation Tuning ◽  
Visual Behavior ◽  
Receptive Field Properties

The archer fish is well known for its extreme visual behavior in shooting water jets at prey hanging on vegetation above water. This fish is a promising model in the study of visual system function because it can be trained to respond to artificial targets and thus to provide valuable psychophysical data. Although much behavioral data have indeed been collected over the past two decades, little is known about the functional organization of the main visual area supporting this visual behavior, namely, the fish optic tectum. In this article we focus on a fundamental aspect of this functional organization and provide a detailed analysis of receptive field properties of cells in the archer fish optic tectum. Using extracellular measurements to record activities of single cells, we first measure their retinotectal mapping. We then determine their receptive field properties such as size, selectivity for stimulus direction and orientation, tuning for spatial frequency, and tuning for temporal frequency. Finally, on the basis of all these measurements, we demonstrate that optic tectum cells can be classified into three categories: orientation-tuned cells, direction-tuned cells, and direction-agnostic cells. Our results provide an essential basis for future investigations of information processing in the archer fish visual system.

Vernier acuities of neurons in area 17 of cat visual cortex: Their relation to stimulus length and velocity, orientation selectivity, and receptive-field structure

1989 ◽  
Vol 2 (2) ◽  
pp. 165-176 ◽  
Author(s):  
N. V. Swindale ◽  
M. S. Cynader
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Response Threshold ◽  
Orientation Tuning ◽  
Area 17 ◽  
Simple Cells ◽  
Tuning Curves ◽  
Wide Range ◽  
Stimulus Length ◽  
In Cells

AbstractThe sensitivity of neurons in area 17 of the cat's visual cortex to vernier offset was expressed as the percentage reduction in response caused by the introduction of a given offset into a bar stimulus moving across the receptive field. There was a wide variation in sensitivity: in some cells response could be halved by an offset equal to a fifth of receptive-field width (defined as twice the standard deviation of a Gaussian curve fitted to the response profile), while other cells showed no sensitivity. The highest absolute sensitivities of complex and simple cells were similar, although most cells with poor sensitivity were complex.Sensitivity was largely unaffected by changes in stimulus velocity and stimulus length, although there was a tendency for sensitivity to increase with decreasing bar length.Comparisons of orientation tuning curves with vernier tuning curves showed that the response to a vernier stimulus approximated the response to a single bar of the same overall length and an orientation equal to that of a line joining the midpoints of each bar. This was true for a wide range of sensitivity values.Vernier sensitivity was correlated with a measure of length summation H, which is positive when there is net facilitation between the bars, and negative when there is net inhibition. Vernier sensitivity was highest in cells with large values of H, and least in cells where H was negative.We examined a linear model of the simple cell receptive field which, together with a variable response threshold, was able to explain the correlation between vernier acuity and length summation. Although this model accounted qualitatively for many of our findings, the majority of simple cells had tuning curves that were sharper than the predicted ones. This suggests that there are nonlinearities in the behavior of many simple cells whose effect is to increase the sharpness of orientation tuning and consequently vernier sensitivity.

Cat area 17. III. Response properties and orientation anisotropies of corticotectal cells

1986 ◽  
Vol 56 (4) ◽  
pp. 1088-1101 ◽  
Author(s):  
T. G. Weyand ◽  
J. G. Malpeli ◽  
C. Lee ◽  
H. D. Schwark
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Orientation Tuning ◽  
Simple Relationship ◽  
Area 17 ◽  
Vertical Meridian ◽  
Complex Cells ◽  
Receptive Field Properties ◽  
Stimulus Length ◽  
Special Complex

The receptive field properties of antidromically identified corticotectal (CT) cells in area 17 were explored in the paralyzed, anesthetized cat. To compare these with another population of infragranular cells, we also examined the receptive field properties of cells in layer 6. Sixty percent of our sample of CT cells showed increased response to increased stimulus length (length summation) and were classified as standard complex cells. The other 40% showed little or no length summation, were generally end stopped, and were classified as special complex cells. Standard and special complex CT cells have complementary orientation anisotropies: the distribution of orientation preferences of standard complex cells is biased toward obliquely oriented stimuli, whereas special complex cells are biased toward horizontally and vertically oriented stimuli. The receptive fields of the cells in our sample were primarily along the horizontal meridian so we cannot determine if these anisotropies are defined relative to the vertical meridian or relative to the meridian passing through the receptive field. The effects of these anisotropies in preferred orientation are minimized by the broad orientation tuning of CT cells. There was no simple relationship between the direction bias of CT cells and the reported direction bias of tectal cells. In contrast to the heterogeneity of corticotectal cells, layer 6 cells uniformly showed strong length summation, tight orientation tuning, and little spontaneous activity.

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