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

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.

1978 ◽  
Vol 41 (4) ◽  
pp. 948-962 ◽  
Author(s):  
A. G. Leventhal ◽  
H. V. Hirsch

1. Receptive-field properties of neurons in the different layers of the visual cortex of normal adult cats were analyzed quantitatively. Neurons were classified into one of two groups: 1) S-cells, which have discrete on- and/or off-regions in their receptive fields and possess inhibitory side bands; 2) C-cells, which do not have discrete on- and off-regions in their receptive fields but display an on-off response to flashing stimuli. Neurons of this type rarely display side-band inhibition. 2. As a group, S-cells display lower relative degrees of binocularity and are more selective for stimulus orientation than C-cells. In addition, within a given lamina the S-cells have smaller receptive fields, lower cutoff velocities, lower peak responses to visual stimulation, and lower spontaneous activity than do the C-cells. 3. S-cells in all layers of the cortex display similar orientation sensitivities, mean spontaneous discharge rates, peak response to visual stimulation, and degrees of binocularity. 4. Many of the receptive-field properties of cortical cells vary with laminar location. Receptive-field sizes and cutoff velocities of S-cells and of C-cells are greater in layers V and VI than in layers II-IV. For S-cells, preferred velocities are also greater in layers V and VI than in layers II-IV. Furthermore, C-cells in layers V and VI display high mean spontaneous discharge rates, weak orientation preferences, high relative degrees of binocularity, and higher peak responses to visual stimulation when compared to C-cells in layers II and III. 5. The receptive-field properties of cells in layers V-VI of the striate cortex suggest that most neurons that have their somata in these laminae receive afferents from LGNd Y-cells. Hence, our results suggest that afferents from LGNd Y-cells may play a major part in the cortical control of subcortical visual functions.


1982 ◽  
Vol 47 (2) ◽  
pp. 272-286 ◽  
Author(s):  
J. Graham ◽  
N. Berman ◽  
E. H. Murphy

1. One hundred seventy-nine single units were studied in the superior colliculus of seven Dutch-belted rabbits following ablation of the ipsilateral visual cortex. The response characteristics of these units were compared with those of 284 single units recorded from the superior colliculus of 20 intact animals. 2. In both the upper and lower parts of the stratum griseum superficiale and in the stratum griseum intermediate, there were smaller proportions of direction-selective visual units in the decorticated animals than in normal ones. 3. In the upper stratum griseum superficiale, a larger proportion of units responded to stroboscopic illumination in the decorticated animals than in normal ones. Also, in the decorticated animals, there was a larger proportion of units whose responses to a small moving stimulus were inhibited by the simultaneous presentation of stroboscopic illumination. 4. In both the upper and lower parts of the stratum griseum superficiale, a larger proportion of visual units responded well to stationary stimuli and a smaller proportion of visual units showed habituation in decorticated animals compared to normal ones. 5. In the lower stratum griseum superficiale, the receptive fields of units were larger and were more elongated in the anterior-posterior dimension in the decorticated animals than in normal ones. 6. In the two preparations, units did not differ in responsiveness or spontaneous activity; and visual units did not differ in the sustained or transient nature of their responses, the selectivity for light or dark stimuli, the selectivity for onset or offset of the stimuli, or the selectivity for stimulus velocity. 7. This study provides evidence for the importance of the visual corticotectal projection in the elaboration of the visual receptive-field properties of units in the superior colliculus of the rabbit. In addition, this study shows that the subdivisions of the superior colliculus are differentially affected by the loss of the visual corticotectal projection.


1985 ◽  
Vol 53 (5) ◽  
pp. 1158-1178 ◽  
Author(s):  
B. O. Braastad ◽  
P. Heggelund

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)


2003 ◽  
Vol 90 (2) ◽  
pp. 822-831 ◽  
Author(s):  
James R. Müller ◽  
Andrew B. Metha ◽  
John Krauskopf ◽  
Peter Lennie

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.


1986 ◽  
Vol 55 (5) ◽  
pp. 1057-1075 ◽  
Author(s):  
C. J. Bruce ◽  
R. Desimone ◽  
C. G. Gross

Although the tectofugal system projects to the primate cerebral cortex by way of the pulvinar, previous studies have failed to find any physiological evidence that the superior colliculus influences visual activity in the cortex. We studied the relative contributions of the tectofugal and geniculostriate systems to the visual properties of neurons in the superior temporal polysensory area (STP) by comparing the effects of unilateral removal of striate cortex, the superior colliculus, or of both structures. In the intact monkey, STP neurons have large, bilateral receptive fields. Complete unilateral removal of striate cortex did not eliminate visual responses of STP neurons in the contralateral visual hemifield; rather, nearly half the cells still responded to visual stimuli in the hemifield contralateral to the lesion. Thus the visual properties of STP neurons are not completely dependent on the geniculostriate system. Unilateral striate lesions did affect the response properties of STP neurons in three ways. Whereas most STP neurons in the intact monkey respond similarly to stimuli in the two visual hemifields, responses to stimuli in the hemifield contralateral to the striate lesion were usually weaker than responses in the ipsilateral hemifield. Whereas the responses of many STP neurons in the intact monkey were selective for the direction of stimulus motion or for stimulus form, responses in the hemifield contralateral to the striate lesion were not selective for either motion or form. Whereas the median receptive field in the intact monkey extended 80 degrees into the contralateral visual field, the receptive fields of cells with responses in the contralateral field that survived the striate lesions had a median border that extended only 50 degrees into the contralateral visual field. Removal of both striate cortex and the superior colliculus in the same hemisphere abolished the responses of STP neurons to visual stimuli in the hemifield contralateral to the combined lesion. Nearly 80% of the cells still responded to visual stimuli in the hemifield ipsilateral to the lesion. Unilateral removal of the superior colliculus alone had only small effects on visual responses in STP. Receptive-field size and visual response strength were slightly reduced in the hemifield contralateral to the collicular lesion. As in the intact monkey, selectivity for stimulus motion or form were similar in the two visual hemifields. We conclude that both striate cortex and the superior colliculus contribute to the visual responses of STP neurons. Striate cortex is crucial for the movement and stimulus specificity of neurons in STP.(ABSTRACT TRUNCATED AT 400 WORDS)


1992 ◽  
Vol 9 (1) ◽  
pp. 47-64 ◽  
Author(s):  
W. Burke ◽  
B. Dreher ◽  
A. Michalski ◽  
B. G. Cleland ◽  
M. H. Rowe

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.


1993 ◽  
Vol 335 (2) ◽  
pp. 214-227 ◽  
Author(s):  
Richard D. Mooney ◽  
Michael M. Nikoletseas ◽  
Tod D. King ◽  
Steven V. Savage ◽  
Xiaoguang Huang

1983 ◽  
Vol 50 (1) ◽  
pp. 102-124 ◽  
Author(s):  
B. E. Stein ◽  
N. S. Gaither

The receptive-field properties of single cells in the optic tectum of Iguana iguana were studied using the same procedures as have been used in this laboratory in studying its mammalian homologue, the superior colliculus. Surprisingly, despite some species-specific characteristics, the range of physiological properties of tectal and superior collicular cells appeared to be strikingly similar. This observation is not consistent with the notion that functional differences between these structures evolved as a consequence of the tremendous elaboration of mammalian neocortex and its involvement in sensory processes. The internal organization of visual tectal receptive fields was observed to be very much like that described in mammals. This included a similar distribution of on-off areas, the presence of both spatial summation and spatial inhibition within the excitatory receptive-field borders, suppressive areas just beyond these borders, and a marked tendency for habituation. In addition, many cells showed distinct directional preferences that were strongly influenced by the velocity of movement through the receptive field. Furthermore, the receptive fields of bimodal and trimodal cells showed topographic correspondences as in mammals, although the sizes of the fields were often large, thereby emphasizing the lack of an exact register between modalities. In contrast to the findings in mammals, however, a preference for stationary over moving stimuli was observed in most neurons, and specializations in iguana tectal cells representing the fovea were noted that have not been described in other species. These foveal specializations include a distinct preference for stationary over moving stimuli, the absence of directional selectivity, and the presence of a majority of cells responding at light onset only. It is suggested that the similarities in the organization and response properties of cells of the optic tectum and superior colliculus reflect the retention of ancestral characteristics through various levels of vertebrate evolution. Furthermore, the subtle species differences in the properties of these cells appear to reflect adaptations to specific ecological pressures rather than general evolutionary trends.


1986 ◽  
Vol 56 (4) ◽  
pp. 1088-1101 ◽  
Author(s):  
T. G. Weyand ◽  
J. G. Malpeli ◽  
C. Lee ◽  
H. D. Schwark

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.


2005 ◽  
Vol 15 (01n02) ◽  
pp. 31-40
Author(s):  
BASABI BHAUMIK ◽  
ALOK AGARWAL ◽  
MANISH MANOHAR

The primary visual cortex is organized into clusters of cells having similar receptive fields (RFs). A purely feedforward model has been shown to produce realistic simple cell receptive fields. The modeled cells capture a wide range of receptive field properties of orientation selective cortical cells. We have analyzed the responses of 78 nearby cell pairs to study which RF properties are clustered. Orientation preference shows strongest clustering. Orientation tuning width (hwhh) and tuning height (spikes/sec) at the preferred orientation are not as tightly clustered. Spatial frequency is also not as tightly clustered and RF phase has the least clustering. Clustering property of orientation preference, orientation tuning height and width depend on the location of cells in the orientation map. No such location dependence is observed for spatial frequency and RF phase. Our results agree well with experimental data.


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