Spatial reciprocity of connections between areas 17 and 18 in the cat

1995 ◽  
Vol 73 (9) ◽  
pp. 1339-1347 ◽  
Author(s):  
P. A. Salin ◽  
H. Kennedy ◽  
J. Bullier
Keyword(s):  
Area 17 ◽  
Fluorescent Tracers ◽  
Double Labeling ◽  
Area 18 ◽  
Axon Terminals ◽  
Density Maps ◽  
Anterograde Tracers ◽  
Convergence And Divergence ◽  
Areas 17 And 18 ◽  
Anterograde Tracer

We examined whether the interconnections between areas 17 and 18 are spatially reciprocal, i.e., whether a column of cells in area 17 receives from the same region of area 18 as it sends projections to, and vice versa. We addressed this question by making side by side injections of retrograde fluorescent tracers in area 18, calculating the convergence and divergence of the connections from area 17 to 18. We compared these values with previously reported values of divergence and convergence of the projections from area 18 to area 17. The results demonstrate that there is a good match between the convergence and divergence of the area 17 to area 18 connection and, respectively, the divergence and convergence of the reverse connection. We confirmed directly the spatial reciprocity by injecting simultaneously in area 17 a retrograde and an anterograde tracer and by analyzing quantitatively the density of anterograde and retrograde labeling across the surface of area 18. There was an excellent match between the density maps of retrogradely labeled cells and anterogradely labeled axon terminals in area 18. Connections between areas 17 and 18 therefore exhibit large degrees of convergence and divergence and are spatially reciprocal. Thus, a given column of cells within one of these two areas is reciprocally interconnected with a large region of the opposite area. Such an organization may provide the basis for synchronization of firing of neurons across these two areas, as revealed by cross-correlation studies.Key words: double labeling, fluorescent tracers, retrograde and anterograde tracers, convergence and divergence.

Postnatal development of perisomatic GABAergic axon terminals on neurons projecting from area 17 to area 18 of the cat visual cortex

1999 ◽  
Vol 16 (1) ◽  
pp. 35-44 ◽  
Author(s):  
FERNANDO PÉREZ-CERDÁ ◽  
LUIS MARTÍNEZ-MILLÁN ◽  
CARLOS MATUTE
Keyword(s):  
Visual Cortex ◽  
Postnatal Development ◽  
Developmental Stages ◽  
Time Frame ◽  
Projection Neurons ◽  
Area 17 ◽  
Gamma Aminobutyric Acid ◽  
Area 18 ◽  
Axon Terminals ◽  
Cat Visual Cortex

We have studied the postnatal development of presumptive axon terminals (puncta) which were recognized by antibodies to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) and were located on the somata of area 17 neurons projecting to the ipsilateral area 18 of the visual cortex in cats ranging from 7 days of age to adulthood. Projection neurons were retrogradely labeled by injection of horseradish peroxidase conjugated to wheat germ agglutinin into the ipsilateral area 18. These neurons were mainly pyramidal in shape at all the developmental stages examined and the adult distribution of labeled cells was reached by 21 days. Subsequent GABA postembedding immunohistochemistry using high-resolution light microscopy was carried out to study the development of GABAergic terminals on cell bodies of identified projecting neurons in layers II–III. At all ages examined, we found perisomatic GABAergic puncta on these cells. Their density showed a significant increase from postnatal days 7 to 45, and then remained largely constant through adulthood. Since GABAergic puncta are considered the light-microscopic correlate of GABAergic synaptic terminals, our results support the idea of a developmentally regulated increase in the inhibitory activity of local interneurons on area 17 pyramidal neurons projecting to area 18 in the cat visual cortex which occurs within the same time frame as that of the acquisition of the mature operation of these cells.

Organization of orientation and direction selectivity in areas 17 and 18 of cat cerebral cortex

1987 ◽  
Vol 58 (4) ◽  
pp. 676-699 ◽  
Author(s):  
N. E. Berman ◽  
M. E. Wilkes ◽  
B. R. Payne
Keyword(s):  
Receptive Fields ◽  
Direction Selectivity ◽  
Preferred Orientation ◽  
Wide Field ◽  
Area 17 ◽  
Stimulus Motion ◽  
Area 18 ◽  
Preferred Direction ◽  
Area Centralis ◽  
Areas 17 And 18

1. The organization of subunits and sequences subserving preferred stimulus orientation and preferred direction of stimulus motion in cat cerebral cortical areas 17 and 18 was determined by making vertical, tangential, and oblique microelectrode penetrations into those areas. 2. Quantitative measurements of direction selectivity indicated that not all shades of direction selectivity are equally represented in area 17. Peaks in the distribution of direction indices may correspond to the bidirectional, direction biased, and direction selective categories used in qualitative studies. 3. The relationship between preferred direction and location in the visual field was examined for units with receptive fields centered more than 15 degrees from the area centralis. Simple cells had orientation preferences that tended to be parallel to radii extending out from the area centralis. Wide-field complex cells had orientation preferences that tended to be parallel to concentric circles centered on the area centralis; the direction preferences of this group were biased toward motion away from the area centralis. 4. Unit pairs separated by 200 microns or less were 4.2 times as likely to have the same preferred direction as to have opposite preferred directions, indicating that, on average, strings of five neurons have similar direction preferences. 5. Tracks in area 18 showed a similar pattern to those in area 17. 6. In the vertical tracks in area 17 a small proportion (12%) of the units recorded in infragranular layers had preferred orientations that deviated 30 degrees or more from the first unit recorded in the same column. The presence of these cells most likely reflects the relative crowding of columns in infragranular layers, which occurs at the crown of the lateral gyrus. Columns with such large jumps in preferred orientation were not observed in area 18, which occupies a relatively flat region of cortex. 7. In both areas 17 and 18 direction preference in vertical tracks usually reversed at least once, either between supra- and infragranular layers or within infragranular layers. Along these same tracks, orientation preference usually did not change. 8. In tangential tracks, preferred direction and orientation preferences changed together in small increments. Occasionally a large jump in preferred direction would occur with only a small change in preferred orientation. These large jumps were considered to mark the boundaries of the direction sequences. Most frequently these boundaries were separated by 400-600 microns. This value is approximately half the size of a complete set of orientation preferences (700-1,200 microns).(ABSTRACT TRUNCATED AT 400 WORDS)

X- and Y-mediated current sources in areas 17 and 18 of cat visual cortex

1990 ◽  
Vol 4 (02) ◽  
pp. 135-145 ◽  
Author(s):  
David Ferster
Keyword(s):  
Current Source ◽  
Current Source Density ◽  
Area 17 ◽  
Field Potentials ◽  
Optic Nerves ◽  
Area 18 ◽  
Source Density ◽  
Density Analysis ◽  
Areas 17 And 18 ◽  
Stimulation Of

AbstractX- and Y-mediated input to areas 17 and 18 of the cat visual cortex was studied using current-source-density analysis of field potentials evoked by stimulation of the optic nerves. A cuff-shaped electrode was used for stimulation so that Y axons, by virtue of their larger diameters, would have lower electrical thresholds than X axons. The effect in each cortical area of activating Y axons alone could therefore be determined by low-&litude stimulation of the optic nerves. Current-source densities were calculated by two separate methods. (1) In five experiments, field potentials were measured sequentially at different cortical depths with a single tungsten electrode. Current densities were then calculated by computer. (2) In two experiments, current densities were derived in real time from field potentials recorded simultaneously from three sites with a multi-electrode probe. The calculation was performed by an analog circuit specially designed for this purpose. This method has several advantages over the standard, single-electrode method. At stimulus strengths sufficient to activate the majority of Y axons in the optic nerves, but subthreshold to most X axons, the field potentials evoked in area 17 changed little from layer to layer. When the current-source-density analysis was applied to these potentials, no significant sources or sinks were detectable. Only when the stimulus strength was raised to the point that both X and Y axons were activated by the stimulus were any current sources or sinks detected in area 17. The currents were similar in time course and laminar pattern to those recorded after stimulation of the optic chiasm. In area 18, large sources and sinks were evoked by stimulation of Y axons alone. These currents changed little when the stimulus strength was increased to activate X axons as well. Area 18, therefore, in contrast to area 17, seems to be dominated by Y input and receives little X input. These results support the conclusions of the accompanying paper in which synaptic potentials were recorded intracellularly from cortical neutrons. The intracellular experiments failed to show substantial Y input to area 17. The projections of X and Y axons may therefore be much more highly segregated into areas 17 and 18 than previously thought. Alternatively, the nature of the Y input to area 17 may be very different from that to area 18 in that it cannot be easily detected with intracellular or current-source-density techniques.

Visual callosal projections in the adult ferret

1992 ◽  
Vol 9 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Antony M. Grigonis ◽  
Rosemary B. Rayos Del Sol-Padua ◽  
E. Hazel Murphy
Keyword(s):  
Visual Cortex ◽  
Horseradish Peroxidase ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Cell Distribution ◽  
Area 17 ◽  
Area 18 ◽  
Areas 17 And 18 ◽  
Radial Organization

AbstractThe laminar and tangential organization of visual callosal projections of areas 17 and 18 were investigated in the adult ferret, using histochemical methods to visualize axonally transported horseradish peroxidase (HRP). Normal adult ferrets were given injections of HRP throughout one visual cortex or had gelfoam soaked in HRP applied to the transected corpus callosum. The ferret callosal cell distribution has a greater tangential extent in area 18 than in area 17. In addition, the radial organization of callosal cells in areas 17 and 18 differs: three times as many infragranular cells are present in area 18 than in area 17, although the number of supragranular cells is similar for both areas 17 and 18. Since the projections of alpha retinal ganglion cells are reported to be exclusively contralateral in the ferret (Vitek et al., 1985), callosal projections may make a major contribution to the binocularity of neurons in area 18.

Nonlinearity of spatial summation in simple cells of areas 17 and 18 of cat visual cortex

1991 ◽  
Vol 66 (5) ◽  
pp. 1667-1679 ◽  
Author(s):  
D. Ferster ◽  
B. Jagadeesh
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Spatial Summation ◽  
Area 17 ◽  
Simple Cells ◽  
Area 18 ◽  
Cat Visual Cortex ◽  
Spatial Frequencies ◽  
Areas 17 And 18 ◽  
Y Cells

1. Nonlinearity of spatial summation in areas 17 and 18 of cat visual cortex was compared with the type of spatial nonlinearity that differentiates X and Y cells in the lateral geniculate nucleus (LGN) and retina. The comparisons were made to examine to what extent the information from X and Y cells may remain separated in higher visual centers. 2. Responses of simple cells in areas 17 and 18 were recorded while stationary, optimally oriented sinewave gratings were sinusoidally modulated within the receptive field of the cell. Both the spatial frequency and spatial phase of the stimulus were varied. 3. Y cells in the retina and LGN are defined by the presence of a specific form of spatial nonlinearity. When tested with contrast-modulated sinewave gratings of spatial frequencies about three-fold greater than the optimal, their responses are dominated by a frequency-doubled component. The amplitude of the frequency-doubled component is not dependent on the spatial phase of the stimulus. 4. Many simple cells in the cortex showed a form of spatial nonlinearity similar to the defining nonlinearity found in retinal and geniculate Y cells. A frequency-doubled response dominated at spatial frequencies more than threefold greater than the optimal spatial frequency. When this response was present, it was phase independent. 5. More than 50% of the simple cells in area 18 showed the Y-like spatial nonlinearity. Fewer than 10% of the simple cells in area 17 showed the Y-like spatial nonlinearity. 6. The virtual absence of Y-like nonlinearity in area 17 and its relative abundance in area 18 suggest that the functional separation between the parallel X and Y pathways remains distinct within areas 17 and 18 of cat visual cortex.

Response properties of visual cortical neurons in cats reared in stroboscopic illumination

1983 ◽  
Vol 49 (3) ◽  
pp. 686-704 ◽  
Author(s):  
H. Kennedy ◽  
G. A. Orban
Keyword(s):  
Visual Field ◽  
Receptive Fields ◽  
Normal Animal ◽  
Area 17 ◽  
Central Vision ◽  
Area 18 ◽  
Areas 17 And 18 ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
High Pass

1. The response properties of 182 units were studied in the primary visual cortices (155 in area 18 and 27 in area 17) in eight cats reared from birth in a stroboscopically illuminated environment (frequency, 2/s; duration, 200 microseconds). Multihistogram quantitative testing was carried out in 82 units (64 in area 18 and 18 in area 17). Two hundred three neurons recorded and quantitatively tested in areas 17 and 18 of the normal adult cat were used for comparison. 2. Spatial characteristics of receptive fields investigated using hand-held stimuli were found to be abnormal. The correlation between receptive-field width and eccentricity was lost in area 18 and consequently, receptive fields were significantly wider in area 18 subserving central vision. Cells could be classified according to the spatial characteristics of their receptive fields. There was a much smaller proportion of end-stopped cells in strobe-reared animals. Orientation tuning in the deprived animals was normal except for a small number of cells that showed no selectivity for stimulus orientation. 3. Compilation of velocity-response curves made it possible to classify areas 17 and 18 neurons into four categories: velocity low-pass, velocity broad-band, velocity tuned, and velocity high-pass cells. The proportion of velocity high-pass cells was reduced in area 18 subserving peripheral vision, as was the proportion of velocity-tuned cells in area 18 subserving central vision. 4. In the strobe-reared animal velocity sensitivity was somewhat different from that of the normal animal. Neurons in area 18 subserving the peripheral visual field failed to respond to fast velocities. Neurons in area 17 subserving the central visual field in strobe-reared animals responded to slightly higher velocities than in the normal animal. 5. In the deprived animals the number of neurons that were selective to the direction of motion was strongly reduced. The majority of neurons failed to show a selectivity for direction at all velocities. A number of neurons could be directional at some velocities but were unreliable, since they inverted their preferred direction with velocity changes. 6. Binocular convergence onto visual cortical cells was perturbed. In area 18 the majority of neurons were driven by the contralateral eye. In area 17 most neurons could be driven only by either the ipsilateral or contralateral eye. 7. Quantitative testing (of direction selectivity, sensitivity to high velocities, response latency, and strength) and qualitative testing (receptive-field width, end stopping, and ocular dominance) showed that the normal influence of eccentricity on functional properties was strongly reduced by strobe rearing.

The projections to the superior temporal sulcus from areas 17 and 18 in the rhesus monkey

1976 ◽  
Vol 193 (1111) ◽  
pp. 199-207 ◽  
Keyword(s):  
Rhesus Monkey ◽  
Small Region ◽  
Superior Temporal Sulcus ◽  
Visual Area ◽  
Area 17 ◽  
Area 18 ◽  
Electrolytic Lesions ◽  
Areas 17 And 18 ◽  
Made In

When small electrolytic lesions area made in area 18 and [ 3 H]proline is injected into area 17 of the same side, the inputs to the visual area of the superior temporal sulcus, from these two areas can he mapped separately and independently in the same animal. By using this approach, it was found that both area 17 and area 18 project to the same small region in the posterior bank of the superior temporal sulcus. We conclude that the latter area receives an overlapping input from area 17 and from area 18.

The projection of the lateral geniculate nucleus upon the cortex in the cat

1967 ◽  
Vol 169 (1014) ◽  
pp. 107-126 ◽  
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Small Cells ◽  
Lateral Part ◽  
Area 17 ◽  
Medial Part ◽  
Cell Degeneration ◽  
Cortical Projection ◽  
Area 18 ◽  
Lateral Geniculate ◽  
Areas 17 And 18

The retrograde cell degeneration in the lateral geniculate nucleus of the cat has been studied after lesions of the visual and adjoining areas of the cortex. Following lesions which are limited to area 17, the medium and small cells of the main laminae of the nucleus degenerate; damage restricted to area 18 does not result in any localized, severe degeneration, but com­bined destruction of areas 17 and 18 causes all the cells—large, medium and small—of the main laminae and the central interlaminar nucleus to degenerate. Cellular change in the medial interlaminar nucleus is only found after involvement of area 19. When the cortex of the middle suprasylvian gyrus is removed in addition to these areas the degeneration in the lateral geniculate nucleus is much more severe, and there is loss of the laminar pattern due to severe gliosis in the central interlaminar nucleus. There is a well-defined topical organiza­tion in the geniculo-cortical projection, and in the antero-posterior dimension it is the same to all areas of the visual cortex, anterior parts of the nucleus projecting anteriorly and posterior parts posteriorly. Medial parts of the main laminae are related to the lateral part of area 17 and to the medial part of area 18, and lateral parts of the laminae project to the medial part of area 17 and to the lateral part of area 18. After partial lesions which involve both areas 17 and 18 the cellular degeneration affects the laminae differentially along their antero-posterior extent, that in lamina A being the most anterior and that in lamina B the most posterior; in sagittal sections such a band, or column, of degeneration passes from antero-superior to postero-inferior at right angles to the plane of the laminae.

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