Electrophysiology of lateral and dorsal terminal nuclei of the cat accessory optic system

1984 ◽  
Vol 51 (2) ◽  
pp. 276-293 ◽  
Author(s):  
K. L. Grasse ◽  
M. S. Cynader
Keyword(s):  
Receptive Fields ◽  
Average Diameter ◽  
Bimodal Distribution ◽  
Direction Selectivity ◽  
Visual Responses ◽  
Optic System ◽  
Accessory Optic System ◽  
Lateral Direction ◽  
Area Centralis ◽  
Similar Range

Visual responses were examined quantitatively in 96 units in the lateral (LTN) and dorsal (DTN) terminal nuclei of the cat accessory optic system (AOS). The receptive fields of LTN and DTN cells were quite large, with an average diameter of approximately 60 degrees. Individual cell receptive fields, which could be as small as 30 degrees vertically by 15 degrees horizontally or as large as 100 by 100 degrees, always included the area centralis. Large, moving textured stimuli provoked optimal modulation in these cells. In response to a 100 by 80 degrees random-dot pattern moving at a constant velocity, nearly all cells in both the LTN and DTN displayed a high degree of direction selectivity. Directional response profiles were subjected to a vector analysis that generated two quantities proportional to the direction and magnitude of the major excitatory (E vectors) and inhibitory (I vectors) responses of individual cells. Directional vectors of the LTN displayed a strikingly bimodal distribution: E vectors of individual LTN cells pointed either upward (25 of 49) or downward (23 of 49). I vectors also pointed either up or down in a direction opposite to that of the E vector for the same cell. E and I vectors in both LTN and DTN units were separated by approximately 180 degrees. With few exceptions, E vectors of DTN cells pointed in a horizontal-medial direction, while DTN I vectors pointed in a horizontal-lateral direction. A relatively broad range of stimulus velocities (0.8-102.4 degrees/s) evoked maximal excitation in individual LTN units. The majority of LTN cells, however, achieved maximal excitation at velocities between 0.8 and 12.8 degrees/s. The deepest inhibition was elicited over a range of velocities from 0.2 to 102.4 degrees/s, with two major peaks at 0.8 and 12.8 degrees/s. A similar range of velocity sensitivity was observed in DTN cells: maximal excitation was obtained for stimulus velocities from 1.6 to 102.4 degrees/s, with most DTN cells showing the greatest excitatory response between 6.4 and 12.8 degrees/s. A broad range of inhibitory velocity tuning was also observed in DTN units, with most cells exhibiting the deepest inhibitory modulation at 25.6 degrees/s. The majority of LTN and DTN units were driven most effectively through the eye contralateral to the recording site. Nonetheless, a large percentage of LTN (78%) and DTN (93%) cells could be driven to some extent through both eyes. Despite this conspicuous ipsilateral eye influence, no units were found in either the LTN or the DTN that were driven solely through the ipsilateral eye.(ABSTRACT TRUNCATED AT 400 WORDS)

The accessory optic system of rabbit. II. Spatial organization of direction selectivity

1988 ◽  
Vol 60 (6) ◽  
pp. 2055-2072 ◽  
Author(s):  
J. I. Simpson ◽  
C. S. Leonard ◽  
R. E. Soodak
Keyword(s):  
Receptive Field ◽  
Spatial Organization ◽  
Inferior Olive ◽  
Receptive Fields ◽  
Vertical Plane ◽  
Direction Selectivity ◽  
Optic System ◽  
Accessory Optic System ◽  
Present Sample ◽  
Ventral Tegmental

1. To compare the spatial organization of the direction selectivity of neurons in the medial terminal nucleus (MTN) of the accessory optic system with that of neurons in the adjacent ventral tegmentum, extracellular single-unit recordings were made in the anesthetized rabbit. The ventral tegmental neurons were located in a region called the visual tegmental relay zone (VTRZ), which is defined by the ventral tegmental terminal field of contralaterally projecting MTN neurons. 2. Some of the present sample of MTN neurons (5 of 34) had monocular receptive fields composed of two parts distinguished by a marked difference in the orientation of their respective direction-selective tuning curves. For one part of the receptive field the preferred excitatory direction was "up," while for the other part it was "down." Such receptive fields for one eye were called bipartite, whereas the more usually encountered MTN receptive fields, which could be characterized by a single direction-selective tuning curve, were called uniform. 3. Of the 16 neurons recorded from the VTRZ, all but one were binocular. For these neurons, both uniform and bipartite receptive fields were found for each eye alone. The only monocular neuron encountered in the VTRZ had a contralateral, bipartite receptive field. 4. The spatial organization of the direction selectivity of bipartite receptive fields strongly suggests that they are suited to represent rotation of the visual field about a horizontal axis located in the vertical plane that divides the receptive field into two parts. 5. The boundary between the two parts of the bipartite receptive fields was found using handheld visual stimuli at one of two azimuthal locations, either close to 45 degrees or between 95 and 125 degrees (the 0 degree reference was rostral in the midsagittal plane). This particular structure of the bipartite receptive fields suggests that their preferred rotation axes have a close spatial relation to the best-response axes of the semicircular canals. 6. Seven VTRZ neurons were antidromically activated by electrical stimulation of the ipsilateral dorsal cap of the inferior olive. Since the receptive fields of VTRZ neurons have many of the structural features characteristic of the receptive fields of rostral dorsal cap neurons we conclude that the spatial organization of the receptive fields of dorsal cap neurons is, for the most part, synthesized prior to the inferior olive.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals The Accessory Optic System Contributes to the Spatio-Temporal Tuning of Motion-Sensitive Pretectal Neurons

2003 ◽  
Vol 90 (2) ◽  
pp. 1140-1151 ◽  
Author(s):  
Nathan A. Crowder ◽  
Hugo Lehmann ◽  
Marise B. Parent ◽  
Douglas R.W. Wylie
Keyword(s):  
Receptive Fields ◽  
Sine Wave ◽  
Excitatory Input ◽  
Direction Selectivity ◽  
Oculomotor Control ◽  
Optic System ◽  
Accessory Optic System ◽  
Preferred Direction ◽  
Before And After ◽  
Spatio Temporal

The nucleus of the basal optic root (nBOR) of the accessory optic system (AOS) and the pretectal nucleus lentiformis mesencephali (LM) are involved in the analysis of optic flow that results from self-motion and are important for oculomotor control. These neurons have large receptive fields and exhibit direction selectivity to large moving stimuli. In response to drifting sine wave gratings, LM and nBOR neurons are tuned to either low spatial/high temporal frequencies (SF, TF) or high SF/low TF stimuli. Given that velocity = TF/SF, these are referred to as “fast” and “slow” neurons, respectively. There is a heavy projection from the AOS to the pretectum, although its function is unknown. We recorded the directional and spatio-temporal tuning of LM units in pigeons before and after nBOR was inactivated by tetrodotoxin injection. After nBOR inactivation, changes in direction preference were observed for only one of 18 LM units. In contrast, the spatio-temporal tuning of LM units was dramatically altered by nBOR inactivation. Two major effects were observed. First, in response to motion in the preferred direction, most (82%) neurons showed a substantially reduced (μ = –67%) excitation to low SF/high TF gratings. Second, in response to motion in the anti-preferred direction, most (63%) neurons showed a dramatically reduced (μ = –78%) inhibition to high SF/low TF gratings. Thus the projection from the nBOR contributes to the spatio-temporal tuning rather than the directional tuning of LM neurons. We propose a descriptive model whereby LM receives inhibitory and excitatory input from “slow” and “fast” nBOR neurons, respectively.

scholarly journals Temporal Frequency and Velocity-Like Tuning in the Pigeon Accessory Optic System

2003 ◽  
Vol 90 (3) ◽  
pp. 1829-1841 ◽  
Author(s):  
Nathan A. Crowder ◽  
Michael R.W. Dawson ◽  
Douglas R.W. Wylie
Keyword(s):  
Motion Detection ◽  
Temporal Frequency ◽  
Sine Wave ◽  
Direction Selectivity ◽  
Large Field ◽  
Apparent Velocity ◽  
Correlation Model ◽  
Optic System ◽  
Accessory Optic System ◽  
Optokinetic Response

Neurons in the accessory optic system (AOS) and pretectum are involved in the analysis of optic flow and the generation of the optokinetic response. Previous studies found that neurons in the pretectum and AOS exhibit direction selectivity in response to large-field motion and are tuned in the spatiotemporal domain. Furthermore, it has been emphasized that pretectal and AOS neurons are tuned to a particular temporal frequency, consistent with the “correlation” model of motion detection. We examined the responses of neurons in the nucleus of the basal optic root (nBOR) of the AOS in pigeons to large-field drifting sine wave gratings of varying spatial (SF) and temporal frequencies (TF). nBOR neurons clustered into two categories: “Fast” neurons preferred low SFs and high TFs, and “Slow” neurons preferred high SFs and low TFs. The fast neurons were tuned for TF, but the slow nBOR neurons had spatiotemporally oriented peaks that suggested velocity tuning (TF/SF). However, the peak response was not independent of SF; thus we refer to the tuning as “apparent velocity tuning” or “velocity-like tuning.” Some neurons showed peaks in both the fast and slow regions. These neurons were TF-tuned at low SFs, and showed velocity-like tuning at high SFs. We used computer simulations of the response of an elaborated Reichardt detector to show that both the TF-tuning and velocity-like tuning shown by the fast and slow neurons, respectively, may be explained by modified versions of the correlation model of motion detection.

The accessory optic system of rabbit. I. Basic visual response properties

1988 ◽  
Vol 60 (6) ◽  
pp. 2037-2054 ◽  
Author(s):  
R. E. Soodak ◽  
J. I. Simpson
Keyword(s):  
Ganglion Cells ◽  
Receptive Fields ◽  
Extracellular Recording ◽  
Vestibular Stimulation ◽  
Visual Response ◽  
Optic System ◽  
Accessory Optic System ◽  
Response Properties ◽  
Tuning Curves ◽  
Sinusoidal Oscillations

1. The response properties of accessory optic system (AOS) neurons were assessed using single-unit extracellular recording from each of the three AOS terminal nuclei [medial, lateral, and dorsal terminal nuclei (MTN, LTN, and DTN)] in the anesthetized rabbit. 2. AOS neurons had large, monocular (contralateral) receptive fields (tens of degrees on a side) and exhibited a pronounced selectivity to the speed and direction of movement of large, textured patterns. The greatest responses occurred at slow speeds on the order of 0.5 degrees/s. 3. MTN and LTN neurons responded best to movement in near vertical directions. However, the stimulus directions corresponding to the greatest excitation and the greatest inhibition both had a posterior component and, thus, the preferred excitatory and inhibitory directions were not opposite each other. DTN neurons responded most strongly to horizontal movement and were excited by temporal to nasal movement. 4. AOS neurons were unresponsive to natural vestibular stimulation presented as sinusoidal oscillations of the rabbit about the yaw, pitch, and roll axes. 5. The response properties of AOS neurons are remarkably similar to those of the ON, direction-selective ganglion cells of the rabbit retina, and therefore this class of ganglion cell is most likely the predominant, if not the only, direct retinal input to the AOS. The local direction-selective properties of AOS neurons can be accounted for by combining the tuning curves of ON, direction-selective ganglion cells in a simple manner. 6. The low speed preference of AOS neurons, along with their large receptive fields suggests that they are suited to complement the vestibular system in detecting self-motion.

Spatio-temporal receptive-field structure of phasic W cells in the cat retina

1995 ◽  
Vol 12 (1) ◽  
pp. 117-139 ◽  
Author(s):  
M.H. Rowe ◽  
L.A. Palmer
Keyword(s):  
Receptive Field ◽  
Input Signal ◽  
Receptive Fields ◽  
Correlation Method ◽  
Direction Selectivity ◽  
Field Structure ◽  
Local Motion ◽  
Accessory Optic System ◽  
Spatio Temporal ◽  
Local Receptive Fields

AbstractThe spatio-temporal receptive-field structure of 54 phasic W cells in cat retinas has been examined using the reverse-correlation method of Jones and Palmer (1987). Within this sample, 12 cells had on-center, 16 off-center, and 26 on-off receptive fields. Three of the on-center and seven of the on-off cells were directionally selective. Forty percent of the cells in this sample had local receptive fields consisting of two or more distinct subregions. However, no correlation was observed between the number of subregions in the local receptive field and other response properties such as center sign or direction selectivity. In all cases, individual subregions, including those in on-off cells, appear to be produced by a half-wave rectification of the input signal. For 76% of the cells, these local receptive fields were contained within large suppressive fields which could be seen to extend for at least 10 deg in all directions with no apparent spatial structure. The mechanism producing the suppressive field also appears to involve a rectification of the input signal, and has a relatively high spatial resolution. Furthermore, the suppressive field itself is only responsive to moving or flickering stimuli; large, stationary gratings have no effect on the output of the local receptive-field mechanism. Thus, the overall receptive-field organization of these cells is particularly well suited for detecting local motion. The remaining 24% of cells in the sample lacked suppressive fields, and consequently responded well to large moving stimuli, but these cells were otherwise similar in their receptive-field properties to cells with suppressive fields. The significance of these properties is discussed in the context of the projections of phasic W cells to the superior colliculus and accessory optic system.

Morphology of the turtle accessory optic system

2003 ◽  
Vol 20 (6) ◽  
pp. 639-649 ◽  
Author(s):  
JOHN MARTIN ◽  
NAOKI KOGO ◽  
TIAN XING FAN ◽  
MICHAEL ARIEL
Keyword(s):  
Visual Processing ◽  
Ganglion Cells ◽  
Computer Software ◽  
Dorsal Side ◽  
Visual Responses ◽  
Optic System ◽  
Neural Signals ◽  
Accessory Optic System ◽  
Full Field

Neural signals of the moving visual world are detected by a subclass of retinal ganglion cells that project to the accessory optic system in the vertebrate brainstem. We studied the dendritic morphologies and direction tuning of these brainstem neurons in turtle (Pseudemys scripta elegans) to understand their role in visual processing. Full-field checkerboard patterns were drifted on the contralateral retina while whole-cell recordings were made in the basal optic nucleus in an intact brainstem preparation in vitro. Neurobiotin diffused into the neurons during the recording and was subsequently localized in brain sections. Neuronal morphologies were traced using appropriate computer software to analyze their position in the brainstem. Most labeled neurons were fusiform in shape and had numerous varicosities along their processes. The majority of dendritic trees spread out in a transverse plane perpendicular to the rostrocaudal axis of the nucleus. Neurons near the brainstem surface were often oriented tangential to that surface, whereas more cells at the dorsal side of the nucleus were oriented radial to the brainstem surface. Further analysis of Nissl-stained neurons revealed the largest neurons are located in the rostral and medial portions of the nucleus although neurons are most densely packed in the middle of the nucleus. The preferred directions of the visual responses of the neurons in this sample did not correlate with their morphology and position in the nucleus. Therefore, the morphology of the cells in the turtle accessory optic system appears dependent on its position within the nucleus while its visual responses may depend on the synaptic inputs that contact each cell.

scholarly journals Categorically distinct types of receptive fields in early visual cortex

2016 ◽  
Vol 115 (5) ◽  
pp. 2556-2576 ◽  
Author(s):  
Vargha Talebi ◽  
Curtis L. Baker
Keyword(s):  
Visual Cortex ◽  
System Identification ◽  
Cortical Neurons ◽  
Temporal Dynamics ◽  
High Reliability ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Natural Image ◽  
Visual Responses ◽  
Neurophysiological Studies

In the visual cortex, distinct types of neurons have been identified based on cellular morphology, response to injected current, or expression of specific markers, but neurophysiological studies have revealed visual receptive field (RF) properties that appear to be on a continuum, with only two generally recognized classes: simple and complex. Most previous studies have characterized visual responses of neurons using stereotyped stimuli such as bars, gratings, or white noise and simple system identification approaches (e.g., reverse correlation). Here we estimate visual RF models of cortical neurons using visually rich natural image stimuli and regularized regression system identification methods and characterize their spatial tuning, temporal dynamics, spatiotemporal behavior, and spiking properties. We quantitatively demonstrate the existence of three functionally distinct categories of simple cells, distinguished by their degree of orientation selectivity (isotropic or oriented) and the nature of their output nonlinearity (expansive or compressive). In addition, these three types have differing average values of several other properties. Cells with nonoriented RFs tend to have smaller RFs, shorter response durations, no direction selectivity, and high reliability. Orientation-selective neurons with an expansive output nonlinearity have Gabor-like RFs, lower spontaneous activity and responsivity, and spiking responses with higher sparseness. Oriented RFs with a compressive nonlinearity are spatially nondescript and tend to show longer response latency. Our findings indicate multiple physiologically defined types of RFs beyond the simple/complex dichotomy, suggesting that cortical neurons may have more specialized functional roles rather than lying on a multidimensional continuum.

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)

Response Properties of Optic Flow Neurons in the Accessory Optic System of Hummingbirds vs. Zebra Finches and Pigeons

2021 ◽  
Author(s):  
Andrea H Gaede ◽  
Vikram B Baliga ◽  
Graham Smyth ◽  
Cristian Gutiérrez-Ibáñez ◽  
Douglas Leonard Altshuler ◽  
...  
Keyword(s):  
Optic Flow ◽  
Receptive Fields ◽  
Bird Species ◽  
Visual Response ◽  
Zebra Finches ◽  
Optic System ◽  
Accessory Optic System ◽  
Stimulus Velocity ◽  
Response Properties ◽  
Optokinetic Responses

Optokinetic responses function to maintain retinal image stabilization by minimizing optic flow that occurs during self-motion. The hovering ability of hummingbirds is an extreme example of this behaviour. Optokinetic responses are mediated by direction-selective neurons with large receptive fields in the accessory optic system (AOS) and pretectum. Recent studies in hummingbirds showed that, compared to other bird species, (i) the pretectal nucleus lentiformis mesencephali (LM) is hypertrophied, (ii) LM has a unique distribution of direction preferences, and (iii) LM neurons are more tightly tuned to stimulus velocity. In this study, we sought to determine if there are concomitant changes in the nucleus of the basal optic root (nBOR) of the AOS. We recorded the visual response properties of nBOR neurons to largefield drifting random dot patterns and sine wave gratings in Anna's hummingbirds and zebra finches and compared these with archival data from pigeons. We found no differences with respect to the distribution of direction preferences: Neurons responsive to upwards, downwards and nasal-to-temporal motion were equally represented in all three species, and neurons responsive to temporal-to-nasal motion were rare or absent (<5%). Compared to zebra finches and pigeons, however, hummingbird nBOR neurons were more tightly tuned to stimulus velocity of random dot stimuli. Moreover, in response to drifting gratings, hummingbird nBOR neurons are more tightly tuned in the spatio-temporal domain. These results, in combination with specialization in LM, supports a hypothesis that hummingbirds have evolved to be "optic flow specialist" to cope with the optomotor demands of sustained hovering flight.

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