Visual Responses of the Human Superior Colliculus: A High-Resolution Functional Magnetic Resonance Imaging Study

2005 ◽  
Vol 94 (4) ◽  
pp. 2491-2503 ◽  
Author(s):  
Keith A. Schneider ◽  
Sabine Kastner
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
High Resolution ◽  
Superior Colliculus ◽  
Visual Fields ◽  
Visual Response ◽  
Visual Responses ◽  
Subcortical Structures ◽  
Stimulus Motion ◽  
Low Contrast

The superior colliculus (SC) is a multimodal laminar structure located on the roof of the brain stem. The SC is a key structure in a distributed network of areas that mediate saccadic eye movements and shifts of attention across the visual field and has been extensively studied in nonhuman primates. In humans, it has proven difficult to study the SC with functional MRI (fMRI) because of its small size, deep location, and proximity to pulsating vascular structures. Here, we performed a series of high-resolution fMRI studies at 3 T to investigate basic visual response properties of the SC. The retinotopic organization of the SC was determined using the traveling wave method with flickering checkerboard stimuli presented at different polar angles and eccentricities. SC activations were confined to stimulation of the contralateral hemifield. Although a detailed retinotopic map was not observed, across subjects, the upper and lower visual fields were represented medially and laterally, respectively. Responses were dominantly evoked by stimuli presented along the horizontal meridian of the visual field. We also measured the sensitivity of the SC to luminance contrast, which has not been previously reported in primates. SC responses were nearly saturated by low contrast stimuli and showed only small response modulation with higher contrast stimuli, indicating high sensitivity to stimulus contrast. Responsiveness to stimulus motion in the SC was shown by robust activations evoked by moving versus static dot stimuli that could not be attributed to eye movements. The responses to contrast and motion stimuli were compared with those in the human lateral geniculate nucleus. Our results provide first insights into basic visual responses of the human SC and show the feasibility of studying subcortical structures using high-resolution fMRI.

Visual responses of pulvinar and collicular neurons during eye movements of awake, trained macaques

1991 ◽  
Vol 66 (2) ◽  
pp. 485-496 ◽  
Author(s):  
D. L. Robinson ◽  
J. W. McClurkin ◽  
C. Kertzman ◽  
S. E. Petersen
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Visual Responses ◽  
Stimulus Motion ◽  
Stimulus Movement ◽  
Pursuit Eye Movements ◽  
Extraretinal Signal ◽  
Wide Range

1. We recorded from single neurons in awake, trained rhesus monkeys in a lighted environment and compared responses to stimulus movement during periods of fixation with those to motion caused by saccadic or pursuit eye movements. Neurons in the inferior pulvinar (PI), lateral pulvinar (PL), and superior colliculus were tested. 2. Cells in PI and PL respond to stimulus movement over a wide range of speeds. Some of these cells do not respond to comparable stimulus motion, or discharge only weakly, when it is generated by saccadic or pursuit eye movements. Other neurons respond equivalently to both types of motion. Cells in the superficial layers of the superior colliculus have similar properties to those in PI and PL. 3. When tested in the dark to reduce visual stimulation from the background, cells in PI and PL still do not respond to motion generated by eye movements. Some of these cells have a suppression of activity after saccadic eye movements made in total darkness. These data suggest that an extraretinal signal suppresses responses to visual stimuli during eye movements. 4. The suppression of responses to stimuli during eye movements is not an absolute effect. Images brighter than 2.0 log units above background illumination evoke responses from cells in PI and PL. The suppression appears stronger in the superior colliculus than in PI and PL. 5. These experiments demonstrate that many cells in PI and PL have a suppression of their responses to stimuli that cross their receptive fields during eye movements. These cells are probably suppressed by an extraretinal signal. Comparable effects are present in the superficial layers of the superior colliculus. These properties in PI and PL may reflect the function of the ascending tectopulvinar system.

Both striate cortex and superior colliculus contribute to visual properties of neurons in superior temporal polysensory area of macaque monkey

1986 ◽  
Vol 55 (5) ◽  
pp. 1057-1075 ◽  
Author(s):  
C. J. Bruce ◽  
R. Desimone ◽  
C. G. Gross
Keyword(s):  
Visual Field ◽  
Receptive Field ◽  
Superior Colliculus ◽  
Striate Cortex ◽  
Visual Stimuli ◽  
Receptive Fields ◽  
Visual Responses ◽  
Stimulus Motion ◽  
Visual Hemifields ◽  
Visual Properties

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)

Visual Field Accuracy and Eye Movement Direction: A Child's Eye View

1980 ◽  
Vol 50 (2) ◽  
pp. 631-636
Author(s):  
Evans Mandes
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Eye Movement ◽  
Visual Fields ◽  
Movement Direction

Post-exposural eye movements were studied in 32 adults and 24 7-yr.-old children. Stimuli were binary figures exposed tachistoscopically in both visual fields simultaneously. The data showed significant correlations between direction of eye movement and locus of recognition for both children and adults. No significant differences were found in frequencies of eye movements of children and adults. The data are interpreted in terms of the facilitative effects of post-exposural eye movements upon perception for both groups.

The functional influence of nicotinic cholinergic receptors on the visual responses of neurones in the superficial superior colliculus

2000 ◽  
Vol 17 (2) ◽  
pp. 283-289 ◽  
Author(s):  
K.E. BINNS ◽  
T.E. SALT
Keyword(s):  
Superior Colliculus ◽  
Nicotinic Receptors ◽  
Visual Stimulation ◽  
Glutamate Release ◽  
Drug Application ◽  
Receptor Activation ◽  
Visual Input ◽  
Visual Response ◽  
Visual Responses ◽  
Parabigeminal Nucleus

In the rat, the superficial gray layer (SGS) of the superior colliculus receives glutamatergic projections from the contralateral retina and from the visual cortex. A few fibers from the ipsilateral retina also directly innervate the SGS, but most of the ipsilateral visual input is provided by cholinergic afferents from the opposing parabigeminal nucleus (PBG). Thus, visual input carried by cholinergic afferents may have a functional influence on the responses of SGS neurones. When single neuronal extracellular recording and iontophoretic drug application were employed to examine this possibility, cholinergic agonists were found to depress responses to visual stimulation. Lobeline and 1-acetyl-4-methylpiperazine both depressed visually evoked activity and had a tendency to reduce the background firing rate of the neurones. Carbachol depressed the visual responses without any significant effect on the ongoing activity, while the muscarinic receptor selective agonist methacholine increased the background activity of the neurones and reduced their visual responses. Lobeline was chosen for further studies on the role of nicotinic receptors in SGS. Given that nicotinic receptors are associated with retinal terminals in SGS, and that the activation of presynaptic nicotinic receptors normally facilitates transmitter release (in this case glutamate release), the depressant effects of nicotinic agonists are intriguing. However, many retinal afferents contact inhibitory neurones in SGS; thus it is possible that the increase in glutamate release in turn facilitates the liberation of GABA which goes on to inhibit the visual responses. We therefore attempted to reverse the effects of lobeline with GABA receptor antagonists. The depressant effects of lobeline on the visual response could not be reversed by the GABAA antagonist bicuculline, but the GABAB antagonist CGP 35348 reduced the effects of lobeline. We hypothesize that cholinergic drive from the parabigeminal nucleus may activate presynaptic nicotinic receptors on retinal terminals, thereby facilitating the release of glutamate onto inhibitory neurones. Consequently GABA is released, activating GABAB receptors, and thus the ultimate effect of nicotinic receptor activation is to depress visual responses.

Reading with Visual Field Defects

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 11-11 ◽  
Author(s):  
S Trauzettel-Klosinski
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Reading Ability ◽  
Reading Speed ◽  
Visual Fields ◽  
Zero Point ◽  
Normal Subjects ◽  
Visual Field Defects ◽  
Video Tape ◽  
Field Defects

The influence of different visual field defects on the reading performance was examined with potential adaptive strategies to improve the reading process in mind. By means of an SLO, the retinal fixation locus (RFL) was determined with the use of single targets and text, and eye movements scanning the text were recorded on video tape. Additionally, eye movements were monitored by an Infrared Limbus Tracker. Visual fields were assessed by the Tübingen Manual and/or automatic perimetry. Normal subjects, and patients with central scotomata, ring scotomata, and hemianopic field defects (HFD) were examined. The main pathological reading parameters were an increase of saccade frequency and regressions per line, and a decrease of reading speed. In patients with field defects involving the visual field centre, fixation behaviour is significant for regaining reading ability. In absolute central scotoma, the lost foveal function promotes eccentric fixation. The remaining problem is insufficient resolution of the RFL, which can be compensated for by magnification of the text. In patients with insufficient size of their reading visual field, due to HFD and ring scotoma, it is crucial that they learn to use a new RFL despite intact foveolar function. Preconditions for reading have been found to be: (1) sufficient resolution of the RFL, (2) a reading visual field of a minimum extent, and (3) intact basic oculomotor function. In patients with visual field defects involving the centre, a sensory-motor adaptation process is required: the use of a new RFL as the new centre of the visual field and as the new zero point for eye-movement coordinates.

Organization of monkey superior colliculus: intermediate layer cells discharging before eye movements

1976 ◽  
Vol 39 (4) ◽  
pp. 722-744 ◽  
Author(s):  
C. W. Mohler ◽  
R. H. Wurtz
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Eye Movement ◽  
Intermediate Layer ◽  
Visual Fields ◽  
Saccadic Eye Movements ◽  
Superficial Layer ◽  
Cell Discharge ◽  
Intermediate Layers ◽  
Dorsal Edge

1. We investigated the characteristics of cells in the intermediate layers of the superior colliculus that increase their rate of discharge before saccadic eye movements. Eye movements were repeatedly elicited by training rhesus monkeys to fixate on a spot of light and to make saccades to other spots of light when the fixation spot was turned off. 2. The eye movement cells showed consistent variations with their depth within the colliculus. The onset of the cell discharge led the eye movement by less time and the duration of the discharge was shorter as the cell was located closer to the dorsal edge of the intermediate layers. The movements fields (that area of the visual field where a saccade into the area is preceded by a burst of cell discharges) of each successive cell also became smaller as the cells were located more dorsally. The profile of peak discharge frequency remained fairly flat throughout the movement field of the cells regardless of depth of the cell within the colliculus. 3. A new type of eye movement-related cell has been found which usually lies at the border between the superficial and intermediate layers. This cell type, the visually triggered movement cell, increased its rate of discharge before saccades made to a visual stimulus but not before spontaneous saccades of equal amplitude made in the light or the dark. A vigorous discharge of these cells before an eye movement was dependent on the presence of a visual target; the cells seemed to combine the visual input of superficial layer cells and the movement-related input of the intermediate layer cells. The size of the movement fields of these cells were about the same size as the visual fields of superficial layer cells just above them...

Use of interrupted saccade paradigm to study spatial and temporal dynamics of saccadic burst cells in superior colliculus in monkey

1994 ◽  
Vol 72 (6) ◽  
pp. 2754-2770 ◽  
Author(s):  
E. L. Keller ◽  
J. A. Edelman
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Temporal Dynamics ◽  
Saccadic Eye Movements ◽  
Eye Position ◽  
Visual Response ◽  
Intermediate Layers ◽  
Saccade Onset ◽  
Spatial And Temporal Dynamics ◽  
Motor Error

1. We recorded the spatial and temporal dynamics of saccade-related burst neurons (SRBNs) found in the intermediate layers of the superior colliculus (SC) in the alert, behaving monkey. These burst cells are normally the first neurons recorded during radially directed microelectrode penetrations of the SC after the electrode has left the more dorsally situated visual layers. They have spatially delimited movement fields whose centers describe the well-studied motor map of the SC. They have a rather sharp, saccade-locked burst of activity that peaks just before saccade onset and then declines steeply during the saccade. Many of these cells, when recorded during saccade trials, also have an early, transient visual response and an irregular prelude of presaccadic activity. 2. Because saccadic eye movements normally have very stereotyped durations and velocity trajectories that vary systematically with saccade size, it has been difficult in the past to establish quantitatively whether the activity of SRBNs temporally codes dynamic saccadic control signals, e.g., dynamic motor error or eye velocity, where dynamic motor error is defined as a signal proportional to the instantaneous difference between desired final eye position and the actual eye position during a saccade. It has also not been unequivocally established whether SRBNs participate in an organized spatial shift of ensemble activity in the intermediate layers of the SC during saccadic eye movements. 3. To address these issues, we studied the activity of SRBNs using an interrupted saccade paradigm. Saccades were interrupted with pulsatile electrical stimulation through a microelectrode implanted in the omnipauser region of the brain stem while recordings were made simultaneously from single SRBNs in the SC. 4. Shortly after the beginning of the stimulation (which was electronically triggered at saccade onset), the eyes decelerated rapidly and stopped completely. When the high-frequency (typically 300-400 pulses per second) stimulation was terminated (average duration 12 ms), the eye movement was reinitiated and a resumed saccade was made accurately to the location of the target. 5. When we recorded from SRBNs in the more caudal colliculus, which were active for large saccades, cell discharge was powerfully and rapidly suppressed by the stimulation (average latency = 3.8 ms). Activity in the same cells started again just before the onset of the resumed saccade and continued during this saccade even though it has a much smaller amplitude than would normally be associated with significant discharge for caudal SC cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of serotonin on retinotectal-, corticotectal-, and glutamate-induced activity in the superior colliculus of the hamster

1993 ◽  
Vol 70 (2) ◽  
pp. 723-732 ◽  
Author(s):  
X. Huang ◽  
R. D. Mooney ◽  
R. W. Rhoades
Keyword(s):  
Superior Colliculus ◽  
Optic Chiasm ◽  
Superficial Layer ◽  
Response Suppression ◽  
Visual Response ◽  
Evoked Responses ◽  
Average Response ◽  
Visual Responses ◽  
Unit Recording ◽  
Visual Cortical

1. Single-unit recording and iontophoretic techniques were used to test the effects of serotonin (5-HT) on the responses of neurons in the superficial layers (the stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). 2. Iontophoresis of 5-HT produced a visual response suppression of 40% or greater in 78.1% (n = 50) of 64 neurons tested. 5-HT did not augment the visual responses of any of the cells tested. The average response suppression was 75.3 +/- 21.2% (mean +/- S.D.). 3. Iontophoresis of 5-HT had significantly different effects on activation of SC cells by optic chiasm (OX) and visual cortical (CTX) stimulation. Application of 5-HT suppressed the OX-evoked responses of 96.9% (n = 31) of the 32 SC cells tested by at least 40%, and the average response suppression for all 32 neurons tested was 87.1 +/- 22.5%. Application of 5-HT suppressed the responses of only 35.7% (n = 10) of the 28 cells tested with CTX stimulation by at least 40%. The average response suppression for all 28 cells was 35.3 +/- 38.8%. 4. The effects of 5-HT on the glutamate-evoked responses of SC cells that were synaptically "isolated" by concurrent application of Mg2+ were also evaluated. Application of 5-HT produced a response suppression > or = 40% in 29.7% (n = 19) of the 64 neurons tested under these conditions. The average response suppression for all of the cells tested was 28.4 +/- 35.7%. This effect of 5-HT was significantly weaker than that on visually evoked responses of these neurons. 5. The present results demonstrate that 5-HT markedly depresses the visual responses of most superficial layer SC neurons. They suggest further that much of this effect is mediated by presynaptic inhibition of retinotectal transmission.

Visual, presaccadic, and cognitive activation of single neurons in monkey lateral intraparietal area

1996 ◽  
Vol 76 (5) ◽  
pp. 2841-2852 ◽  
Author(s):  
C. L. Colby ◽  
J. R. Duhamel ◽  
M. E. Goldberg
Keyword(s):  
Eye Movements ◽  
Stimulus Onset ◽  
Cognitive Factors ◽  
Visual Response ◽  
Single Neurons ◽  
Visual Responses ◽  
Related Activity ◽  
Lateral Intraparietal Area ◽  
Fixation Task ◽  
Saccade Task

1. Posterior parietal cortex contains neurons that are visually responsive and active in relation to saccadic eye movements. We recorded from single neurons in a subregion of parietal cortex, the lateral intraparietal area (LIP), in alert rhesus monkeys. To characterize more completely the circumstances under which LIP neurons are responsive, we used five tasks designed to test the impact of sensory, motor, and cognitive factors. We obtained quantitative data in multiple tasks in 91 neurons. We measured neural activity during central fixation and in relation to stimulus onset and saccade onset. 2. LIP neurons have visual responses to the onset of a stationary stimulus in the receptive field. These visual responses occurred both in tasks that require a subsequent eye movement toward the stimulus and in tasks in which eye movements are not permitted, indicating that this activity is sensory rather than presaccadic. 3. Visual responses were enhanced when the monkey had to use information provided by the stimulus to guide its behavior. The amplitude of the sensory response to a given stimulus was increased in a task in which the monkey would subsequently make a saccade to the location signaled by the stimulus, as compared with the amplitude of the visual response in a simple fixation task. 4. The visual response was also enhanced when the monkey attended to the stimulus without looking at it. This result shows that enhancement does not reflect saccade preparation because the response is enhanced even when the monkey is not permitted to make a saccade. Instead, enhancement reflects the allocation of attention to the spatial locus of the receptive field. 5. Many LIP neurons had saccade-related activity in addition to their visual responses. The visual response for most neurons was stronger than the saccade-related activation. 6. Saccade-related activity was independent of visual activity. Similar presaccadic activity was observed in trials that included a recent visual stimulus (memory-guided saccade task) and in trials with no visual stimulus (learned saccade task). 7. We observed increases in activity during fixation in tasks in which the monkey could anticipate the onset of a behaviorally significant stimulus. LIP neurons usually showed low levels of background firing in the fixation task during the period before stimulus onset. This background activity was increased in the peripheral attention and memory-guided saccade tasks during the period when the monkey was waiting for a behaviorally relevant stimulus to appear. 8. The results from these several tasks indicate that LIP neurons are activated in a variety of circumstances and are not involved exclusively in sensory processing or motor planning. The modulation of sensory responses by attention and anticipation suggests that cognitive factors play a major role in parietal function.

scholarly journals Visuospatial coding in primate prefrontal neurons revealed by oculomotor paradigms

1990 ◽  
Vol 63 (4) ◽  
pp. 814-831 ◽  
Author(s):  
S. Funahashi ◽  
C. J. Bruce ◽  
P. S. Goldman-Rakic
Keyword(s):  
Prefrontal Cortex ◽  
Visual Field ◽  
Visual Cues ◽  
Neuron Activity ◽  
Delayed Response ◽  
Visual Response ◽  
Visual Responses ◽  
Directional Tuning ◽  
Vertical Meridian ◽  
Visual Probe

1. Visual responses and their relationship to delay-period activity were studied by recording single neuron activity from the prefrontal cortex of rhesus monkeys while they performed an oculomotor delayed-response (ODR) and a visual probe (VP) task. In the ODR task, the monkey was required to maintain fixation of a central spot of light throughout the cue (0.5 s) and delay (3 s) periods and then make a saccadic eye movement to one of four or eight locations where the visual cue had been presented. In the VP task, the same visual stimuli that were used in the ODR task were presented for 0.5 s, but no response was required. The VP task was thus employed to test the passive visual response and, by comparison with cue-elicited activity in the ODR task, to examine the degree of behavioral enhancement present in prefrontal visual activity. 2. Among 434 neurons recorded from the prefrontal cortex within and surrounding the principal sulcus (PS), 261 had task-related activity during at least one phase of the ODR task, and 74 of these had phasic visual responses to the onset of the visual cues with a median latency of 116 ms. The visual responses of 69 neurons were excitatory, and 5 neurons were inhibited. Five of the neurons with excitatory visual responses also responded transiently after the offset of the cue. 3. Visual responses were classified as directional for 71 PS neurons (96%) in that excitatory or inhibitory responses occurred only for location of cues in a restricted portion of the visual field. Only 3 PS neurons were omnidirectional, i.e., responded equivalently to cues in all locations tested. 4. The best direction and tuning specificity of all PS neurons with directional visual responses were estimated from parameters yielding the best fit to a Gaussian-shaped tuning function. The best direction for the majority (71%) of neurons was toward the visual field contralateral to the hemisphere where the neuron was located. The remaining neurons had their best directions in the ipsilateral field (18%) or along the vertical meridian (11%). 5. The specificity of directional tuning for PS visual responses was quite variable, ranging from neurons that responded only to one of the eight cue locations to neurons that responded to all eight, but in a clearly graded fashion. The standard deviation parameter of the Gaussian curve indexed the breadth of directional tuning of each neuron; its median value was 37 degrees.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document