Visual responses with and without fixation: neurons in premotor cortex encode spatial locations independently of eye position

1998 ◽  
Vol 118 (3) ◽  
pp. 373-380 ◽  
Author(s):  
M. S. A. Graziano ◽  
Charles G. Gross
Keyword(s):  
Premotor Cortex ◽  
Eye Position ◽  
Visual Responses ◽  
Spatial Locations

Primate premotor cortex: modulation of preparatory neuronal activity by gaze angle

1995 ◽  
Vol 73 (2) ◽  
pp. 886-890 ◽  
Author(s):  
D. Boussaoud
Keyword(s):  
Neuronal Activity ◽  
Premotor Cortex ◽  
Target Position ◽  
Delay Period ◽  
Coordinate Space ◽  
Eye Position ◽  
Related Activity ◽  
Visuomotor Task ◽  
Small Spot ◽  
The Right

1. This study investigated whether the neuronal activity of a cortical area devoted to the control of limb movements is affected by variations in eye position within the orbit. Two rhesus monkeys were trained to perform a conditional visuomotor task with an instructed delay period while maintaining gaze on a fixation point. 2. The experimental design required each monkey to put its hand on a metal touch pad located at arm's length and fixate a small spot of light presented on a computer screen. Then a visual cue came on, at the fixation point or elsewhere, the color of which instructed the monkey to move its limb to one of two touch pads according to a conditional rule. A red cue meant a movement to the left, whereas a green one instructed a movement to the right. The cue lasted for a variable delay period (1-3 s), and the monkey had to wait for its offset, the go signal, before performing the correct response. The fixation point and the cues were presented at various screen locations in a combination that allowed examination of whether eye position and/or target position modulate the neuronal activity. Because the monkeys' heads were fixed, all changes in eye position reflected movements in a craniocentric, head-centered, coordinate space. 3. The activity of single neurons was recorded from dorsal premotor cortex (PMd). For most neurons (79%), the activity during the instructed delay period (set-related activity) reflects the direction of the upcoming limb movement but varies significantly with eye position.(ABSTRACT TRUNCATED AT 250 WORDS)

Eye Position Effects on the Neuronal Activity of Dorsal Premotor Cortex in the Macaque Monkey

1998 ◽  
Vol 80 (3) ◽  
pp. 1132-1150 ◽  
Author(s):  
Driss Boussaoud ◽  
Christophe Jouffrais ◽  
Frank Bremmer
Keyword(s):  
Reference Frame ◽  
Neuronal Activity ◽  
Premotor Cortex ◽  
Macaque Monkey ◽  
Limb Movement ◽  
Movement Direction ◽  
Eye Position ◽  
Dorsal Premotor Cortex ◽  
Position Effects ◽  
The Brain

Boussaoud, Driss, Christophe Jouffrais, and Frank Bremmer. Eye position effects on the neuronal activity of dorsal premotor cortex in the macaque monkey. J. Neurophysiol. 80: 1132–1150, 1998. Visual inputs to the brain are mapped in a retinocentric reference frame, but the motor system plans movements in a body-centered frame. This basic observation implies that the brain must transform target coordinates from one reference frame to another. Physiological studies revealed that the posterior parietal cortex may contribute a large part of such a transformation, but the question remains as to whether the premotor areas receive visual information, from the parietal cortex, readily coded in body-centered coordinates. To answer this question, we studied dorsal premotor cortex (PMd) neurons in two monkeys while they performed a conditional visuomotor task and maintained fixation at different gaze angles. Visual stimuli were presented on a video monitor, and the monkeys made limb movements on a panel of three touch pads located at the bottom of the monitor. A trial begins when the monkey puts its hand on the central pad. Then, later in the trial, a colored cue instructed a limb movement to the left touch pad if red or to the right one if green. The cues lasted for a variable delay, the instructed delay period, and their offset served as the go signal. The fixation spot was presented at the center of the screen or at one of four peripheral locations. Because the monkey's head was restrained, peripheral fixations caused a deviation of the eyes within the orbit, but for each fixation angle, the instructional cue was presented at nine locations with constant retinocentric coordinates. After the presentation of the instructional cue, 133 PMd cells displayed a phasic discharge (signal-related activity), 157 were tonically active during the instructed delay period (set-related or preparatory activity), and 104 were active after the go signal in relation to movement (movement-related activity). A large proportion of cells showed variations of the discharge rate in relation to limb movement direction, but only modest proportions were sensitive to the cue's location (signal, 43%; set, 34%; movement, 29%). More importantly, the activity of most neurons (signal, 74%; set, 79%; movement, 79%) varied significantly (analysis of variance, P < 0.05) with orbital eye position. A regression analysis showed that the neuronal activity varied linearly with eye position along the horizontal and vertical axes and can be approximated by a two-dimensional regression plane. These data provide evidence that eye position signals modulate the neuronal activity beyond sensory areas, including those involved in visually guided reaching limb movements. Further, they show that neuronal activity related to movement preparation and execution combines at least two directional parameters: arm movement direction and gaze direction in space. It is suggested that a substantial population of PMd cells codes limb movement direction in a head-centered reference frame.

Neural Correlates of Divided Attention in Natural Scenes

2016 ◽  
Vol 28 (9) ◽  
pp. 1392-1405 ◽  
Author(s):  
Sabrina Fagioli ◽  
Emiliano Macaluso
Keyword(s):  
Real World ◽  
Divided Attention ◽  
Premotor Cortex ◽  
Natural Scenes ◽  
Multiple Streams ◽  
Top Down ◽  
Frontoparietal Network ◽  
Object Categories ◽  
Visual Hemifields ◽  
Spatial Locations

Individuals are able to split attention between separate locations, but divided spatial attention incurs the additional requirement of monitoring multiple streams of information. Here, we investigated divided attention using photos of natural scenes, where the rapid categorization of familiar objects and prior knowledge about the likely positions of objects in the real world might affect the interplay between these spatial and nonspatial factors. Sixteen participants underwent fMRI during an object detection task. They were presented with scenes containing either a person or a car, located on the left or right side of the photo. Participants monitored either one or both object categories, in one or both visual hemifields. First, we investigated the interplay between spatial and nonspatial attention by comparing conditions of divided attention between categories and/or locations. We then assessed the contribution of top–down processes versus stimulus-driven signals by separately testing the effects of divided attention in target and nontarget trials. The results revealed activation of a bilateral frontoparietal network when dividing attention between the two object categories versus attending to a single category but no main effect of dividing attention between spatial locations. Within this network, the left dorsal premotor cortex and the left intraparietal sulcus were found to combine task- and stimulus-related signals. These regions showed maximal activation when participants monitored two categories at spatially separate locations and the scene included a nontarget object. We conclude that the dorsal frontoparietal cortex integrates top–down and bottom–up signals in the presence of distractors during divided attention in real-world scenes.

Effects of Observer Orientation on Perception of Ego- and Exocentric Spatial Locations

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 237-237
Author(s):  
J Li ◽  
M M Cohen ◽  
C W DeRoshia ◽  
L T Guzy
Keyword(s):  
Tracking System ◽  
Systematic Errors ◽  
Visual Environment ◽  
Head Orientation ◽  
Eye Position ◽  
Systematic Bias ◽  
Egocentric Location ◽  
Spatial Locations ◽  
Infrared Tracking ◽  
Straight Ahead

Perceived eye position and/or the perceived location of visual targets are altered when the orientation of the surrounding visual environment (Cohen et al, 1995 Perception & Psychophysics571 433) or that of the observer (Cohen and Guzy, 1995 Aviation, Space, and Environmental Medicine66 505) is changed. Fourteen subjects used biteboards as they lay on a rotary bed that was oriented head-down −15°, −7.5°, supine, head-up +7.5°, and +15°. In the dark, subjects directed their gaze and set a target to the apparent zenith (exocentric location); they also gazed at a subjective ‘straight ahead’ position with respect to their head (egocentric location). Angular deviations of target settings and changes in vertical eye position were recorded with an ISCAN infrared tracking system. Results indicated that, for exocentric locations, the eyes deviate systematically from the true zenith. The gain for compensating changes in head orientation was 0.69 and 0.73 for gaze direction and target settings, respectively. In contrast, ‘straight ahead’ eye positions were not significantly affected by changes in the subject's orientation. We conclude that subjects make systematic errors when directing their gaze to an exocentric location in near-supine positions. This suggests a systematic bias in the integration of extra-ocular signals with information regarding head orientation. The bias may result from underestimating changes in the orientation of the head in space. In contrast, for egocentric locations, where head orientation information can potentially be discarded, gaze directions were unaffected by head orientation near supine.

Visual responses in the postarcuate cortex (area 6) of the monkey that are independent of eye position

1983 ◽  
Vol 50-50 (2-3) ◽  
Author(s):  
M. Gentilucci ◽  
C. Scandolara ◽  
I.N. Pigarev ◽  
G. Rizzolatti
Keyword(s):  
Eye Position ◽  
Visual Responses ◽  
Cortex Area ◽  
Area 6

scholarly journals Dissociation of visual and saccade-related responses in superior colliculus neurons

1980 ◽  
Vol 43 (1) ◽  
pp. 207-232 ◽  
Author(s):  
L. E. Mays ◽  
D. L. Sparks
Keyword(s):  
Superior Colliculus ◽  
Visual Stimulation ◽  
Usual Sense ◽  
Eye Position ◽  
Visual Responses ◽  
Retinal Position ◽  
Position Information ◽  
Visual Cells ◽  
Retinal Stimulation ◽  
Saccade Onset

1. Single-unit activity was recorded from the superior colliculus (SC) of monkeys trained to look to visual targets presented on an oscilloscope screen. On one task, target localization required that information concerning the retinal position of the target be combined with information concerning current or future eye position. This task also permitted a dissociation between the site of retinal stimulation and the metrics of the saccade triggered by the stimulation. 2. Vigorous visual responses of superficial SC neurons may occur that do not result in the activation of underlying saccade-related cells. The activity of these neurons signals the occurrence of a visual stimulus, whether or not the stimulus is selected for foveal viewing. 3. Saccade-related (SR) discharges of most intermediate and deep-layer SC neurons precede saccades with particular vectors, regardless of the region of retinal activation initiating the saccade. The discharge of these neurons is tightly coupled to saccade onset, even if changes in eye position have occurred since target appearance. Thus, the discharge of these SR neurons must occur after retinal error and eye-position signals have been combined to compute the necessary saccade vector. For most SR neurons, direct retinal activation of overlying visual neurons had no effect on either the vigor or probability of a SR discharge. The discharge of overlying visual cells is neither necessary nor sufficient to activate most SR cells. 4. The discharge of some SR cells is dependent on prior activation of overlying visual cells. Of 53 SR cells, only 3 were completely dependent on visual stimulation, while another 8 discharged less vigorously if corresponding visual activation failed to occur. 5. About one-quarter of the SR cells showed long-lead preburst activity. This activation was characterized by a low level of firing, which began after the saccade signal and continued until a saccade-linked burst occurred. 6. Cells were isolated that were visually responsive yet discharged prior to saccades in the absence of appropriate retinal stimulation. No component of the discharge of these quasi-visual (QV) cells appeared to be motor in the usual sense. The activity of these neurons appears to reflect eye-position error (the difference between actual and desired eye position) and to hold this information in spatial register until a saccade occurs or is cancelled. 7. It is concluded that the presumed linkage, implied in earlier versions of the foveation hypothesis, between the superficial layers (receiving direct retinal inputs) and the deeper layers of the SC is not necessary for the activation of SR neurons. Results suggest that the SC must generate or receive a signal that combines retinal error and eye-position information. These findings are discussed in terms of current models of the saccadic-control system.

Residual eye-movements in macaque and their effects on visual responses of neurons

2002 ◽  
Vol 19 (1) ◽  
pp. 31-38 ◽  
Author(s):  
JASON FORTE ◽  
JONATHAN W. PEIRCE ◽  
JAMES M. KRAFT ◽  
JOHN KRAUSKOPF ◽  
PETER LENNIE
Keyword(s):  
Random Walk ◽  
Eye Movements ◽  
Muscle Relaxant ◽  
Average Distance ◽  
Sampling Period ◽  
Eye Position ◽  
Square Root ◽  
Visual Responses ◽  
Rhythmic Movements ◽  
Macaque Monkeys

We recorded continuously, with high precision, the positions of the eyes in anesthetized macaque monkeys prepared for physiological recording. Most recordings were made after the infusion of muscle relaxant to immobilize the eyes; in some cases we also were able to record eye position for periods before the eyes were immobilized. In all monkeys, the eyes moved continuously by as much as 0.5 deg over a 10-min sampling period. The average distance moved was proportional to the square root of the sampling period, as would be expected from a random walk. The movements had three distinct components: slow drifts, and two rhythms driven by the pulse and respiration. The rhythmic movements occurred only under paralysis: they were not discernible in measurements made before the infusion of muscle relaxant. The movements of the eye in the paralyzed animal can have substantial effects on the measured physiological characteristics of neurons. For excursions in the midrange of those we observed, a neuron's sensitivity to a spatial frequency of 10 cycle/deg might be underestimated by as much as a factor of three, depending on the method by which responses were averaged. We show how the effects of eye-movements can be mitigated by appropriate data analysis.

Processing of Visual Signals for Direct Specification of Motor Targets and for Conceptual Representation of Action Targets in the Dorsal and Ventral Premotor Cortex

2009 ◽  
Vol 102 (6) ◽  
pp. 3280-3294 ◽  
Author(s):  
Tomoko Yamagata ◽  
Yoshihisa Nakayama ◽  
Jun Tanji ◽  
Eiji Hoshi
Keyword(s):  
Visual Information ◽  
Action Plan ◽  
Premotor Cortex ◽  
Spatial Location ◽  
Action Selection ◽  
The Other ◽  
Visual Signals ◽  
Conceptual Level ◽  
Visual Responses ◽  
Symbolic Action

Previous reports have indicated that the premotor cortex (PM) uses visual information for either direct guidance of limb movements or indirect specification of action targets at a conceptual level. We explored how visual inputs signaling these two different categories of information are processed by PM neurons. Monkeys performed a delayed reaching task after receiving two different sets of visual instructions, one directly specifying the spatial location of a motor target (a direct spatial-target cue) and the other providing abstract information about the spatial location of a motor target by indicating whether to select the right or left target at a conceptual level (a symbolic action-selection cue). By comparing visual responses of PM neurons to the two sets of visual cues, we found that the conceptual action plan indicated by the symbolic action-selection cue was represented predominantly in dorsal PM (PMd) neurons with a longer latency (150 ms), whereas both PMd and ventral PM (PMv) neurons responded with a shorter latency (90 ms) when the motor target was directly specified with the direct spatial-target cue. We also found that excited, but not inhibited, responses of PM neurons to the direct spatial-target cue were biased toward contralateral preference. In contrast, responses to the symbolic action-selection cue were either excited or inhibited without laterality preference. Taken together, these results suggest that the PM constitutes a pair of distinct circuits for visually guided motor act; one circuit, linked more strongly with PMd, carries information for retrieving action instruction associated with a symbolic cue, and the other circuit, linked with PMd and PMv, carries information for directly specifying a visuospatial position of a reach target.

Coding of peripersonal space in inferior premotor cortex (area F4)

1996 ◽  
Vol 76 (1) ◽  
pp. 141-157 ◽  
Author(s):  
L. Fogassi ◽  
V. Gallese ◽  
L. Fadiga ◽  
G. Luppino ◽  
M. Matelli ◽  
...  
Keyword(s):  
Eye Movements ◽  
Premotor Cortex ◽  
Visual Stimuli ◽  
Peripersonal Space ◽  
Eye Position ◽  
Neck Muscle ◽  
Retinal Position ◽  
Stimulus Velocity ◽  
Sensory Stimuli ◽  
Somatosensory Neurons

1. We studied the functional properties of neurons in the caudal part of inferior area 6 (area F4) in awake monkeys. In agreement with previous reports, we found that the large majority (87%) of neurons responded to sensory stimuli. The responsive neurons fell into three categories: somatosensory neurons (30%); visual neurons (14%); and bimodal, visual and somatosensory neurons (56%). Both somatosensory and bimodal neurons typically responded to light touch of the skin. Their RFs were located on the face, neck, trunk, and arms. Approaching objects were the most effective visual stimuli. Visual RFs were mostly located in the space near the monkey (peripersonal space). Typically they extended in the space adjacent to the tactile RFs. 2. The coordinate system in which visual RFs were coded was studied in 110 neurons. In 94 neurons the RF location was independent of eye position, remaining in the same position in the peripersonal space regardless of eye deviation. The RF location with respect to the monkey was not modified by changing monkey position in the recording room. In 10 neurons the RF's location followed the eye movements, remaining in the same retinal position (retinocentric RFs). For the remaining six neurons the RF organization was not clear. We will refer to F4 neurons with RF independent of eye position as somatocentered neurons. 3. In most somatocentered neurons (43 of 60 neurons) the background level of activity and the response to visual stimuli were not modified by changes in eye position, whereas they were modulated in the remaining 17. It is important to note that eye deviations were constantly accompanied by a synergic increase of the activity of the ipsilateral neck muscles. It is not clear, therefore, whether the modulation of neuron discharge depended on eye position or was a consequence of changes in neck muscle activity. 4. The effect of stimulus velocity (20-80 cm/s) on neuron response intensity and RF extent in depth was studied in 34 somatocentered neurons. The results showed that in most neurons the increase of stimulus velocity produced an expansion in depth of the RF. 5. We conclude that space is coded differently in areas that control somatic and eye movements. We suggest that space coding in different cortical areas depends on the computational necessity of the effectors they control.

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