Audiovisual stimulus-driven contributions to spatial orienting in ecologically valid situations: An fMRI study

2012 ◽  
Vol 25 (0) ◽  
pp. 16
Author(s):  
Davide Nardo ◽  
Valerio Santangelo ◽  
Emiliano Macaluso
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Computational Models ◽  
Spatial Relationship ◽  
Visual Saliency ◽  
Occipital Cortex ◽  
Audiovisual Stimulus ◽  
Spatial Orienting ◽  
Posterior Parietal

Mechanisms of audiovisual attention have been extensively investigated, yet little is known about their functioning in ecologically-valid situations. Here, we investigated brain activity associated with audiovisual stimulus-driven attention using naturalistic stimuli. We created 120 short videos (2.5 s) showing scenes of everyday life. Each video included a visual event comprising a lateralized (left/right) increase in visual saliency (e.g., an actor moving an object), plus a co-occurring sound either on the same or the opposite side of space. Subjects viewed the videos with/without the associated sounds, and either in covert (central fixation) or overt (eye-movements allowed) viewing conditions. For each stimulus, we used computational models (‘saliency maps’) to characterize auditory and visual stimulus-driven signals, and eye-movements (recorded in free viewing) as a measure of the efficacy of these signals for spatial orienting. Results showed that visual saliency modulated activity in the occipital cortex contralateral to the visual event; while auditory saliency modulated activity in the superior temporal gyrus bilaterally. In the posterior parietal cortex activity increased with increasing auditory saliency, but only when the auditory stimulus was on the same side as the visual event. The efficacy of the stimulus-driven signals modulated activity in the visual cortex. We conclude that: (1) audiovisual attention can be successfully investigated in real-like situations; (2) activity in sensory areas reflects a combination of stimulus-driven signals (saliency) and their efficacy for spatial orienting; (3) posterior parietal cortex processes auditory input as a function of its spatial relationship with the visual input.

scholarly journals Electrical microstimulation evokes saccades in posterior parietal cortex of common marmosets

2019 ◽  
Vol 122 (4) ◽  
pp. 1765-1776 ◽  
Author(s):  
Maryam Ghahremani ◽  
Kevin D. Johnston ◽  
Liya Ma ◽  
Lauren K. Hayrynen ◽  
Stefan Everling
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Common Marmoset ◽  
Primate Species ◽  
Oculomotor Control ◽  
Electrical Microstimulation ◽  
Cortical Areas ◽  
Posterior Parietal ◽  
The Common

The common marmoset ( Callithrix jacchus) is a small-bodied New World primate increasing in prominence as a model animal for neuroscience research. The lissencephalic cortex of this primate species provides substantial advantages for the application of electrophysiological techniques such as high-density and laminar recordings, which have the capacity to advance our understanding of local and laminar cortical circuits and their roles in cognitive and motor functions. This is particularly the case with respect to the oculomotor system, as critical cortical areas of this network such as the frontal eye fields (FEF) and lateral intraparietal area (LIP) lie deep within sulci in macaques. Studies of cytoarchitecture and connectivity have established putative homologies between cortical oculomotor fields in marmoset and macaque, but physiological investigations of these areas, particularly in awake marmosets, have yet to be carried out. Here we addressed this gap by probing the function of posterior parietal cortex of the common marmoset with electrical microstimulation. We implanted two animals with 32-channel Utah arrays at the location of the putative area LIP and applied microstimulation while they viewed a video display and made untrained eye movements. Similar to previous studies in macaques, stimulation evoked fixed-vector and goal-directed saccades, staircase saccades, and eyeblinks. These data demonstrate that area LIP of the marmoset plays a role in the regulation of eye movements, provide additional evidence that this area is homologous with that of the macaque, and further establish the marmoset as a valuable model for neurophysiological investigations of oculomotor and cognitive control. NEW & NOTEWORTHY The macaque monkey has been the preeminent model for investigations of oculomotor control, but studies of cortical areas are limited, as many of these areas are buried within sulci in this species. Here we applied electrical microstimulation to the putative area LIP of the lissencephalic cortex of awake marmosets. Similar to the macaque, microstimulation evoked contralateral saccades from this area, supporting the marmoset as a valuable model for studies of oculomotor control.

Representation of Eye Position in the Human Parietal Cortex

2010 ◽  
Vol 104 (4) ◽  
pp. 2169-2177 ◽  
Author(s):  
Adrian L. Williams ◽  
Andrew T. Smith
Keyword(s):  
Parietal Cortex ◽  
Cortical Neurons ◽  
Posterior Parietal Cortex ◽  
Visual Stimulation ◽  
Block Design ◽  
Occipital Cortex ◽  
Brain Regions ◽  
Eye Position ◽  
Posterior Aspect ◽  
Posterior Parietal

Neurons that signal eye position are thought to make a vital contribution to distinguishing real world motion from retinal motion caused by eye movements, but relatively little is known about such neurons in the human brain. Here we present data from functional MRI experiments that are consistent with the existence of neurons sensitive to eye position in darkness in the human posterior parietal cortex. We used the enhanced sensitivity of multivoxel pattern analysis (MVPA) techniques, combined with a searchlight paradigm, to isolate brain regions sensitive to direction of gaze. During data acquisition, participants were cued to direct their gaze to the left or right for sustained periods as part of a block-design paradigm. Following the exclusion of saccade-related activity from the data, the multivariate analysis showed sensitivity to tonic eye position in two localized posterior parietal regions, namely the dorsal precuneus and, more weakly, the posterior aspect of the intraparietal sulcus. Sensitivity to eye position was also seen in anterior portions of the occipital cortex. The observed sensitivity of visual cortical neurons to eye position, even in the total absence of visual stimulation, is possibly a result of feedback from posterior parietal regions that receive eye position signals and explicitly encode direction of gaze.

scholarly journals Non-predictive online spatial coding in the posterior parietal cortex when aiming ahead for catching

2017 ◽  
Author(s):  
Sinéad A. Reid ◽  
Joost C. Dessing
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Parietal Cortex ◽  
Magnetic Stimulation ◽  
Posterior Parietal Cortex ◽  
Target Position ◽  
Occipital Cortex ◽  
Spatial Coding ◽  
Posterior Parietal ◽  
First Time

Catching movements must be aimed ahead of the moving ball, which may require predictions of when and where to catch. Here, using Transcranial Magnetic Stimulation we show for the first time that, although interception movements were clearly aimed at the predicted final target position, the Superior Parietal Occipital Cortex (SPOC) displayed non-predictive online spatial coding. The ability to aim ahead for catching must thus arise downstream within the parietofrontal network for reaching.

Eye movements elicited by electrical stimulation of area PG in the monkey

1991 ◽  
Vol 65 (6) ◽  
pp. 1243-1253 ◽  
Author(s):  
D. D. Kurylo ◽  
A. A. Skavenski
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Eye Position ◽  
Low Velocity ◽  
Posterior Parietal ◽  
Rostral Region ◽  
To Receive ◽  
Stimulation Of

1. Eye positions of monkeys were tracked while low-current electrical stimulation was delivered to area PG of the posterior parietal cortex. Stimulation was delivered while monkeys were in darkness, while they were in a dimly illuminated room, or while they actively fixated on small lamps to receive a liquid reward. 2. Resulting eye movements fell into one of three categories, depending roughly on the area stimulated. Stimulation of caudal regions generally resulted in saccades that were of approximately equivalent amplitudes and directions. When more rostral areas were stimulated, saccades were generally produced that directed the eyes toward roughly the same position in the head. Distributed throughout all regions were sites for which elicited saccades did not fall clearly into either of these coordinate bases. Stimulation of lateral areas produced low-velocity eye movements that were directed ipsilaterally from the stimulated hemisphere. 3. Stimulation made while monkeys fixated on target lamps produced saccades with more variability and less amplitude than those produced while monkeys were in darkness. Low-velocity eye movements could only be elicited while monkeys were in darkness. 4. Craniocentric saccades typically brought the eyes to within a 10-20 degrees area, and saccades could not be produced when the initial eye position was near this area. Craniocentric saccades were always greater than 5 degrees in amplitude. 5. It is concluded that area PG is organized into at least two zones that differ in the way by which they code saccades. A caudal region codes saccades in a way similar to that found in the frontal cortex and superior colliculus of primates. A rostral region codes saccades in a craniocentric manner, although it is restricted only to gross redirection of gaze without the accuracy monkeys are capable of using in directing their eyes.

Lateralization of the Posterior Parietal Cortex for Internal Monitoring of Self- versus Externally Generated Movements

2007 ◽  
Vol 19 (11) ◽  
pp. 1827-1835 ◽  
Author(s):  
Kenji Ogawa ◽  
Toshio Inui
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Brain Activity ◽  
Occipital Cortex ◽  
Clinical Findings ◽  
Visual Occlusion ◽  
Mouse Cursor ◽  
Posterior Parietal ◽  
Human Motor ◽  
The Right

Internal monitoring or state estimation of movements is essential for human motor control to compensate for inherent delays and noise in sensorimotor loops. Two types of internal estimation of movements exist: self-generated movements, and externally generated movements. We used functional magnetic resonance imaging to investigate differences in brain activity for internal monitoring of self- versus externally generated movements during visual occlusion. Participants tracked a sinusoidally moving target with a mouse cursor. On some trials, vision of either target (externally generated) or cursor (self-generated) movement was transiently occluded, during which subjects continued tracking by estimating current position of either the invisible target or cursor on screen. Analysis revealed that both occlusion conditions were associated with increased activity in the presupplementary motor area and decreased activity in the right lateral occipital cortex compared to a control condition with no occlusion. Moreover, the right and left posterior parietal cortex (PPC) showed greater activation during occlusion of target and cursor movements, respectively. This study suggests lateralization of the PPC for internal monitoring of internally versus externally generated movements, fully consistent with previously reported clinical findings.

scholarly journals Electrical microstimulation evokes saccades in posterior parietal cortex of common marmosets

2019 ◽  
Author(s):  
Maryam Ghahremani ◽  
Kevin D. Johnston ◽  
Liya Ma ◽  
Lauren K. Hayrynen ◽  
Stefan Everling
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Common Marmoset ◽  
Primate Species ◽  
Oculomotor Control ◽  
Electrical Microstimulation ◽  
Cortical Areas ◽  
Posterior Parietal ◽  
The Common

AbstractThe common marmoset (Callithrix jacchus) is a small-bodied New World primate, increasing in prominence as a model animal for neuroscience research. The lissencephalic cortex of this primate species provides substantial advantages for the application of electrophysiological techniques such as high-density and laminar recordings, which have the capacity to advance our understanding of local and laminar cortical circuits and their roles in cognitive and motor functions. This is particularly the case with respect to the oculomotor system, as critical cortical areas of this network such as the frontal eye fields (FEF) and lateral intraparietal area (LIP) lie deep within sulci in macaques. Studies of cytoarchitecture and connectivity have established putative homologies between cortical oculomotor fields in marmoset and macaque, but physiological investigations of these areas, particularly in awake marmosets, have yet to be carried out. Here, we addressed this gap by probing the function of posterior parietal cortex (PPC) of the common marmoset using electrical microstimulation. We implanted two animals with 32-channel Utah arrays at the location of the putative area LIP and applied microstimulation while they viewed a video display and made untrained eye movements. Similar to previous studies in macaques, stimulation evoked fixed-vector and goal-directed saccades, staircase saccades, and eye blinks. These data demonstrate that area LIP of the marmoset plays a role in the regulation of eye movements, provide additional evidence that this area is homologous with that of the macaque, and further establish the marmoset as valuable model for neurophysiological investigations of oculomotor and cognitive control.New & NoteworthyThe macaque monkey has been the preeminent model for investigations of oculomotor control, but studies of cortical areas are limited as many of these areas are buried within sulci in this species. Here we applied electrical microstimulation to the putative area LIP of the lissencephalic cortex of awake marmosets. Similar to the macaque, microstimulation evoked contralateral saccades from this area, supporting the marmoset as a valuable model for studies of oculomotor control.

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