Effects of Gaze Direction in Vision and Audition

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 137-137
Author(s):  
W H Ehrenstein ◽  
J Lewald ◽  
L Schlykowa
Keyword(s):  
Visual Cues ◽  
Posterior Parietal Cortex ◽  
Reaction Times ◽  
Visual Sensitivity ◽  
Gaze Direction ◽  
The Gaze ◽  
Visual Shift ◽  
Stimulus Speed ◽  
Posterior Parietal ◽  
Visual Reference

We asked to what extent the respective gaze direction influences (i) the spatial congruence of perceived direction of auditory and visual cues, and (ii) the discrimination of the direction of target motion. With fixed head position, subjects directed their gaze in various positions and localised auditory targets (band-pass noise, 2 kHz) presented at one of nine positions (straight ahead, or four symmetric positions to the left or right separated by 2.75 deg, respectively). Forced-choice judgements, whether the sound was perceived to the left or right of a visual reference light, show that the azimuth of the sound was perceived as slightly shifted to the left of a visual reference when the gaze was directed to the left, and vice versa. The maximum of this relative auditory - visual shift was 4.7 deg over a range of 45 deg (left or right) of gaze directions. In (ii), a spot of light started at the centre of a monitor and moved at 2 or 12 deg s−1 leftward or rightward. Subjects reported the direction by pressing a key; their gaze was directed at 0, 8, or 16 deg to the left or right. Mean choice-reaction times increased with increasing gaze eccentricity, but differently depending on stimulus direction and speed: with left fixation they were shorter for leftward than rightward motion; with right fixation they were shorter for rightward motion. This effect was stronger for the slow than for the fast stimulus speed. Thus, facilitation occurs when stimuli move with moderate velocity toward the direction of gaze. While the auditory-visual shift in (i) may reflect an incomplete transformation of spatial (craniocentric and oculocentric) coordinates as suggested by recordings in the primate midbrain, the results in (ii) conform with reports of specialised units in the posterior parietal cortex (areas LIP, 7a, MST) that, in registering oculomotor position, modulate visual sensitivity.

scholarly journals Saccades, attentional orienting and disengagement: the effects of anodal tDCS over right posterior parietal cortex (PPC) and frontal eye field (FEF)

2021 ◽  
Author(s):  
Lorenzo Diana ◽  
Patrick Pilastro ◽  
Edoardo N. Aiello ◽  
Aleksandra K. Eberhard-Moscicka ◽  
René M. Müri ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Right Hemisphere ◽  
Reaction Times ◽  
Gap Effect ◽  
Frontal Eye Field ◽  
Attentional Orienting ◽  
Eye Field ◽  
Posterior Parietal ◽  
The Right

ABSTRACTIn the present work, we applied anodal transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and frontal eye field (FEF) of the right hemisphere in healthy subjects to modulate attentional orienting and disengagement in a gap-overlap task. Both stimulations led to bilateral improvements in saccadic reaction times (SRTs), with larger effects for gap trials. However, analyses showed that the gap effect was not affected by tDCS. Importantly, we observed significant effects of baseline performance that may mediate side- and task-specific effects of brain stimulation.

scholarly journals A fronto-temporo-parietal network disambiguates potential objects of joint attention

2019 ◽  
Author(s):  
P. M. Kraemer ◽  
M. Görner ◽  
H. Ramezanpour ◽  
P. W. Dicke ◽  
P. Thier
Keyword(s):  
Joint Attention ◽  
Posterior Parietal Cortex ◽  
A Priori ◽  
Gaze Direction ◽  
Gaze Following ◽  
A Priori Information ◽  
Object Choice ◽  
Posterior Parietal ◽  
Per Se ◽  
Priori Information

AbstractWe use the other’s gaze direction to identify her/his object of interest and to shift our attention to the same object, i.e. to establish joint attention. However, gaze direction may not be sufficient to unambiguously identify the object of interest as the other’s gaze may hit more than one object. In this case, the observer must use a priori information to disambiguate the object choice. Using fMRI, we suggest that the disambiguation is based on a 3-component network. A first component, the well-known ‘gaze following patch’ in the posterior STS is activated by gaze following per se. BOLD activity here is determined exclusively by the usage of gaze direction and is independent of the need to disambiguate the relevant object. On the other hand, BOLD activity revealing a priori information for the disambiguation and starting early enough to this end is confined to a patch of cortex at the inferior frontal junction. Finally, BOLD activity reflecting the convergence of both, a priori information and gaze direction, needed to shift attention to a particular object location is confined to the posterior parietal cortex.

scholarly journals Single unit activity in marmoset posterior parietal cortex in a gap saccade task

2019 ◽  
Author(s):  
Liya Ma ◽  
Janahan Selvanayagam ◽  
Maryam Ghahremani ◽  
Lauren K. Hayrynen ◽  
Kevin D. Johnston ◽  
...  
Keyword(s):  
Eye Movements ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Reaction Times ◽  
Saccadic Eye Movements ◽  
Neuronal Population ◽  
Single Unit Activity ◽  
Cortical Control ◽  
Posterior Parietal ◽  
Saccadic Reaction Times

ABSTRACTAbnormal saccadic eye movements can serve as biomarkers for patients with several neuropsychiatric disorders. To investigate cortical control mechanisms of saccadic responses, the common marmoset (Callithrix jacchus) is a promising non-human primate model. Their lissencephalic brain allows for accurate targeting of homologues of sulcal areas in the macaque brain. Here we recorded single unit activity in the posterior parietal cortex of two marmosets using chronic microelectrode arrays, while the monkeys performed a saccadic task with Gap trials (stimulus onset lagged fixation point offset by 200ms) interleaved with Step trials (fixation point disappeared when the peripheral stimulus appeared). Both marmosets showed a gap effect—shorter saccadic reaction times (SRTs) in Gap vs. Step trials. On average, stronger gap-period response across the entire neuronal population preceded shorter SRTs on trials with contralateral targets, although this correlation was stronger among the 15% ‘gap neurons’, which responded significantly during the gap. We also found 39% ‘target neurons’ with significant visual target-related responses, which were stronger in Gap trials and correlated with the SRTs better than the remaining cells. Compared with slow saccades, fast saccades were preceded by both stronger gap-related and target-related response in all PPC neurons, regardless of whether such response reached significance. Our findings suggest that the PPC in the marmoset contains an area that is involved in the modulation of saccadic preparation and plays roles comparable to those of area LIP in macaque monkeys in eye movements.SIGNIFICANCE STATEMENTAbnormal saccadic eye movements can serve as biomarkers for different neuropsychiatric disorders. So far, processes of cerebral cortical control of saccades are not fully understood. Non-human primates are ideal models for studying such processes, and the marmoset is especially advantageous since their smooth cortex permits laminar analyses of cortical microcircuits. Using electrode arrays implanted in the posterior parietal cortex of marmosets, we found neurons responsive to key periods of a saccadic task in a manner that contribute to cortical modulation of saccadic preparation. Notably, this signal was correlated with subsequent saccadic reaction times and was present in the entire neuronal population. We suggest that the marmoset model will shed new light on the cortical mechanisms of saccadic control.

scholarly journals Visual attention is not limited to the oculomotor range

2019 ◽  
Vol 116 (19) ◽  
pp. 9665-9670 ◽  
Author(s):  
Nina M. Hanning ◽  
Martin Szinte ◽  
Heiner Deubel
Keyword(s):  
Visual Attention ◽  
Reaction Times ◽  
Saccadic Eye Movements ◽  
Visual Sensitivity ◽  
Attentional Orienting ◽  
Attentional Deficits ◽  
The Gaze ◽  
Eye Movement Disorders ◽  
Saccade Preparation ◽  
Healthy Participants

Both patients with eye movement disorders and healthy participants whose oculomotor range had been experimentally reduced have been reported to show attentional deficits at locations unreachable by their eyes. Whereas previous studies were mainly based on the evaluation of reaction times, we measured visual sensitivity before saccadic eye movements and during fixation at locations either within or beyond participants’ oculomotor range. Participants rotated their heads to prevent them from performing large rightward saccades. In this posture, an attentional cue was presented inside or outside their oculomotor range. Participants either made a saccade to the cue or maintained fixation while they discriminated the orientation of a visual noise patch. In contrast to previous reports, we found that the cue attracted visual attention regardless of whether it was presented within or beyond participants’ oculomotor range during both fixation and saccade preparation. Moreover, when participants aimed to look to a cue that they could not reach with their eyes, we observed no benefit at their actual saccade endpoint. This demonstrates that spatial attention is not coupled to the executed oculomotor program but instead can be deployed unrestrictedly also toward locations to which no saccade can be executed. Our results are compatible with the view that covert and overt attentional orienting are guided by feedback projections of visual and visuomotor neurons of the gaze control system, irrespective of oculomotor limitations.

scholarly journals Integration of target and hand position signals in the posterior parietal cortex: effects of workspace and hand vision

2012 ◽  
Vol 108 (1) ◽  
pp. 187-199 ◽  
Author(s):  
Christopher A. Buneo ◽  
Richard A. Andersen
Keyword(s):  
Parietal Cortex ◽  
Visual Cues ◽  
Posterior Parietal Cortex ◽  
Single Cells ◽  
Arm Movement ◽  
Movement Planning ◽  
Hand Position ◽  
Position Information ◽  
Limb Position ◽  
Posterior Parietal

Previous findings suggest the posterior parietal cortex (PPC) contributes to arm movement planning by transforming target and limb position signals into a desired reach vector. However, the neural mechanisms underlying this transformation remain unclear. In the present study we examined the responses of 109 PPC neurons as movements were planned and executed to visual targets presented over a large portion of the reaching workspace. In contrast to previous studies, movements were made without concurrent visual and somatic cues about the starting position of the hand. For comparison, a subset of neurons was also examined with concurrent visual and somatic hand position cues. We found that single cells integrated target and limb position information in a very consistent manner across the reaching workspace. Approximately two-thirds of the neurons with significantly tuned activity (42/61 and 30/46 for left and right workspaces, respectively) coded targets and initial hand positions separably, indicating no hand-centered encoding, whereas the remaining one-third coded targets and hand positions inseparably, in a manner more consistent with the influence of hand-centered coordinates. The responses of both types of neurons were largely invariant with respect to the presence or absence of visual hand position cues, suggesting their corresponding coordinate frames and gain effects were unaffected by cue integration. The results suggest that the PPC uses a consistent scheme for computing reach vectors in different parts of the workspace that is robust to changes in the availability of somatic and visual cues about hand position.

scholarly journals The effects of a TMS double lesion to a cortical network

2019 ◽  
Author(s):  
Ian G.M. Cameron ◽  
Andreea Cretu ◽  
Femke Struik ◽  
Ivan Toni
Keyword(s):  
Posterior Parietal Cortex ◽  
Reaction Times ◽  
Brain Regions ◽  
Network Nodes ◽  
Dorsolateral Prefrontal ◽  
Functional Consequences ◽  
Posterior Parietal ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation ◽  
Single Lesion

AbstractTranscranial magnetic stimulation (TMS) has contributed to our understanding of the functions of individual brain regions, but its use to examine distributed functions throughout a network has been more limited. We assess the functional consequences of a TMS pulse to the oculomotor network which was first perturbed by continuous theta-burst stimulation (cTBS), to examine the potential for additive effects from lesions to two network nodes. Twenty-three humans performed pro-(look towards) and anti-(look away) saccades after receiving cTBS to right frontal eye fields (FEF), dorsolateral prefrontal cortex (DLPFC) or somatosensory cortex (S1) (control). On a subset of trials, a TMS pulse was applied to right posterior parietal cortex (PPC). We assessed changes in saccade amplitudes, performance (percentage correct) and reaction times, as these parameters relate to computations in networks involving these nodes. We observed impairments in ipsilateral anti-saccade amplitudes following DLPFC cTBS that were enhanced by a PPC pulse, but that were not enhanced relative to the effect of the PPC pulse alone. There was no evidence for effects from the double lesion to performance or reaction times. This suggests that computations are distributed across the network, such that even a single lesion is consequential.

Posterior parietal cortex mediates encoding processes in change blindness

2009 ◽  
Author(s):  
Philip Tseng ◽  
Cassidy Sterling ◽  
Adam Cooper ◽  
Bruce Bridgeman ◽  
Neil G. Muggleton ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Change Blindness ◽  
Posterior Parietal

The Grasp Cell Hypothesis: Near-miss effect points to common neurological machinery in posterior parietal cortex for controllable objects and concepts

2018 ◽  
Author(s):  
Imogen M Kruse
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Near Miss ◽  
Illusion Of Control ◽  
Gambling Behaviour ◽  
Drug Seeking ◽  
Spatial Influence ◽  
Reward Probability ◽  
Posterior Parietal ◽  
Action Value

The near-miss effect in gambling behaviour occurs when an outcome which is close to a win outcome invigorates gambling behaviour notwithstanding lack of associated reward. In this paper I postulate that the processing of concepts which are deemed controllable is rooted in neurological machinery located in the posterior parietal cortex specialised for the processing of objects which are immediately actionable or controllable because they are within reach. I theorise that the use of a common machinery facilitates spatial influence on the perception of concepts such that the win outcome which is 'almost complete' is perceived as being 'almost within reach'. The perceived realisability of the win increases subjective reward probability and the associated expected action value which impacts decision-making and behaviour. This novel hypothesis is the first to offer a neurological model which can comprehensively explain many empirical findings associated with the near-miss effect as well as other gambling phenomena such as the ‘illusion of control’. Furthermore, when extended to other compulsive behaviours such as drug addiction, the model can offer an explanation for continued drug-seeking following devaluation and for the increase in cravings in response to perceived opportunity to self-administer, neither of which can be explained by simple reinforcement models alone. This paper therefore provides an innovative and unifying perspective for the study and treatment of behavioural and substance addictions.

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