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Scientific Reports May 2024Mental rotation is the ability to rotate mental representations of objects in space. Shepard and Metzler's shape-matching tasks, frequently used to test mental rotation,... (Comparative Study)
Comparative Study
Mental rotation is the ability to rotate mental representations of objects in space. Shepard and Metzler's shape-matching tasks, frequently used to test mental rotation, involve presenting pictorial representations of 3D objects. This stimulus material has raised questions regarding the ecological validity of the test for mental rotation with actual visual 3D objects. To systematically investigate differences in mental rotation with pictorial and visual stimuli, we compared data of university students from a virtual reality experiment. Comparing both conditions within subjects, we found higher accuracy and faster reaction times for 3D visual figures. We expected eye tracking to reveal differences in participants' stimulus processing and mental rotation strategies induced by the visual differences. We statistically compared fixations (locations), saccades (directions), pupil changes, and head movements. Supplementary Shapley values of a Gradient Boosting Decision Tree algorithm were analyzed, which correctly classified the two conditions using eye and head movements. The results indicated that with visual 3D figures, the encoding of spatial information was less demanding, and participants may have used egocentric transformations and perspective changes. Moreover, participants showed eye movements associated with more holistic processing for visual 3D figures and more piecemeal processing for pictorial 2D figures.
Topics: Humans; Female; Male; Eye Movements; Young Adult; Adult; Rotation; Reaction Time; Photic Stimulation; Space Perception; Virtual Reality; Visual Perception; Head Movements; Saccades
PubMed: 38811593
DOI: 10.1038/s41598-024-60370-6 -
Science Advances May 2024Fluctuations in the activity of sensory neurons often predict perceptual decisions. This connection can be quantified with a metric called choice probability (CP), and...
Fluctuations in the activity of sensory neurons often predict perceptual decisions. This connection can be quantified with a metric called choice probability (CP), and there is a longstanding debate about whether CP reflects a causal influence on decisions or an echo of decision-making activity elsewhere in the brain. Here, we show that CP can reflect a third variable, namely, the movement used to indicate the decision. In a standard visual motion discrimination task, neurons in the middle temporal (MT) area of primate cortex responded more strongly during trials that involved a saccade toward their receptive fields. This variability accounted for much of the CP observed across the neuronal population, and it arose through training. Moreover, pharmacological inactivation of MT biased behavioral responses away from the corresponding visual field locations. These results demonstrate that training on a task with fixed sensorimotor contingencies introduces movement-related activity in sensory brain regions and that this plasticity can shape the neural circuitry of perceptual decision-making.
Topics: Animals; Visual Cortex; Decision Making; Macaca mulatta; Male; Neurons; Movement; Motion Perception; Saccades; Photic Stimulation
PubMed: 38809984
DOI: 10.1126/sciadv.adk7214 -
PloS One 2024Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the...
Saccadic eye movements enable us to search for the target of interest in a crowded scene or, in the case of goal-directed saccades, to simply bring the image of the peripheral target to the very centre of the fovea. This mechanism extends the use of the superior image processing performance of the fovea over a large visual field. We know that visual information is processed quickly at the end of each saccade but estimates of the times involved remain controversial. This study aims to investigate the processing of visual information during post fixation oscillations of the eyeball. A new psychophysical test measures the combined eye movement response latencies, including fixation duration and visual processing times. When the test is used in conjunction with an eye tracker, each component that makes up the 'integrated saccade latency' time, from the onset of the peripheral stimulus to the correct interpretation of the information carried by the stimulus, can be measured and the discrete components delineated. The results show that the time required to process and encode the stimulus attribute of interest at the end of a saccade is longer than the time needed to carry out the same task in the absence of an eye movement. We propose two principal hypotheses, each of which can account for this finding. 1. The known inhibition of afferent retinal signals during fast eye movements extends beyond the end point of the saccade. 2. The extended visual processing times measured when saccades are involved are caused by the transient loss of spatial resolution due to eyeball instability during post-saccadic oscillations. The latter can best be described as retinal image smear with greater loss of spatial resolution expected for stimuli of low luminance contrast.
Topics: Humans; Saccades; Adult; Male; Female; Reaction Time; Visual Perception; Fixation, Ocular; Young Adult; Photic Stimulation; Visual Fields; Time Factors
PubMed: 38809939
DOI: 10.1371/journal.pone.0302459 -
Sisli Etfal Hastanesi Tip Bulteni 2024The aim of this study was to evaluate vestibulo-ocular reflex (VOR) of individuals over 60 years of age who have not been diagnosed with a specific vestibular pathology.
OBJECTIVES
The aim of this study was to evaluate vestibulo-ocular reflex (VOR) of individuals over 60 years of age who have not been diagnosed with a specific vestibular pathology.
METHODS
Bilateral six-semicircular canal video head impulse test (vHIT), Dizziness Handicap Inventory and European Evaluation of Vertigo scales were applied to participants.
RESULTS
In total, 103 participants were included in the study (75 male, 28 female), and the mean age was 69.35 ± 7.41 years. The mean age of 7th decade group was 64.32±3.12 (59 participants; 38 male, 21 female), and the mean age of 8th decade and older group was 76.11±5.93 (44 participants; 37 male, 7 female). No significant differences were found between the VOR gains of the lateral or vertical semicircular canals between the 7th decade and 8th decade and older groups (p>0.05). In the 8th decade and older group, the presence of right lateral semicircular canal corrective saccade and left posterior semicircular canal corrective saccade showed a positively moderate correlation with VOR gains of the same semicircular canals (r=0.455, p=0.002, and r=0.518, p=0.001, respectively). No significant correlation was found between age and VOR gain in the 7th decade group, however, there was a negatively weak correlation between age and left lateral semicircular canal VOR gain (r=-0.366, p=0.017) in the 8th decade and older group.
CONCLUSION
While assessing the age-related changes in VOR using vHIT, it must be considered that the changes related to aging of the vestibular system begin to emerge in the population over 70 years of age, and corrective saccade findings may be more informative than VOR gains in revealing these changes.
PubMed: 38808050
DOI: 10.14744/SEMB.2023.31967 -
PloS One 2024When comprehending speech, listeners can use information encoded in visual cues from a face to enhance auditory speech comprehension. For example, prior work has shown...
When comprehending speech, listeners can use information encoded in visual cues from a face to enhance auditory speech comprehension. For example, prior work has shown that the mouth movements reflect articulatory features of speech segments and durational information, while pitch and speech amplitude are primarily cued by eyebrow and head movements. Little is known about how the visual perception of segmental and prosodic speech information is influenced by linguistic experience. Using eye-tracking, we studied how perceivers' visual scanning of different regions on a talking face predicts accuracy in a task targeting both segmental versus prosodic information, and also asked how this was influenced by language familiarity. Twenty-four native English perceivers heard two audio sentences in either English or Mandarin (an unfamiliar, non-native language), which sometimes differed in segmental or prosodic information (or both). Perceivers then saw a silent video of a talking face, and judged whether that video matched either the first or second audio sentence (or whether both sentences were the same). First, increased looking to the mouth predicted correct responses only for non-native language trials. Second, the start of a successful search for speech information in the mouth area was significantly delayed in non-native versus native trials, but just when there were only prosodic differences in the auditory sentences, and not when there were segmental differences. Third, (in correct trials) the saccade amplitude in native language trials was significantly greater than in non-native trials, indicating more intensely focused fixations in the latter. Taken together, these results suggest that mouth-looking was generally more evident when processing a non-native versus native language in all analyses, but fascinatingly, when measuring perceivers' latency to fixate the mouth, this language effect was largest in trials where only prosodic information was useful for the task.
Topics: Humans; Female; Male; Language; Adult; Speech Perception; Phonetics; Young Adult; Face; Visual Perception; Eye Movements; Speech; Eye-Tracking Technology
PubMed: 38805447
DOI: 10.1371/journal.pone.0304150 -
Neurology International May 2024(1) Background: Niemann-Pick type C1 (NP-C1) is a lysosomal storage disorder that results in the defective trafficking of cholesterol and other cellular lipids in the...
(1) Background: Niemann-Pick type C1 (NP-C1) is a lysosomal storage disorder that results in the defective trafficking of cholesterol and other cellular lipids in the endosomal-lysosomal pathway. This rare autosomal recessive disorder presents in three forms based on the age of onset. The adult form presents in patients greater than 15 years of age but is rarely seen after the age of 30. Common symptoms of the late adult-onset category of NP-C1 include progressive cognitive impairment and ataxia, with psychiatric and movement disorders presenting less frequently than in other forms of NP-C1. Dystonic movement disorders present most frequently, along with chorea, myoclonus, and parkinsonism. Herein, we present a rare case of NP-C1, diagnosed at age 35 with an initial symptom of supranuclear palsy. The goal of the presented case is to highlight the importance of the neurological examination and an inclusive differential diagnosis in patients with new-onset supranuclear palsy. (2) Methods: A single case report. (3) Results: A 46-year-old male with a past medical history of NP-C1 was admitted to the hospital for respiratory distress. He was noted to have a supranuclear gaze palsy with partially preserved voluntary saccades to the right. His mother revealed that he first had difficulty moving his eyes at the age of 34. After multiple consultations and genetic testing one year later, he was diagnosed with NP-C1. (4) Conclusions: Because NP-C1 affects many regions of the brain responsible for eye movements, neurological eye assessments can be a useful tool in diagnoses. Furthermore, eye movement abnormalities may be the initial presenting symptom of NP-C1, predisposing patients to misdiagnosis with progressive supranuclear palsy and other conditions that may mimic early-stage NP-C1. Definitive diagnosis is achieved through genetic testing. Filipin staining test was the gold standard in the past. The NP-C Suspicion Index was developed to assist in diagnoses, but its efficacy is unclear with late adult-onset NP-C1. Although no cure exists, early identification can facilitate an improved symptom management course for patients. Miglustat, a glucosylceramide synthase (GCS) inhibitor, is the approved therapy in Europe specific to NP-C1 for slowing and preventing the neurological manifestations of NP-C1. Delays between symptom onset and treatment initiation are likely to result in poorer outcomes and a progression of neurological symptoms. High doses may present tolerance concerns, especially in cases of delayed treatment and advanced neurological deficit.
PubMed: 38804481
DOI: 10.3390/neurolint16030042 -
Data in Brief Jun 2024This paper presents data collected by Pedrotti et al. (2022, 2024) [1,2], which includes videos captured using a Dikablis head-mounted eye tracker (Ergoneers GmbH,...
This paper presents data collected by Pedrotti et al. (2022, 2024) [1,2], which includes videos captured using a Dikablis head-mounted eye tracker (Ergoneers GmbH, Germany), along with the corresponding raw data. The data collection aimed to assess participants' ability to recognize breathing in a simulated cardiac arrest scenario. Equipped with the eye tracker, participants entered a room where a manikin was positioned on the floor. Their task was to determine if the manikin was breathing and respond accordingly, such as initiating cardiopulmonary resuscitation if the victim was not breathing. Our analysis focused on examining looking time on the manikin's thorax by inspecting the videos. Potential applications of the dataset [3] include identifying fixation and saccades using custom algorithms, analyzing pupil diameter data, and conducting secondary analyses involving participant characteristics like age and gender as independent variables.
PubMed: 38799716
DOI: 10.1016/j.dib.2024.110530 -
Neuron May 2024Anchoring goals to spatial representations enables flexible navigation but is challenging in novel environments when both representations must be acquired...
Anchoring goals to spatial representations enables flexible navigation but is challenging in novel environments when both representations must be acquired simultaneously. We propose a framework for how Drosophila uses internal representations of head direction (HD) to build goal representations upon selective thermal reinforcement. We show that flies use stochastically generated fixations and directed saccades to express heading preferences in an operant visual learning paradigm and that HD neurons are required to modify these preferences based on reinforcement. We used a symmetric visual setting to expose how flies' HD and goal representations co-evolve and how the reliability of these interacting representations impacts behavior. Finally, we describe how rapid learning of new goal headings may rest on a behavioral policy whose parameters are flexible but whose form is genetically encoded in circuit architecture. Such evolutionarily structured architectures, which enable rapidly adaptive behavior driven by internal representations, may be relevant across species.
PubMed: 38795708
DOI: 10.1016/j.neuron.2024.04.036 -
Investigative Ophthalmology & Visual... May 2024Post-saccadic oscillations (PSOs) reflect movements of gaze that result from motion of the pupil and lens relative to the eyeball rather than eyeball rotations. Here, we...
PURPOSE
Post-saccadic oscillations (PSOs) reflect movements of gaze that result from motion of the pupil and lens relative to the eyeball rather than eyeball rotations. Here, we analyzed the characteristics of PSOs in subjects with age-related macular degeneration (AMD), retinitis pigmentosa (RP), and normal vision (NV). Our aim was to assess the differences in PSOs between people with vision loss and healthy controls because PSOs affect retinal image stability after each saccade.
METHODS
Participants completed a horizontal saccade task and their gaze was measured using a pupil-based eye tracker. Oscillations occurring in the 80 to 200 ms post-saccadic period were described with a damped oscillation model. We compared the amplitude, decay time constant, and frequency of the PSOs for the three different groups. We also examined the correlation between these PSO parameters and the amplitude, peak velocity, and final deceleration of the preceding saccades.
RESULTS
Subjects with vision loss (AMD, n = 6, and RP, n = 5) had larger oscillation amplitudes, longer decay constants, and lower frequencies than subjects with NV (n = 7). The oscillation amplitudes increased with increases in saccade deceleration in all three groups. The other PSO parameters, however, did not show consistent correlations with either saccade amplitude or peak velocity.
CONCLUSIONS
Post-saccadic fixation stability in AMD and RP is reduced due to abnormal PSOs. The differences with respect to NV are not due to differences in saccade kinematics, suggesting that anatomic and neuronal variations affect the suspension of the iris and the lens in the patients' eyes.
Topics: Humans; Saccades; Retinitis Pigmentosa; Female; Male; Fixation, Ocular; Middle Aged; Macular Degeneration; Aged; Pupil; Lens, Crystalline; Adult; Visual Acuity
PubMed: 38787546
DOI: 10.1167/iovs.65.5.39 -
Frontiers in Neuroscience 2024Time and space are two intertwined contexts that frame our cognition of the world and have shared mechanisms. A well-known theory on this case is "A Theory of Magnitude...
Time and space are two intertwined contexts that frame our cognition of the world and have shared mechanisms. A well-known theory on this case is "A Theory of Magnitude (ATOM)" which states that the perception of these two domains shares common mechanisms. However, evidence regarding shared computations of time and space is intermixed. To investigate this issue, we asked human subjects to reproduce time and distance intervals with saccadic eye movements in similarly designed tasks. We applied an observer model to both modalities and found underlying differences in the processing of time and space. While time and space computations are both probabilistic, adding priors to space perception minimally improved model performance, as opposed to time perception which was consistently better explained by Bayesian computations. We also showed that while both measurement and motor variability were smaller in distance than time reproduction, only the motor variability was correlated between them, as both tasks used saccadic eye movements for response. Our results suggest that time and space perception abide by the same algorithm but have different computational properties.
PubMed: 38774789
DOI: 10.3389/fnins.2024.1387641