Superior Temporal Area Research Articles

Preparation of Novel 129Xe Nanoprobe and Its Application in Acupuncture Treatment of Refractory Peripheral Facial Paralysis with fMRI

The NMR sensitivity of hyperpolarized 129Xe is much stronger than that of traditional proton, but single Xe has no targeting property. The Xe signal of new “cage” molecule can be obtained by combining it with molecular “cage,” which provides design ideas for the preparation of hyperpolarized 129Xe nanoprobes. A kind of nano material with polycyclic aromatic hydrocarbons shell is synthesized, and its 129Xe loading, particle size and fluorescence properties are measured by Hyper-CEST. The material is injected into the vein of patients with refractory peripheral facial paralysis in the form of solution. The patients are all treated with acupuncture. AFNI software is used to compare the fMRI data of patients before and after treatment and healthy control group. The average diameter of the prepared nano particles is 130 nm, and the average Z potential of nano materials is 25 mV. The fluorescence effects of monomers and nano materials with the same concentration are compared. Nano materials can emit strong fluorescence, and the assembly of monomers can enhance the fluorescence intensity. The results of Hyper-CEST 129Xe magnetic resonance testing show that the nano materials have strong CEST signal at 208 ppm, which means that the nano materials are suitable to carry Xe molecules, thus forming hyperpolarized 129Xe molecular cages. The nanoprobe solution loaded with 129Xe is injected into the vein of patients with refractory peripheral facial paralysis. Before and after acupuncture and moxibustion treatment, there are obvious signal enhancement in posterior central gyrus, thalamus, paracentral lobe, cerebellum, superior temporal gyrus and other areas of the brain, because the activated brain areas of acupuncture and moxibustion have been significantly enlarged, which proves that nanoprobe + acupuncture treatment is helpful to the analysis of the central operation mechanism of refractory peripheral facial paralysis.

Stellar Neuroretinitis as Presenting Sign of Behcet’s Disease

A 40-year-old One-eyed patient (right eye) acuity history of post-traumatic burst in his left eye at the age of 6 years. Consult for a decrease of vision on his right eye that has progressed for 3 weeks. Ophthalmic examination found visual acuity: 2/10 P10 in the right eye, the left eye presents enophthalmos with an opacified cornea; the anterior segment was normal in the right eye, fundus examination shows hyalitis graded 1+, papillary edema, peripapillary hemorrhages and stellar macular exudates, cottony nodules, copper arteries with vascular sheathing of the superior temporal branch and areas of retinal ischemia (Figure 1). The inflammatory and serological assessment is negative. Fluorescein retinal angiography shows papillary diffusion of fluorescein and vasculitis (Figure 2). We find serous retinal detachment on OCT (Figure 3). The general examination found bipolar aphthosis. The diagnosis of Behçet’s disease is retained. Treatment with immunosuppressants allowed the regression of papillary edema with persistence of some macular exudates and great improvingin visual acuity.

Properties of smooth pursuit and visual motion reaction time to second-order motion stimuli.

A large number of psychophysical and neurophysiological studies have demonstrated that smooth pursuit eye movements are tightly related to visual motion perception. This could be due to the fact that visual motion sensitive cortical areas such as meddle temporal (MT), medial superior temporal (MST) areas are involved in motion perception as well as pursuit initiation. Although the directional-discrimination and perceived target velocity tasks are used to evaluate visual motion perception, it is still uncertain whether the speed of visual motion perception, which is determined by visuomotor reaction time (RT) to a small target, is related to pursuit initiation. Therefore, we attempted to determine the relationship between pursuit latency/acceleration and the visual motion RT which was measured to the visual motion stimuli that moved leftward or rightward. The participants were instructed to fixate on a stationary target and press one of the buttons corresponding to the direction of target motion as soon as possible once the target starts to move. We applied five different visual motion stimuli including first- and second-order motion for smooth pursuit and visual motion RT tasks. It is well known that second-order motion induces lower retinal image motion, which elicits weaker responses in MT and MST compared to first-order motion stimuli. Our results showed that pursuit initiation including latency and initial eye acceleration were suppressed by second-order motion. In addition, second-order motion caused a delay in visual motion RT. The better performances in both pursuit initiation and visual motion RT were observed for first-order motion, whereas second-order (theta motion) induced remarkable deficits in both variables. Furthermore, significant Pearson’s correlation and within-subjects correlation coefficients were obtained between visual motion RT and pursuit latency/acceleration. Our findings support the suggestion that there is a common neuronal pathway involved in both pursuit initiation and the speed of visual motion perception.

Neural Selectivity for Visual Motion in Macaque Area V3A.

The processing of visual motion is conducted by dedicated pathways in the primate brain. These pathways originate with populations of direction-selective neurons in the primary visual cortex, which projects to dorsal structures like the middle temporal (MT) and medial superior temporal (MST) areas. Anatomical and imaging studies have suggested that area V3A might also be specialized for motion processing, but there have been very few studies of single-neuron direction selectivity in this area. We have therefore performed electrophysiological recordings from V3A neurons in two macaque monkeys (one male and one female) and measured responses to a large battery of motion stimuli that includes translation motion, as well as more complex optic flow patterns. For comparison, we simultaneously recorded the responses of MT neurons to the same stimuli. Surprisingly, we find that overall levels of direction selectivity are similar in V3A and MT and moreover that the population of V3A neurons exhibits somewhat greater selectivity for optic flow patterns. These results suggest that V3A should be considered as part of the motion processing machinery of the visual cortex, in both human and non-human primates.

Flexible coding of object motion in multiple reference frames by parietal cortex neurons.

Neurons represent spatial information in diverse reference frames, but it remains unclear whether neural reference frames change with task demands and whether these changes can account for behavior. We examined how neurons represent the direction of a moving object during self-motion, while monkeys switched, from trial to trial, between reporting object direction in head- and world-centered reference frames. Self-motion information is needed to compute object motion in world coordinates, but should be ignored when judging object motion in head coordinates. Neural responses in the ventral intraparietal area are modulated by the task reference frame, such that population activity represents object direction in either reference frame. In contrast, responses in the lateral portion of the medial superior temporal area primarily represent object motion in head coordinates. Our findings demonstrate a neural representation of object motion that changes with task requirements.

Functional brain connectivity in ex utero premature infants compared to in utero fetuses

Brain structural changes in premature infants appear before term age. Functional differences between premature infants and healthy fetuses during this period have yet to be explored. Here, we examined brain connectivity using resting state functional MRI in 25 very premature infants (VPT; gestational age at birth <32 weeks) and 25 healthy fetuses with structurally normal brain MRIs. Resting state data were evaluated using seed-based correlation analysis and network-based statistics using 23 regions of interest (ROIs) per hemisphere. Functional connectivity strength, the Pearson correlation between blood oxygenation level dependent signals over time across all ROIs, was compared between groups. In both cohorts, connectivity between homotopic ROIs showed a decreasing medial to lateral gradient. The cingulate cortex, medial temporal lobe and the basal ganglia shared the strongest connections. In premature infants, connections involving superior temporal, hippocampal, and occipital areas, among others, were stronger compared to fetuses. Premature infants showed stronger connectivity in sensory input and stress-related areas suggesting that extra-uterine environment exposure alters the development of select neural networks in the absence of structural brain injury.

Pre-reading language abilities and the brain’s functional reading network in young children

Early childhood is an important period for language development that lays the foundation for future reading abilities. However, little research has focused on the functional brain systems supporting pre-reading language abilities in typically developing children. Here, we investigated functional connectivity using passive viewing functional magnetic resonance imaging (fMRI) in 50 healthy children aged 2.85–5.07 years (3.84 ​± ​0.60 years, 22 female/28 male). Children completed the NEPSY-II Phonological Processing and Speeded Naming subtests and underwent fMRI while watching a movie of their choice. Functional connectivity was measured between key brain reading areas (bilateral angular gyrus, superior temporal gyrus, and inferior frontal gyrus) and the rest of the brain. Age-adjusted pre-reading scores positively correlated with functional connectivity between (1) the right angular gyrus and superior temporal gyrus, (2) the bilateral angular gyri and right pars triangularis and motor areas, (3) the left superior temporal gyrus and bilateral medial frontal gyrus and right cerebellum, (4) the left pars triangularis and middle occipital gyrus and insula, and (5) the right pars triangularis and the bilateral thalamus. Higher pre-reading scores were associated with stronger negative functional connectivity between (1) the left angular gyrus and auditory cortex, (2) the left superior temporal gyrus and occipital vision areas, (3) the right pars triangularis and medial frontal region, and (4) the right superior temporal gyrus and the posterior cingulate/precuneus. These results suggest better integration of the reading network, as well as its connections with other brain areas that support language or reading, and more dissociation between reading areas and the default mode network, in young children with better pre-reading skills. Our findings show that relationships between functional connectivity and pre-reading language skills are evident in young children even before formal reading instruction.

Cerebral Hemodynamic Responses to the Sensory Conflict Between Visual and Rotary Vestibular Stimuli: An Analysis With a Multichannel Near-Infrared Spectroscopy (NIRS) System.

Sensory conflict among visual, vestibular, and somatosensory information induces vertiginous sensation and postural instability. To elucidate the cognitive mechanisms of the integration between the visual and vestibular cues in humans, we analyzed the cortical hemodynamic responses during sensory conflict between visual and horizontal rotatory vestibular stimulation using a multichannel near-infrared spectroscopy (NIRS) system. The subjects sat on a rotatory chair that was accelerated at 3°/s2 for 20 s to the right or left, kept rotating at 60°/s for 80 s, and then decelerated at 3°/s2 for 20 s. The subjects were instructed to watch white stripes projected on a screen surrounding the chair during the acceleration and deceleration periods. The white stripes moved in two ways; in the “congruent” condition, the stripes moved in the opposite direction of chair rotation at 3°/s2 (i.e., natural visual stimulation), whereas in the “incongruent” condition, the stripes moved in the same direction of chair rotation at 3°/s2 (i.e., conflicted visual stimulation). The cortical hemodynamic activity was recorded from the bilateral temporoparietal regions. Statistical analyses using NIRS-SPM software indicated that hemodynamic activity increased in the bilateral temporoparietal junctions (TPJs) and human MT+ complex, including the medial temporal (MT) area and medial superior temporal (MST) area in the incongruent condition. Furthermore, the subjective strength of the vertiginous sensation was negatively correlated with hemodynamic activity in the dorsal part of the supramarginal gyrus (SMG) in and around the intraparietal sulcus (IPS). These results suggest that sensory conflict between the visual and vestibular stimuli promotes cortical cognitive processes in the cortical network consisting of the TPJ, the medial temporal gyrus (MTG), and IPS, which might contribute to self-motion perception to maintain a sense of balance or equilibrioception during sensory conflict.

Intrinsic functional architecture of the human speech processing network

Speech engages distributed temporo-fronto-parietal brain regions, however a comprehensive understanding of its intrinsic functional network architecture is lacking. Here we investigate the human speech processing network using the largest sample to date, high temporal resolution resting-state fMRI data, network stability analysis, and theoretically informed models. Network consensus analysis revealed three stable functional modules encompassing: (1) superior temporal plane (STP) and Area Spt, (2) superior temporal sulcus (STS) + ventral frontoparietal cortex, and (3) dorsal frontoparietal cortex. The STS + ventral frontoparietal cortex module showed the highest participation coefficient, and a hub-like organization linking STP with frontoparietal cortical nodes. Node-wise analysis revealed key connectivity features underlying this modular architecture, including a leftward asymmetric connectivity profile, and differential connectivity of STS and STP, with frontoparietal cortex. Our findings, replicated across cohorts, reveal a tripartite functional network architecture supporting speech processing and provide a novel template for future studies.

Interhemispheric and Intrahemispheric Connectivity From the Left Pars Opercularis Within the Language Network Is Modulated by Transcranial Stimulation in Healthy Subjects.

Neural activity related to language can be modulated within widespread networks following learning or in response to disruption—including the experimental application of noninvasive brain stimulation. However, the spatiotemporal characteristics of such modulation remain insufficiently explored. The present study combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to explore the modulation of activity across the language network following continuous theta-burst stimulation (cTBS) of the left pars opercularis. In 10 healthy subjects (21 ± 2 years old, four females), neuronavigated cTBS was delivered over the left pars opercularis of the frontal operculum (part of the traditional Broca’s area) at 80% of active motor threshold (AMT) stimulation intensity. Real cTBS and sham cTBS were performed in two different visits separated by at least 48 h. Before, immediately, and 10 min after cTBS, 30 single pulses of TMS were delivered to the left pars opercularis at 80% of the resting motor threshold (RMT), whereas EEG was simultaneously recorded. We examined the cTBS-induced modulation of phase locking values (PLVs) between the TMS-evoked potentials (TEPs) recorded over the pars opercularis and those recorded over its right-hemispheric homolog area, the left supramarginal area, and the left superior temporal area in different EEG frequency bands and different time windows following cTBS. cTBS to the left pars opercularis induced within the gamma band: (1) a significant increase in TEP phase synchronization between the left and right pars opercularis at an early time window (250–350 ms) following cTBS; and (2) significantly increased PLV with the left supramarginal area and the left superior temporal area at a later time window (600–700 ms). In the theta and delta band, cTBS to the left pars opercularis induced significantly increased phase synchronization of TEPs between the left pars opercularis and the posterior left hemispheric language areas at a late time window. In sham condition, there was a significant decrease in TEP phase synchronization of the high beta band between left pars opercularis and left superior temporal area at 200–300 ms. These results contribute to characterize the dynamics of the language network and may have implications in the development of noninvasive stimulation protocols to promote the language rehabilitation in aphasia patients.

Social perspective-taking shapes brain hemodynamic activity and eye movements during movie viewing.

Putting oneself into the shoes of others is an important aspect of social cognition. We measured brain hemodynamic activity and eye-gaze patterns while participants were viewing a shortened version of the movie ‘My Sister’s Keeper’ from two perspectives: that of a potential organ donor, who violates moral norms by refusing to donate her kidney, and that of a potential organ recipient, who suffers in pain. Inter-subject correlation (ISC) of brain activity was significantly higher during the potential organ donor’s perspective in dorsolateral and inferior prefrontal, lateral and inferior occipital, and inferior–anterior temporal areas. In the reverse contrast, stronger ISC was observed in superior temporal, posterior frontal and anterior parietal areas. Eye-gaze analysis showed higher proportion of fixations on the potential organ recipient during both perspectives. Taken together, these results suggest that during social perspective-taking different brain areas can be flexibly recruited depending on the nature of the perspective that is taken.

Sensory Modality-Independent Activation of the Brain Network for Language.

The meaning of a sentence can be understood, whether presented in written or spoken form. Therefore, it is highly probable that brain processes supporting language comprehension are at least partly independent of sensory modality. To identify where and when in the brain language processing is independent of sensory modality, we directly compared neuromagnetic brain signals of 200 human subjects (102 males) either reading or listening to sentences. We used multiset canonical correlation analysis to align individual subject data in a way that boosts those aspects of the signal that are common to all, allowing us to capture word-by-word signal variations, consistent across subjects and at a fine temporal scale. Quantifying this consistency in activation across both reading and listening tasks revealed a mostly left-hemispheric cortical network. Areas showing consistent activity patterns included not only areas previously implicated in higher-level language processing, such as left prefrontal, superior and middle temporal areas, and anterior temporal lobe, but also parts of the control network as well as subcentral and more posterior temporal-parietal areas. Activity in this supramodal sentence-processing network starts in temporal areas and rapidly spreads to the other regions involved. The findings indicate not only the involvement of a large network of brain areas in supramodal language processing but also that the linguistic information contained in the unfolding sentences modulates brain activity in a word-specific manner across subjects.SIGNIFICANCE STATEMENT The brain can extract meaning from written and spoken messages alike. This requires activity of both brain circuits capable of processing sensory modality-specific aspects of the input signals as well as coordinated brain activity to extract modality-independent meaning from the input. Using traditional methods, it is difficult to disentangle modality-specific activation from modality-independent activation. In this work, we developed and applied a multivariate methodology that allows for a direct quantification of sensory modality-independent brain activity, revealing fast activation of a wide network of brain areas, both including and extending beyond the core network for language.

Critical area for memory decline after mesial temporal resection in epilepsy patients.

Mesial temporal lobe epilepsy (MTLE) surgery is associated with a risk of memory decline after surgery, but the effect of the extent and locus of temporal resection on postoperative memory function are controversial. The authors' aim in this study was to confirm if selective resection is effective in preserving memory function and identify critical areas for specific memory decline after temporal resection. In this single-center retrospective study, the authors investigated data from patients who underwent unilateral MTLE surgery between 2005 and 2015. Data from 74 MTLE patients (60.8% of whom were female; mean [SD] age at surgery 32 years [8.91 years] and duration of epilepsy 16 years [9.65 years]) with histologically proven hippocampal sclerosis were included. Forty-two patients underwent left-sided surgery. The resection area was manually delineated on each patient's postoperative T1-weighted images. Mapping was performed to see if the resected group, compared with the nonresected group, had worse postoperative memory in various memory domains, including verbal item, verbal associative, and figural memory. Overall, 95.9% had a favorable epilepsy outcome. In verbal item memory, resection of the left lateral temporal area was related to postoperative decline in immediate and delayed recall scores of word lists. In verbal associative memory, resection of the anterior part of the left hippocampus, left parahippocampal area, and left lateral temporal area was related to postoperative decline in immediate recall scores of word pairs. Resection of the posterior part of the left hippocampus, left parahippocampal area, and left lateral temporal area was related to delayed recall scores of the same task. Similarly, in the figural memory, postoperative decline of immediate recall scores was associated with the resection of the anterior part of the right hippocampus, amygdala, parahippocampal area, and superior temporal area, and decline of delayed recall scores was related to resection of the posterior part of the right hippocampus and parahippocampal area. Using voxel-based analysis, which accounts for the individual differences in the resection, the authors found a critical region for postoperative memory decline that is not revealed in the region-of-interest or groupwise comparison. Particularly, resection of the hippocampus was related to associative memory. In both verbal and visual memory, resection of the anterior part of the hippocampus was associated with immediate recall, and resection of the posterior part of the hippocampus was associated with delayed recall. Therefore, the authors' results suggest that selective resection may be effective in preserving postoperative memory decline.

Unilateral visual impairment in a patient undergoing chemotherapy: a case report and clinical findings

BackgroundVisual impairment occurred as an infrequent form of chemotherapeutic toxicity and was often underestimated despite of several reports. We described a case of acute unilateral visual impairment after one cycle of intravenous chemotherapy of a normal dose, aiming at raising attention to chemotherapy-induced ocular toxicity.Case presentationThe patient developed a progressive vision loss in the right eye during the chemotherapy. After one cycle of intravenous chemotherapy, her visual acuity decreased by 0.6 in the right eye (VOD = 0.4) compared to the previous value of 1.0 (VOD = 1.0). No evidence of ocular infiltration was observed from the cerebral magnetic resonance imaging (MRI). During her follow-up period, we documented the ophthalmologic examinations including visual acuity, visual field (VF), visual evoked potential (VEP), electroretinogram (ERG), fundus photograph (FP), fundus fluorescein angiography (FFA) and optical coherence tomography (OCT). Ophthalmoscope examination and fundus photograph showed optic disc edema, fuzzy boundary and linear hemorrhages in her right eye. Fundus fluorescein angiography (FFA) revealed capillary underdevelopment at the nasal and superior temporal area of the optic disc in the early phase and capillary fluorescein leakage in the late phase. The result of VEP test suggested the impaired function of the optic nerve. Thus, a diagnosis of nonarteritic anterior ischemic optic neuropathy (NAION) was made by the ophthalmologist according to these results. The patient was prescribed prednisone combined with neuroprotective drugs, which did not work. After the cessation of chemotherapy, her impaired vision gradually recovered.ConclusionsThis is the first reported case of acute visual impairment in a patient who underwent chemotherapy of a normal dose. It is indicated that while receiving benefits from chemotherapy, cancer patients simultaneously suffer from the risk of vision loss.

Localisation atypique d’un colobome cristallinien

Nous rapportons le cas d'un patient âgé de 37 ans, sans antécédents pathologiques particuliers, se présentant à la consultation d'ophtalmologie pour changement de correction optique. L'examen de l'œil droit retrouve une acuité visuelle corrigée à 6/10ème, une réfraction automatique à -1,50 (-6,25 à 56°), l'examen du segment antérieur retrouve un colobome cristallinien en supéro-temporal avec défect zonulaire allant de 8h à 11h et une opacité cristallinienne en regard. L'examen de l'iris et du fond d'œil sont normaux. L'examen de l'œil gauche est sans particularité. Les colobomes sont des malformations congénitales de l'œil secondaires à une anomalie de fermeture de la fente fœtale. Le colobome cristallinien reste une localisation rare de cette malformation; secondaire à un colobome uvéal entraîne un aspect d'indentation de la périphérie du cristallin, sa localisation est classiquement inféro-nasale. La particularité de notre cas est la localisation du colobome cristallinien en supéro-temporale. Il faut rechercher une opacité cristallinienne en regard d'autres anomalies colobomateuses, et des malformations oculaires associées comme la cataracte, la microphtalmie ou l'ectopie cristallinienne.

Computational Mechanisms for Perceptual Stability using Disparity and Motion Parallax.

Walking and other forms of self-motion create global motion patterns across our eyes. With the resulting stream of visual signals, how do we perceive ourselves as moving through a stable world? Although the neural mechanisms are largely unknown, human studies (Warren and Rushton, 2009) provide strong evidence that the visual system is capable of parsing the global motion into two components: one due to self-motion and the other due to independently moving objects. In the present study, we use computational modeling to investigate potential neural mechanisms for stabilizing visual perception during self-motion that build on neurophysiology of the middle temporal (MT) and medial superior temporal (MST) areas. One such mechanism leverages direction, speed, and disparity tuning of cells in dorsal MST (MSTd) to estimate the combined motion parallax and disparity signals attributed to the observer's self-motion. Feedback from the most active MSTd cell subpopulations suppresses motion signals in MT that locally match the preference of the MSTd cell in both parallax and disparity. This mechanism combined with local surround inhibition in MT allows the model to estimate self-motion while maintaining a sparse motion representation that is compatible with perceptual stability. A key consequence is that after signals compatible with the observer's self-motion are suppressed, the direction of independently moving objects is represented in a world-relative rather than observer-relative reference frame. Our analysis explicates how temporal dynamics and joint motion parallax-disparity tuning resolve the world-relative motion of moving objects and establish perceptual stability. Together, these mechanisms capture findings on the perception of object motion during self-motion.SIGNIFICANCE STATEMENT The image integrated by our eyes as we move through our environment undergoes constant flux as trees, buildings, and other surroundings stream by us. If our view can change so radically from one moment to the next, how do we perceive a stable world? Although progress has been made in understanding how this works, little is known about the underlying brain mechanisms. We propose a computational solution whereby multiple brain areas communicate to suppress the motion attributed to our movement relative to the stationary world, which is often responsible for a large proportion of the flux across the visual field. We simulated the proposed neural mechanisms and tested model estimates using data from human perceptual studies.

Computer-Based Cognitive Training Improves Brain Functional Connectivity in the Attentional Networks: A Study With Primary School-Aged Children.

We have shown that a computer-based program that trains schoolchildren in cognitive tasks that mainly tap working memory (WM), implemented by teachers and integrated into school routine, improved cognitive and academic skills compared with an active control group. Concretely, improvements were observed in inhibition skills, non-verbal IQ, mathematics and reading skills. Here, we focus on a subsample from the overarching study who volunteered to be scanned using a resting state fMRI protocol before and 6-month after training. This sample reproduced the aforementioned behavioral effects, and brain functional connectivity changes were observed within the attentional networks (ATN), linked to improvements in inhibitory control. Findings showed stronger relationships between inhibitory control scores and functional connectivity in a right middle frontal gyrus (MFG) cluster in trained children compared to children from the control group. Seed-based analyses revealed that connectivity between the r-MFG and homolateral parietal and superior temporal areas were more strongly related to inhibitory control in trained children compared to the control group. These findings highlight the relevance of computer-based cognitive training, integrated in real-life school environments, in boosting cognitive/academic performance and brain functional connectivity.

Retinal Stabilization Reveals Limited Influence of Extraretinal Signals on Heading Tuning in the Medial Superior Temporal Area.

Heading perception in primates depends heavily on visual optic-flow cues. Yet during self-motion, heading percepts remain stable, even though smooth-pursuit eye movements often distort optic flow. According to theoretical work, self-motion can be represented accurately by compensating for these distortions in two ways: via retinal mechanisms or via extraretinal efference-copy signals, which predict the sensory consequences of movement. Psychophysical evidence strongly supports the efference-copy hypothesis, but physiological evidence remains inconclusive. Neurons that signal the true heading direction during pursuit are found in visual areas of monkey cortex, including the dorsal medial superior temporal area (MSTd). Here we measured heading tuning in MSTd using a novel stimulus paradigm, in which we stabilize the optic-flow stimulus on the retina during pursuit. This approach isolates the effects on neuronal heading preferences of extraretinal signals, which remain active while the retinal stimulus is prevented from changing. Our results from 3 female monkeys demonstrate a significant but small influence of extraretinal signals on the preferred heading directions of MSTd neurons. Under our stimulus conditions, which are rich in retinal cues, we find that retinal mechanisms dominate physiological corrections for pursuit eye movements, suggesting that extraretinal cues, such as predictive efference-copy mechanisms, have a limited role under naturalistic conditions.SIGNIFICANCE STATEMENT Sensory systems discount stimulation caused by an animal's own behavior. For example, eye movements cause irrelevant retinal signals that could interfere with motion perception. The visual system compensates for such self-generated motion, but how this happens is unclear. Two theoretical possibilities are a purely visual calculation or one using an internal signal of eye movements to compensate for their effects. The latter can be isolated by experimentally stabilizing the image on a moving retina, but this approach has never been adopted to study motion physiology. Using this method, we find that extraretinal signals have little influence on activity in visual cortex, whereas visually based corrections for ongoing eye movements have stronger effects and are likely most important under real-world conditions.

The rough sound of salience enhances aversion through neural synchronisation

Being able to produce sounds that capture attention and elicit rapid reactions is the prime goal of communication. One strategy, exploited by alarm signals, consists in emitting fast but perceptible amplitude modulations in the roughness range (30–150 Hz). Here, we investigate the perceptual and neural mechanisms underlying aversion to such temporally salient sounds. By measuring subjective aversion to repetitive acoustic transients, we identify a nonlinear pattern of aversion restricted to the roughness range. Using human intracranial recordings, we show that rough sounds do not merely affect local auditory processes but instead synchronise large-scale, supramodal, salience-related networks in a steady-state, sustained manner. Rough sounds synchronise activity throughout superior temporal regions, subcortical and cortical limbic areas, and the frontal cortex, a network classically involved in aversion processing. This pattern correlates with subjective aversion in all these regions, consistent with the hypothesis that roughness enhances auditory aversion through spreading of neural synchronisation.

Asymmetric smooth pursuit eye movements and visual motion reaction time.

Smooth pursuit eye movements often show directional asymmetry in pursuit initiation or steady‐state pursuit in both humans and monkeys. It has been demonstrated that the initial part of smooth pursuit is driven by visual motion related signals in cortical areas. Parietal cortex such as middle temporal (MT) and medial superior temporal (MST) areas are known to be involved in visual motion perception as well as pursuit initiation. Therefore, the purpose of this study is to determine whether directional asymmetry in pursuit initiation is associated with visual motion perception. We used a step‐ramp paradigm to induce horizontal smooth pursuit eye movements and then tested visual motion reaction time (RT). Visual motion RT was measured to the visual motion stimuli that moved leftward or rightward, which is an important parameter of our sensory motor processing based on visual motion perception. Nineteen healthy male subjects participated in the study. We found that some of our subjects showed directional asymmetries in initial pursuit acceleration between the leftward and rightward directions, which were consistent with an asymmetric bias in visual motion RT. Therefore, our results suggest that asymmetric pursuit initiation is associated with, at least in part, a bias of visual motion perception. These results could be due to a common neuronal pathway involved in both pursuit initiation and visual motion RT.