Abstract:
:The human visual system is strikingly insensitive to speed changes attributed to the need to infer visual acceleration, observed during stationary fixation, indirectly by comparing velocities integrated over time. The objective of this study was to test if smooth pursuit eye movements improve the detection of speed changes. This was expected for two reasons: first, pursuit reduces the retinal image slip velocity, leading to smaller Weber fractions for velocity changes; secondly, pursuit provides acceleration-dependent retinal position cues unavailable during stationary fixation such as displacements of the target image away from the fovea due to unexpected changes in target velocity. In a first set of experiments thresholds for just noticeable speed changes were measured in ten healthy human subjects confronted with a horizontally moving target, changing its velocity unpredictably during its ramp-like movement. During stationary fixation, the Weber fraction averaged 0.13 for a starting velocity of the target being 15 degrees /s. Smooth pursuit of the same target significantly reduced the Weber fraction down to 0.08. In a second set of experiments, the discrimination of speed changes was tested in patients (n=10) with pursuit disturbances characterized by increased retinal image slip and unidirectional retinal image displacements. These patients showed a strong perceptual bias to report speed increments and an insensitivity to speed decrements. We argue that this asymmetry is a necessary consequence of a mechanism exploiting retinal position errors for the detection of speed change, confronted with directionally biased errors due to the pursuit impairment. In summary, the detection of speed changes is facilitated by pursuit eye movements but is highly susceptible to pursuit insufficiencies.
journal_name
Exp Brain Resjournal_title
Experimental brain researchauthors
Haarmeier T,Thier Pdoi
10.1007/s00221-005-0216-6keywords:
subject
Has Abstractpub_date
2006-04-01 00:00:00pages
345-57issue
3eissn
0014-4819issn
1432-1106journal_volume
170pub_type
杂志文章abstract::An economical method of computing the source densities underlying human scalp-recorded event-related potentials (ERPs) is used to investigate the topography of "evaluation potentials" elicited when a subject assess the outcome of a goal-directed activity. No sign of a generative focus was observed in frontal locations...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00235821
更新日期:1984-01-01 00:00:00
abstract::The hypothesis that anticipatory postural adjustments (APAs) may concur in generating the directional preference experienced during limb coupled movements was tested by measuring the electromyographic and mechanic postural actions elicited when moving: (1) one single arm/hand and, (2) both limbs, iso- or antidirection...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-008-1470-1
更新日期:2008-09-01 00:00:00
abstract::The aim of this study was to determine whether vestibular information related to head acceleration is available for triggering postural responses to perturbations of stance in the freely-standing cat. Linear accelerations of the head were recorded during postural responses evoked by linear translations of the support ...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00228511
更新日期:1991-01-01 00:00:00
abstract::Neurostimulation, e.g., transcranial direct current stimulation (tDCS), shows promise as an effective cognitive intervention. In spite of low spatial resolution, limited penetration, and temporary influence, evidence highlights tDCS-linked cognitive benefits in a range of cognitive domains. The left posterior parietal...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-014-4090-y
更新日期:2014-12-01 00:00:00
abstract::Besides luminance change, the pupil responds to changes in spatial pattern, color content and target motion. Our experimental results show that transient pupillary constriction can also be elicited by dichoptically viewing a change in stereoscopic stimuli composed of dynamic random-dot stereograms from an initially fl...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-004-2161-1
更新日期:2005-01-01 00:00:00
abstract::Could task performance be constrained by our ability to fully engage necessary neural processing through effort of will? The StartReact phenomenon suggests that this might be the case, as voluntary reaction times are substantially reduced by loud sounds. Here, we show that loud auditory stimulation can also be associa...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-010-2474-1
更新日期:2011-01-01 00:00:00
abstract::The representation of the two eyes in striate cortex (V1) of Cebus monkeys was studied by electrophysiological single-unit recordings in normal animals and by morphometric analysis of the pattern of ocular dominance (OD) stripes, as revealed by cytochrome oxidase histochemistry in V1 flat-mounts of enucleated animals....
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF02259100
更新日期:1992-01-01 00:00:00
abstract::The aim of this study was to examine the post-exercise effects of fatiguing the wrist extensor muscles of a single arm on postural tremor and muscle activity in both arms. Previous research has shown that, for neurologically normal subjects, the tremor seen within a single limb segment is uncorrelated to that seen con...
journal_title:Experimental brain research
pub_type: 临床试验,杂志文章
doi:10.1007/s00221-005-0050-x
更新日期:2005-12-01 00:00:00
abstract::Thaw-mount autoradiography was used to map target neurons for tritiated steroids in the brains of ovariectomized rhesus monkeys. In five females, studies were performed 60 min after the administration of 3H-estradiol. Of these, two females were pretreated for five days with daily injections of 2 mg testosterone propio...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00235647
更新日期:1986-01-01 00:00:00
abstract::Anxious individuals have been shown to interpret others' emotional states negatively. Since most studies have used facial expressions as emotional cues, we examined whether trait anxiety affects the recognition of emotion in a dynamic face and voice that were presented in synchrony. The face and voice cues conveyed ei...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-011-2668-1
更新日期:2011-09-01 00:00:00
abstract::We examined modulation of transmission of short-latency excitation produced by distal hindlimb cutaneous input, as well as fluctuations in motoneuron membrane potential and input resistance, in flexor digitorum longus (FDL) motoneurons during fictive locomotion. Fictive stepping was induced in unaesthetized, decerebra...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00248749
更新日期:1988-01-01 00:00:00
abstract::It is widely believed that cells in area 17 send axons specifically to neurons in other cortical areas whose receptive fields coincide with their own. We asked whether this was true in cats for area 17's projection to a large suprasylvian visual area, the Clare-Bishop area. Receptive fields were plotted at multiple si...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00250246
更新日期:1988-01-01 00:00:00
abstract::It is known that kittens reared in ways that restrict movement while visual stimulation is received exhibit deficits in visually guided behavior. Presumably, the behavioral dysfunction is due to a lack of sensorimotor coordination during visual exposure. The current investigation was undertaken to study this effect bo...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00238794
更新日期:1978-09-15 00:00:00
abstract::Extracellular focal synaptic potentials (FSPs) were recorded in forelimb segments of cats in the region where corticospinal volleys (pyramidal stimulation) gave a maximal FSP. No FSP was recorded in this region on stimulation of the medial part of the lateral reticular nucleus (LRN), provided that ventral spinal pathw...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00235897
更新日期:1982-01-01 00:00:00
abstract::We investigated whether the order of gaze shifts affected spatial and temporal aspects of discrete bimanual pointing movements. Ten male participants concurrently executed bimanual pointing movements as quickly and accurately as possible to left and right lateral targets presented with the same and different amplitude...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-009-1950-y
更新日期:2009-10-01 00:00:00
abstract::Abnormal automatic postural responses are thought to contribute to balance impairment in Parkinson's disease. However, because postural responses are modifiable by stance, we have speculated that some postural abnormalities in patients with Parkinson's disease are secondary to their stooped stance. We have studied thi...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s002210050644
更新日期:1999-02-01 00:00:00
abstract::Effects of redox reagents on excitatory and inhibitory synaptic responses as well as on the bidrectional plasticity of alpha-amino-3-hydroxy-5-methylisoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor-mediated synaptic responses were studied in CA1 pyramidal neurons in rat hippocampal slices. The o...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF02450332
更新日期:1997-02-01 00:00:00
abstract::Attention-deficit hyperactivity disorder (ADHD) is a prevalent psychiatric disorder in children that often continues into adulthood. It has been suggested that motor impairments in ADHD are associated with underlying cerebellar pathology. If such is the case, individuals with ADHD should be impaired on motor tasks req...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-014-4190-8
更新日期:2015-04-01 00:00:00
abstract::Extracellular recordings of neuronal activity made in the lumbosacral spinal segments of the anesthetized cat have disclosed the existence of a set of neurons in Rexed's laminae III-VI that discharged in a highly synchronized manner during the occurrence of spontaneous negative cord dorsum potentials (nCDPs) and respo...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-002-1303-6
更新日期:2003-02-01 00:00:00
abstract::The aim of this study was to evaluate the modulation of muscle activity during locomotor-like movements by different walking speeds in subjects with a motor complete spinal cord injury (SCI) compared to actively--and passively-walking control subjects without neurological deficit. Stepping movements on a treadmill wer...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-006-0509-4
更新日期:2006-10-01 00:00:00
abstract::Even the simplest volitional movements must be precisely coordinated with anticipatory postural adjustments. Little is currently known about the neural networks that coordinate these adjustments in healthy adults. We measured brain activity prior to movement during a bimanual load-lifting task, designed to elicit anti...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-010-2470-5
更新日期:2011-01-01 00:00:00
abstract::The horizontal and vertical components of the positions of both eyes of rhesus monkeys were measured during periods of binocularly stable eye positions (eye pauses) while the animals fixated a small target. Differences between monocular and binocular viewing, as well as effects of target size and background illuminati...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00236231
更新日期:1984-01-01 00:00:00
abstract::The present study examined the kinematics of unrestricted reaches to prismatically-displaced targets. The kinematic analysis allowed us (1) to document how and where in the reach adjustments were made to compensate for the prismatic displacement. (2) to detail the changes that occur in the characteristics of reaches d...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00230245
更新日期:1989-01-01 00:00:00
abstract::During everyday life, healthy adults occasionally trip over an obstacle that they knew was there. These 'spontaneous' trips can provide insight into the circumstances leading to trips and falls. The goal of this study was to describe the errors in foot placement and/or foot elevation that resulted in a spontaneous con...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-012-3253-y
更新日期:2012-11-01 00:00:00
abstract::Clear vision of objects moving in three-dimensional space near an observer is attained by a combination of smooth-pursuit and vergence eye movements. The two systems must interact with the vestibular system to maintain the image of the object on the fovea. Previous studies showed that training with smooth-pursuit vest...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-003-1777-x
更新日期:2004-05-01 00:00:00
abstract::The fluorescent dye diamidino yellow was injected into parts of the developing visual and auditory systems in the rat. The dye was retrogradely transported by projecting neurones and was found to stain pyknotic profiles within the labelled cell populations. It is thus possible to visualize directly the death of neuron...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/BF00228865
更新日期:1990-01-01 00:00:00
abstract::For 1 week, healthy human participants ( n=7) were devoid of normal vision by exposure to prism lenses that optically rotated their perceived world around the line of sight by 180 degrees. Adaptation to such prisms involved sustained and vigorous practice of the ability to redirect the unadapted efferent motor command...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-002-1097-6
更新日期:2002-06-01 00:00:00
abstract::The flexion reflex modulation pattern was investigated in nine people with a chronic spinal cord injury during stepping using body weight support on a treadmill and manual assistance by therapists. Body weight support was provided by an upper body harness and was adjusted for each subject to promote the best stepping ...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-009-1854-x
更新日期:2009-07-01 00:00:00
abstract::The ability of Huntington's disease patients to co-ordinate their two hands with and without external cueing was investigated. Twelve Huntington's disease patients and sex- and age-matched controls performed a bimanual cranking task at two speeds (0.5 Hz, 1.5 Hz) and phase relationships (in-phase, anti-phase), with an...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s002210000485
更新日期:2000-10-01 00:00:00
abstract::The current study examined whether the amount and location of available movement information influenced the stability of visuomotor coordination. Participants coordinated a handheld pendulum with an oscillating visual stimulus in an inphase and antiphase manner. The effects of occluding different amounts of phase at d...
journal_title:Experimental brain research
pub_type: 杂志文章
doi:10.1007/s00221-009-1982-3
更新日期:2012-09-01 00:00:00