Variability in the temporal dynamics of object-based attentional selection.

Our attention can be directed to specific locations in our visual field (space-based attention), or to specific objects (object-based attention). However, object-based attention tends to be less pronounced than space-based attention and can vary greatly between individuals. Here we investigated whether the low prevalence of object-based effects is related to variability in the temporal dynamics of attentional selection.

Contextual and own-age effects in age perception.

Our judgement of certain facial characteristics such as emotion, attractiveness or age, is affected by context. Faces that are flanked by younger faces, for example, are perceived as being younger, whereas faces flanked by older faces are perceived as being older. Here, we investigated whether contextual effects in age perception are moderated by own age effects.

Effects of cue validity on attentional selection.

Visual attention can be allocated to locations or objects, leading to enhanced processing of information at the specific location (space-based effects) or specific object (object-based effects). Previous studies have observed object-based effects to be smaller and less robust than space-based effects, with large individual differences in their temporal occurrence. Studies on space- and object-based effects are often based on a two-rectangle paradigm in which targets appear at cued locations more often than uncued locations.

No Common Factor Underlying Decline of Visual Abilities in Mild Cognitive Impairment.

Introduction: Recent work has shown an association between cognitive and visual impairments and two main theories were advanced, namely the sensory deprivation and the common cause theories. Most studies considered only basic visual functions such as visual acuity or visual field size and evaluated the association with dementia.

Objectives: To reconcile between these theories and to test the link between visual and cognitive decline in mildly cognitive impaired people.

A Search Advantage for Horizontal Targets in Dynamic Displays.

Several lines of evidence point to the existence of a visual processing advantage for horizontal over vertical orientations. We investigated whether such a horizontal advantage exists in the context of top-down visual search. Inspired by change detection studies, we created displays where a dynamic target -- a horizontal or a vertical group of five dots that changed contrast synchronously -- was embedded within a randomly flickering grid of dots.

Selective age-related changes in orientation perception.

Orientation perception is a fundamental property of the visual system and an important basic processing stage for visual scene perception. Neurophysiological studies have found broader tuning curves and increased noise in orientation-selective neurons of senescent monkeys and cats, results that suggest an age-related decline in orientation perception. However, behavioral studies in humans have found no evidence for such decline, with performance being comparable for younger and older participants in orientation detection and discrimination tasks.

Associations between genetic variations and global motion perception.

The cholinergic system is known to strongly modulate perceptual and cognitive processes, and the alpha7 subunit of the cholinergic nicotinic receptor (CHRNA7) is broadly expressed within the visual system. Here, we assessed whether genetic variations of CHRNA7 affect coherent motion perception. Motion perception has been shown to decline with age, and it has previously been suggested that the effects of genetic variations are magnified by age.

No evidence for a common factor underlying visual abilities in healthy older people.

The world's population is aging at an increasing rate. Even in the absence of neurodegenerative disorders, healthy aging affects perception and cognition. In the context of cognition, common factors are well established.

Motion perception as a model for perceptual aging.

Research on functional changes across the adult lifespan has been dominated by studies related to cognitive processes. However, it has become evident that a more comprehensive approach to behavioral aging is needed. In particular, our understanding of age-related perceptual changes is limited.

An advantage for horizontal motion direction discrimination.

Discrimination performance is better for cardinal motion directions than for oblique ones, a phenomenon known as the oblique effect. In a first experiment of this paper, we tested the oblique effect for coarse motion direction discrimination and compared performance for the two cardinal and two diagonal motion directions. Our results provide evidence for the oblique effect for coarse motion direction discrimination.

Visual attention, biological motion perception, and healthy ageing.

Biological motion perception is the ability of the visual system to perceive complex human movement patterns. The previous studies have shown a direct link between attentional abilities and performance on biological motion tasks, both of which have been shown to deteriorate with age. However, it is not known whether there is a direct link between age-related deficits in biological motion processing and attention.

Sex-related differences in vision are heterogeneous.

Despite well-established sex differences for cognition, audition, and somatosensation, few studies have investigated whether there are also sex differences in visual perception. We report the results of fifteen perceptual measures (such as visual acuity, visual backward masking, contrast detection threshold or motion detection) for a cohort of over 800 participants. On six of the fifteen tests, males significantly outperformed females.

Behavioural evidence for distinct mechanisms related to global and biological motion perception.

The perception of human motion is a vital ability in our daily lives. Human movement recognition is often studied using point-light stimuli in which dots represent the joints of a moving person. Depending on task and stimulus, the local motion of the single dots, and the global form of the stimulus can be used to discriminate point-light stimuli.

Temporal aspects of natural scene categorisation in healthy ageing.

The visual system has an extraordinary capability to extract categorical information from complex scenes. Age-related deficits in visual temporal processing have been found with both low-level and high-level stimuli. However, it is unknown to which extent those deficits extend to the processing of complex scenes.

Neural changes related to motion processing in healthy aging.

Behavioral studies have found a striking decline in the processing of low-level motion in healthy aging whereas the processing of more relevant and familiar biological motion is relatively preserved. This functional magnetic resonance imaging (fMRI) study investigated the neural correlates of low-level radial motion processing and biological motion processing in 19 healthy older adults (age range 62-78 years) and in 19 younger adults (age range 20-30 years). Brain regions related to both types of motion stimuli were evaluated and the magnitude and time courses of activation in those regions of interest were calculated.

Motion coherence and direction discrimination in healthy aging.

Perceptual functions change with age, particularly motion perception. With regard to healthy aging, previous studies mostly measured motion coherence thresholds for coarse motion direction discrimination along cardinal axes of motion. Here, we investigated age-related changes in the ability to discriminate between small angular differences in motion directions, which allows for a more specific assessment of age-related decline and its underlying mechanisms.

Global form and motion processing in healthy ageing.

The ability to perceive biological motion has been shown to deteriorate with age, and it is assumed that older adults rely more on the global form than local motion information when processing point-light walkers. Further, it has been suggested that biological motion processing in ageing is related to a form-based global processing bias. Here, we investigated the relationship between older adults' preference for form information when processing point-light actions and an age-related form-based global processing bias.

Local form interference in biological motion perception.

Replacing the local dots of point-light walkers with complex images leads to significant detriments to performance in biological motion detection and discrimination tasks. This detriment has previously been shown to be larger when the local elements match the global shape in object category and facing direction. In contrast, studies using Navon stimuli have demonstrated that local interference on global processing primarily occurs when local elements are dissimilar to the global form.

Spatial and temporal aspects of visual backward masking in children and young adolescents.

The development of visual functions is very diverse. Some visual functions mature within the first year of life, whereas maturation for other functions extends into adolescence. The reasons for these developmental differences are largely unknown.

Effects of aging on identifying emotions conveyed by point-light walkers.

The visual system is able to recognize human motion simply from point lights attached to the major joints of an actor. Moreover, it has been shown that younger adults are able to recognize emotions from such dynamic point-light displays. Previous research has suggested that the ability to perceive emotional stimuli changes with age.

Ageing and visual spatiotemporal processing.

Ageing affects many visual functions. Here, we investigated the effects of ageing on vernier acuity and backward masking using the shine-through paradigm. We divided healthy older adults (>60 years) into two groups depending on whether vernier duration was comparable to younger adults (Older Adults 1) or not (Older Adults 2).

Small effects of smoking on visual spatiotemporal processing.

Nicotine is an important stimulant that is involved in modulating many neuronal processes, including those related to vision. Nicotine is also thought to play a key role in schizophrenia: A genetic variation of the cholinergic nicotine receptor gene, alpha-7 subunit (CHRNA7) has been shown to be associated with stronger backward masking deficits in schizophrenic patients. In this study, we tested visual backward masking in healthy smokers and non-smokers to further understand the effects of nicotine on spatiotemporal vision.

Long-lasting visual integration of form, motion, and color as revealed by visual masking.

When two similar visual stimuli are presented in rapid succession at the same location, they fuse. For example, a red and a green disk are perceived as one single yellow disk. Likewise, verniers with opposite offset directions are perceived as one vernier with an almost aligned vernier offset.

How alcohol intake affects visual temporal processing.

Alcohol affects vision. However, the influence of alcohol on visual processing is largely unknown. Here, we investigated the effects of alcohol on visual spatiotemporal processing.