What is Hyperphantasia?
Hyperphantasia is the condition of having extremely vivid mental imagery. It is the opposite condition to aphantasia, where mental visual imagery is not present. The experience of hyperphantasia is more common than aphantasia, and has been described as “as vivid as real seeing”.
What does akinetopsia mean?
Akinetopsia refers to “motion blindness”, which is a higher visual processing disorder from an extra-striate lesion, in which a patient has difficulty specifically perceiving objects in motion with variable severity and rarely complete. This is a very rare condition with only a few reported cases in the literature.
What does akinetopsia look like?
Patients with akinetopsia say that smooth movements of objects appear as a discontinuous freeze frame image [2]. Therefore, patients have difficulty, for example, in pouring tea into a cup because the fluid appears to be frozen, like a glacier [3].
Can oscillopsia go away?
Some conditions, like multiple sclerosis, are treatable. In other cases, oscillopsia is permanent.
How do you test for oscillopsia?
Oscillopsia can be quantified objectively by functional vestibular tests, and subjectively by questionnaires. Recently, a new technique for testing functionally effective gaze stabilization was developed: the functional Head Impulse Test (fHIT).
What is the waterfall illusion?
Waterfall illusion, or motion aftereffect, is an illusion of movement. It is experienced after watching a stimulus moving in one direction for some time, and then looking at a stationary scene. The stationary scene appears to have movement (in the opposite direction to the moving stimulus that one previously watched).
What is Riddoch phenomenon?
Statokinetic dissociation (SKD), which is often called Riddoch phenomenon or Riddoch syndrome, is the ability to perceive visual motion consciously in a blind visual field [1] and has been observed in individuals with lesions in the anterior visual pathways [2] or the oc- cipital lobe [3].
What causes Simultagnosia?
Causes. Simultanagnosia results from bilateral lesions to the junction between the parietal and occipital lobes. These lesions could result from a stroke or traumatic brain injury. It is also possible for simultanagnosic symptoms to develop from degenerative disorders.
What is aperture problem?
The aperture problem refers to the fact that the motion of a one-dimensional spatial structure, such as a bar or edge, cannot be determined unambiguously if it is viewed through a small aperture such that the ends of the stimulus are not visible.
Is Akinetopsia real?
Akinetopsia (Greek: a for “without”, kine for “to move” and opsia for “seeing”), also known as cerebral akinetopsia or motion blindness, is an extremely rare neuropsychological disorder, having only been documented in a handful of medical cases, in which a patient cannot perceive motion in their visual field, despite …
What is motion aftereffect illusion?
The motion aftereffect is a powerful illusion of motion in the visual image caused by prior exposure to motion in the opposite direction. For example, when one looks at the rocks beside a waterfall they may appear to drift upwards after one has viewed the flowing water for a short period-perhaps 60 seconds.
What is a Reichardt detector?
Reichardt Detectors are hypothetical neural circuits postuated for how the brain can track motion. In a Reichard detector, a cell in the brain receives input from two receptors in the eye, call them A and B. The input from A is delayed.
How does the brain solve the aperture problem?
How does the brain solve this problem? We solve the aperture problem through parallel processing- perceiving everything at once and convergence which leads to larger receptive fields and more complex tuning.
How do I fix an aperture problem?
How do humans detect motion?
The eye is by far the most effective organ for sensing movement. Some animals are especially sensitive to visual stimuli that move in specific ways. … Features of human visual experience also suggest that movement detectors exist in the human brain.
Are Reichardt detectors direction sensitive?
Figure 6.12 shows a neural circuitry model, called a Reichardt detector, which responds to directional motion in the human vision system. It is also sensitive to a particular direction of motion based on the relative locations of the receptive fields of the input neurons. …
How do feature detectors work?
Feature detection is a process by which the nervous system sorts or filters complex natural stimuli in order to extract behaviorally relevant cues that have a high probability of being associated with important objects or organisms in their environment, as opposed to irrelevant background or noise.