Related Experiment Video
Updated: Aug 2, 2026
10:27
Training Synesthetic Letter-color Associations by Reading in Color
Published on: February 20, 2014
Visual imagery and visual semantics in the cerebral hemispheres in schizophrenia
1King's College Hospital, London, UK.
Schizophrenia Research
|January 1, 1993
Summary
Patients with schizophrenia and affective disorder showed a right hemisphere advantage for visual imagery tasks but lacked the expected left hemisphere advantage for semantic tasks, suggesting potential hemispheric imbalances contributing to visual hallucinations.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Psychiatry
Background:
- Hemispheric specialization influences visual processing.
- Patients with schizophrenia and affective disorder exhibit distinct cognitive profiles.
- Visual hallucinations in schizophrenia may relate to hemispheric processing deficits.
Purpose of the Study:
- To investigate hemisphere differences in visual processing for patients with schizophrenia and affective disorder compared to normal subjects.
- To examine visual-semantic and visual-imagery task performance across hemispheres.
- To explore the relationship between hemispheric function and visual hallucinations.
Main Methods:
- Divided visual field tasks were administered to assess hemispheric processing.
- Two conditions were used: a visual-semantic task (living/non-living judgment) and a visual-imagery task (size comparison).
- Reaction times were measured for all participants.
Main Results:
- Both patient groups exhibited a right hemisphere advantage on the visual-imagery task.
- Schizophrenic patients' right hemispheres maintained normal size-comparison-RT relationships, indicating intact visual imagery.
- Patients failed to demonstrate the expected left hemisphere advantage on the visual-semantic task.
Conclusions:
- Visual imagery mechanisms appear intact in schizophrenia, with a right hemisphere advantage observed.
- A deficit in left hemisphere semantic processing may contribute to visual hallucinations in schizophrenia.
- Hemispheric imbalance could play a role in the pathophysiology of visual hallucinations.
Related Concept Videos
01:24Vision
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
01:05Cerebral Hemispheres
The human brain, a complex organ, is functionally divided into two cerebral hemispheres—left and right. These hemispheres are interconnected by a structure of paramount importance, the corpus callosum. This substantial bundle of neural fibers is not just a bridge between the hemispheres but a crucial element for the brain's comprehensive functioning. It enables efficient communication between the two hemispheres, allowing each side of the brain to control and receive sensory and motor...
01:28Lateralization
Brain lateralization refers to the division of mental processes and functions between the two hemispheres of the brain, a phenomenon that optimizes neural efficiency and underpins complex abilities in humans. This specialization allows each hemisphere to perform tasks where it has a comparative advantage, facilitating more refined cognitive capabilities across different domains.
01:26Visual System
Light enters the eye through the cornea, a transparent, dome-shaped surface covering the surface of the eyeball that helps to direct and focus incoming light. This light is then channeled toward the pupil, an adjustable opening whose size is controlled by the iris. The iris, a pigmented muscle, regulates the amount of light entering the eye by contracting or dilating the pupil, thereby ensuring optimal light levels for clear vision.
Once through the pupil, the light passes through the lens, a...
Once through the pupil, the light passes through the lens, a...
01:12Visual Agnosia
Visual agnosia is a condition characterized by the inability to recognize visually presented objects despite having normal vision. For instance, a person with visual agnosia can describe the shape and color of an object but cannot identify or name it. This impairment does not affect their visual field, acuity, color vision, brightness discrimination, language, or memory. An example of this condition in a social setting is someone at a dinner party asking for "that silver thing with a round end"...
01:30Positive Symptoms of Schizophrenia: Hallucinations and Delusions
Schizophrenia is a complex mental health disorder that can manifest with various positive symptoms, including thought, movement, and behavior disorders. These symptoms significantly disrupt cognitive and motor functions, leading to profound effects on an individual's ability to engage with the world.
Thought Disorders
Disorganized and unusual thought processes mark thought disorders in schizophrenia. One key feature is disorganized speech, where an individual's conversation includes loosely...
Thought Disorders
Disorganized and unusual thought processes mark thought disorders in schizophrenia. One key feature is disorganized speech, where an individual's conversation includes loosely...