Modern concept of cortical fields
Modern concepts of cerebral cortex activity are based on the principle of multifunctionality of cortical fields. Science has finally abandoned the outdated idea of functional equipotentiality (equivalence and complete interchangeability of cortical areas).
It has been proven that the right and left hemispheres are not equivalent in their physiological significance and contribution to mental activity. This fundamental property of the nervous system determines the division of labor between parts of the brain.
Classification of interhemispheric asymmetry
The division of functions between the left and right halves of the cortex manifests at several levels. Traditionally, three main types of interhemispheric asymmetry are distinguished:
- Sensory asymmetry — the unequal perception of information from sense organs by different hemispheres.
- Motor asymmetry — the difference in providing motor activity (e.g., dominant hand).
- Mental asymmetry — the specialization of the hemispheres in various forms of thinking and emotional response.
Characteristics of the left hemisphere
In the vast majority of people, the left hemisphere is dominant. It takes on key analytical and management tasks.
Main functions:
- Provision and comprehension of speech.
- Control of motor actions of the right hand.
- Execution of verbal and strictly logical thinking.
Psychological profile of the left-hemisphere type: Such individuals gravitate toward theory and possess an extensive vocabulary. They are characterized by pronounced goal-directedness, high motor activity, and an excellent ability to forecast — the ability to anticipate the development of events.
Characteristics of the right hemisphere
Unlike the logical left hemisphere, the right hemisphere specializes in holistic and imaginative perception of the world.
Main functions:
- Perception of object shapes and spatial relationships.
- Active participation in intuitive thinking processes.
Psychological profile of the right-hemisphere type: The activity of this hemisphere is brightly manifested in specific (practical or creative) types of activities. Such people are distinguished by their ability to subtly sense the surrounding environment and deeply experience emotions.
Systemic organization of brain activity
Despite the clear division of functions, the brain works as a single whole. Both hemispheres continuously cooperate with each other. This integration is necessary to achieve useful adaptive results and an adequate body response to environmental changes.
Functional differences between the halves of the brain persist throughout life, while the dominance of one of the hemispheres ultimately determines the basic psychological properties of a person's personality.
Briefly: answers to topical questions
Which anatomical structures provide morphological connection and information exchange between the hemispheres?
Morphological connection between the hemispheres is provided by commissural fibers (neurofibrae commissurales), which connect their symmetrical areas. These structures include:
- Corpus callosum (corpus callosum) — the largest commissure of the telencephalon.
- Anterior commissure (commissura anterior) — connects symmetrical areas of the hemispheres.
- Commissure of fornix (commissura fornicis) — also belongs to commissural fibers.
Where are Broca's and Wernicke's cortical speech centers localized?
Cortical speech centers are located in specific zones of the dominant (usually left) hemisphere.
- Broca's area — localized in the posterior part (lower third) of the inferior frontal gyrus.
- Wernicke's area — located in the posterior parts of the first (superior) temporal gyrus.
What is the role of the right hemisphere in speech activity?
The right hemisphere participates in speech activity at the stage of motor realization of an utterance. Impulses from Broca's area go to the facial areas of the motor cortex of both the left and right hemispheres. In the precentral gyrus of the right hemisphere, along with the left, detailed programs are created for the motor centers of the cranial nerves, which is necessary for the innervation of speech muscles and proper articulation.
L-L: Left — Logic. R-S: Right — Space.
Class and exam questions
What is the core rationale behind abandoning the concept of functional equipotentiality?
This signifies the recognition that cortical fields are not absolutely identical and interchangeable. The modern concept is based on their multifunctionality and specificity.
Which hemisphere is responsible for event forecasting?
The ability to anticipate events (forecasting) is part of the psychological profile of an individual with a dominant left hemisphere.
How do the hemispheres interact with each other?
They actively cooperate to achieve useful adaptive results while maintaining their functional differences.
What else to study on this topic
- Mechanisms of sensory asymmetry formation
- Manifestations of motor asymmetry in everyday activity
- Features of mental asymmetry
- The role of the right hemisphere in intuitive thinking
- Hemispheric cooperation in organism adaptation
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