Core Postulates of the Immunological Hypothesis
According to this theory, the capacity of the nervous system to encode and recall experience shares a deep similarity with how the body recognizes foreign agents (antigens) upon secondary exposure. This process is grounded in genetic predetermination.
The cell surface membrane of immunocompetent cells (lymphocytes) is genetically equipped from the outset with a comprehensive repertoire of diverse antibodies. These structural molecules act as specialized receptors awaiting encounters with matching antigens. An important foundational concept here is clonality: all lymphocytic cells possessing completely identical protein receptors are grouped into a single specific clone.
Dynamics of the Response: From Primary Encounter to Memory Cells
The interaction of the organism with a novel stimulus triggers a cascade of strictly defined reactions.
- Primary response. Initial exposure to an antigen induces active proliferation—a rapid increase in the number of corresponding lymphocytes. At this point, the clone is fully established and differentiates into two functionally distinct cell populations:
- Effector cells — their lifespan is strictly limited to only a few days.
- Memory cells — remain circulating in the organism throughout its entire lifespan.
- Secondary response. Upon re-exposure to the same antigen, the process proceeds differently. The surviving memory cells possess the unique ability to rapidly differentiate into newly formed cells of both types, providing a swift and efficient response.
Application of Immunological Principles to the Nervous System
Applying these immunological principles directly to the nervous system helps explain the neurophysiological consolidation of memory traces.
It is hypothesized that during learning and memory formation, there is enhanced synthesis of specific protein antigens. These molecules are targetedly secreted into the perisynaptic space of neurons. Their presence and accumulation in this critical zone act as the trigger for processes completely analogous to those occurring during an immune response, ensuring the reliable long-term storage of information in the brain.
Ashmarin's Immunochemical Hypothesis of Memory
Special attention is given to the immunochemical hypothesis proposed by I. P. Ashmarin. It details cellular mechanisms by focusing on the close interaction of neurons not merely with each other, but with clones of astrocytic glial cells.
The mechanism of memory trace development includes the following stages:
- Primary induction of astrocyte proliferation occurs, followed by their synthesis of specific antibodies.
- These newly synthesized antibodies specifically interact with the postsynaptic membranes of the exact neurons involved in the functional response.
- As a result of this protein binding, synaptic transmission in the corresponding synapses is markedly facilitated.
Just as with lymphocytes in the immune system, an astrocyte clone formed in this manner retains its structure and persists in neural tissue throughout the individual's life, serving as the physical substrate for long-term memory.