K. Lashley's theory of equipotentiality
The holographic hypothesis grew out of classical experiments by the American neuropsychologist K. Lashley. He trained laboratory rats in instrumental defensive tasks and then surgically removed various areas of their cerebral cortex.
The main result of these experiments upended views on memory localization: it turned out that the severity of memory impairments depended solely on the volume of damaged brain tissue, rather than on which specific zone was destroyed. Based on this, Lashley formulated the principle of equipotentiality. According to it, different areas of the cortex are completely equivalent in terms of storing engrams (memory traces).
Essence of K. Pribram's hypothesis
Building on Lashley's data, K. Pribram proposed a concept explaining the mechanism of such distributed storage. It is based on an analogy with an optical hologram, where any fragment contains the image of the entire object.
Images of past events are restored in consciousness when coherent (i.e., mutually coordinated) external or internal influences activate their representations in various brain structures. These representations are organized not as single storage cells, but as cellular ensembles with distributed information.
Following the initial recognition of a familiar object, all additional information about it is instantly reproduced because the entire ensemble is activated.
Formation mechanisms and operating levels
Cellular ensembles function by generating slow potentials (postsynaptic and dendritic). Within the physical analogy, these ensembles play the role of peculiar optical wave filters or screens.
The interaction of information with such "filters" occurs on multiple levels:
- Peripheral receptors — the initial stage of signal reception.
- Subcortical structures — intermediate processing.
- Cerebral cortex — the highest level (its columnar organization plays a special role).
At each of these levels, correlational interaction of external stimuli with configurations of internal excitations takes place. The incoming information is instantly distributed across all neural levels. At the molecular level, protein molecules participate in the organization of the holographic engram, with resonant frequencies coherent to the stimuli that trigger the memory.
Connection with the theory of functional systems
The holographic principle organically complements the theory of functional systems. Memory does not exist in isolation — it is inherent to every individual element of the dominant functional system. At the same time, each element in the process of its activity reflects the current state of the entire system.
Of particular importance is the dominant motivation, which acts as the leading component. The mechanism of excitation propagation looks like this:
- The pacemaker zone, which initiates the process, is located in the hypothalamus.
- Through ascending activating pathways, motivational excitations widely "spread" across multiple brain structures.
- Convergence occurs: excitations from conditioned and reinforcing stimuli simultaneously arrive at neurons united by the dominant motivation, forming a unified holographic pattern.
Imagine a broken holographic plate: even in the smallest fragment, the entire image is visible. Similarly, in the brain, the memory engram is "smeared" across the cellular ensembles of the cortex, which is why the volume of tissue matters, not a specific point.
Class and exam questions
What is the principle of equipotentiality?
That different areas of the cerebral cortex are equivalent in their ability to store memory traces (engrams). Memory loss during trauma depends on the volume of removed tissue, not on the localization of the lesion.
Which brain structure acts as a pacemaker during memory retrieval?
The pacemaker zone is located in the hypothalamus. From there, ascending activating influences spread motivational excitations to other brain structures.
What is the molecular basis of the holographic engram?
Specific protein molecules participate in the formation of the memory trace. Their resonant frequencies are coherent (coordinated) with the stimuli that reproduce the memory.
What else to study on this topic
- The role of slow postsynaptic and dendritic potentials in the generation of cellular ensembles
- Columnar organization of the cerebral cortex as the structural basis of holographic memory
- Mechanisms of convergence of conditioned and reinforcing stimuli on neurons
- Interaction of peripheral receptors and subcortical structures during information filtering
- Architecture of dominant motivation in the theory of functional systems
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