Behind the Scenes of The Brain Show

by Zeev Nitsan

  Aspects of the Structural and Operational Infrastructure of Memory

  Our memory is like a loom that weaves threads connecting the representations of perception impressions of the various senses. The connecting networks are scattered, and their winding paths create integration of inputs derived from single senses, such as the visual and audio input.

  Memory can be defined as a mental state anchored in a biochemical bedding.

  The patterns of neural activity are at the basis of mental conceptualization.

  Each material or abstract concept we think about is represented in a unique neural activity pattern, which virtually resurrects it.

  Our short-term memory is created by means of repetitive cycles—groups of neurons that are mutually linked and operated together in a circular continuum of bioelectrical signals; one signal activates the other, and vice versa, in a loop-like pattern.

  The preservation of the mutual activity pattern forms the active recollection—retaining information in momentary consciousness.

  The intensity of the repetitive resonance decreases as time goes by unless the pattern of resonance is preserved and reinforced.

  Once a certain loop-like cycle, which is a three-dimensional networking pattern between neurons, has been created, its destiny, and, as a result, the destiny of the information it contains, is determined according to the intensity and duration of its activity. If it crosses the crucial threshold, its chances of becoming a LTM will greatly increase. In such a scenario, the pattern of loop-like activity intensifies itself from time to time by increasing the linkage between the neurons at its basis. The increase of linkage is formed according to the rule that is known as the Hebb Rule, named after physiologist Donald Hebb, who explained the intensification of the connection between neurons through repetitive resonance. As early as 1888, Freud came up with the supposition of reinforcement of the connection between two neurons when the neural potential (the bioelectrical signal) is projected at the same time. He defined the phenomenon as the “rule of connection that derives from simultaneous timing.” Later on, Hebb developed and elaborated the supposition, which was later named after him, and characterized it as the profound pattern of neural learning.

  The repetitive resonance—the pattern of repetitive sequences of bioelectrical currents that are at the basis of initial memory (working memory)—is not a passive code that is available for the conscious mind from time to time but, rather, an active code that constantly changes and is involved in constant dialogue.

  Our working memory is also a “resonant memory,” since it is based on preserving information by means of resonance. In fact, the resonance loop is the basic mechanism of our working memory.

  The destiny of most perception impressions that exist as resonant loops at the representation stage can be compared to a candle in the wind. Most of them are extinguished and fade away before they have a chance to become permanent lights.

  The physiological infrastructure at the basis of the short-term memory is not completely clear, but it is known that its nature is different from the nature of the infrastructure at the basis of the LTM.

  “Anagram” is the term describing the change in the structure of junctions between neurons, which makes the links between them—the structural-biological layer of our memory—durable. This change grants our memory the ability to be preserved for the long term. The anagram can also be defined as inscribing information in neurons, the pattern of material footprints of memory.

  Before our memory codes are encoded in the solid slate of the anagram, they exist in a highly fragile state, in which they “echo.” The echoing is done through a repetitive, lasting activation of the same neural paths that preserve them in a repetitive activation pattern of a “loop.” Most “resonant loops” tend to fade away before they manage to cross the river of memory and reach the bank on which the anagram is created. This stage is susceptible to fading unless it is preserved above a certain critical threshold or the information preserved is presented repetitively on the screens of “present consciousness” of our working memory. The moment of formation of a structural memory footprint, which is the moment of anagram creation, constitutes the point at which our echoing memories have reached the safe shore of LTM.

  When our perception impressions are young and only echo, the weight of the structural changes is light. The moment of encoding involves changes in the structure of connecting junctions between neurons, and the latter become more sensitive and accessible to the transition of bioelectrical action potentials. This is the moment when the status of our memory changes, and it goes up the ladder toward the layer of LTM.

  The result of the structural changes that intensify the connection between the neurons is the transformation of a short-term memory into LTM. It seems that this process is composed of two stages; at the first stage, the changes are only related to function. Such changes involve, inter alia, changing the tendency of certain openings on the surface of the neuron’s membrane. These openings, which are called “ions channels,” enable the entrance of molecules with electrical charge.

  This change is followed by the second process, a more sustainable one, which is the change at the structural level—change in the physical connection patterns, which actually means changes in the wiring between neurons.

  The lasting mutual activity of neurons that are interconnected leads to changes in wiring, which means changes in the structure of the connection pattern between neurons by means of creating new neural communication junctions (synapses). These junctions are added to more senior junctions that inducted their creation. The LTM is created by means of activation of genes in the nucleus of the neurons that are encoded into “connection strengthening” proteins. These proteins improve the transmission of signals in the existing synapses and, in addition, induct the creation of new synapses (a process called “synaptogenesis”). These proteins lead to prosperity of the neurons that are part of the information encoding network and upgrade the wiring between them, which results in expanding the “bandwidth” of the communication pathway between them and improving its durability.

  At certain nerve junctions, genetic mechanisms are activated within the cells and encourage the growth of additional junctions between the involved neurons. Now the cells connect at more durable nerve junctions, which are more suitable for a lasting signals’ transmission with fewer disruptions.

  Eric Kandel won the Noble Prize in Medicine in 2000 for this discovery when he exposed the fact that repetitive cycles and resonant loops between neurons that constantly echo have a trophic and permanent induction on the cells that compose them.[25] This effect leads to the creation of a thicker cerebral tissue, and it depends on activity and lasts throughout life.

  Memory registration on the whole is reflected at the material level, as a bulb of ultra-thin threads (axons) that are interrelated and create a sort of “three-dimensional cloud” composed by neurons whose connection pattern is the infrastructure of the structure of specific memory.

  In order to transform short-term memory into LTM, sleeping genes must be awakened.

  Deepening the footprints of memory is accomplished by diving from the surface of echoing waves into the depths of the cell—into the DNA. The DNA encodes reinforcement proteins to the nerve junction, such as the protein called CREB.

  CREB is the name of a protein that has a central role in reinforcing the inter-synaptic connections between neurons and thus contributes to the transformation of a temporary connection (short-term memory) into permanent connection (long-term memory). CREB is like a wedding ring that changes the status of a relationship from temporary to permanent.

  Flies that were inducted, by means of genetic engineering, with intensive production of CREB became “superflies” that demonstrated superiority with regard to performing learned tasks in comparison with nonengineered flies.

  The process of learning new information is manifested in the design of specific communication pathways in the neural network in the
brain. Certain communication pathways enjoy reinforcement, and electrical signals pass through them more easily compared to communication pathways that were not prioritized by means of reinforcing the connection between their components. The reinforced pathway constitutes a structural representation that is in correlation with the information it represents. Studies show that not only the intensity of the electrical message is reinforced in pathways that became prioritized through a learning process, but more complex processes that create a correlation between the frequency of the transferred stimulus and the intensity of the reaction also take place. This process shares similarities with the mode of fine-tuning of a radio station to a unique frequency of electromagnetic waves. This mechanism allows for “selective reception”: the addressee neuron receives only the messages it is tuned to and deletes the “noise” (the components of information it is not tuned to absorb) from its worldview.

  The positive effect of constant learning and memorizing lasts throughout all seasons of our life.

  The secret of lasting memorizing lies in the fact that it lengthens the candle thread and improves the chances of the flame of information to become a permanent part of LTM.

  The action of conversing information with short life expectancy (the working memory that exists at the prefrontal cortex) into information encoded for the long- term, mediated by the hippocampus, is the core of the learning process.

  The hippocampus, which means seahorse in Greek, because it resembles the shape of a seahorse, is a magnificent conversion station that constitutes the gate to the kingdom of LTM.

  It seems that the hippocampus is a type of dynamic supermap that contains the locations of brain sites in which different aspects of experience impressions are kept and, during recollection, upon recollection, create the memory of the entire experience.

  Legendary Memory

  Information that captivates the heart of our attention beam will be carried in the carriage of the senses to the brain palace; will enjoy a short, jiggly dance with the short-term memory; and, if the short-term memory approves, will win the right to proceed toward the LTM boulevard. There, its recording will be imprinted in the boulevard of anagrams in the brain, as the palms of Hollywood superstars are imprinted at the Walk of Fame.

  Four-Dimensional Preservation

  It seems that our memory is also characterized by a unique shooting pattern (a bioelectrical signal that has typical shape and duration) that is formed at the three-dimensional networking that encodes them. In this sense, one may claim that memories are encoded in four dimensions: in the three spatial planes and in the plane of time (in this sense, the term “chrono-architecture” fits in).

  Memory is, to some extent, a web of addresses that helps retrieve the various memory components spread throughout various graded scales (strips of continuity). For instance, a memory of a trip to the South Pole might include the following data: the measure of fatigue on the first day was seven, the level of internal arousal was eleven, satisfaction from food was five, and so on. The main emotional imprint of the trip will be a changing mix of the various measures. Different components of the experience are mixed and merged into a composition of the overall experience and the emotional imprint it leaves behind. Thus, the unique impression of the experience is preserved.

  Strips of continuity that are hidden in the links between cells in a three-dimensional pattern constitute the structural infrastructure that encodes the recording of experience, and the links encode “a continuum of intensities” for the different aspects of the experience.

  Whenever we invoke a certain memory and the recollection process takes place, we reunite the components of the experience that were scattered to various brain areas.

  Recollection is formed from a continuum of links between the various measures of an experience. For example, the concept “cold” in the archive of a person who is fond of journeys might invoke this continuum of impressions in his brain: the most intense cold—while climbing the Everest, medium cold—during the trip to South America, heat wave—on the trip to the Sahara, etc.

  Studies have shown that the process of preserving an LTM is an ongoing process that requires constant maintenance; it’s not a one-time process. It seems that there is a sort of molecular engine that preserves the change in the neural activation pattern caused by learning at the nerve tracks. The disruption in the operation of that molecular engine, copies of which exist in all of the neurons, disrupts the preservation of memory.

  The Lego Blocks of the Memory Palaces

  Prevalent memory components become modular; they are constructed with a type of universal building blocks, that can be used for creating memories from new experiences.

  This economical pattern omits the need for encoding a huge amount of perception impressions that share similar characteristics individually.

  The stages of memory consolidation, preservation, and maintenance are characterized by unique and typical electric activity at the junctions of the neurons that share the “secret” of the specific memory.

  At the stage of memory retrieval/remembering, structures that are mostly located at the thalamus and the ventral frontal lobe put the coded perception impressions into patterns so that they become more coherent and make more sense. This is how a memory that matches the picture of perceived reality and fits the directionality requirements of the arrow of time (from past to present and from present to future) is reborn.

  While we are sleeping at night, the memory impressions that appear in our dreams do not pass the stage of being put into logical patterns that is typical of wakefulness, and it seems that this can explain the surreal nature of dreams.

  Brain Areas—The Land of Memory

  It seems that archives of mental maps that enable us to recruit different brain areas to the task of assembling memory (the process of recollecting) are located mainly at the cerebellum, at structures of the central core of the brain called the basal ganglia and at the hippocampus. These areas contain supermaps that contain, in a nesting manner, the maps of memory-details preservation sites.

  The hippocampus has a central role in turning experience recording into personal, long-term memories.

  The “hippocampus spider” weaves a three-dimensional spider’s web between concrete entities representations, and it seems that it has the role of the “great integrator.”

  A major supermap that is located at the hippocampus enables it to compose the holy grail of memory out of the various pieces of information.

  The hippocampus interweaves the pieces of information, composing memory as a whole as beads that make an “anagram necklace.” The hippocampus is in charge of coordinating the time and place between the various brain areas that store memory components. The manner in which such a magnificent coordination is performed is still not sufficiently clear to brain researchers.

  The creation of personal memory of experience, which stores the details of our personal autobiography (also referred to as “episodic memory”), mostly relies on the hippocampus and the structures of the temporal lobes. The creation of procedural memory (memory of “how to perform”—for example, how to brush one’s teeth) mostly relies on the basal ganglia at the central core of the brain and the cerebellum. In various types of brain injury, the procedural memory shows better survivability compared to the episodic memory.

  The meta-memory is the information we have regarding our overall memory capacity—the knowledge about the knowledge. People who have suffered an injury at the frontal lobes have difficulties in evaluating which knowledge is stored in their memory and which is absent. It is thus likely that the capabilities of the meta-memory derive from the activity of the frontal lobes.

  The Address of Our Memories

  “The future memory” is a term that refers to our ability to see future scenarios in our mind’s eye, and it mainly relies on extrapolation of existing information that is stored in our memory.

  This ability is formed through the activity of the temporal lobes.
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  The amygdala is in charge of the emotional aspect of memories. The memory of beliefs and habits is centered at the cerebrum cortex and the basal ganglia. The nondeclarative, procedural memory of the sequence of actions required for performing a task is probably located mainly at the cerebellum and the basal ganglia.

  The G-Spot of Memory

  Each memory has its own G-spot—a point in time in which it is “at its peak.”

  After a certain amount of time from the time of encoding, the memory fades away as a result of aging and lack of reviving. There is a time peak on the timeline in which the memory is at its best. Afterward, it might gradually fade away when not used.

  Studies have shown that there are glucocorticoids (hormones in charge of the metabolism of carbohydrates, proteins and fats, such as cortisol, which takes part in regulating the level of glucose) receptors at the hippocampus. These receptors are activated whenever there is a high concentration of stress hormones, like cortisol, at times of distress. This finding might provide an additional supporting explanation for the claim that mild arousal improves memory function, while intense stress disrupts such functions. This pattern of effect can be graphically represented as an inverted U-curve (this principal is called the Yerkes-Dodson law after researchers Robert M. Yerkes and John D. Dodson, who presented it in 1908). It is assumed that, at times of distress, the higher levels of cortisol decrease the efficiency of the hippocampus’ activity and, at the same time, increases the amygdala’s activity.