Behind the Scenes of The Brain Show

by Zeev Nitsan

  The right half of the brain is bigger, among both girls and boys, until the end of the second year of life, and it is probably the half that is more dominant in the mental life of infants during the first three years of their life. We can say that infants are mostly “right-brain” creatures. They experience thrills and feelings that are mostly not conceptualized verbally. During the first two years of life, the dialogue between mother and baby takes place primarily as communication between the right half of the mother’s brain and the right half of her baby’s brain. Facial expressions, nonverbal gestures, and the tone of discourse (the melody of words) are main components in this dialogue.

  The age in which a certain mental skill is learned often determines the brain area that will be in charge of encoding this skill. In other words, the same skill learned at different ages will sometimes be encoded in different brain areas. For instance, a language learned in early childhood is encoded in different brain areas from a language learned at a later stage of life.

  Freud spoke about windows of psychological development during childhood, which shape our tendencies throughout life, and it seems that the insight regarding the existence of time windows for development is also valid with respect to the complex soul structures that are formed within us.

  The ethologist (researcher of animals’ behavior) Konrad Lorenz found that newly born goslings ascribe the role of protective mother to the main figure they are exposed to during the time window that ranges from fifteen hours to three days from the moment they are hatched. Such a “maternal imprinting” is a complex mental mechanism that is, of course, not resistant to errors. Lorenz himself became a “mother goose” with respect to newly born goslings that were exposed to his presence within this window of time.[47]

  Studies about children’s dreams show that they follow, in their content, the children’s cognitive and mental development. The reflections in preschool children’s dreams are mostly immobile and flat and lack significant mobility components, and just a small part of them reflects emotions and memories. Extrapolation of these findings has led some researchers to conclude that the sleep of a human embryo is practically free of dreams in their customary sense.

  The importance of the time-restricted window of development was demonstrated in a famous experiment, though one that involves some problematic ethical aspects, in which it was found that the normal function of the sense of sight depends on exposure to visual stimulation within the narrow window of time of early development. A kitten’s eye was sewn shut between the third and eighth week of its life to prevent exposure to visual stimulation. When the stitches were removed and its eye reopened, it was found that this eye was totally blind and that the areas of the visual cortex in the occipital lobe, which would be in charge of processing information from the closed eye, did not develop. Later, these areas took charge of processing visual information from the other eye, together with areas of “normal” visual-processing areas—in the opposite occipital lobe (in accordance with the assumption that real-estate assets in the brain are valuable and there is no such a thing as “deserted property,” and that the brain, as a tough employer, does not allow hidden unemployment within its border). The damage was irreversible; as the kitten grew older it remained blind in one eye for the rest of its life. This experiment demonstrated the insight that was also confirmed in other experiments—that life experiences in critical periods of time shape our brain, and in their absence our brain is shaped irreversibly.

  It seems that different functional systems in the nervous system have their own typical “critical time windows of development.” Thus, for example, in order to create excellent lingual mastery, the process of language learning should take place by the age of eight, approximately. If learning takes place afterward, the lingual range of sounds is assimilated less accurately, and the language is encoded in a different brain system from the one in which mother tongues are encoded.

  A window of opportunity also exists for imprinting a rhythmical preference, as a result of exposure to musical rhythms that are common in the culture in which a person grows up.

  Babies are able to notice a wide range of sounds that is composed of all the sounds that exist in human languages. Once the “window of opportunity” is closed, however, with respect to the development of the cortex that processes auditory information, the range of sounds processed by the brain becomes very limited. A brain map that contains the sounds of the language to which the baby is exposed is formed. The number of key sounds that have priority in terms of brain processing is estimated to be about a thousand. As aforementioned, babies who are exposed to Japanese at the age of six months are capable of noticing the difference between “R” and “L,” but when they become a year old this distinction between the sounds that are not part of the Japanese language will become very difficult for them.

  Our musical taste, which changes throughout the years, reflects, at least to a certain extent, the “brain rhythms” that change in different periods of life. Our brain also has rhythmical seasons; it operates according to different “musical seasons.” Perhaps there is a need for compatibility between the rhythms of our brain and musical rhythms in order to experience maximal emotional enjoyment. Since the brain rhythms change in different brain seasons, in different stages of life, it means that our musical taste also changes according to the musical seasons of the brain.

  Preferences, which are “acquired tastes” (in the sense that they are formed after birth), are embedded within a neural tissue similar to that of innate preferences, which are genetically dictated. Thus, as adults, we are usually unable to distinguish between acquired preferences and innate ones, since their biological nature becomes identical.

  Contribution of the Innate and the Acquired

  When a brain is formed, genes and their delegates, the proteins and hormones, sketch the outline of the basic structural infrastructure, to which the reciprocal relations with the environment are added as a shaping element.

  Innate information and acquired information outline the communication pathways in the brain together. The language of genetic straitjacket and the language of acquired insights are translated into the same language—the language of wiring neurons in the brain. Our brain is used to shape adaptive reactions to reality tests.

  The process of the nullifying of neural junctions in which there is no sufficient activity takes place from the early stages of brain development. We are all born with a brain full of billions of excess neural junctions, which will be reinforced if sufficient activity takes place in them (in the sense of sufficient volume of activity that exceeds the threshold). In case where the activity that takes place in them is not sufficient, however, they will become dismantled and nullified. These junctions of nerves are designed to store neural representations of the world in which we find ourselves. The huge amount of redundant neural junctions (prior to the dilution that takes place in accordance with the activity pattern) has led researchers to claim that they enable representation of almost all possible worlds into which we might be born.

  Infectious Behavioral Disorder

  We can learn how sensitive our brain tissue is to environmental factors from a surprising finding. It was found that a very small minority of children who were affected with a throat infection generated by Streptococcus developed obsessive-compulsive disorder (OCD) over time.

  A structural finding that was found compatible was an increase in volume, at a rate of 25 percent, of a brain structure called the “caudate nucleus.” It seems that the correlation is causative. The structural change in the caudate nucleus, which derived from the Streptococcal infection, induces the behavioral disorder. Although it is a very rare condition, it indicates that the landscape of the brain is also prone to undergoing acquired changes that are induced by environmental factors, such as a tiny bacterium, which reshape our brain and result in behavioral changes.

  The Gut-Brain Axis

  In a broader perspective we can mention the Microbiome—the
community of microorganisms that inhabit the niches of the human body’s’ spaces in health and disease. In this manner, our body is an open ecological system.

  According to a well-known demographic assumption, the amount of the microbial population in our body is estimated to outnumber the amount of human cells by ten times. (A funny remark was based on that old estimate: “You are only ten percent of what you think you are…”.) Newer estimates assume that the number of microbial cells outnumbering the human cells in our body by a much smaller gap.

  We frequently use antibiotics (anti-biotics) that, besides harming the disease –causing microbes, also damage many other microbial cells, including those that work in harmony with our body’s cells, and even in synergism. On the other hand, we use too few probiotics (pro-biotics) that enrich the types of microbes that support and improve our health. We should use the “biotics” substances in a more rational way as “eco-biotics”—medication suited to our body as an ecological environment—therefore balancing its ecology to serve our health.

  The phrase “gut feeling” is apparently an intuitive expression to a deep truth: the dialog between our body’s microbial inhabitants and our emotions. Many substances that are produced by our body’s microbiome are absorbed into the blood. Part of them reach our brain and influence its function as well. This complex dialog is termed “the gut-brain axis.” It seems that this axis is an important influencing factor on our inner cognitive and emotional climate.

  Infancy Memories

  Procedural memory is characterized by being nonexplicit and includes information that, after being encoded and consolidated, does not require conceptualization by means of words or projection onto the screen of consciousness. It operates in an automatic pattern, and there is no need to focus our beam of attention on it.

  This type of memory is used by babies in their infancy. Today it is believed that only at about the age of two is information encoded in a significant manner as explicit memory, in the sense of conscious memory of information. The conscious memory relies mostly on the crutches of language; once a language is acquired, it is used more often. Thus, our experiences from early infancy are encoded as procedural memories and not explicit memories. Some psychiatrists believe that exposing these unconscious memories to the sun of consciousness might ease the suffering of those who suffer from various mental problems.

  Registration of an experience, which includes the time of occurrence, the order of events, and the inner emotional soundtrack that accompanies it (linking self-world), will be remembered consciously only if it is encoded as an episodic memory. In absence of such labeling (along with the physiological sequence typical of encoding such a memory), the event will not be part of the conscious layer, but it might still have an impact on our behavior.

  Oblivion—Amnesia of Infancy

  Information that does not “flow” to our consciousness, since it is not consciously remembered, is not necessarily inaccessible to pathways that impact our behavior. Its implicit impact, though unconscious, might influence our behavior.

  Although there are no explicit memories from the first two years of our life available to our consciousness, there are memories that are immersed in emotions embedded within the limbic system and accompany us for the rest of our life.

  During the first two years of life, the hippocampus and the frontal lobes have yet to undergo the structural and functional maturation that will enable them to perform their role appropriately. It might explain the phenomenon of the amnesia of infancy. Memories we encode during these years will not be remembered as episodic memories that we will be able to recall consciously at a later stage. Knowledge, which is important and highly essential for life, is acquired during these years, but it is not consciously available for retrieval; rather, it is embedded in our brain as habits and skills (implicit and semantic knowledge).

  Thus, it can be assumed that there is no way of reconstructing conscious experiences that are preserved as episodic memory from approximately the first two years of our life in a reliable manner.

  During early childhood, the hippocampus and the frontal lobes are still immature in the structural and functional sense; thus, both the memory-encoding aspect and the memory-retrieval aspect, in their mature version, are still immature as well. At this age, along with the retrieval difficulty there is also difficulty in creating replicable, reality-compatible memory due to the immaturity of the hippocampus (which is a key component in encoding the impressions of the senses as memories).

  The immaturity of the structures that are essential to the formation, preserving, and retrieval of episodic memory causes the difficulty in preserving the recordings of events of a personal nature during these years.

  When a memory of an episodic nature in someone younger than two years old arises, it is best to refer to it as a memory that was created by means of reconstructing sources of information rather than as a direct episodic memory. It is more likely that it derives from “backward construction” of the components of memory and does not represent a real-time experience from that period.

  Episodic “infancy memories” are often a collage of impressions created at a later age out of family documentation, inferences made at a later time, and stories of family members. Sometimes they include a hint of the “sin of backward bias.”

  Memories from this period are likely to have been created by means of inferences originating in implicit and semantic unconscious memories, or by means of a quilt that was made after listening to parents’ stories, reviewing picture albums, reading memoirs, etc.

  The cluster of memes and insights that are encoded into patterns that conceptualize the environment during infancy serve as primary mental scaffolding for our perceptual building of the world. Later on, when the tower of insights is already higher or even reconstructed, those primary mental scaffoldings are no longer useful, and so they fade away—thus the assumption that in absence of activity in the neural cycles, which store our infancy insights, they vanish and become nullified. On the other hand, according to an assumption that won great support, these memories remain concealed in the brain but are not available to our consciousness. It may be that the networks between the neurons that were preserved from our first years of life constitute the core of the nerves’ networks, which become more expanded and rich in junctions as we grow up.

  The Brain During Childhood

  Brain-Sculpting Period

  During the first years of life, most of the networking cycles in the brain are created in conflicting patterns of connection and disconnection. Along with the process of brain cells grouping into a common cycle of activity, a conflicting process takes place at the same time and sets a threshold of activity as a condition for survival. The synapses in which “traffic load” does not cross the threshold are doomed to gradual fading until they are totally nullified.

  From birth until about the age of three, the number of links (synapses) between neurons multiplies (a process called “synaptogenesis”) by approximately twenty, so from the age of two or three an expanded process of pruning is formed (called “synaptic pruning”). This process thins out the density of the “synaptic forest.” The rate of thinning out is usually estimated at half the number of synapses—thus the number of synapses in different brain areas in the brain of a young adult is estimated as half the number in the brain of a three-year-old child.[48]

  Communication junctions (synapses) between the neurons that are selected for networking survive, whereas those that were not selected perish. Thus the number of connections between neurons decreases, but the richness and complexity of our brain cycles increases. The considerable decrease in the number of synapses is formed based on the meritocracy approach (a term taken from social studies and that refers to a society ruled by a select group of the most-talented people). Only the synapses of the neural networks that encode useful, high-quality information survive.

  Quite a large number of brain researchers believe that the large-scaled pruning that ta
kes place during the first years of life is, in fact, economical. They believe that the excessive growth of neural networks followed by a controlled pruning process of networks that do not encode information that is substantial to our life is a “cheaper” process, energy-wise, and less time-consuming compared to a process of forming accurate neural networking in the first place.

  Childhood is the main period in life in which the saga of eradicating low-activity neural networking junctions takes place. The principles of “whatever is not used is lost” and, on the other hand, “connections that are frequently activated are preserved” exist throughout our life. Paradoxically, the oxymoron “destruction is creation” is valid in this case. The pruning of redundant elements enables brain networking, which encodes complex meanings and insights, similar to creating a sculpture from a raw chunk of stone.

  The “Sally–Anne test” is a test in which a sequence of pictures that describe the behavior of two girls, Sally and Anne, is presented. In the first picture, Sally puts her doll in the pram. In the second picture, Sally leaves the room and, after Sally is gone, Anne takes the doll from the pram and puts it in a box. Soon afterward Sally comes back. The children are asked to interpret the sequence of pictures by answering three questions: Where is the doll? Where did Sally put the doll? Where will Sally look for the doll? The age range at which most “small people” manage to predict Sally’s thought correctly is three to four years. At the age of three, most children still err and say that Sally will look for the doll in the box. It is difficult for them to put themselves in Sally’s mental position and answer according to the knowledge they have about the doll’s location. At the age of four, most children give the correct answer: Sally will look for the doll in the pram because this is where she left it before she left the room. This answer reflects their capacity to identify mentally with Sally’s thoughts. This is, in fact, a test that examines the skill of “understanding the soul of the other.” Success in the Sally–Anne test and the ability to understand the other’s soul derive mostly from the operation of the frontal cortex.[49]