Association between Experiences and Representations: Memory, Dreaming, Dementia and Consciousness
aa r X i v : . [ q - b i o . O T ] J un Association between Experiences andRepresentations: Memory, Dreaming,Dementia and Consciousness
Xiaoqiu HuangDepartment of Computer Science and Plant Sciences InstituteIowa State UniversityAmes, Iowa 50011, USA
Running Title: Memory, Dreaming, Dementia and ConsciousnessCorresponding Author:E-mail [email protected] (515) 294-2432Fax (515) 294-0258Key Words: Memory formation, Sleep 1 bstract
The mechanisms underlying major aspects of the human brain remain amystery. It is unknown how verbal episodic memory is formed and integratedwith sensory episodic memory. There is no consensus on the function andnature of dreaming. Here we present a theory for governing neural activity inthe human brain. The theory describes the mechanisms for building memorytraces for entities and explains how verbal memory is integrated with sensorymemory. We infer that a core function of dreaming is to move charged particlessuch as calcium ions from the hippocampus to association areas to primaryareas. We link a high level of calcium ions concentrations to Alzheimer’s disease.We present a more precise definition of consciousness. Our results are a stepforward in understanding the function and health of the human brain andprovide the public with ways to keep a healthy brain. ntroduction The human brain is fascinating but elusive. The mechanisms underlying major as-pects of the brain remain a mystery. It is unknown how verbal episodic memory isformed and integrated with sensory episodic memory. There is no consensus on thefunction and nature of dreaming. There is no precise definition of consciousness. Howdoes behavior affect brain health? Here we address these questions.The cognitive neuroscience of memory is in need of transformation (Nadel et al.2012). Memory is attributed to changes in neural synapses by synaptic plasticity(Martin and Morris 2002). It is unclear how these changes in different brain areasare coordinated. Another question of interest concerns the mechanisms for buildinga representation of a facial image of a person in the brain. Existing episodic memorytheories are concerned only with sensory episodic memory (Squire 1992; Nadel andMoscovitch 1997; Eichenbaum and Cohen 2001; Bussey and Saksida 2007; Teyler andRudy 2007; Cowell et al. 2010; Nadel et al. 2012); no issues are addressed concerningthe existence and formation of verbal episodic memory. We describe a theory forgoverning neural activity in the human brain, called the theory of associativity. Weaddress these questions in the framework of the theory.Memory is linked to sleep as studies show that memory depends on getting suffi-cient sleep (Ellenbogen et al. 2006). Sleep is divided into two types: rapid eye move-ment (REM) and non-REM. Most dreaming occurs in REM sleep (Hobson 2009). Aprimary function of sleep is thought to consolidate or transform memory from thehippocampus into the neocortex (Nadel et al. 2012). There is no agreement on thepurpose and mechanism of dream construction (Freud 1900; Hobson and McCarley1977; Jouvet 1999; Revonsuo 2000). Existing theories of dreaming could not explainwhy dreaming is physiologically and evolutionarily important or why children havemuch longer REM sleep than adults. We develop a theory of dreaming based on thetheory of associativity to address these questions.Memory is also linked to Alzheimer’s disease (AD) as memory loss is the mostcommon symptom. AD is characterized by extreme shrinkage of the cerebral cortex3nd hippocampus. AD is linked to disrupted REM sleep (Bliwise 2004). Quitea few well-known people such as Isaac Newton and Albert Einstein in the arts andsciences are believed to have the Asperger syndrome (James 2003). How is intelligenceassociated with common neural disorders? We provide new knowledge to explain theselinks based on the new theories of associativity and dreaming.Memory is involved in consciousness as conscious experiences are encoded andstored by memory mechanisms. There is no rigorous definition of consciousness,although theories are proposed to explain consciousness in terms of neural activitiesin the brain (Edelman 2004; Koch 2012). Existing definitions could not recognizenon-human consciousness in other animals or explain why consciousness evolved asan adaptive advantage. We present a new definition that is both philosophical andoperational. The definition is used to address these questions.
Theory of Associativity
We expand classical properties of synaptic plasticity (Bliss and Collingridge 1993;Martin and Morris 2002) and prevalent views in the cognitive neuroscience of memory(O’Keefe and Nadel 1978; Squire 1992; Nadel and Moscovitch 1997; Eichenbaum andCohen 2001; Bussey and Saksida 2007; Teyler and Rudy 2007; Cowell et al. 2010)into a version called the theory of associativity, which forms the basis for the brain’sneural activity. The theory describes the relationship between information attendedto by the brain and its neural activity. The theory is described as follows. Thereare two major types of information: verbal and non-verbal sensory, with sensoryinformation further divided into subtypes. A special example of verbal information istime, which has no sensory perception. Neurons are activated by synaptic plasticityto form synaptic connections when the brain attends to an instance of informationduring learning. A block is a group of connected neurons that are always activatedtogether. Blocks that are activated at the same time can be connected by synapticplasticity into a structure. How long the structure persists depends on the lengthand intensity of attention and emotion as well as the type of neurons involved. The4tructure can be strengthened through retrieval or rehearsal. In general, for someinteger m ≥
0, structures at level at most m that are activated at the same time canbe connected into a structure at level m + 1, where a structure at level 0 is a block.The hippocampus is the control center for combining components into a structurein the neocortex. The neocortex consists of primary sensory and sensory associationareas, spatial areas, primary verbal and verbal association areas, and primary motorand motor association areas. Note that verbal and visual information processing isknown to involve nonoverlapping brain areas (Newman et al. 2007). The visual asso-ciation areas are divided into the ventral visual stream (VVS) for entity representationand the dorsal visual stream (DVS) for representation of entity location and motion(Ungerleider and Mishkin 1982). The spatial areas are activated to perceive a sketchof a spatial arrangement of entities in a scene during recollection. Sensory struc-tures are distributed in sensory association areas; verbal structures are distributedin verbal association areas. Association areas are capable of forming structures bysynaptic plasticity in different locations. However, the hippocampus coordinates theencoding activity in all the association areas to avoid forming duplicate structuresin different locations for the same instance of information. Components (in associ-ation areas) that are activated at the same time are first combined into a structurein the hippocampus. Then the structure is formed in the association areas by trans-forming the hippocampal connections between the components into the associationareas. Sensory hippocampal connections can be transformed through rehearsal, whileverbal hippocampal connections can be immediately transformed and later strength-ened through recollection. Note that the hippocampus is known to have increasedactivation for spatial compared to verbal information (Ryan et al. 2010).Complex sensory and verbal memory traces for an entity (individual, class, orbackground) are constructed through combination and recursion. The memory tracefor a visual image of a person’s face is constructed in VVS through rehearsal. Thememory trace is a structure at level n for some integer n ≥ n −
1, are alreadyin VVS (Bussey and Saksida 2007). The assumption is certainly true at n = 1,5here the structures at level 0 are blocks in VVS. (It can be shown similarly thatblocks in VVS can be constructed through combination and recursion from low-levelcomponents in VVS.) When the visual image is attended to, the components areactivated and combined in the hippocampus according to the spatial relationshipin DVS between the components. Some of the components are common, whereasthe others are unique ones encoding the specific visual features of the image. Theconnections in the hippocampus to the components are transformed into VVS whenthe visual image is repeatedly attended to. Similarly, the verbal memory trace for aperson’s name can be constructed in a verbal association area.There are two necessary conditions for building sensory and verbal structures foran entity in the neocortex. First, the sensory perception of the entity is different fromthat of any other entity. Second, there is a unique verbal reference to identify theentity. For example, if the entity is a known person, then both conditions are satisfied.If the entity is an unknown person, then the second condition is not satisfied. If theentity is a tiger, then both conditions are not normally satisfied. If the entity is aclass of tigers, then both conditions are satisfied for the class. The creation of aunique verbal reference for an entity is the brain’s way of indicating that the entityis worth attending to. So the brain can ignore some aspects of the world by notcreating unique verbal references for them. This observation suggests that languageevolved for memory by indicating which aspects of the world are worth attending toand remembering.The verbal structure for a verbal reference is formed first. The structure consistsof common components linked by unique connections, with its meaning defined asthe sensory perception of the entity. Then the sensory structure for the entity isformed. The sensory structure also consists of common components linked by uniqueconnections. In addition, the unique connections of the sensory and verbal structuresare linked. The linkage allows the sensory structure to be strengthened throughrecollection by activating the verbal structure. The linkage is also crucial in formingsensory and verbal episodic memory at the same time. The sharing of commoncomponents in forming structures is an efficient way of building memory traces for6any known people in the neocortex. The visual structure for each known personhas unique connections to encode the unique visual feature of the person.Consider an example of forming and activating the connected visual and verbalstructures for a female friend. The connection between the structures is formed dur-ing initial encounters with her in which her verbal name and facial image are encodedtogether and therefore the structures are connected. The connection is strengthenedon each subsequent encounter in which seeing her face and activating the visual struc-ture concur with calling her name and activating the verbal structure in a greeting.Thus, seeing her face activates the visual and verbal structures at the same time,and so does thinking of her name. This observation is supported by previous findings(Martin and Chao 2001; Goldberg et al. 2006).Similarly, there are two necessary conditions for building sensory and verbal struc-tures for an action. The sensory perception of the action is different from that of anyother action; there is a unique verbal reference to identify the action. The sensoryand verbal structures for a known action such as walking or eating are connected sothat performing or observing the action activates both structures.We are in a position to explain how declarative memory is formed. Declarativememory is divided into verbal memory and sensory memory. Both sensory memoryand verbal memory each have multiple levels of organization according to the theoryof associativity. The integration of sensory memory with verbal memory can beunderstood in terms of the two human memory properties discussed above.Consider episodic memory formation at the integration level when a person at-tends an event in which the person is engaged in an activity with a few entities ata time in a place. Assume that the person is familiar with the entities, place andactivity and that the person already has visual and verbal memory traces for themat the entity level in association areas. In order for the person to get to the placeon time, the verbal memory traces for the event and its place and time have to beactivated before the event. Upon arriving at the place, seeing the place activates thevisual and verbal memory traces for the place. When the person is engaged in theactivity with the entities, engaging in the activity activates its verbal memory trace7nd recognizing the entities activates their visual and verbal memory traces. At thesame time, a new memory trace for the scene is formed in the hippocampus based onthe spatial information in DVS on the arrangement of the entities. The new memorytrace for the scene represents a spatial arrangement of the entities in the scene, witheach entity represented by a part in the trace. The activated visual and verbal entitymemory traces are connected to the corresponding entity parts in the hippocampus.Then the connections in the hippocampus enable the fragile connections among theactivated term-level verbal memory traces to be formed in the verbal association ar-eas. The fragile verbal connections in the verbal association areas can be strengthenedby recollection. The memory trace for the event consists of a verbal structure withconnections to all the activated entity-level verbal memory traces as components inthe verbal association areas, a visual structure in the hippocampus with connectionsto all the activated entity/action-level visual memory traces as components, and con-nections between the two structures in the hippocampus. The entire memory traceis strengthened through recollection, which is made by activating the verbal memorytraces for the event and its place and time through the perception of their verbalterms.In general, a conscious experience is associated with a superstructure distributedacross the hippocampus and association areas. The superstructure is made up of ver-bal structures with components and their connections in verbal association areas andsensory structures with components in sensory association areas and their connectionsin the hippocampus. The verbal structures are outside the hippocampus and are con-nected to the sensory structures in the hippocampus. An example superstructure isshown in Figure 1. An index of the superstructure is a subset of its verbal compo-nents such that its activation triggers the activation of the whole superstructure. Theindex is used to recollect the experience associated with the superstructure. Notethat no superstructure is a component of another superstructure. Superstructuresare different if each of them has its own unique synaptic connections such that notwo of them are activated together. There are infinitely different superstructures tobe associated with infinitely different possible experiences. Note that it is possible for8 ✐(cid:0)(cid:0)✁✂✄☎(cid:0)✆✝❱❡✞❜✄✟ ✄✝✝✁✂✐✄t✐✁✠ ✄✞❡✄ ❉✁✞✝✄✟ ♦✐✝✆✄✟ ✝t✞❡✄☎ ❱❡✠t✞✄✟ ♦✐✝✆✄✟ ✝t✞❡✄☎ Figure 1: A memory superstructure formed when a scene with three entities is at-tended to. The superstructure consists of three groups of memory structures (onegroup per entity) that are connected together in both the hippocampus (the openrectangle) and a verbal association area. Each group has a verbal structure, a hip-pocampal structure (a placeholder), and a visual structure, which are represented bysmall-, medium- and large-sized objects of the same shape, respectively. The struc-tures along with their connections in each group are shown in the same color. Spatialinformation on the arrangement of the entities in the scene is passed through thedorsal visual stream and encoded in the hippocampus.two different superstructures to share common verbal or sensory components becausethe superstructures are formed at different times. The sharing of components is effi-cient in the usage of neurons and is necessary because all components are singular inthe brain. The association between conscious experiences and their superstructuresis contingent on the singularity of components and superstructures.The theory of associativity supports the view that language, a system of sound-meaning associations, evolved for memory, which is related to the view of Hauseret al. (2002) that language evolved for internal thought. For each entity, its ver-bal representation (sound) is connected with its sensory representation (meaning) forsimultaneous activation; for each experience, its verbal representation (sound) is con-nected with its sensory representation (meaning) for simultaneous activation. Theseconnections allow the brain to understand precisely the sensory meaning of each ver-9al sound. The sound is an efficient and permanent way to represent the meaning; themeaning is replayed back as a recorder to strength the neural representation for thesound. The sound is also used to recollect the meaning. In general, the meaning of asound is specified as a unique pattern of brain activation. A new sound can be recur-sively defined by specifying as its meaning a combination of sounds with well-formedmeanings.The theory of associativity is consistent with previous studies in that episodicmemory and semantic memory are different views of the same underlying neuralnetworks (Rajah and McIntosh 2005; Burianova and Grady 2007). The episodicview is obtained by selecting all the parts representing unique and concrete personalexperiences, while the semantic view is obtained by selecting all the parts representinggeneral facts and abstract concepts. Both episodic memory and semantic memoryinvolve verbal and sensory information.
Dreaming
Dreaming is related to memory processing because a dream can be recollected thenext morning. Further, dreaming is thought to involve memory activation (Stickgoldet al. 2001). Thus, an approach to understanding dreaming is by studying neuralactivation. Activation is an electro-chemical process by which neurons interact totransmit information (Bliss and Collingridge 1993). In the direction of transmission,each of the neurons in turn opens its membrane channels to let in a flood of calciumions as charged particles. A side effect of activation is that extracellular calciumions are pulled in the direction of transmission. During waking, sensory informationconstantly reaches sense organs, resulting in frequent instances of activation. Theseinstances of activation cause calcium ions to flow in from primary sensory areas tosensory association areas to the hippocampus. Thus, at the end of the day, thehippocampus and association areas have a significantly increased level of extracellularcalcium ions than the primary sensory areas. Note that before sleep, the hippocampusand association areas also contain intracellular calcium ions as calcium influx never10eases during waking.During dreaming, visual imagery is often perceived in primary visual areas; evi-dence for the involvement of primary visual areas is that blind people whose primaryvisual cortex is never activated have no visual imagery in their dreams (Hurovitz et al.1999) and that increased activity in the visual cortex is observed during REM sleep(Braun et al. 1997). The visual imagery is a result of activation in the hippocam-pus and visual association areas. The activation starts with an encoding operationin the hippocampus and transmits information from the hippocampus to the visualassociation areas to the primary visual areas. Thus, we propose that a function ofdreaming is to flow calcium ions out from the hippocampus to association areas toprimary areas.Another approach to understanding dreaming is by studying dream contents.Dreams are thought to be constructed from memory because dreams share very littlesimilarity to waking events and are rarely replays of memory (Stickgold et al. 2001).The theory of associativity holds that the perception of sensory information is asso-ciated with the activation of its sensory and verbal memory traces. For example, theperception of a tiger in a dream is a result of the activation of the visual and verbalmemory traces for the tiger. The theory can explain how a dream is constructed. Forexample, one occasionally dreams of a fearful event that one has never experiencedbut has feared of in one’s waking life. Before the dream, one’s memory contains theconnected sensory and verbal memory traces for each of the entities and action in theevent. The verbal memory traces for the terms that refer to the entities and action areconnected as one has expressed fear of such an event in verbal thought. The dreamis triggered by an occurrence of one of the entities in an unrelated event during theprevious day. The memory trace for the dream is constructed at the integration levelduring activation by connecting the sensory memory traces for the entities and actionin the hippocampus to create a scene of the event. Then the dream is experienced asa result of the activation.Virtual experiences are constructed during dreaming by forming unreal memory.In contrast, real experiences during waking life lead to the formation of real memory.11ecause unreal memory is easily distinguished from real memory, dreaming causes nointerference to real memory. It appears that memory has a temporal structure suchthat real memory is formed in currently active association areas during waking andunreal memory is formed in currently dormant association areas during dreaming.Our examination of dream contents offers support for the view that a major functionof dreaming is to redistribute calcium ions without disrupting real memory. Althoughunreal memory appears to be of no use, making unreal memory strengthens the asso-ciation between sensory perception and sensory representation activation. Emotionsin dreams are thought to create large opposite charges to pull calcium ions in thedirection of information transmission.Each dream is a unique experience, which is produced by activating a uniquesuperstructure. In addition, dreams are the window through which we see the powerof superstructures in representing complex experiences. These observations supportthat the association between experiences and their superstructures is preserved bothin waking life and in dreaming. The new view on calcium inflow during waking andcalcium outflow during dreaming is called the calcium theory. The calcium theoryprovides no support for memory consolidation or transformation during sleep becauseit would be confusing to make unreal and real memory during sleep.The calcium theory predicts that the amount of sensory encoding in dreams ispositively related to the amount of sensory encoding in waking life. The reason isthat the amount of calcium flowing out from the hippocampus to sensory associationareas to primary sensory areas during dreaming is positively related to the amount ofcalcium flowing in during waking life. It is likely that this relationship is maintainedby using waking sources as dream triggers. I have many times experienced dreams thatwere constructed around dream triggers encountered randomly during the previousdays. This observation further supports the view that the contents of dreams arerandom but their molecular processes are important to the brain’s function.Our justification for the function of dreaming also applies to dreams with onlyverbal thoughts. The amount of calcium flowing out from verbal association areas toprimary verbal areas during dreaming is positively related to the amount of calcium12owing in during waking life. If a great deal of thinking without any visual imageryhappens during the day, then dreams at night are full of verbal thoughts.Dreams occur mostly during REM sleep. Sleep begins with a short period ofREM sleep, repeats with a long period of non-REM sleep and a short period of REMsleep, and ends with short periods of REM sleep. Electroencephalography (EEG)waves are known to show that brain activities during REM sleep and waking lifeare similar. The calcium theory holds that waking life and dreaming are involved incomplementary instances of activation. So EEG wave data provide support for thecalcium theory.The calcium theory provides an explanation of why a young child spends muchmore time than an adult in REM sleep. The young brain is much more involvedin sensory and verbal learning than the mature brain. As a result, the young brainhas higher calcium concentrations in the hippocampus and association areas than themature brain. The young brain needs much more REM sleep to reduce the highercalcium concentrations. The calcium theory can also explain why an animal needsto sleep at night to shut down sensory systems completely or partially. During sleep,the animal’s brain flows calcium ions out to primary areas.The amount of exposure to sunlight during waking is known to be positively re-lated to the amount of sleep at night. The calcium theory also gives an explanation tothis relationship. Attending to objects and scenes in bright sunlight leads to strongcalcium signals in primary visual areas as light signals are translated into calciumsignals, which produces strong calcium inflow to and influx in visual association areasand the hippocampus. Thus, more exposure to sunlight during waking requires moresleep at night to carry out calcium efflux and outflow. Note that it is also possi-ble that more calcium ions in association areas and the hippocampus produce moreneurotransmitters such as serotonin for sleep.The amount of physical activities during waking is also known to be positivelyrelated to the amount of sleep at night. Calcium homeostasis can be used to explainthis relationship. The amount of physical activities is positively related to the amountof calcium ions entering muscle cells in the body as calcium influx induces muscle13ontractions for physical activities. The amount of calcium ions entering muscle cellsduring physical activities is equal to the amount of calcium ions pumped out of musclecells during rest to maintain calcium homeostasis (Berridge et al. 2003). Thus, morephysical activities during waking amount to less time to pump calcium ions out ofmuscle cells during waking and more time to pump calcium ions out of muscle cellsduring sleep. This relationship suggests communication between muscle cells andneurons during sleep so that the brain sleeps long enough to complete calcium effluxin muscle cells.We sum up a core function of sleep as follows. The function of sleep is to movecalcium ions from the hippocampus to association areas to primary areas. The func-tion consists of two alternate steps of moving intracellular calcium ions out of neuronsand moving extracellular calcium ions away. The function of sleep can not be per-formed during waking because primary areas continuously transmit calcium ions toassociation areas to the hippocampus and calcium influx constantly occurs. Anotherfunction of sleep is to move calcium ions out of muscle cells in the body so that theycan enter muscle cells during waking.
Dementia, Headaches and Relaxation
Alzheimer’s disease (AD) patients have reduced REM sleep in proportion to the extentof their dementia (Bliwise 2004). Dreams occur mainly in REM sleep. Thus, ADpatients have fewer and shorter dreams, and have increased calcium concentrationsin the hippocampus and association areas, according to the calcium theory. Weconclude that widespread neuron death in the neocortex and hippocampus is linkedto increased calcium ions concentrations in these brain areas. This conclusion is notsurprising as increased calcium ions concentrations are known to kill cells (Orreniuset al. 2003). The new finding linking increased calcium ions concentrations to ADsupports the view that calcium as a neural signaling molecule has a role in generatingcommon neural disorders (Krey and Dolmetsch 2007; Marambaud et al. 2009).The calcium theory also links calcium to common headaches. After a day of14ork or study involving calcium inflow in the brain, the brain feels dizzy and sleepy.However, after a good night’s sleep involving calcium outflow, the brain feels fresh.The dizziness and sleepiness is a warning sign from the brain in response to increasedcalcium ions concentrations in the hippocampus and association areas. Thus, calciumis linked to headaches. The new finding is consistent with previous findings linkingcalcium signaling to migraine (Gargus 2009).The calcium theory gives an explanation of a personal mystery. When I constantlypay attention to people speaking in a faculty meeting for one and a half hours, I geta headache immediately after the meeting. However, at the coming night, I geta better night’s sleep with a lot of dreams. The headache disappear completelythe next morning. This mystery happens to me every time I attend a meeting.According to the calcium theory, constant attendance to people leads to constantactivation involving calcium inflow to and calcium influx in the hippocampus andvisual association areas. A much higher level of calcium ions in these areas causesheadaches. At the coming night, sleeping with the higher level of calcium ions in thehippocampus and association areas causes the brain to take more sleep time to getcalcium ions out of and away from the neurons in these areas. On the other hand, ifthe brain were not able to function well during sleep, then a buildup of calcium ionsin these areas would occur and cause harm to neurons because calcium ions are usedas a signaling molecule.This story brings up an important issue of reducing instances of activation tominimize the occurrences of headaches. Activation is induced by attention (Newmanet al. 2007). So one way of reducing instances of activation is to shift attention tosomething else that is not stressful. Another way is to relax the brain by makingextremely slow body movements without thinking of or looking at anything. Thesetechniques work well for me to reduce occurrences of headaches. In general, relaxationexercises such as Qigong and Tai Chi are shown to have significant benefits such asdecrease in cortisol levels (Jahnke et al. 2010). The calcium theory predicts thatrelaxation exercises are good for the brain: they inhibit activation, keep the brain inrelaxed states, and help with sleep by inducing calcium influx in muscle cells.15alcium ions are involved through activation in memory, learning and thinking;they are also involved as a signaling molecule in common neural disorders. Thus,calcium ions link intelligence to common neural disorders. The ability to remember,learn and think depends on the ease with which instances of activation occur. Onthe other hand, too frequent instances of activation lead to a buildup of calcium ionsin association areas and the hippocampus, which is harmful to neurons. In general,calcium ions link waking behavior to brain health as attending to information andfocusing on thought are part of waking behavior.A type of waking behavior thought to be beneficial to brain health is meditation(Cahn and Polich 2006). The meditating brain can be characterized by using EEGelectrical waves. EEG waves in the cerebral cortex are classified into four maindivisions named beta, alpha, theta and delta in a decreasing order of wave frequency.Beta waves are associated with waking alert mental states; alpha waves with relaxedmental states; theta and delta waves often with sleep. A subtype of beta waves isassociated with activation of receptors of glutamate, an excitatory neurotransmitterof the brain. Excessive activation of glutamate receptors can cause neural dysfunctionand cell death through excessive calcium influx (Marambaud et al. 2009). In addition,our common experiences with sleep are that if the brain is kept in excited states for along time, then the brain has difficulty performing its normal function such as gettinginto sleep and staying in sleep for a sufficiently long time. Meditation helps the brainby training the brain to transit and stay out of the beta wave state. Keeping thebrain in the alpha wave state for a sufficient amount of time and in the beta wavestate for a limited amount of time is beneficial to brain health.
Consciousness
The new knowledge that dreaming involves flowing calcium ions out of the hippocam-pus and association areas by forming unreal memory and temporarily paralyzing mus-cles suggests that whole sleep be considered a state of unconsciousness. On the otherhand, during waking, if consciousness is not reflected in behavior that causes the16pecies to survive, then it is lost, where behavior includes body movements, com-munication between members of the species, and any other instance of motor areaactivation. Thus, behavior is part of consciousness that matters. For example, apredator is avoided by running away or hiding; prey is actively pursued. Accordingto the theory of associativity, if a sensation and a behavior often occur at the sametime, then their representations in the brain are connected by synaptic plasticity.Therefore, associated sensations and behaviors concur automatically because theyare wired together in the brain. Thus, experiences are encoded in the associationbetween sensory areas and motor areas in the brain.The above analysis suggests that consciousness be defined as the ability to behavefor one’s own welfare through the association between sensory areas and motor areasin one’s brain. The theory of associativity explains the neural mechanisms thatunderlie consciousness. The association between a stimulus and a behavior indicatesthat the brain not only has a representation of the stimulus, but also is able to reflectit in the behavior. The level of consciousness is assessed by measuring the complexityof behaviors or the extent of the association between stimuli and behaviors. Unlikesensations, many forms of behavior can be objectively observed even for animals.Other mammals are conscious by the new definition, which agrees with our in-tuition. Studies of their memory show that the animals have representations forexperiences in their brains. The animals clearly demonstrate the ability to behavefor their own welfare. It is also easy to conclude from the new definition that con-sciousness evolved as a survival advantage. For example, the ability to discover andremember better ways to find foods and avoid danger allows an individual to gain anadaptive advantage. Humans have the highest level of consciousness among animalsbased on the complexity of their behaviors such as language behaviors.Machines do not have natural consciousness, where natural consciousness refersto the ability that is developed by nature. Machines can be constructed by humansto have synthetic consciousness when humans understand how their brain works.17 iscussion
We have presented a few ideas concerning the function and health of the human brain.The new definition of consciousness emphasizes that behavior matters. It fittinglyapplies to the brain; behavior matters a great deal to the function and health of thebrain. For example, sleep is known to be necessary for the brain and memory. Thenew calcium theory explains why it is so. The calcium theory is a by-product of thenew theory of associativity for explaining how verbal memory is formed. These ideassuggest several directions for future studies of the human brain.First, these ideas arrive at a perfect time as the Brain Research through AdvancingInnovative Neurotechnologies (BRAIN) Initiative is in the process of being launched(Insel et al. 2013). The theory of associativity gives a high-level description of how thebrain forms representations of the outside world. One goal of the BRAIN Initiativecan be to collect experimental data to confirm, revise, or expand the theory. Anothergoal can be to use neural calcium imaging technology to study the distribution ofintracellular and extracellular calcium ions in the primary areas and association areasand hippocampus before and after sleep. A third goal can be to find out the role ofcalcium as a second messenger in generating common neural disorders and headaches.Second, it is important to find effective ways of keeping the brain in a highlyhealthy and functional condition over a lifetime. Tactile massage and relaxationexercises are known to reduce stress. Do these activities on a daily basis relax thebrain by reducing calcium ions in the hippocampus and association areas? On theother hand, people are now bombarded with information by watching TV, surfingthe Internet, playing games, and using smartphones. People are also required to beproductive at work by constantly attending and responding to fast-changing eventsand situations. Do these daily activities over long hours cause damage to the brainby building up calcium ions in the hippocampus and association areas? This questionis specially important for brains that are prone to activation.Third, getting a good night’s sleep is an effective way of keeping a healthy brain.Strength exercises in the morning and afternoon are known to help with night’s sleep.18owever, idling the brain and inducing no calcium inflow during the day do not leadto a good night’s sleep because there is no work to do during sleep according tothe calcium theory. Because dreams tend to be constructed around waking sources,getting sensory and verbal information during the day facilitates the construction ofdreams at night. As light signals received by the eyes are translated into calciumsignals in the brain, the type and intensity of light exposed during the day have animpact on night’s sleep. How do the amount and type of information received inwaking along with environments affect night’s sleep? As sleep depends on certainbiochemical reactions, it is necessary to eat a variety of foods during the day thatcontain the chemicals required for sleep. What kinds of foods help with night’s sleep?The human brain is the most valuable natural resource on the earth. The ideasproposed in this paper suggest that behavior affects the function and health of thebrain through processes involving calcium as a second messenger. It is important totake the best care of the brain with healthy behaviors over a lifetime because it ismore difficult if ever possible to reverse the damage done to the brain with unhealthybehaviors. Although more studies on the effects of behaviors on the brain are needed,warning signs such as headaches from the brain are valuable indicators of the effectsof unhealthy behaviors on the brain.
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