The CNS Efficiency Model of the Chiropractic Subluxation Theory

1. The CNS Efficiency Model of the Chiropractic Subluxation Theory Fred Clary, DC, DIBCN

2. Looking Back to Move Forward Subluxation • Hippocrates 400BC • Randall Holme 1688 • Hieronymous 1746 • Harrison 1821 • Palmers 1910 • Stephenson 1927 • Wyke 1967 • Whatmore 1968 • Korr 1975 • Flesia/Faye 1983 • Lantz 1990

3. If Fundamentally You Are the Same as everyone else…

4. IF You are thinking outside the Box…You Still See the box…

5. Neurology Milestones or Dead Dogmas • Before late 1990’s, brain tissue can not heal • After 2001, the brain is highly plastic, continually adapting and modifying throughout adult life • Before 2002, the thalamus is a midbrain afferent relay structure • After 2002, the thalamus regulates the quantity and quality of information reaching the cortex and modifies the information before its final destination • Before 2000, no adult stem cells exist in the CNS • After 2000, adult stems cells found, they are numerous and act as glia cells when not regenerating circuits

6. Your World View • Paradigm: A set of assumptions, concepts, values, and practices that constitutes a way of viewing reality … • A scientific paradigm filters : • what is to be observed and scrutinized, • the kind of questions that are supposed to be asked and probed for answers in relation to this subject, • how these questions are to be structured, • how the results of scientific investigations should be interpreted.

7. Paradigm Shift

8. Paradigm Shift • Paradigm Shift : Only happens when anomalies or inconsistencies arise within a given paradigm and present problems that we are unable to solve within a given paradigm. • Our view of reality must change, as must the way we perceive, think, and value the world. We must take on new assumptions and expectations that will transform our theories, traditions, rules, and standards of practice. We must create a new paradigm in which we are able to solve the insolvable problems of the old paradigm.

9. Evolution and the Brain • Let us now consider how this general idea (of evolution through natural selection) could be applied to the nervous system. • Neurons are born and differentiate in ways that are not conditioned by their future functions as elements of neural circuits • Our understanding how functions ... can emerge from these beginnings, … is worth remembering that fundamental attributes of the nervous system such as the circuitry underlying locomotion or escape behavior are probably also present as a rather stereotyped and evolutionarily conserved set of cells and connections. • It is at least possible to envisage that there is a fundamental framework of circuitry just as there is a scaffolding of initial pathways.

10. Evolution and the Brain • One would imagine that there has been a strong selective pressure to make «fundamental frameworks of CNS circuitry» as stable and efficient as possible from a developmental point of view. • This involves not only stabilizing the formation of the individual circuits, but also providing for general means to adapt them to unforeseeable perturbations, i.e. general mechanisms of functional plasticity (e.g., learning) and of developmental plasticity • It has been argued that there must also be a mechanism to assess and adjust the functional connectivity of the circuit in order to optimize its performance. • Energy efficiency of processing, interpreting, summation and filtering information must be the mechanism the nervous system uses to assess and adjust the functional connectivity to it's optimize performance. • BATE, M. (1998) Making sense of behavior. Int. J. Dev. Biol. 42: 507-509. • GODA, Y. (1995) Memory mechanisms. A common cascade for long-term memory. Curr. Biol. 5: 136-138 • FRIEDRICH, M.J. (2000). Research with Drosophila provides clues to enhancing human memory. JAMA 284: 2857-2858

11. Inefficient CNS Processing involved in ALL Disease • Multiple Sclerosis: Functional connectivity analysis suggests that altered inter-hemispheric interactions between dorsal and lateral prefrontal regions may provide an adaptive mechanism that could limit clinical expression of the disease distinct from recruitment of novel processing regions. Together, these results suggest that therapeutic enhancement of the coherence of interactions between brain regions normally recruited (functional enhancement), as well as recruitment of alternative areas or use of complementary cognitive strategies (both forms of adaptive functional change), may limit expression of cognitive impairments in multiple sclerosis. • Sarah Cader. Reduced brain functional reserve and altered functional connectivity in patients with multiple sclerosis. Brain (2006), 129, 527–537

12. Inefficient CNS Processing involved in ALL Disease • Drug Addiction: …transition to addiction results from genetic, developmental, and sociological vulnerabilities, combined with pharmacologically induced plasticity in brain circuitry that strengthens learned drug-associated behaviors at the expense of adaptive responding for natural rewards. Advances over the last decade have identified the brain circuits most vulnerable to drug-induced changes, as well as many associated molecular and morphological underpinnings. Kalivas PW .Drug addiction as a pathology of staged neuroplasticity. Neuropsychopharmacology. 2008 Jan;33(1):166-80. Epub 2007 Sep 5.

13. Inefficient CNS Processing involved in ALL Disease • Depression: In contrast to the null findings for behavioral data, pretreatment, depressed patients showed diminished activity in the dorsolateral prefrontal cortex and diminished functional connectivity between the dorsolateral prefrontal cortex and dorsal anterior cingulate cortex. The altered functional connectivity appears to be persistent. Further, at least some of the prefrontal hypoactivity seems to be an episodic characteristic of acute depression amenable to treatment. • Aizenstein HJ .Am J Geriatr Psychiatry. 2009 Jan;17(1):30-42. Altered functioning of the executive control circuit in late-life depression: episodic and persistent phenomena.

14. Inefficient CNS Processing involved in ALL Disease • Autism: These findings suggest that the neural basis of altered cognition in autism entails a lower degree of integration of information across certain cortical areas resulting from reduced intracortical connectivity. The results add support to a new theory of cortical functional underconnectivity in autism, which suggest a deficit in integration of information at the neural and cognitive levels • Marcel Adam Just. Functional and Anatomical Cortical Underconnectivity in Autism: Evidence from an fMRI Study of an Executive Function Task and Corpus Callosum Morphometry. Cerebral Cortex April 2007;17:951--961

15. Inefficient CNS Processing involved in ALL Disease • Pain & Awareness: Thalamus and thalamo-cortical pathways seem to be linked to the hypnotic effects of anesthesia and deep sedation. Connectivity studies also confirm this…. • Ramani R,Understanding anesthesia through functional imaging.Curr Opin anaesthesiol. 2008 Oct;21(5):530-6.

16. Inefficient CNS Processing involved in ALL Disease • Alzheimer’s: We have been able to show that in mildly demented Alzheimer's disease patients the breakdown in memory for unfamiliar faces is due, at least in part, to a reduction in functional connectivity… • Cheryl L. Grady .Altered brain functional connectivity and impaired short-term memory in Alzheimer's disease. Brain, Apr 2001; 124: 739 - 756.

17. Inefficient CNS Processing involved in ALL Disease • Headache: Until recently, primary headache disorders, such as migraine and cluster headache were considered to be vascular in origin. However, advances in neuroimaging techniques, such as positron emission tomography, single photon emission computed tomography and functional magnetic resonance imaging have augmented the growing clinical evidence that these headaches are primarily driven from the brain. Brain functional circuitry, signaling and connectivity. • Connectivity is the functional relationships and communication between different regions of the CNS. • Cohen AS . Functional neuroimaging of primary headache disorders. Expert Rev Neurother. 2006 Aug;6(8):1159-71.

18. Inefficient CNS Processing involved in ALL Disease • Heart Disease: That the brain may be involved in cardiovascular regulation has been acknowledged for over a century. That cardiac arrhythmias may result from cortical derangement has been less well recognized. • Oppenheimer S. Cerebrogenic cardiac arrhythmias: cortical lateralization and clinical significance. Clin Auton Res. 2006 Feb;16(1):6-11.

19. Inefficient CNS Processing involved in ALL Disease • Heart Function: There is extraordinary neuroplasticity of the sympathetic nervous system in adulthood, a structural and functional neuronal ebb and flow according to the demands placed on it. • Kreusser MM, Haass M, Buss SJ, Hardt SE, Gerber SH, Kinscherf R, Katus HA, Backs J. Injection of nerve growth factor into stellate ganglia improves norepinephrine re-uptake into failing hearts. Hypertension 2006;47:209 –215 • The connectivity and neural drive to the heart varies according to efficiency and neuroplasticity tenets. Demands for the circuit and efficiency of that circuit control resource use and thus its functional performance.

20. Inefficient CNS Processing involved in ALL Disease • Immune System: The brain and the immune system are the two major adaptive systems of the body. During an immune response the brain and the immune system "talk to each other" and this process is essential for maintaining homeostasis. Two major pathway systems are involved in this cross-talk: the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS) …the role of SNS are also discussed in the context of their clinical implication in certain infections, major injury and sepsis, autoimmunity, chronic pain and fatigue syndromes, and tumor growth. • Elenkov IJ .The sympathetic nerve--an integrative interface between two supersystems: the brain and the immune system. Pharmacol Rev. 2000 Dec;52(4):595-638. • The brain and the immune system, or the "supersystems", a term recently coined by Tada (1997), are the two major adaptive systems of the body. Although the immune system has been often regarded as autonomous, the last two to three decades provided strong evidence that the central nervous system (CNS) receives messages from the immune system and vice versa messages from the brain modulate immune functions. Thus, the brain and the immune system are involved in functionally relevant cross-talk, whose main function is to maintain homeostasis

21. Inefficient CNS Processing involved in ALL Disease • IBS/GI Disturbances: According, positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) have been widely used to study neural mechanisms underlying visceral sensations. IBS and other GI disease display altered connectivity and functional changes in the brain compared to healthy volunteers. • Rapps N. Brain imaging of visceral functions in healthy volunteers and IBS patients.J Psychosom Res. 2008 Jun;64(6):599-604

22. Disease and Dysponesis • Dysponesis is defined as a reversible physiological state consisting of unnoticed, misdirected neuro-physical reactions (e.g. abnormal muscle activity) to various agents (environmental events, bodily sensations, emotions, and thoughts) and the repercussions of these reactions throughout the organism. These errors in energy expenditure that are capable of producing functional disorders consist mainly of covert errors in action, potential output from the motor and pre-motor areas of the cortex, and consequences of that output. • Whatmore, GB. (1968) Dysponesis: A Neurophysiological Factor in Functional Disorders. Behavioral Science, Vo. 13, p.102

23. Disease and Dysponesis • Dysponesis (inefficient efferent output due to inefficient processing) is capable of producing a variety of physiological disturbances within the organism. By affecting nervous system function, it can alter regulation and thereby alter organ function of any system of the body. • If one only treats the structural or psychological issues in a patient, results will be disappointing, as dysponesis is a neurophysiologic response pattern (CNS program) that will survive structural and behavior therapy. The Neurophysiological response must be changed. The program must be changed. The connectivity and functional signaling between areas of the CNS must be changed to have a long-term successful outcome. • Dysponesis plays a role in the resultant neurophysiologic sequela. • Dysfunctional disorders produce neuropathologic signaling errors within the CNS circuitry and vice versa. • Whatmore, G.B. & Kohli, D.R.: The Physiopathology and Treatment of Functional Disorders. Grune & Stratton, New York, 1974

24. Disease and Dysponesis • Dysponesis embodies the tenets of traditional chiropractic philosophy and the technology of the 21st century. Acknowledging the devastating effects of the vertebral subluxation upon human health, the chiropractor now has the clinical and intellectual tools to effectively lead humanity into a healthful and fulfilling 21st century. - Christopher Kent, D.C., FCCI

25. The Importance of Metabolic Efficiency in Neural Processing • Brains are animal’s evolutionary responses to demands that are as basic to life as the requirement for energy and the need to collect , transmit, process and store information. Because nervous systems are specialized for speed, efficiency and wide scale integration, some of the molecular and cellar constraints that determine signaling and computation in complex systems will be obvious, i.e. resources like ATP and signing molecules. • Laughlin,SB. (2001).Efficency and complexity in neural coding. Novartis Foundation Symposium 239. p177-192.

26. The Importance of Metabolic Efficiency in Neural Processing • The Metabolic Cost of Neural Informational processing and signaling has often been neglected by theorists attempting to understand the basic mechanisms of brain function. • Allman, JM (1990). The Origin of the NeoCortex. Seminars in Neurosciences 2. 257-62

27. The Importance of Metabolic Efficiency in Neural Processing • The central theory of biology is evolution through natural selection. Information processing , signaling, summation and integration by the nervous system is extremely metabolically expensive. The human brain is the product of optimization and efficiency over million of years of improvements towards adaptations to the internal and external environment and phylogenetic functional prioritizations. • The metabolic cost and energy expense of information processing is the most important constraint in the evolution of the nervous system. • Gotts, S. (2003). Mechanisms underlying enhanced processing efficiency in Neural systems. A dissertation presented to the Department of Psychology-Carnegie Mellon University

28. The Importance of Metabolic Efficiency in Neural Processing • Energy usage is tightly coupled to neural performance. • The high metabolic rate of the CNS is product of neural activity. • Every signaling event uses energy, and neurons are constantly active and densely packed. • Laughlin,SB (2001). Energy as a constraint on the coding and processing of sensory information. Current Opinion in Neurobiology 11:475-480. • Metabolic efficiency will only be an important determinant of the evolution and design of signaling systems when metabolic costs impose a significant penalty on the parent organism. • Laughlin, S. The metabolic cost of neural information. Nature Neuroscience. Vol.1 no. 1 May 1998, page 36

29. The Importance of Metabolic Efficiency in Neural Processing • The adult brain accounts for 20% of the adult body’s resting metabolic energy use while it accounts for only 2% of the total body mass. 80% of the mammalian brain’s energy use is accounted by neural signing and processing. The child spends 50% of all metabolic expense on CNS processing. • Attwell, D. (2001)An energy budget for signaling in in the grey matter of the brain. Journal of Cerebral Blood Flow and Metabolism. 21(10),1133-45.

30. The Importance of Metabolic Efficiency in Neural Processing • The brain is finite and the moment to moment energy supply is finite despite the ‘requests’ of the CNS to process and run numerous programs. Demand always outweighs supply. • Energy Metabolism is central to life because cells cannot exist without an adequate supply of ATP. The CNS is particularly sensitive to any disturbance in energy supply. • Erecinska, M. (2004) Energy metabolism in mammalian brain development. • Energy limitation is a major factor in shaping the normal operation of the brain’s circuitry. Management of Resources is the primary and superseding impact on CNS function • Ames, A. (2000). CNS energy metabolism as related to function. Brain Research Reviews 34:42-68

31. Thalamic neuron theory Thalamic neuron theory: theoretical basis for the role played by the central nervous system (CNS) in the causes and cures of all diseases. • Lee. TN. Med-Hypotheses. 1994 Nov; 43(5): 285-302 • The Mid Brain is older and more protected than the Cortex and takes metabolic priority. • The thalamus influences a wide variety of sensory and motor processes in the telencephalon, including gating of sensory information • Melissa J. Coleman. Thalamic Gating of Auditory Responses in Telencephalic Song Control Nuclei.The Journal of Neuroscience, September 12, 2007 • 27(37):10024 • The thalamus regulates the quantity and quality of information reaching the cortex and modifies the information before its final destination • R. W. Guillery, S. M. Sherman. The role of the thalamus in the flow of information to the cortex. Phil. Trans. R. Soc. Lond. B 2002 357, 1695-1708

32. Thalamic neuron theory

33. The Thalamic Neuron Theory • The Thalamic Neuron Theory (TNT) postulates that the central nervous system (CNS) is involved in all disease processes, as the CNS not only processes incoming physical and chemical information from the periphery, it also sends out physiological commands to the periphery in order to maintain homeostasis for the entire body. Inherent in its capacity to learn and adapt (i.e. to habituate) is the CNS' ability to learn to be sick (pathological habituation) by looking in certain deranged central neural circuitries, leading to chronic disease states

34. The Thalamic Neuron Theory • Uncontrolled flow of information into the cortex (thalamic filtering and integration dysfunction) leads to mental health disorders and other systemic dis-eases. • Kornhuber, J. The Etiopathogenesis of Schizophrenias. Pharmoco-psychiatry 2004;S103-S112.

35. The Thalamic Neuron Theory • The unique characteristic actions of the thalamus allow the thalamus to modify all of the messages passing through the thalamus for perceptual processing. It is important to recognize that ALL copies of motor instructions pass through the thalamus. These instructions are subject to rich modulatory influences That come intrinsically from the thalamus and from every are of the brain. The output is very modified in and out of the midbrain! • Guillery, RW. Branching Thalamic Afferents link Action and Perception. Journal of Neurophysiology. Vol. 90. August 2003. p.539.

36. Neuroplasticity and Pain • We now know that not only modulation but also plastic changes may take place at the level of peripheral receptors, at the spinal cord, or at higher cerebral centers….changes can be of short duration, last days, months, or may potentially be irreversible . • Steen Petersen-Felixa. Neuroplasticity – an important factor in acute and chronic pain. SWISS MED WKLY 2002;132:273–278

37. Neuroplasticity • Brain plasticity refers to the brain’s ability to undergo functional and structural alterations in response to internal and external environmental changes • A. May. Structural Brain Alterations following 5 Days of Intervention: Dynamic Aspects of Neuroplasticity. Cerebral Cortex January 2007;17:205--210

38. Neuroplasticity • The main thing to know is that even the adult brain is not "hard-wired" with fixed and immutable neuronal circuits. Many people have been taught to believe that once a brain injury occurs, there is little to do to repair the damage. This is simply not the case and there is no fixed period of time after which "plasticity" is blocked or lost. We simply do not know all of the conditions that can enhance neuronal plasticity in the intact and damaged brain, but new discoveries are being made all of the time. There are many instances of cortical and subcortical (thalamic!) rewiring of neuronal circuits in response to training as well as in response to injury. • There is solid evidence that neurogenesis, the formation of new nerve cells, occurs in the adult, mammalian brain--and such changes can persist well into old age.

39. Neuroplasticity • To review, plasticity is the selective elimination of axons, dendrites, axon and dendrite branches, and synapses, without loss of the parent neurons, which occurs during normal development of the nervous system, as well as in response to injury or disease. The widespread developmental phenomena of exuberant axonal projections and synaptic connections require both small-scale and large-scale axon pruning to generate precise efficient connectivity. This pruning provides a mechanism for neural plasticity in the developing and adult nervous system, as well as a mechanism to evolve differences between species in a projection system. • Such pruning is also required to remove damaged axonal connections or those that are perceived by local mechanisms as not being efficient for the required circuit, to stabilize the affected neural circuits, and to initiate their maturation or repair. Pruning occurs through retraction, degeneration or functional degradation. • To maintain energy efficiency (whether the program is physiological or not), the CNS, through neuroplasticity, will actually change the cells themselves!

40. Neuroplasticity: Summary • Cellular mechanisms: • Changes in synaptic strength • Structural changes: • Synaptogenesis • Axon sprouting • Cortical and SubCortical reorganization: • Constant changes based on use • Remapping after injury: adjacent areas take over • Rehabilitation helps preserve map • Rehabilitation helps strengthen secondary connections

41. Its Biology (Evolutionary Biology). Not Opinions… • Not all neural plasticity is beneficial • The brain is driven by efficiency, so if a bad (e.g. Pain) program continues to run the brain simply becomes plastic and saves resources. The Pain program becomes efficient. Less input is requires to get the same output (result) whether its physiological or pathological… • Chronic Pain, LBP, HA may be a result of efficiency driven neuroplasticity and not simply Atlas Right… • The brain is only concerned with the now…

42. Neuroplasticity Refs • Gross CG.Nat Rev Neurosci. 2000 Oct;1(1):67-73.Neurogenesis in the adult brain: death of a dogma. • Turlejski K .Prog Brain Res. 2002;136:39-65.Life-long stability of neurons: a century of research on neurogenesis, neuronal death and neuron quantification in adult CNS. • Kempermann G.Ernst Schering Res Found Workshop. 2002;(35):17-28.Neuronal stem cells and adult neurogenesis. • Helen E. Scharfman .Is More Neurogenesis Always Better?Science. 2007 January 19; 315(5810): 336–338. • Taupin P.Adult neurogenesis, neuroinflammation and therapeutic potential of adult neural stem cells. Int J Med Sci. 2008 Jun 5;5(3):127-32. • Taupin P.Adult neurogenesis pharmacology in neurological diseases and disorders. Expert Rev Neurother. 2008 Feb;8(2):311-20. • Taupin P.Neurogenesis in the adult central nervous system. C R Biol. 2006 Jul;329(7):465-75. Epub 2006 May 26. • Taupin P.Adult neurogenesis in the mammalian central nervous system: functionality and potential clinical interest. Med Sci Monit. 2005 Jul;11(7):RA247-252. Epub 2005 Jun 29. • Ma DK,Adult neural stem cells in the mammalian central nervous system. Cell Res. 2009 Jun;19(6):672-82.

43. Physiopathology • Physiopathology – clinicians have long been aware of structural pathology and the ability of these anatomical or biochemical abnormalities to produce malfunction. Malfunctions produced in this manner are termed pathophysiology by the health care community. • Malfunction resulting from processing or signaling errors within the circuitry of nervous system is termed physiopathology.Because of the presence of both inborn and acquired CNS neuronal interconnections (acquired because of efficiency driven neuroplasticity), processing and signaling errors can be produced and maintained • Arnsten AF. Stress signaling pathways that impair prefrontal cortex structure and function. Nat Rev Neurosci. 2009 Jun;10(6):410-22.

44. Physiopathology detected by fMRI • To our knowledge, this is the first study to use fMRI to differentiate pain processing in patients with PTSD compared with trauma controls. Compared with controls, veterans with PTSD revealed an analgesic response when subjected to heat stimuli. Patients with PTSD showed altered pain processing in brain areas associated with affective and cognitive pain processing, such as the insula, hippocampus, amygdala, and ventrolateral PFC. We propose that the neural pattern with decreased activity in the right amygdala and the bilateral ventrolateral PFC reflects altered pain regulation mechanisms in patients with PTSD. • Gueze, E. Altered Pain Processing in Veterans With Posttraumatic Stress Disorder. Arch Gen Psychiatry. 2007;64:76-85

45. What is the Chiropractic Subluxation Complex • The CNS is the most expensive metabolic tissue • The Evolutionary constraint on the organism is CNS energy efficiency • The CNS attempts to be efficient in its signaling, connectivity and processing • The CNS chooses the highest priority programs to run first with its finite resources and energy supply • Neuroplasticity is activated as programs (connections/signaling) continue to run over time. This neuroplasticity drives the program to run with lower resource utilization • The brain become “efficient” at a dysfunctional program, because it has saved resources in the short term. • Pain, Symptoms, Dis-ease and Disability arise if a non-physiological program is “reinforced” or if other physiological programs are neglected because of lack of resources. • The “Interference” in the nerve system was between your ears…

46. What is the Chiropractic Subluxation Complex • Subtle rotations in the spine may be physiologic or pathologic adaptations…Evolutionary pruning would have removed non-advantageous traits over millions of years of selection. After millions of years of adaptation, only traits that don’t have a negative value are left behind. • Pure Symmetry is NOT part of the normal evolution, efficiency and biological fitness are a part of normal evolutionary and the natural selection historical evidentiary pool for humans • When a human adapts for functional movement that program must not only take into account vertebral geography, but musculature tension, facial tension, anticipated pre & post motor activity states, available instantaneously resources including global and individual musculature constraints, energy and metabolic efficiency. Subtle vertebral body rotations may be the best instantaneous physiological decision for the human. • If we HEDO, thump a high spot, we should ask, “…did that body want that high spot because that small local fixation saved the greatest amount of resources globally and made them as efficient as possible in the short term?...” • Do we work against what the brain is trying to do…

47. Big Words…Big Concepts • Neurophysiological Partitioning: since the CNS controls and regulates all physiological processes of the human body, optimizations must occur at the microscopic cellular level in the nervous system first. • All these changes can be explained by considering the process of energy efficiency of neural communication and neural processing. Energy (available ATP) is finite. It is reasonable to assume that the limiting factor for this energy efficiency optimization process is the use of available ATP. Thus, to optimize neurological programs, the CNS will shunt and mobilize ATP to the areas of greatest physiological need in the CNS. • Synergistic Neurophysiological Efficiency: Over time, all neural processing moves to the most energy efficient state. Neuroplasticity is driven by long term efficiency of the information processing NOT the long term survival needs of the individual. (Survival is ‘weeded’ out by natural selection) • Neuronal communication and computation are efficient when considered in the dual (synergistic) context of energy and information rather the either context alone.

48. Where is the “Subluxation” • CNS Integration and Summation or Bone Out of Place? • Epigenetically unfolding our potential as a species or Bone Out of Place?

49. Life is all about choices… • In all of its functions, the brain seeks optimum efficiency, or the path of least resistance. If one particular function is not accessible, the brain will automatically go on to the next most efficient process for doing that particular task. If the second task is not available, it will go on to the third or the fourth most efficient way. Because each alternative process is less efficient, it becomes more stressful and energy expensive.

50. The Truth