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This article is from
Creation 40(3):14–17, July 2018

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The incredible human brain

As powerful evidence for a Designer’s existence, look no further than inside your head

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brain
Credit: nerthuz/123RF Stock Photo

The human central nervous system (CNS) consists of the brain and spinal cord, including roughly 100 billion nerve cells, and about 10 times more neuroglia, or supporting cells. The nerve tissue outside the CNS is called the peripheral nervous system. It delivers sensory information to the CNS, as well as carrying commands from the CNS to organs, such as muscles and glands. While the 1.4 kg mass (3 pounds) of tissue that makes up the brain might not look impressive, it is often described as the most complex arrangement of matter in the known universe.

The 3-D world we experience, with sights, sounds, tastes, smells, and bodily sensations, is essentially constructed by our brains. Every second awake, signals from our environment of one kind or another are converted into electrical currents (of ions—called action potentials) by sensory receptors in the skin or by special senses (like smell, vision, and hearing). These currents, bearing no obvious resemblance to the information they carry, travel into the brain via nerve fibres (cables, if you like), and there somehow the information is decoded.

The original signal is interpreted so that a person sees the world in vivid colour, hears the sound of a waterfall, experiences the heat of a hot summer’s day, feels a breeze on the skin, and smells the sausages on the barbeque. And this can happen all at the same time; i.e., really fast. How does the brain do this? No one knows, but it must involve signal processing way beyond our current understanding.

Brain mythology

One myth is that we only use about 10% of it, and if we could only learn to use the rest then we would become savants. However, we do use the rest of our brains, only not all of it at once. If all your cerebral cortex were active simultaneously then you would most likely be having some sort of generalized epileptic seizure rather than experiencing special mental powers. The brain uses about 20% of the body’s energy, most of it by nerve cells generating action potentials to communicate with other cells. Hence, using only the resources required to do a task is an energy-efficient design feature.

Different regions of the brain perform different tasks. For example, if you are having problems with your Internet connection, you call your Internet service provider, not the post office. Similarly, if the motor areas of your cortex are planning a movement of your foot, the command to move is sent to the muscles via motor neurons located in the spinal cord, not to a sound processing area in the temporal lobe. Brain activation is very dynamic; the areas processing information changing constantly, as the situation dictates.

Often the brain is compared to a computer, and while they both contain complex circuits that carry current, the analogy only goes so far. Consider long-term memory. Computer memory uses transistors to store information, with each transistor capable of two states (on or off, equivalent to one or zero respectively), and so with billions of these tiny electronic devices you can store a lot of information. But in the brain, it does not appear to be in any specific region, but is rather spread across the brain. The hippocampus appears critical for the consolidation of long-term memories, with the strengthening of synaptic connections between nerve cells thought to be how long-term memory is stored.

However, how exactly this allows information to be stored or encoded, and later retrieved, is a mystery.

How does our ‘body clock’ work? (semi-technical)

melatonin-secretion

As an example of the intricate wiring of the brain’s circuits, consider the release of the hormone melatonin from the tiny pineal gland, the main site of its synthesis inside the brain. Melatonin has various physiological roles, including circadian rhythm control (the internal body clock that tells our bodies when to sleep, rise, eat, etc.). This is involved in the ‘jet lag’ experienced by jetsetters. The hypothalamus of the brain, which controls both the autonomic nervous system and hormone system, is involved in regulating the body’s circadian rhythm through the circuitous connection its suprachiasmatic nucleus (SCN) makes with the pineal gland. The tiny SCN, situated near the optic chiasm (crossover), receives direct input from the retina’s ganglion nerve cells, via the retinohypothalamic tract, thereby allowing eye light exposure to synchronize the body’s 24-hour internal clock. This explains why exposure to daylight helps reset it. Subsequently, the SCN controls circadian rhythms through connections with another hypothalamic nucleus, the paraventricular nucleus (PVN). The PVN in turn signals the sympathetic preganglionic nerve cells located in the thoracic spinal cord. These sympathetic nerve cells then synapse on postganglionic nerve cells in the superior cervical ganglion. From there, the noradrenergic postganglionic nerve fibres (NE) finally innervate the pineal gland. The pineal gland produces melatonin in darkness, but not in bright light, and so the amount of melatonin secreted is regulated by the incoming nerve stimulus, which in turn is determined by the amount of light-stimulated signal received by the SCN. The melatonin is released into the blood, and the level of hormone in the brain influences the 24-hour day/night rhythm. If it all seems very complicated, then ask yourself, how could such an intricate pathway be put together except by purposeful design?

This description omits all the complex interactions between neurotransmitters and receptors at the synapses (connections between nerves), as well as the manufacture of the hormone, and how the receptors of melatonin at the target nerve cells got there. Is it even feasible that natural selection sorting random mutations could put the information into the DNA to even construct one part of such a pathway, given the steps and complexity involved? White matter (myelinated nerve fibres) makes up a considerable portion of the CNS. It connects numerous different regions of the brain and spinal cord in a very orderly way, often involving one or more synaptic connections en route. How did this order arise without intelligent planning?

upparsorn/123RF Stock Photoexposure-to-bright-light
Fig 2. Exposure to bright light in the evening has been shown to suppress melatonin production in preschool-age children, whose circadian system seems very sensitive to light, suggesting that evening light exposure in early childhood could increase the risk of developing evening sleep disturbances.2

A biological ‘computer’?

Both computers and brains will malfunction if physically damaged. However, the brain, depending on the nature of the damage, often has enough built-in redundancy and neuroplasticity (the ability to reorganize its connections) that other parts of the brain can take over the role of the damaged regions. As an extreme example, consider the removal of a cerebral hemisphere (essentially half the brain) as happens in the treatment of some extreme seizure disorders (an operation pioneered by the creationist neurosurgeon Dr Ben Carson1). Where this happens at a relatively young age, the long-term effects on cognitive function are often minimal, due to the amazing neuroplasticity of the brain. On the other hand, if a computer is physically damaged, it cannot repair itself. Since there would not have been any half-brained ‘hominids’ (ape-men), how could ‘evolution’ create the ability of the brain to reconfigure itself when half is removed?

The consciousness conundrum

eraxion/123RF Stock Photocentral-peripheral-nervous-systems
Fig 3. The central and peripheral nervous systems.

No satisfactory explanation exists for consciousness. In fact, there is not even a satisfactory definition of it. However, it certainly involves the quality of awareness. When talking about consciousness, issues such as the mind–body problem often come up, concerning the connection between mental processes involving the mind (e.g., consciousness) and physical processes involving the brain. The mind can be thought of as being the ability of an individual to think, reason, feel, will, perceive, be aware, etc. As such, it seems intertwined with consciousness, and is also difficult to define in scientific terms. In the words of Richard Restak, a world expert in neuroscience:

Mind is not a physical structure like the brain; it is not a ‘thing’. Mind has no visible form, no aroma, no taste; it can’t be held in the hand like the brain. Thoughts, the products of the mind, do not require physicality to exist. Thoughts, however, are meaningless without minds that can think and interpret them.3

No one knows how the mind works and how it links with the physical activity of the brain. Claims that the mind is simply the product of the evolved brain are simply Darwinian pledges of allegiance, not statements conveying knowledge. The materialist (or reductionist) insists that everything can be reduced to matter and its movements. This means that in the brain, mental events, such as thinking, emotions, and awareness, must break down to merely interactions between nerve cells and associated molecules, if mind and consciousness are ‘physically’ part of the brain.

It is ironic that the device (mind) used to devise this nihilistic junk falsifies the very philosophy it espouses, since it cannot be described in reductionist terms, or reduced to ‘just matter’. We are clearly not mindless accidental robots whose actions are determined by our genes or a chain of chemistry since the so-called big bang.

Language

Eraxion/123RF Stock PhotoBrocas-Wernickes-area
Fig 4. Broca’s area and Wernicke’s area

Children have an innate capacity to learn language, something that adults find harder. We know from clinical studies in the 19th century that Broca’s area and Wernicke’s area (see Fig. 4) are involved in speaking and comprehension of language respectively. There are also many other brain regions involved in language. However, localizing aspects of language function to a brain region does not lessen the mystery of how it works, any more than knowing that engines power cars informs you how engines work.

I roll my eyes in disbelief when I read about supposedly ‘magic bullet’ language mutations, such as a ‘Tree of Knowledge’ mutation, being seriously proposed as responsible for our unique way of thinking and communicating,4 as if it were that simple!

God’s Word and the human mind

There are biblical injunctions to love God with all our minds (Luke 10:27), renew our minds (Romans 12:2), to have the same attitude as Christ Jesus (Philippians 2:5), to meditate on God’s Word (not on nothing). We are new creations in Christ (2 Corinthians 5:17). Our attitudes and beliefs are influenced by what we feed our minds on (Philippians 4:8–9, Romans 8:6). As Christians, we are to set our minds on things above, not on earthly things (Colossians 3:2).

References and notes

  1. Batten, D., Creationist contributions to science, Creation 36(4):16–18, 2014; creation.com/creationist-scientist-contributions. Return to text.
  2. Akacem, L.D., et al., Physiol Rep, 6(5), 2018, e13617 | 10.14814/phy2.13617. Return to text.
  3. Restak, R.M., Mind: The Big Questions, Quercus Editions Ltd, London, pp. 17–18, 2012. Return to text.
  4. Line, P., A history of humankind distorted by evolutionary thinking (review of Sapiens: A brief history of humankind by Yuval Noah Harari, J. Creation, 31(3):38–42, 2017. Return to text.