What is the anatomy of consciousness? - Chapter 14

What is the mind-brain problem?

The problem of consciousness, or otherwise known as the mind-brain problem was originally the realm of philosophy. Dualism, from Descartes, states that the mind and brain are two distinct and separate phenomena, and that conscious experience is nonphysical and beyond the scope of the physical sciences. Materialism asserts that both mind and body are physical mediums and that understanding the physical workings of the body and brain well enough will lead to an understanding of the mind. 

The definition of consciousness is: consciousness is having perceptions, thoughts, and feelings; awareness. The conscious state has a lot of possible contents. But, explaining how the firing of neurons generates sentience is known in the world as the 'hard problem' of consciousness and some people think it will never be explained. The hard problem holds explaining how the chemical interactions of the body produce our subjective conscious experience. 

What is the anatomy of consciousness?

The processes that are apparent in the brainstem and thalamus are sufficient for an organism to be alive, awake, alert and aware of the current moment and place someone or something is currently in. The reticular activating system is involved in arousal, regulating the sleep-wake cycle and mediating the attention. Our conscious experience is expanded by processing in the cerebral cortex.

What are the levels of arousal and consciousness?

While a level of wakefulness is necessary for consciousness, consciousness is not necessary for wakefulness. Patients with unresponsive wakefulness syndrome, or the vegetative state, are 'awaken' from a coma. They are not conscious, in contrast with a minimally conscious state patient, who can localize pain and nonreflex movements. Complicating the diagnosis is the locked-in syndrome, a condition in which one is unable to move any muscles but is fully conscious and has a normal sleep-wake cycle. LIS is caused by a lesion to the ventral part of the pons in the brainstem, where neurons connect the cerebellum with the cortex. 

The sleep-wake cycle is regulated by a complex interplay of neurotransmitters, neuropeptides, and hormones released by structures located in the basal forebrain, hypothalamus and brainstem. The overarching controller is the biological clock, suprachiasmatic nucleus (SCN) in the hypothalamus. It receives light input directly from the retina, allowing its neurons to synchronize to the day-night cycle. 

When we fall asleep the brain passes through distinct brain states with typical patterns of EEG activity. Stage 4 non-rapid eye movement (NREM) sleep, is where our brain waves are less frequent and have a higher amplitude. Then, throughout the night, we cycle between rapid eye movement (REM) sleep, which has low-amplitude more frequent brain waves. It is also investigated that during sleepwalking, the brain areas that mediate the cognitive control and emotional regulation are asleep. 

What is the organizational architecture of complex systems?

The vast majority of mental processes happen outside of our conscious awareness. The brain is a complex system, and understanding the organization of the parts is also necessary in order to relate the system's structure to its function. The complex system of your brain is a system of systems. A layer can be a single module or groups of modules. Each layer acts independently because if has its own specific protocol, rules that stipulate the allowed interactions, both within a layer and between adjacent layers. 

Understanding that protocol doesn't dictate an outcome is important. The idea that there are many ways to implement a system to produce one behavior is known as multiple realizability. Knowing how it works on a certain level in the organization of the brain, does not automatically mean that you can also predict how the actual functioning is at another level. 

How do you have access to information?

Blindsight refers to the phenomenon in which some patients suffering a lesion in their visual cortex can respond to visual stimuli presented in the blind part of their visual field. But these activities happen outside the realm of the consciousness of the patient. 

Next to blindsight there are a lot of processes active in the brain that go by nonconsious. We only have conscious access to a limited amount of information that is processed by the brain. The subliminal processing of activity in the brain is defined as brain activity that is evoked by a stimulus that is below a certain threshold for awareness. When processing is subliminal, the information is inaccessible to awareness. 

We humans also have the ability to relegate learned tasks and also memories to be put into the nonconscious processing. This enables us to devote our limited time and consciousness attention to the resources that are important, so we can recognize and adapt to certain changes and novel situation in the environment, thus increasing your own change of survival. 

Can mental states affect brain processing?

Any theories about consciousness must consider the question of whether a conscious thought has any control over the brain that processes it. The brain is a decision-making device, guided by experience, that gathers and computes information in real time to inform its decisions. The idea is, and research has shown, that people who believe in having a free will behave differently from those who do not believe in a free will, suggesting that a mental state can affect behavior. 

What are the contents of animal consciousness?

Researchers have looked for evidence or consciousness by studying animal behavior such as tool use and conducting mirror self-recognition tests. Evidence has recently been found that chimpanzees understand that others' behavior is guided by beliefs. Different species of animals also have different contents to their conscious experience, depending on the neural processing that they possess, which in turn is a product of evolution. 

What is sentience?

Sentience encompasses the subjective qualia, phenomenal awareness, raw feelings, and first-person viewpoint of an experience - what it is like to be or do something. 

If the universe and everything in it follow a set of determined laws, then, it was inferred, everything must be determined, including people's behavior and, in fact, their entire lives. Determinism is the philosophical belief that all current and future events and actions, including human cognition, decisions, and behavior are caused by preceding events combined with the laws of nature. 

The quantum theory was developed to explain not just black-body radiation, but also the emission of electrons from the surface of a metal in response to light, as well as why, when an electron loses energy, it stays in orbit and doesn't crash into the nucleus.