The “problem of consciousness” is such a difficult problem that it already starts from defining what the consciousness. We can start describing it as thesubjective experience of themselves and of the worldan uninterrupted flow of perceptions, emotions and thoughts that makes us aware of what happens inside and outside of us. The term consciousness derives from Latin conscientiawhich in turn comes from consccomposed of cum (with) and scire (know) and is such a phenomenon family to seem obvious, but at the same time like this complex to be one of the greatest puzzles of neuroscience and philosophy of the mind. Several scientists and philosophers have tried to give a definition, but the debate is still open and animated, and has come to involve the most disparate research areas, from medicine to physics. The integration between these disciplines and technological innovation are at work to understand how the activity of billions of neurons can produce the richness of the inner experience. Understanding the mechanisms of consciousness could bring relevant benefits not only at the theoretical level, but also in the field clinical (to monitor states of coma o Consciousness disorders) and technological (in the development of increasingly intuitive men-macrine interfaces).
The fundamental elements of consciousness
One of the ways to study consciousness is to break it into some key components. Two of the most discussed aspects in the literature are:
- There awareness of the environment and of themselves: the ability to perceive and interpret external stimuli (such as sounds, lights or smells) and to monitor one’s internal state (thoughts, body sensations, emotions).
- THE’personal identity: the sense of self as a distinct entity, with its own history, a set of memories and a wealth of emotions that differentiate the individual from the rest of the world.
The latter element – that is, the perception of an “I” who lives the experience – is particularly difficult to explain. The brain does not limit itself to elaborating information, but generates a sense of “first person” which makes the experience consciously subjectively, and inserts it into one temporal continuity which creates the sense of unity of what we live. To investigate the intrinsic subjectivity of conscious experience, philosophy forged the term “quaia“, To try to give a name to the set of sensations, feelings and perceptions that characterize the” thing feels “in a specific experience, rather than studying it only in terms of neural circuits.
From neuronal fabric to subjective experience
The modern techniques of neuroimaging (for example, functional magnetic resonance imaging – FMRI and Positroni emission tomography – PET) have allowed us to correla with some mental states with specific brain areas or neural circuits. Some of the most implicated systems in the study of consciousness are:
- Cerebral cortex: the prefrontal cortex is often associated withself -awarenesswhile the parietal, occipital and temporal regions constitute the so -called “Posterior Hot Zone“, That is, an area characterized by a high complexity of interconnections. In the vegetative states, the cerebral cortex activates much less and interacts with other brain areas in a less complex way. On the contrary, in conscious subjects, the stimulation of the cortex generates a complex response, variable in time and in the neural space and not stereotyped. The complexity of this response, measured by”The disturbance complexity index “ (PCI), is a indicator of the state of consciousness
- Talamocortic system: The thalamus plays a crucial role in “unstracting” and filtering sensory information towards the cortex, an interaction that seems fundamental to create a unitary and coherent experience.
- Default Mode Network: a set of particularly active cortical and subcortical areas when the individual is at rest or engaged in introspection activities (such as Remember personal eventsimagine future scenarios or reflect on themselves), while in vegetative states the activity of the DMN is altered.
Yet, however much the correlations between mental states and neural activations can be mapped, to explain how the electrical and chemical activity of these structures genres the subjective experience remains the so -called “difficult problem with consciousness“(Hard problem of consciousness), so defined by the philosopher David Chalmers. Furthermore, the scientific positions on consciousness attribute to it a global character And distributedand this makes it even more difficult to think of being able to find the neural tissue of the conscious states.
The main theories on consciousness
In an attempt to approach a scientific explanation of consciousness, different theories have been proposed. Three of the most discussed are:
Integrated information theory
Developed by the neuroscientist Giulio Tononihypothesizes that consciousness emerges in proportion to the ability of a system of integrate information. In simplified terms, the greater the complexity With which the information is processed unified, the higher the level of consciousness. Some experimental research exploit measures such as the so -called “zap and zip” (transcranial magnetic stimulation followed by analysis of the EEG) to estimate how much information is actually integrated by the brain in a given state, such as waking compared to sleep or anesthesia.
Quantum orchestration theory
Proposed by Roger Penrose And Stuart Hameroffsuggests that consciousness originates within the micro -cums present in the neurons and is linked to mechanics quantum. According to this theory, when a quantum overlap It is “orchestrated”, that is, organized with cognitive information and isolated from the environment, beyond a certain threshold, at that point there would be a moment of consciousness. Although this theory is generally considered rather speculative It has the merit of proposing an alternative approach to the problem, involving physics and biology at a deeper level.
Global working space theory
Formulated by Bernard Bars and developed by other scientists such as Stanislas Dehanesees consciousness as a “stage” in which different components of the brain share information. The contents that reach the “global work space“They become conscious because they are disseminated and distributed between multiple specialized systems (attention, memory, language, etc.). Access to the global work space would have happened through a competition: more “stronger” or “urgent” content, they will win the neuronal challenge and will propagate up to reach the “brain motorways”which would bring them out as conscious.
The difficulties in the empirical study of consciousness
Investigating consciousness experimentally presents unique obstacles. First of all, it is a phenomenon intrinsically subjectivedifficult to reduce to simple behavioral measures or readings of brain activity. In addition, the neural processes at the basis of this unitary experience probably involve a large number of areas And circuitswhich influence each other.
Techniques such as theEEG (electroencephalogram) and the FMRI allow to correlate the activity of specific brain regions with the presence or absence of conscious content (for example, the perception of a visual stimulus), but they don’t reveal “why” Exactly that particular activation is accompanied to the subjective experience. Some research lines try to isolate the so -called neural correlates of consciousness (NCC, neural correlated of consciousness), or the minimum neural signatures necessary and sufficient for a conscious experience, but clarify the causal link between such related and the emergence of consciousness is A company still far away from being concluded.
Despite the complexity of the theme, the research on consciousness continues to progress: new non -invasive brain stimulation methods, increasingly sophisticated experiments that combine with behavioral and neurophysiological data, and the integration between different disciplines (neuroscience, physics, philosophy, IT sciences) are expanding the range of hypothesis And tools. The problem of consciousness is so vast as to determine the frame of entire other spheres of knowledge, from epistemology to the philosophy of free will. Already in the 1980s, Libet raised the problem of the illusion of the free will: In his experiments he tried to know the outcome of voluntary acts even before people were aware of it, reading the cerebral electrical changes that preceded not only the act, but also awareness.
