question: How can we imagine hearing sounds and seeing images, all inside our heads?
comment: All hearing and all vision is just electrical and chemical activity in your brain. Some of those actions arise from signals sent from sensory organs (e.g., eyes and ears), and some originate in the brain itself. The point is the brain's wiring is built to "see" and "hear" with or without direct sensory input.
passages: Section::::Brain activation.
  
  A study using fMRI while subjects were asked to imagine precise visual figures, to mentally disassemble them, or mentally blend them, showed activity in the occipital, frontoparietal, posterior parietal, precuneus, and dorsolateral prefrontal regions of the subject's brains.
  
  Section::::Evolution of imagination.
   According to psychologist and cognitive scientist Steven Pinker, our experiences of the world are represented in our minds as mental images. These mental images can then be associated and compared with others, and can be used to synthesize completely new images. In this view, mental images allow us to form useful theories of how the world works by formulating likely sequences of mental images in our heads without having to directly experience that outcome. Whether other creatures have this capability is debatable.
   The previously mentioned and numerous related studies have led to a relative consensus within cognitive science, psychology, neuroscience, and philosophy on the neural status of mental images. In general, researchers agree that, while there is no homunculus inside the head viewing these mental images, our brains do form and maintain mental images as image-like wholes. The problem of exactly how these images are stored and manipulated within the human brain, in particular within language and communication, remains a fertile area of study.
   BULLET::::2. Imaginary - In Teresa of Avila's "The Interior Castle", an imaginary vision is defined as one where nothing is seen or heard by the senses of seeing or hearing, but where the same impression is received that would be produced upon the imagination by the senses if some real object were perceived by them. Niels Christian Hvidt refers to them as visions recognized through mechanisms of the human psyche that are made up of things a soul has acquired through contact with reality.
   What we have in our minds in a waking state and what we imagine in dreams is very much of the same nature. Dream images might be with or without spoken words, other sounds or colours. In the waking state there is usually, in the foreground, the buzz of immediate perception, feeling, mood and as well as fleeting memory images. In a mental state between dreaming and being fully awake is a state known as 'day dreaming' or a meditative state, during which "the things we see in the sky when the clouds are drifting, the centaurs and stags, antelopes and wolves" are projected from the imagination. Rudolf Arnheim has attempted to answer the question: what does a mental image look like? In Greek philosophy, the School of Leucippus and Democritus believed that a replica of an object enters the eye and remains in the soul as a memory as a complete image. Berkeley explained that parts, for example, a leg rather than the complete body, can be brought visually to the mind. Arnheim considers the psychologist, Edward B. Titchener's account to be the breakthrough in understanding something of how the vague incomplete quality of the image is 'impressionistic' and carries meaning as well as form.
   Section::::In experimental psychology.
  
  Cognitive psychologists and (later) cognitive neuroscientists have empirically tested some of the philosophical questions related to whether and how the human brain uses mental imagery in cognition.
   Section::::Quotes.
  
  “Superior pattern processing is the essence of the evolved human brain.”
  
  “The human brain is particularly adept at imagination, an ability responsible for both understanding and escaping reality.”
  
  “Nerve cells possess an innate ability to respond adaptively to intermittent challenges in ways that help them perform optimally and counteract the adversities of aging, thereby forestalling Alzheimer’s and Parkinson’s diseases.”
  
  “Imagination is an advanced form of mental pattern processing that enables the formulation and testing of hypotheses, which is required to establish the truth and to predict future outcomes.
   The human brain constructs a world inside our head based on what it samples from the surrounding environment. However, sometimes it tries to organize this information it thinks best while other times it fills in the gaps. This way in which our brain works is the basis of an illusion.
  
  Section::::Auditory.
   Section::::Image perception.:Dreaming.
   The visual pathway is not a one-way street. Higher areas of the brain can also send visual input back to neurons in lower areas of the visual cortex. [...] As humans, we have the ability to see with the mind's eye—to have a perceptual experience in the absence of visual input. For example, PET scans have shown that when subjects, seated in a room, imagine they are at their front door starting to walk either to the left or right, activation begins in the visual association cortex, the parietal cortex, and the prefrontal cortex—all higher cognitive processing centers of the brain.
   Section::::Defining criteria.:Brain regions.
  
  The thalamus is a section of the brain responsible for relaying sensory and motor signals to the cerebral cortex. As stimuli pass through the thalamus, there are specific regions dedicated to each sense, and therefore is able to sort out the multiple parts of an environment an individual experiences in a given moment. Two of these regions are specific to vision and hearing respectively, which may be responsible for the order in which sensory information is coded and then perceived within the cerebral cortex.
   Mental images are an important topic in classical and modern philosophy, as they are central to the study of knowledge. In the "Republic", Book VII, Plato has Socrates present the Allegory of the Cave: a prisoner, bound and unable to move, sits with his back to a fire watching the shadows cast on the cave wall in front of him by people carrying objects behind his back. These people and the objects they carry are representations of real things in the world. Unenlightened man is like the prisoner, explains Socrates, a human being making mental images from the sense data that he experiences.
   The phenomenology of imagination is discussed In "The Imaginary: A Phenomenological Psychology of the Imagination" (), also published under the title "The Psychology of the Imagination", is a 1940 book by Jean-Paul Sartre, in which he propounds his concept of the imagination and discusses what the existence of imagination shows about the nature of human consciousness.
  
  The imagination is also active in our perception of photographic images in order to make them appear real.
  
  Section::::Memory.
   The rudiments of a biological basis for the mind's eye is found in the deeper portions of the brain below the neocortex, or where the center of perception exists. The thalamus has been found to be discrete to other components in that it processes all forms of perceptional data relayed from both lower and higher components of the brain. Damage to this component can produce permanent perceptual damage, however when damage is inflicted upon the cerebral cortex, the brain adapts to neuroplasticity to amend any occlusions for perception. It can be thought that the neocortex is a sophisticated memory storage warehouse in which data received as an input from sensory systems are compartmentalized via the cerebral cortex. This would essentially allow for shapes to be identified, although given the lack of filtering input produced internally, one may as a consequence, hallucinate—essentially seeing something that isn't received as an input externally but rather internal (i.e. an error in the filtering of segmented sensory data from the cerebral cortex may result in one seeing, feeling, hearing or experiencing something that is inconsistent with reality).
   Section::::Physical basis.
  
  The biological foundation of the mind's eye is not fully understood. Studies using fMRI have shown that the lateral geniculate nucleus and the V1 area of the visual cortex are activated during mental imagery tasks. Ratey writes:
   During auditory verbal imagery, the inferior frontal cortex and the insula were activated as well as the supplementary motor area, left superior temporal/inferior parietal region, the right posterior cerebellar cortex, the left precentral, and superior temporal gyri. Other areas of the brain have been activated during auditory imagery however there hasn’t been an encoding process attributed to it yet such as frontopolar areas, and the subcallosal gyrus.
  
  Section::::Physiology.:Anticipatory imagery.
   Mental representations also allow people to experience things right in front of them—though the process of how the brain interprets the representational content is debated.
  
  Section::::Representational theories of mind.
  
  Representationalism (also known as indirect realism) is the view that representations are the main way we access external reality.
   Section::::Effects.
  
  AVE effects on the EEG are found primarily over the sensory-motor strip, frontally, and in the parietal lobe (somatosensory) regions and slightly less within the prefrontal cortex.
   Memory and mental imagery, often seen as a part of the process of imagination, have been shown to be affected by one another. "Images made by functional magnetic resonance imaging technology show that remembering and imagining sends blood to identical parts of the brain." Various psychological factors can influence the mental processing of and can heighten the chance of the brain to retain information as either long-term memories or short-term memories. John Sweller indicated that experiences stored as long-term memories are easier to recall, as they are ingrained deeper in the mind. Each of these forms require information to be taught in a specific manner so as to use various regions of the brain when being processed. This information can potentially help develop programs for young students to cultivate or further enhance their creative abilities from a young age. The neocortex and thalamus are responsible for controlling the brain's imagination, along with many of the brain's other functions such as consciousness and abstract thought. Since imagination involves many different brain functions, such as emotions, memory, thoughts, etc., portions of the brain where multiple functions occur—such as the thalamus and neocortex—are the main regions where imaginative processing has been documented. The understanding of "how" memory and imagination are linked in the brain, paves the way to better understand one's ability to link significant past experiences with their imagination.
   Section::::Virtual reality.:Animal research.
   There are several theories as to how mental images are formed in the mind. These include the dual-code theory, the propositional theory, and the functional-equivalency hypothesis. The dual-code theory, created by Allan Paivio in 1971, is the theory that we use two separate codes to represent information in our brains: image codes and verbal codes. Image codes are things like thinking of a picture of a dog when you are thinking of a dog, whereas a verbal code would be to think of the word "dog". Another example is the difference between thinking of abstract words such as "justice" or "love" and thinking of concrete words like "elephant" or "chair." When abstract words are thought of, it is easier to think of them in terms of verbal codes—finding words that define them or describe them. With concrete words, it is often easier to use image codes and bring up a picture of a "human" or "chair" in your mind rather than words associated or descriptive of them.
   The brain is capable of creating other types of mental imagery, in addition to visual images, simulating or recreating perceptual experience across all sensory modalities, including auditory imagery of sounds, gustatory imagery of tastes, olfactory imagery of smells, motor imagery of movements, and haptic imagery of touch, incorporating texture, temperature, and pressure.
  
  Notwithstanding the ability to generate mental images across sensory modalities, the term "creative visualization" signifies the process by which a person generates and processes visual mental imagery specifically.
   The eighteenth-century philosopher Bishop George Berkeley proposed similar ideas in his theory of idealism. Berkeley stated that reality is equivalent to mental images—our mental images are not a copy of another material reality but that reality itself. Berkeley, however, sharply distinguished between the images that he considered to constitute the external world, and the images of individual imagination. According to Berkeley, only the latter are considered "mental imagery" in the contemporary sense of the term.
   BULLET::::3. Neurons Unlimited: The brain is neurally plastic (NP) – evolution left open the function of human neurons. The capacity of its neurons to engage in imagination extends its potential to think and feel.
  
  BULLET::::4. Superbrain: The prefrontal cortex (PC) is the brain's "conductor". It directs using inner representations as prompts which organize the brain's "orchestra" of neural “talents”.
  
  BULLET::::5. Mind-Engine: Cognition depends upon brain waves that bind through synchronization of diverse brain areas into mental unity. The prefrontal cortex controls this unification of the brain.
   When we think about the world, or about our past experiences, we represent those things inside our heads. For example, think about the holiday you went on last year. Did you see a picture of where you went, tell yourself a story about what you did, feel the sun on your back and the wind in your hair? Can you bring to mind the smell of your favourite flower or the taste of a favourite meal??
  