The phrase "mind's eye" refers to the human ability for visualization, i.e., for the experiencing of visual mental imagery A mental image is an experience that, on most occasions, significantly resembles the experience of perceiving some object, event, or scene, but occurs when the relevant object, event, or scene is not actually present to the senses. There are sometimes episodes, particularly on falling asleep and waking up (hypnapompic), when the imagery, being of; in other words, one's ability to "see" things with the mind Mind is the aspect of intellect and consciousness experienced as combinations of thought, perception, memory, emotion, will and imagination, including all unconscious cognitive processes. The term is often used to refer, by implication, to the thought processes of reason. Mind manifests itself subjectively as a stream of consciousness.
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Physical basis
The biological foundation of the mind's eye is not fully understood. fMRI Functional MRI or functional Magnetic Resonance Imaging is a type of specialized MRI scan. It measures the hemodynamic response (change in blood flow) related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging. Since the early 1990s, fMRI has come to dominate studies have shown that the lateral geniculate nucleus The lateral geniculate nucleus is the primary processing center for visual information received from the retina of the eye. The LGN is found inside the thalamus of the brain, and is thus part of the central nervous system and the V1 area of the visual cortex The term visual cortex refers to the primary visual cortex and extrastriate visual cortical areas such as V2, V3, V4, and V5. The primary visual cortex is anatomically equivalent to Brodmann area 17, or BA17. The extrastriate cortical areas consist of Brodmann area 18 and Brodmann area 19. There is a visual cortex for each hemisphere of the brain are activated during mental imagery tasks.[1] Ratey writes:
The visual pathway The visual system is the part of the central nervous system which enables organisms to see. It interprets the information from visible light to build a representation of the world surrounding the body. The visual system accomplishes a number of complex tasks, including the reception of light and the formation of monocular representations; the is not a one-way street. Higher areas of the brain The human brain is the center of the human nervous system and is a highly complex organ. Enclosed in the cranium, it has the same general structure as the brains of other mammals, but is over three times as large as the brain of a typical mammal with an equivalent body size. Most of the expansion comes from the cerebral cortex, a convoluted layer can also send visual input back to neurons A neuron (pronounced /ˈnjʊərɒn/ NOOR-on, also known as a neurone or nerve cell) is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core in lower areas of the visual cortex The term visual cortex refers to the primary visual cortex and extrastriate visual cortical areas such as V2, V3, V4, and V5. The primary visual cortex is anatomically equivalent to Brodmann area 17, or BA17. The extrastriate cortical areas consist of Brodmann area 18 and Brodmann area 19. There is a visual cortex for each hemisphere of the brain... 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 Positron emission tomography is a nuclear medicine imaging technique which produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Images of tracer 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 term visual cortex refers to the primary visual cortex and extrastriate visual cortical areas such as V2, V3, V4, and V5. The primary visual cortex is anatomically equivalent to Brodmann area 17, or BA17. The extrastriate cortical areas consist of Brodmann area 18 and Brodmann area 19. There is a visual cortex for each hemisphere of the brain, the parietal cortex The parietal lobe is a lobe in the brain. It is positioned above the occipital lobe and behind (posterior to) the frontal lobe, and the prefrontal cortex The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas - all higher cognitive processing centers of the brain.[2]
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).
Furthermore, the pineal gland is a hypothetical candidate for producing a mind's eye; Dr. Rick Strassman has postulated that during near death experiences (NDE's) and dreaming, the gland might secrete a hallucinogenic chemical 'N,N-Dimethyltryptamine' to produce internal visuals when external sensory data is occluded. [3]
Philosophy
The use of the phrase mind's eye does not imply that there is a single or unitary place in the mind or brain where visual consciousness occurs. Various philosophers have criticized this view, Daniel Dennett Daniel Clement Dennett is an American philosopher whose research centers on the philosophy of mind, philosophy of science and philosophy of biology, particularly as those fields relate to evolutionary biology and cognitive science. He is currently the co-director of the Center for Cognitive Studies, the Austin B. Fletcher Professor of Philosophy, being one of the best-known.[4] However, others, such as Johnjoe McFadden of the University of Surrey The University of Surrey is a university located within the county town of Guildford, Surrey in the South East of England. It received its charter on 9 September 1966, and was previously situated near Battersea Park in south-west London. The institution was known as Battersea College of Technology before gaining university status. Its roots in the United Kingdom The United Kingdom of Great Britain and Northern Ireland[note 7] is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of the island of Ireland, and many small islands. Northern Ireland is the only part of the UK with a land and the New Zealand-based neurobiologist Susan Pockett, have proposed that the brain's electromagnetic field The electromagnetic field is a physical field produced by electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction. It is one of the four fundamental forces of nature (the others are is consciousness itself, thus causing the perception of a unitary location.[5][6]
References
- ^ Imagery of famous faces: effects of memory and attention revealed by fMRI, A. Ishai, J. V. Haxby and L. G. Ungerleider, NeuroImage 17 (2002), pp. 1729-1741.
- ^ A User's Guide to the Brain, John J. Ratey, ISBN 0-375-70107-9, at p. 107.
- ^ Rick Strassman, DMT: The Spirit Molecule: A Doctor's Revolutionary Research into the Biology of Near-Death and Mystical Experiences, 320 pages, Park Street Press, 2001, ISBN 0-89281-927-8
- ^ Consciousness Explained, Daniel C. Dennett, Boston: Little, Brown and Company, 1991. ISBN 0-316-18065-3.
- ^ Our Conscious Mind Could Be An Electromagnetic Field, UniSci.
- ^ Synchronous Firing and Its Influence on the Brain's Electromagnetic Field: Evidence for an Electromagnetic Field Theory of Consciousness, J. McFadden, Journal of Consciousness Studies 9 (2002), part 4, pp. 23–50.
See also
- Mental image A mental image is an experience that, on most occasions, significantly resembles the experience of perceiving some object, event, or scene, but occurs when the relevant object, event, or scene is not actually present to the senses. There are sometimes episodes, particularly on falling asleep and waking up (hypnapompic), when the imagery, being of
- Philosophy of perception The philosophy of perception is concerned with the nature of sensory and perceptual experience, the status of what is given in such experience, and in particular with how beliefs or knowledge about the world can be accounted for and justified on that basis
- Subjective character of experience That all subjective phenomena are associated with a single point of view is called the subjective character of experience. The term was coined and illuminated by Thomas Nagel in his famous paper What is It Like to Be a Bat?
- Third eye The third eye is a mystical and esoteric concept referring in part to the ajna (brow) chakra in certain Eastern and Western spiritual traditions. It is also spoken of as the gate that leads within to inner realms and spaces of higher consciousness. In New Age spirituality, the third eye may alternately symbolize a state of enlightenment or the
- Binding problem The binding problem is one of a number of terms at the interface between neuroscience and philosophy which suffer from being used in several different ways, often in a context that does not explicitly indicate which way the term is being used. Of the many possible usages, two common versions may be useful anchor points. Firstly, there is the
- Visual perception Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision . The various physiological components involved in vision are referred to collectively as the visual system, and are the focus of much research in
- nous Nous is a philosophical term for mind or intellect. Outside of a philosophical context, it is used, in English, to denote "common sense," with a different pronunciation (/naʊs/)
