Mental image
[6] The nature of these experiences, what makes them possible, and their function (if any) have long been subjects of research and controversy in philosophy, psychology, cognitive science, and, more recently, neuroscience.
[9] Due to the fundamentally introspective (reflective) nature of the phenomenon, it has been difficult to assess whether or not non-human animals experience mental imagery.
Philosophers such as George Berkeley and David Hume, and early experimental psychologists such as Wilhelm Wundt and William James, understood ideas in general to be mental images.
[14][15] Others reject the view that the image experience may be identical with (or directly caused by) any such representation in the mind or the brain,[16][17][18][19][20][21] but do not take account of the non-representational forms of imagery.
[22] In this discussion, Cicero observed that allusions to "the Syrtis of his patrimony" and "the Charybdis of his possessions" involved similes that were "too far-fetched"; and he advised the orator to, instead, just speak of "the rock" and "the gulf" (respectively)—on the grounds that "the eyes of the mind are more easily directed to those objects which we have seen, than to those which we have only heard".
Studies using fMRI have shown that the lateral geniculate nucleus and the V1 area of the visual cortex are activated during mental imagery tasks.
Significant positive correlations were also obtained between VVIQ scores and hippocampal structures including Bilateral CA1, CA3, CA4 and Granule Cell (GC) and Molecular Layer (ML) of the Dentate Gyrus (DG).
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.
Rick Strassman and others have postulated that during near-death experiences (NDEs) and dreaming, the gland might secrete the hallucinogenic chemical N,N-Dimethyltryptamine (DMT) to produce internal visuals when external sensory data is occluded.
[32] The functional-equivalency hypothesis is that mental images are "internal representations" that work in the same way as the actual perception of physical objects.
[35] Auditory imagery in general occurs across participants in the temporal voice area (TVA), which allows top-down imaging manipulations, processing, and storage of audition functions.
[39] A meta-analysis of neuroimagery studies revealed significant activation of the bilateral dorsal parietal, interior insula, and left inferior frontal regions of the brain.
[41] Consistent with these findings, a meta-analysis of 27 neuroimaging studies demonstrated imagery-related activity in a region of the left ventral temporal cortex, which was dubbed the Fusiform Imagery Node.
[42] An additional Bayesian analysis excluded a role for occipital cortex in visual mental imagery, consistent with the evidence from neurological patients.
[44] A study on one patient with one occipital lobe removed found the horizontal area of their visual mental image was reduced.
They found that inhibition of these areas through repetitive transcranial magnetic stimulation (rTMS) resulted in impaired visual perception and imagery.
Unenlightened man is like the prisoner, explains Socrates, a human being making mental images from the sense data that he experiences.
His point was that the idea that the rock is just another mental image and has no material existence of its own is a poor explanation of the painful sense data he had just experienced.
To use the analogy of the computer screen, these critics argue that cognitive science and psychology have been unsuccessful in identifying either the component in the brain (i.e., "hardware") or the mental processes that store these images (i.e. "software").
Psychologist Zenon Pylyshyn theorized that the human mind processes mental images by decomposing them into an underlying mathematical proposition.
Shepard and Metzler found the opposite: a linear relationship between the degree of rotation in the mental imagery task and the time it took participants to reach their answer.
Stephen Kosslyn and colleagues[56] showed in a series of neuroimaging experiments that the mental image of objects like the letter "F" are mapped, maintained and rotated as an image-like whole in areas of the human visual cortex.
For example, several studies have provided evidence that people are slower at rotating line drawings of objects such as hands in directions incompatible with the joints of the human body,[57] and that patients with painful, injured arms are slower at mentally rotating line drawings of the hand from the side of the injured arm.
Subsequent neuroimaging studies[59] showed that the interference between the motor and visual imagery system could be induced by having participants physically handle actual 3D blocks glued together to form objects similar to those depicted in the line-drawings.
Amorim et al. have shown that, when a cylindrical "head" was added to Shepard and Metzler's line drawings of 3D block figures, participants were quicker and more accurate at solving mental rotation problems.
[63] 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.
Logie, Pernet, Buonocore and Della Sala (2011) used behavioural and fMRI data for mental rotation from individuals reporting vivid and poor imagery on the VVIQ.
The authors of the study stated that "mental practice alone seems to be sufficient to promote the modulation of neural circuits involved in the early stages of motor skill learning".
[70] Imagery training has been effective in a series of studies, mostly in sport where participants are taught formal skills to improve a mental image.
[citation needed] In general, Vajrayana Buddhism and Bön utilize sophisticated visualization or imaginal (in the language of Jean Houston of Transpersonal Psychology) processes in the Tulpa construction of the yidam sadhana, kye-rim, and dzog-rim modes of meditation and in the yantra, thangka, and mandala traditions, where holding the fully realized form in the mind is a prerequisite prior to creating an 'authentic' new art work that will provide a sacred support or foundation for deity.
