Hyperphantasia

Hyperphantasia is the condition of having extremely vivid mental imagery.[1] It is the opposite condition to aphantasia, where mental visual imagery is not present.[2] The experience of hyperphantasia is more common than aphantasia,[3][4] and has been described as "as vivid as real seeing".[3] Hyperphantasia constitutes all five senses within vivid mental imagery; however, visual mental imagery research dominates the literature and there is a dearth of research on the other four senses.[5]

Research into hyperphantasia is most commonly completed by self-report questionnaires such as the Vividness of Visual Imagery Questionnaire (VVIQ), developed by David Marks in 1973, which evaluates the vividness of an individual's mental imagery out of a score of 80.[5] Individuals scoring from 75 to 80/80 are constituted hyperphantasics, and are estimated to be around 2.5% of the population.[2]

Mechanism

There is no unique mental imagery cortical network; the formation of mental imagery involves many regions of the brain, unsurprisingly as mental imagery shares many common brain regions with other cognitive functions.[6] Neurological evidence has shown that in the creation of imagery, neural activity spans prefrontal, parietal, temporal and visual areas.[5][7] Within the neuroscience of imagery, it is often split into 3 primary mechanisms: 1) the mechanism of triggering imagery 2) the mechanism of generation/manipulation and 3) the mechanism underlying the vividness of the imagery.[5][8]

The mechanism underlying the vividness of imagery which may explain disorders like hyperphantasia is controversial amongst the literature.[9] The current findings of the mechanism of hyperphantasia are related to two regions of the brain: the early visual cortex and the frontal cortex.[8]

Recent research has shown the relationship between the size (surface area) of the early visual cortex (V1-V3), specifically V1 and to a lesser degree V2 (but not V3), negatively predicts imagery strength within individuals.[5][10] This relationship is evidenced across both clinical and non-clinical populations [see § Co-morbidity below].[5]

In contrast, there is a positive relationship between the surface area of the frontal cortex and visual imagery strength.[5][9] This aligns with the reciprocal relationship between the size of primary visual cortices and frontal cortices, with a smaller V1 correlating to a larger frontal cortex.[11] Within the general principle of human cortical organization, there is an anatomical trade-off between primary sensory cortices such as the primary visual cortex and frontal areas. Several lines of evidence suggest that the respective sizes of these areas within individuals predict their vividness of imagery.[5][11][10] Additionally, genetics play a part in determining the surface area of V1, suggesting that genetics may indirectly contribute to hyperphantasia.[5][11]

Beyond the size of these regions, there is evidence that lower resting activity and excitability levels within the primary visual cortex predicts stronger mental imagery and vice versa. This has been confirmed by artificially lowering the excitability of the visual cortex, which subsequently led to increased imagery strength.[7] The relationship between the frontal lobe and the visual cortex form an ‘imagery network’ where the ratio in size and excitability of these two areas relate to imagery strength amongst individuals.[7]

Neuroimaging studies using functional magnetic resonance imaging (fMRI) have additionally demonstrated that hyperphantasiacs have significantly stronger connectivity between their prefrontal cortices (Brodmann's Areas 9, 10, 11 in particular) and their visual cortex in comparison to aphantasiacs.[9]

The mechanism behind vivid imagery appears to come down to the size and excitability of the visual-occipital network and the frontal areas as well as the strength of connectivity between these brain regions. However, these factors can only explain the variations in mental imagery; the specific mechanisms that cause hyperphantasia are still not well documented.[9]

Impacts

Memory

Vivid mental imagery as observed in hyperphantasia impacts people's ability to “mental time travel”, or the ability to remember past events as well as imagine future events.[12] Hyperphantasics have reported more sensory details of episodic memories and future event constructions.[13][5][9]

Episodic and autobiographical memories are reliant on sensory-perceptual data such as visual imagery.[9][5] Concepts such as ‘flashbulb memories’ - which are powerful autobiographical memories that we often relive – are often built on vivid visual snapshots.[13] Evidence has shown that individuals exhibiting increased imagery vividness also often recall autobiographical memories with richer descriptions as well as with more fluency.[13] Additionally, disorders that affect vision and visual imagery such as aphantasia have been linked to autobiographical amnesia, depicting the importance of visual imagery to autobiographical recall.[12][13] This relationship of imagery vividness and improved autobiographical memory recall is evidenced across both clinical and non-clinical populations.[2]

There is a lack of research on the impacts of vivid mental imagery on imagining future events and possible scenarios (episodic future thinking); however, research has shown that increased vivid imagery will predict the “clarity of spatial context, the feeling of emotions, and the intensity and personal importance of the events”.[12] This implies that hyperphantasiacs may be better at planning for the future and predicting how events may impact them. Additionally, this explains why vivid imagery helps with perceptual acuity. Research has shown that higher VVIQ scores predict rapid and more precise decision-making in the face of a threat.[14]

Personality

Hyperphantasia has been shown to be associated with higher levels of ‘openness’ in the Big Five personality traits, using the NEO personality inventory. This entails more openness to "new experiences, broad interests, an active imagination and a likelihood of experiencing more positive and negative emotions more keenly than other people".[9]

Occupation

Research has shown that having hyperphantasia may impact the occupational preference of individuals. Hyperphantasics are significantly more likely to work in traditionally creative roles within "Arts, Design, Entertainment, Sports, and Media" in comparison to their aphantasiac counterparts.[5][2]

Co-morbidity

Vivid imagery has been correlated to several mood disorders, particularly anxiety, major depressive disorder, and bipolar disorder, and having hyperphantasia may exacerbate symptoms of such disorders by subserving ruminating thoughts as well as acting as an “emotional amplifier”.[15][5] For example, vivid ‘flash forwards’ to suicidal acts may increase occurrences of suicide.[5]

The vividness of mental imagery has a key role in the development and continuation of intrusive memories, so for those who suffer from PTSD, having hyperphantasia is a substantial risk factor.[16] Both schizophrenia and Parkinson's disease also may be aggravated by hyperphantasia, as high levels of vivid imagery predict the severity of visual hallucinations.[5] In fact, it is possible that hyperphantasia is a ‘trait maker’ for schizophrenia, with both disorders being associated with a smaller primary visual cortex. Individuals with schizophrenia have a 25% volume reduction of their primary visual cortex (V1) and its total number of neurons.[17]

Additionally, a 2008 study found a connection between hyperphantasia and synesthesia. Sampling a large group of synesthetes, they found that individuals with synesthesia reported more vivid mental images than control groups.[18]

References

  1. ↑ Cossins D (5 June 2019). "How people with extreme imagination are helping explain consciousness". New Scientist. Retrieved 2021-03-10.
  2. 1 2 3 4 Zeman A, Milton F, Della Sala S, Dewar M, Frayling T, Gaddum J, et al. (September 2020). "Phantasia-The psychological significance of lifelong visual imagery vividness extremes". Cortex; A Journal Devoted to the Study of the Nervous System and Behavior. 130: 426–440. doi:10.1016/j.cortex.2020.04.003. hdl:20.500.11820/1ff69a7f-ca92-4745-8165-26f8ca62d6d4. PMID 32446532. S2CID 218486387.
  3. 1 2 Zeman A (4 May 2020). "An update on 'extreme imagination' – aphantasia / hyperphantasia". The Eye's Mind. University of Exeter. Retrieved 13 March 2021.
  4. ↑ Maddox L (14 November 2019). "Aphantasia: what it's like to live with no mind's eye". BBC Science Focus Magazine. Retrieved 2021-03-14.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Pearson J (October 2019). "The human imagination: the cognitive neuroscience of visual mental imagery". Nature Reviews. Neuroscience. 20 (10): 624–634. doi:10.1038/s41583-019-0202-9. PMID 31384033. S2CID 199449027.
  6. ↑ Mellet E, Petit L, Mazoyer B, Denis M, Tzourio N (August 1998). "Reopening the mental imagery debate: lessons from functional anatomy". NeuroImage. 8 (2): 129–139. doi:10.1006/nimg.1998.0355. PMID 9740756. S2CID 44704704.
  7. 1 2 3 Keogh R, Bergmann J, Pearson J (May 2020). "Cortical excitability controls the strength of mental imagery". eLife. 9: e50232. doi:10.7554/eLife.50232. PMC 7200162. PMID 32369016.
  8. 1 2 Kosslyn SM, Ganis G, Thompson WL (September 2001). "Neural foundations of imagery". Nature Reviews. Neuroscience. 2 (9): 635–642. doi:10.1038/35090055. PMID 11533731. S2CID 605234.
  9. 1 2 3 4 5 6 7 Milton F, Fulford J, Dance C, Gaddum J, Heuerman-Williamson B, Jones K, et al. (2021-04-01). "Behavioral and Neural Signatures of Visual Imagery Vividness Extremes: Aphantasia versus Hyperphantasia". Cerebral Cortex Communications. 2 (2): tgab035. doi:10.1093/texcom/tgab035. PMC 8186241. PMID 34296179.
  10. 1 2 Bergmann J, Genç E, Kohler A, Singer W, Pearson J (September 2016). "Smaller Primary Visual Cortex Is Associated with Stronger, but Less Precise Mental Imagery". Cerebral Cortex. 26 (9): 3838–3850. doi:10.1093/cercor/bhv186. PMID 26286919.
  11. 1 2 3 Song C, Schwarzkopf DS, Kanai R, Rees G (June 2011). "Reciprocal anatomical relationship between primary sensory and prefrontal cortices in the human brain". The Journal of Neuroscience. 31 (26): 9472–9480. doi:10.1523/JNEUROSCI.0308-11.2011. PMC 3202235. PMID 21715612.
  12. 1 2 3 D'Argembeau A, Van der Linden M (June 2006). "Individual differences in the phenomenology of mental time travel: The effect of vivid visual imagery and emotion regulation strategies". Consciousness and Cognition. 15 (2): 342–350. doi:10.1016/j.concog.2005.09.001. hdl:2268/2916. PMID 16230028. S2CID 10299410.
  13. 1 2 3 4 Greenberg DL, Knowlton BJ (August 2014). "The role of visual imagery in autobiographical memory". Memory & Cognition. 42 (6): 922–934. doi:10.3758/s13421-014-0402-5. PMID 24554279. S2CID 4089873.
  14. ↑ Imbriano G, Sussman TJ, Jin J, Mohanty A (December 2020). "The role of imagery in threat-related perceptual decision making". Emotion. 20 (8): 1495–1501. doi:10.1037/emo0000610. PMC 6908763. PMID 31192666.
  15. ↑ O'Donnell C, Di Simplicio M, Brown R, Holmes EA, Burnett Heyes S (August 2018). "The role of mental imagery in mood amplification: An investigation across subclinical features of bipolar disorders". Cortex; A Journal Devoted to the Study of the Nervous System and Behavior. 105: 104–117. doi:10.1016/j.cortex.2017.08.010. PMID 28912037. S2CID 2109953.
  16. ↑ Morina N, Leibold E, Ehring T (June 2013). "Vividness of general mental imagery is associated with the occurrence of intrusive memories". Journal of Behavior Therapy and Experimental Psychiatry. 44 (2): 221–226. doi:10.1016/j.jbtep.2012.11.004. PMID 23228560.
  17. ↑ Dorph-Petersen KA, Pierri JN, Wu Q, Sampson AR, Lewis DA (March 2007). "Primary visual cortex volume and total neuron number are reduced in schizophrenia". The Journal of Comparative Neurology. 501 (2): 290–301. doi:10.1002/cne.21243. PMID 17226750. S2CID 27305379.
  18. ↑ Barnett KJ, Newell FN (September 2008). "Synaesthesia is associated with enhanced, self-rated visual imagery". Consciousness and Cognition. 17 (3): 1032–1039. doi:10.1016/j.concog.2007.05.011. PMID 17627844. S2CID 23812834.
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