Mental visual imagery – can a language encoded object generate depictive imagery?

1. Mental visual imagery – can a language encoded object generate depictive imagery? Igor Bascandziev Harvard Graduate School of Education

2. Presentation overview • Introduction • An overview of the debate • What has been found so far • Open questions and motivation • Experiment proposal (research question, design, tasks, anticipated findings) • Limitations

3. Introduction • History (philosophy, cognitive psychology, advent of neuroimaging studies) • The debate – is the visual mental imagery different from the rest of general reasoning? • Zenon Pylyshyn – “same forms of representation as are involved in general reasoning” • Stephen Kosslyn – the mental imagery is not describing the objects, but it depicts objects

4. The depictive nature • The early visual area is topographic, depictive, and functionally activated during perception • If the very same region is functionally engaged during visual imagery, then that should serve as evidence that the visual mental imagery is depictive

5. What has been found • Many studies showed activations in the early visual area during mental imagery • But many studies did not replicate this finding • It’s more complicated than just having any task of mental imagery

6. What has been found – short summary • Activation if object imagery, deactivation if spatial imagery • More likely to find activation if - the task asks for high resolution object detail - if there is an image suppression - if the imaging is conducted with a powerful fMRI (e.g. 4T)

7. What has been found • Neuropsychological evidence that damage in the early visual cortex influences mental imagery • TMS studies showing that temporary disruptions of the early visual cortex cause deficit in the ability to generate mental image • Behavioral studies combined with imaging studies – negative correlation between activation and response time

8. Open questions and implications • If we assume that the visual mental imagery is depictive, then interesting question would be: Whether there is a difference between objects encoded through perception and objects encoded through language?

9. Open questions and implications • It will show whether an object encoded only through language hinges upon the depictive visual imagery • It will suggest that the depictive visual imagery could be strongly influenced by a top down processes

10. Experiment proposal - RQ Is there a difference between the mental imagery of an object encoded through perception and the mental imagery of an object encoded through language?

11. Experiment proposal – design and tasks • Target sample size n=10 • Event related design • Before the scanning • Test to check subjects’ knowledge about animals • Learning period – each subject will learn about visual characteristics of non-existing made-up animals. At the end of the learning, test to check subjects’ knowledge of the made-up animals

12. Experiment proposal – design and tasks • Two conditions (real animal and made-up animal) • The procedure will be similar to the one in Klein et al. (2000). Source: Klein et al. (2000)

13. Experiment proposal – anticipated findings • There will be activation of the early visual area in both conditions • The familiarity with the object will be positively correlated with activations • The familiarity with the object will be positively correlated with the number of correct answers and negatively correlated with the response times

14. Experiment proposal – anticipated findings • As an example, I present Klein et al. (2000) finding

15. Limitations • Difficult to control the familiarity factor • Are the objects really encoded by language, or the subjects just combine previously perceived parts of animals

16. References • DEsposito, M., Detre, J. A., Aguirre, G. K., Stallcup, M., Alsop, D. C., & Tippet, L. J., et al. (1997). A functional MRI study of mental image generation. Neuropsychologia, 35(5), 725-730. • Ishai, A., Haxby, J. V., & Ungerleider, L. G. (2002). Visual imagery of famous faces: Effects of memory and attention revealed by fMRI. NeuroImage, 17(4), 1729-1741. • Klein, I., Paradis, A. L., Poline, J. B., Kosslyn, S. M., & Le Bihan, D. (2000). Transient activity in the human calcarine cortex during visual-mental imagery: An event-related fMRI study. Journal of Cognitive Neuroscience, 12, 15-23. • Kosslyn, S. M. (2005). Mental images and the brain. Cognitive Neuropsychology, 22(3-4), 333-347. • Kosslyn, S. M., Ganis, G., & Thompson, W. L. (2001). Neural foundations of imagery. Nature Reviews Neuroscience, 2(9), 635-642. • Kosslyn, S. M., & Thompson, W. L. (2003). When is early visual cortex activated during visual mental imagery? Psychological Bulletin, 129(5), 723-746. • Mazard, A., Mazoyer, B., Etard, O., Tzourio-Mazoyer, N., Kosslyn, S. M., & Mellet, E. (2002). Impact of fMRI acoustic noise on the functional anatomy of visual mental imagery. Journal of Cognitive Neuroscience, 14(2), 172-186. • Mazard, A., Tzourio-Mazoyer, N., Crivello, F., Mazoyer, B., & Mellet, E. (2004). A PET meta-analysis of object and spatial mental imagery. European Journal of Cognitive Psychology, 16(5), 673-695. • Mellet, E., Tzourio-Mazoyer, N., Bricogne, S., Mazoyer, B., Kosslyn, S. M., & Denis, M. (2000). Functional anatomy of high-resolution visual mental imagery. Journal of Cognitive Neuroscience, 12(1), 98-109. • Nowiński, W. L., Thirunavuukarasuu, A., & Kennedy, D. N. (2001). Brain atlas for functional imaging [computer file] : Clinical and research applications (Version 1.0 ed.). Stuttgart, Germany; New York: George Thieme Verlag; Thieme New York. • Pylyshyn, Z. W. (2002). Mental imagery: In search of a theory. The Behavioral and Brain Sciences, 25(2), 157-82; discussion 182-237. • Toga, A. W., & Mazziotta, J. C. (Eds.). (2000). Brain mapping : The systems. San Diego, Calif., USA: Academic Press.