V1) has also received some neuroscientific support, although evidence is more limited.
Hebb’s third claim that vivid mental imagery is the result of neural reinstatement within early visual areas (e.g. Researchers have consistently reported substantial similarities between neural regions activated by visual imagery and visual perception 2, 3, 23, and there is now significant evidence that measures of neural reinstatement reflect the content 4– 7, 24 and vividness 25– 28 of mental imagery. The advent of multi-voxel pattern analysis 20 (MVPA) has facilitated the assessment of neural reactivation, which is when stimulus-specific activity patterns elicited at perception are reactivated during retrieval 21, 22. Hebb’s first claim that imagery requires the reinstatement of perceptual neural activity has received considerable empirical support over the last decade. the spatially organized elements of a mental image) 2) analogous to the role of saccades and fixations during perception, eye movements during imagery temporally organize the neural reinstatement of such “part-images”, thereby facilitating imagery by reducing interference between different image parts and, 3) the vividness and detail of mental imagery is dependent on the order (first-, second-, third-order, etc.) of neuronal cell assemblies undergoing reactivation, such that reactivation extending into lower order visual regions would elicit greater subjective vividness than reactivation limited to higher-order areas. Hebb proposed a theory of mental imagery comprising three core claims: 1) imagery results from the reactivation of neural activity associated with the sequential perception of “part-images” (i.e.
To date, however, there is scant neuroscientific evidence showing that eye-movement patterns are related to the neural representations that support mental imagery for complex visual scenes. However, mental imagery is an active, constructive process 9, 10 that is subject to the very kinds of capacity limitations that constrain perception and working memory 11, leading some to propose that people engage with mental images in much the same way as they explore the sensory world-using eye-movements to shift the focus of attention to different parts of a mental image 12– 19. To date, much of the work on the neural basis of visual imagery has examined the phenomenon as if mental images were visual snapshots appearing in their totality to a passive inner observer, with few exceptions 8. The idea that mental imagery involves the reactivation of neural activity patterns elicited at perception has now been firmly established 1– 7. These findings support the conception of mental imagery as a simulation of perception, and provide evidence of the supportive role of eye-movement in neural reactivation. Moreover, neural reactivation correlated positively with fixation reinstatement, meaning that image-specific eye movements accompanied image-specific patterns of brain activity during visualization. We observed that the specificity of neural reactivation correlated positively with vivid imagery and with memory for stimulus image details. To investigate these claims, we applied multivariate pattern analyses to functional MRI (fMRI) and eye-tracking data collected while healthy human participants repeatedly viewed and visualized complex images. He also argued that neural reactivation and imagery benefit from the re-enactment of eye movement patterns that first occurred at viewing (fixation reinstatement). Specifically, Hebb claimed that visual imagery results from the reactivation of neural activity associated with viewing images. Half a century ago, Donald Hebb posited that mental imagery is a constructive process that emulates perception.