Visual Imagery is the ability to generate mental images in the absence of perception, that is, “seeing with the mind's eye.” We describe a patient, IM, who suffered from an acute ischemic stroke in the right anterior choroidal artery who appeared to demonstrate relatively isolated impairment in visual imagery. Her cognitive function, including her performance on tests of semantic function, was at ceiling, apart from a deficit in visual memory. IM failed in tasks involving degraded stimuli, object decision involving reality judgments on normal animals, and drawings from memory. By contrast, she was able to match objects seen from an unfamiliar viewpoint and to perform tasks of semantic and visual association. We hypothesize that IM has a visual working memory deficit that impairs her ability to generate full visual representations of objects given their names, individual feature, or partial representations. The deficit appears to be the result of damage to connections between the right thalamus and the right temporal lobe. Our findings may help to clarify the role of the thalamus in the cortical selective engagement processes that underlie working memory. (JINS, 2008, 14, 902–911.)

The interpretation of images in relation to their particular setting on rock surfaces has been highlighted in recent studies into the location of depictions in the natural landscape and shamanistic beliefs and practices. The significance of the approach in this article, however, lies in studying the morphology of the rock surface as an integral part of the visual imagery of the rock art, notably how the physical dimensions of the rock surface were used in recreating the physical landscape familiar to the prehistoric artists. We use experiential and cognitive approaches to visual perception to combine an appreciation of artistic endeavour of rock art with an enhanced understanding of the human capacity for creating such images. The results of this approach to rock art contribute to a better understanding of the creative and cognitive aspects of prehistoric fisher-gatherer-hunter art. A detailed example is discussed showing how the physical landscape was re-created in the morphology of the rock surface by using the motion of skiing to illustrate one of the visual narratives at the site of Zalavruga in northern Russia.

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.