On the Perception of Probable Things: Neural Substrates of Associative Memory, Imagery, and Perception

Abstract

SUMMARY Perception is influenced both by the immediate pattern of sensory inputs and by memories acquired through prior experiences with the world. Throughout much of its illustrious history, however, study of the cellular basis of perception has focused on neuronal structures and events that underlie the detection and discrimination of sensory stimuli. Relatively little attention has been paid to the means by which memories interact with incoming sensory signals. Building upon recent neurophysiological/behavioral studies of the cortical substrates of visual associative memory, I propose a specific functional process by which stored information about the world supplements sensory inputs to yield neuronal signals that can account for visual perceptual experience. This perspective represents a significant shift in the way we think about the cellular bases of perception.

Hierarchical process memory: memory as an integral component of information processing

“…Furthermore, we argue for a hierarchical organization of process memory, in which the timescale of memory-dependent processing gradually increases from early sensory areas to high order areas. The new framework is broadly consistent with the family of distributed memory models described above [7, 8, 10]. …”

“…In this framework, memory is considered a single entity, either active or inactive, with active memories envisioned as a subset of especially labile memories that are currently being used by the brain to process incoming information [9]. More recently, the separation between memory units and processing units has been questioned by neuroscientists who propose local interactions between memory and perception within visual areas [10–12] and beyond [13], as well as by some long-term memory researchers who argue for the involvement of the medial temporal lobe memory system in perceptual processes [14–17]. …”

A voxel-wise encoding model for early visual areas decodes mental images of remembered scenes

“…Feedback projections from these areas send representations of the objects in predicted, imagined or remembered scenes to EVA. When driven by this internal feedback, activity at any one location in EVA indicates that the visual features depicted by local receptive fields would probably be detected if the objects in the scene were presented to the retina (Albright, 2012). Thus a basic prediction of predictive coding theory is that, given an accurate model of the receptive fields in EVA, it should be possible to accurately decode the visual features associated with remembered scenes from activity that is driven entirely by internal feedback.…”

Developing Synaesthesia

“…Some researchers have hypothesized that associative learning is the critical learning mechanism, where the recall event consists of implicit imagery of the synaesthetic concurrent (Albright, 2012). Hence, it seems plausible that synaesthetic experiences may be acquired, and there is already clear evidence that at least some aspects of synaesthesia can be acquired through training.…”