Self Comes to Mind

this engineering problem. They had their cake and ate it: they were able to fit numerous memories in a limited space but retain the ability to retrieve them rapidly and with considerable fidelity. We humans and our fellow mammals never had to microfilm various and sundry images and store them in hard-copy files; we simply stored a nimble formula for their reconstruction and used the existing perceptual machinery to reassemble them as best we could. We were always postmodern.
Memory at Work
     
    Here is the problem, then. Besides creating mapped representations that result in perceptual images, the brain manages a no-less-remarkable achievement: it creates memory records of the sensory maps and plays back an approximation of their original content. This process is known as recall . Remembering a person or event or telling a story necessitates recall; recognizing objects and situations around us necessitates recall as well; so does thinking about objects with which we have interacted and about events we have perceived, and so does the entire imaginative process with which we plan for the future.
    If we are to understand how memory works, we must understand how the brain establishes the record of a map as well as its location. Does it create a facsimile of the thing to be memorized, a sort of hard copy placed in a file? Or does it reduce the image to code—digitize it, as it were? Which? How? Where?
    There is another critical where issue: Where is the record played back during recall, so that the essential properties of the original image can be recuperated? When Dick Diver, in Tender Is the Night , comes to hear the shots again, where in his brain are they being played back? When you think of a friend you lost or of a house you lived in, you conjure up a collection of images of those entities. They are less vivid than the real thing or a photograph. But recalled images can maintain the basic properties of the original, so much so that an ingenious cognitive neuroscientist, Steve Kosslyn, has been able to estimate the relative size of an object recalled and inspected in mind. 3 Where are the images reconstructed so that we can study them in our reverie?
    The traditional answers (although assumptions would be a better word) to this question get their inspiration from a conventional account of sensory perception. Accordingly, different early sensory cortices (largely in the back sections of the brain) bring forward the components of perceptual information by brain pathways to so-called multimodal cortices (largely in the front sections), which integrate them. Perception would operate on the basis of a cascade of processors going in one direction. The cascade would extract, step by step, more and more refined signals, first in the sensory cortices of a single modality (e.g., visual) and later in multimodal cortices, those that receive signals from more than one modality (e.g., visual, auditory, and somatic). The cascade would follow, in general, a caudo-rostral direction (back to front) and would culminate in the anterior temporal and frontal cortices, where the most integrated representations of the ongoing multisensory apprehension of reality are presumed to occur.
    These assumptions are captured by the notion of a “grandmother cell.” A grandmother cell is a neuron somewhere near the top of the processing cascade (e.g., the anterior temporal lobe) whose activity would, in and of itself, comprehensively represent our grandmother when we perceive her. Such single cells (or small ensembles of cells) would hold an all-encompassing representation of objects and events during perception. Not only that, they would also hold a record of those perceived contents. The memory records would be where the grandmother cells are. Even more grandly, and in direct response to the question posed earlier, reactivated grandmother cells would allow the playback of those same perceived contents in their entirety, right there and then. In brief, activity in those neurons would account for the recall of varied and properly integrated images, the face of your grandmother or Dick Diver’s train station shots included. That would be the where of recall.
    I regard the above account as unlikely. By this account, damage to the up-front temporal and frontal lobe cortices, the anterior brain regions, should preclude both normal perception and normal recall. Normal perception would collapse because the neurons capable of creating the fully