An item in today’s Physorg newsletter describes some remarkable neurological research: scientists at CalTech, by showing pictures to test subjects while monitoring brain activity, have managed to associate individual neurons in the medial temporal lobe with specific perceptions.
Dr. Moran Cerf of the California Institute of Technology in Pasadena and colleagues conducted their experiment by showing the subjects images of people, places or objects that were familiar to them, including pictures of celebrities such as Michael Jackson, Marilyn Monroe, and Bill Clinton. They then looked for the neurons that fired when the subject was shown each image.
In each of the subjects they found individual neurons fired when the person looked at a specific image. So there was a “Michael Jackson neuron”, a “Marilyn Monroe neuron”, and others that fired when the person was shown an image of the Eiffel tower, a spider, or other familiar objects or places.
When the neurons corresponding to particular images had been identified, the researchers hooked the electrodes up to a computer that displayed the image corresponding to the neuron that fired. The subject was then asked to think about one of the images. So, for example, a subject was asked to think about Marilyn Monroe. The Marilyn Monroe neuron in the subject’s brain fired, and the information was relayed to the computer, which then displayed Monroe’s image.
Another experiment designed to test how well the subjects could control the single neurons was a fade experiment in which the subject was shown a combined image of two faces: Josh Brolin (star of Goonies) and Marilyn Monroe, and told to think of Josh Brolin. The electrodes sent data on the Josh Brolin and Marilyn Monroe neurons to the computer, which brightened the image of the one causing most neuron firing. As the subject thought of Brolin, the image of Monroe faded out.
This is an impressive result, with enormously important implications.
Next questions: if I have a neuron in my brain that reliably activates when I see or think of Marilyn Monroe, does it really fire only when I see or think of Marilyn Monroe? I’ll be surprised if neural resources are allocated in such a “dedicated” way — a one-to-one mapping of the kind suggested here, with each neuron representing exactly one intentional referent, and doing nothing else; it seems so limiting. I’ve always imagined that the hardware implementation of our memory and intentionality would take the form of configurations of groups of neurons; it seems you’d get more for less that way. And is this “Marilyn” cell activated if I see a picture of Marilyn Monroe without being conscious of it? How about if I dream about her?
And then the much harder question: why that neuron?
Read the story here.