Quantification of Gabor-like receptive fields.

We quantify whether each excitatory neuron in our network model has a Gabor-like receptive field or not, in both our mature young network (30 loops) and the oldest network (80 loops). We assess Gabor-ness by fitting a spatial Gabor profile to each neuron’s receptive field and classify it as Gabor-like if the goodness-of-fit relative to the RF magnitude is sufficiently small; see Methods and [39]. In the bottom subtable, the numerator in each fraction corresponds to classification in old age and the denominator corresponds to classification in youth. For example, of the 123 excitatory neurons with Gabor-like RFs in youth, only 6 retain Gabor-like RFs in old age, while of the 400 − 123 = 277 neurons that are not Gabor-like (“not-Gabor”) in youth we find that 257 of those neurons are not-Gabor in old age.