Announcements. a3 is out, due 2/15 11:59pm Please please please start early quiz will be graded in about a week. a1 will be graded shortly—use glookup to see your grade. Where we stand. Last Week Imaging studies Connectionist representation This Week Backprop traditional AI Coming up
Cognition and Language
Neural Net & Learning
monkey sees experimenter grasp an object
monkey sees experimenter reaches his hand behind a screen to grasp an object
this is what we see in a monkey…
measuring a neuron in the parietal area
humans watching foot , hand and mouth actions without an object
humans watching same actions with an object
integrated, multi-modal representation of actions, along with the objects and locations
Buccino et al., 2001
ProceduralTwo ways of looking at memory:
facts about a situation
Short Term Memory
Long Term MemoryTwo ways of looking at memory:
weakenLTP and Hebb’s Rule
drinks waterWhy is Hebb’s rule incomplete?
ti : target
xi = ∑j wij yj
yi = f(xi)The McCullough-Pitts Neuron
yj: output from unit j
Wij: weight on connection from j to i
xi: weighted sum of input to unit i
fLet’s try an example: the OR function
i1Many answers would work
y = f (w01i1 + w02i2 + w0bb)
recall the threshold function
the separation happens when w01i1 + w02i2 + w0bb = 0
move things around and you get
i2 = - (w01/w02)i1 - (w0bb/w02)
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