Brain Code and Brain Reading. Prof.dr. Jaap Murre University of Maastricht University of Amsterdam [email protected] http://neuromod.org. What principle should it use? Storage capacity Resistance to damage Access speed Serve necessary calculations. What constraints can be identified?
Resistance to damage
Serve necessary calculations
What constraints can be identified?
Neurons are very noisy
They can do only simple calculations
The are severely limited in how they can communicateHow does the brain represent information?
Category node 2 now represents ‘at’
Category node 1 now represents ‘to’
Initial weights are random
Initial winners will be random as well
As time goes by, winners to similar inputs will tend to be located close together
Weights are moved towards input
Inputs are: .9 .9 .7
Weights are: .5 .3 .9
New weight are: .6 .4 .8
.9 .9 .7
Codes for action and movement
overview of the
Area 5 neuron during repeated reaching movements: each
individual trial gives a rather imprecise signal
Based on the idea of ‘muscles as springs’ by Feldman
Fields A and B combined predict field <AB> (see C). When A and B are stimulated the resulting field (see D) corresponds to the theoretical field <AB>
Is our knowledge represented in a localized or distributed fashion?
Trying to find categories in the brain
82 out of 395 were category selectiveFreedman, Riesenhuber, Poggio, & Miller (Science, 2001)
(single-cell, lateral pre-frontal in monkey)
Jim Haxby’s (2001) study
Voxels that respond to faces, also respond to houses and other categories
face cat house bottle scissor shoe random chair
Marieke van der Linden other categoriesFCDC
Miranda van Turennout FCDC
Jaap Murre UvA
Methods other categories
Pretest 15 subjects
Task: 1-back with feedback
Subjects will be trained on categorizing birds that are indistinguishable to the untrained eye.
3 Training sessions on 3 consecutive days other categories
2 fMRI sessions: pre- and post training
Factors: Training (categorization, visual, untrained)
Morph level (60, 75, 90)
20 sec 12 sec 20 sec 12 sec 20 sec 12 sec 20 sec
Each block will be repeated 6x, the order will be randomized
Total scan time: 57.6 min.
Artificial Intelligence approach to cognitive modeling
Functional (computational) model of visual processing in V1/V2, V4, and IT.
With Eric Postma, Joyca Lacroix, and Jaap van den Herik (Universiteit Maastricht)