1. CYCLES IN BRAIN Kaushik Majumdar Systems Science and Informatics Unit
ISI, Bangalore Centre

2. Talking and Understanding: Broca’s Area

3. Talking and Understanding: Wernicke’s Area

4. Cortical Interconnections

5. Functional Areas

6. Sensory Processing: Vision

7. Bottom-Up and Top-Down Processing
Engel et al., Nat. Rev. Neurosci., Oct 2001
Bottom-Up and Top-Down Processing

8. Feed Forward and Feed Back Connections
Jantzen et al., Journal of Cognitive Neuroscience, 2009
Feed Forward and Feed Back Connections

9. Thalamo-Cortical Loops and Cortico-Cortical Loops

10. Schematic Thalamo-Cortical Connections
Mumford, Biological Cybernetics, 65: 135 – 145, 1991.
Schematic Thalamo-Cortical Connections

11. Thalamus as Active Black Board
Mumford, Biological Cybernetics, 65: 135 – 145, 1991.
Thalamus as Active Black Board
Process 1
Process 2
Process 4
Process 3
Shared Memory

12. Cortico-Cortical Pathways by Layer
Mumford, Biological Cybernetics, 66: 241 – 251, 1992.
Cortico-Cortical Pathways by Layer A B

13. How to find the loops? Magnetic Resonance Imaging (MRI)
a) Granger causality
b) Diffusion tensor imaging
Mathematical modeling

14. Magnetic Resonance Imaging

15. T1 and T2 Time

16. MRI (cont)

17. MRI (summarized)
Grey matter
White matter

18. Diffusion Tensor Imaging (DTI) and functional MRI (fMRI)
Wandell & Dougherty, SPIE Vol. 6057, , 2006.
Diffusion Tensor Imaging (DTI) and functional MRI (fMRI)
x → y or y → x y x

19.
Granger Causality

20. 3D Fiber Tracts of Human Brain
C. Lenglet, PhD Thesis, INRIA Sophia Antipolis, France, 2006.
3D Fiber Tracts of Human Brain

21. Probabilistic Estimation of Loops
Majumdar, Cognitive Neurodynamics, 2(1), 2008.
Probabilistic Estimation of Loops
Probability in each direction is 1/6. Z6 -Y -X 5 4 3 2 1 +X
Probability of a cortical path to loop around is +Y

22. THANK YOU