Need a textbook? Email Sheldon

1. Need a textbook? Email Sheldon

2. Goals and Methods What is the goal of Cognitive Neuroscience?

3. Goals and Methods • Broad goal is to understand how the brain accomplishes cognitive processes such as attention, memory, language and consciousness • There are several smaller questions in this: • What structures do what jobs? • How is information represented in these structures? • How is information passed between these structures?

4. Anatomy • What is the difference between Structural Anatomy and Functional Anatomy? • What roles do each play in our understanding of the brain?

5. Structural Anatomy • Brain structures are identified in a hierarchical fashion (with substantial randomness) • Hemispheres -> Lobes -> Sulci & Gyri • Sulci and Gyri are all named • but somewhat variable across individuals

6. Structural Anatomy • Brodmann Areas defined by cytoarchitecture • map of variations in cellular morphology • It is probably not coincidence that Broadman areas are also generally functionally distinct

7. Connectivity • Anatomists are also concerned with brain regions and how they are interconnected • Interconnectedness occurs at various levels: • interneurons • cortico-cortical connections • thalamo-cortical and cortico-thalamic • afferent = “to” (e.g. sensory) and efferent = “from” (e.g. motor)

8. Connectivity • How do anatomists study connectivity? • Retrograde Tracers (e.g. horseradish peroxidase) follow axons back to where they came from • Anterograde Tracers (e.g. dextran) follow axons to where they are going

9. Connectivity • Diffusion Tensor Imaging (DTI) • MRI Technique that traces long white matter tracts

10. Connectivity • “Ascending” and “descending” projections in sensory systems • estimate: for every ascending projection there are ten descending projections

11. Connectivity • “Ascending” and “descending” projections in sensory systems • estimate: for every ascending projection there are ten descending projections Why would we have descending projections?

12. Connectivity • It is the inter-connectivity of the brain that (probably) allows it to perform the vastly complex processes of cognition

13. Structural and Functional Imaging • There are a number of well known techniques to create images of brain anatomy • CAT scan, MRI, X-Ray, • Note however that structural and functional images are not the same thing!

14. Structural and Functional Imaging • There are a number of well known techniques to create images of brain anatomy • CAT scan, MRI, X-Ray, • Note however that structural and functional images are not the same thing! • Which is more useful? If you could go back in time and give one of these techniques to the earliest neuroscientists, which would it be?

15. Structural and Functional Imaging • This is a Functional MRI Image !?

16. Structural and Functional Imaging • This is a structural MRI image (an “anatomical” image)

17. Structural and Functional Imaging • What you really want is both images co-registered

18. Structural and Functional Imaging • What you really want is both images co-registered • Why? What’s wrong with the functional image alone?

19. Structural and Functional Imaging • Functional images tend to be lower resolution and fail to convey spatial information Pixels

20. Structural and Functional Imaging • Structural images have finer (smaller) pixels Pixels