1. IST8A Fall 2008 Introduction to the Brain

2. Outline of Topics 1.Imaging: postmortem and MRI 2.Brain Macro anatomy – lobes, tissues, cortex, hippocampus, amygdala, connectivity 3.Brain Micro anatomy – Neurons 4.Dynamics of brain change over time 5.Our lab: healthy normal aging vs. dementia

3. Studies of Brain Form and Function Postmortem brains Used for precise anatomical measurements Living subjects (computer analysis) Use MRI imaging to track form and function in living individuals

4. The Human Brain Cerebrum and Cerebellum -Cerebrum divided into four regions, Frontal, Parietal. Occipital, Temporal -Highly convoluted surface with 6 layers of cells in the cortex.

5. Four Cerebral Lobes (viewed from midline)

6. MRI Images Magnetic Resonance Imaging Intense magnetic and radio frequency fields Quantum mechanics High resolution imaging: 1. anatomical (features in fine detail) 2. functional (activations) Lauterbur and Mansfield – Nobel Prize 2003

7. Sample MRI Images High resolution anatomical MRI 3D and 2D views Skull in place and stripped

8. Axial (horizontal) Coronal Whole Head MRI Slices

9. Sagittal Whole Head Slice

10. Macro Anatomy: coronal and sagittal views Gray White CSF Amygdala (one on each side) Hippocampus Tissue Types

11. Brain Connectivity: Memory Structures hippocampifornix Frontal-occipital fasciculi (axon bundles) External view for context

12. An elephant never forgets: comparison of elephant and human hippocampus Elephant hippocampi (red) Human hippocampi Source: www.allmanlab.caltech.edu/PDFs/Hakeem2005.pdf

13. Brain Connectivity: Visual streams Source: The Primary Visual Cortex, by Matthew Schmolesky, http://webvision.med.utah.edu/Visual Cortex.html http://webvision.med.utah.edu/Visual Cortex.html Source: http://philosophy.hku.hk/courses/cogsci/media/visionstreams.jpg Incoming Dorsal and Ventral

14. Micro Anatomy: The Neuron Components: 1.Cell body (gray matter) 2.Dendrites 3.Axon (white matter – from myelin sheathes) Axons may be very long e.g. front to back of brain or length of spinal chord Source: www.enchantedlearning.com

15. Neuron Function Neurons are electrochemical signaling cells. Signals (action potentials) travel down axons to terminal boutons Synapse: tiny space between axonal boutons and dendrites of the next neuron Neurotransmitters: released across synapse by arrival of action potential. Received by post-synaptic dendrites.

16. Neuron communication Source: http://www.niaaa.nih.gov/Resources/GraphicsGallery/Neuroscience/synapse.htm

17. Aging and the Brain What anatomical differences occur between young and old? What about between healthy normal aging and dementia? What steps can be taken to minimize or prevent unhealthy changes?

18. Categories of Aging Very healthy normal Mild cognitive impairment Alzheimer’s Disease

19. Brain change over 1 year: patterns of gray matter loss NormalAlzheimer’s

20. Normal vs. Alzheimer’s Gross feature differences Two structures illustrated in these slides differ greatly between normal (right) and Alzheimer’s Coronal view (from front) Sagittal view (from side; frontal lobe to left) Alzheimer’sNormal Ventricles (fluid filled cavities) Hippocampi (long- term memory). Left hippocampus in green oval. Ventricles greatly enlarged Hippocampi severely shrunken and surrounded by fluid (black spaces)