1. 1 Cerebrum November 6, 2013 Chapter 13: 496 - 505 Dr. Diane M. Jaworski Frontal Temporal Occipita l Parietal

2. 2 The Cerebrum Is the largest part of the brain Controls all conscious thoughts and intellectual functions Processes somatic and visceral sensory and motor information

3. 3 Functional Principles of the Cerebrum Each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of the body Specific regions of the cerebral cortex have specific functions, but there is overlap in function Primary motor and sensory areas are organized into topographic maps representing specific body regions Although similar in structure, the 2 hemispheres have different functions (e.g., language on left, face recognition on right)

4. 4 Hemispheric Lateralization “brain sided-ness” does not always correspond to “handed-ness” Right side - “Creative”: - Musical and artistic awareness - Spatial and pattern perception - Face recognition - Emotional part of speech Left side - “Analytical”: - Spoken and written language - Numerical and scientific skills - Reasoning © McKinley et al. A & P 2013

5. The Corpus Callosum is made of the axons (white matter) of cortical neurons communicating between the left and right cerebral hemispheres 5 © McKinley et al. A & P 2013

6. 6 Everyone has the same pattern of gyri and sulci on their cerebral cortex Different gyri deal with different types of information Sulcus shallow depression (plural: sulci) Gyrus elevated ridge (plural: gyri)

7. 7 © McKinley et al. A & P 2013

8. 8 Different areas of the cortex perform different functions “Primary” areas : neurons receive sensory information or directly send out motor instructions “Association” areas : neurons make sense of sensory information or plan motor activities (muscle movements)

9. 9 © McKinley et al. A & P 2013

10. 10 © McKinley et al. A & P 2013

11. 11 Frontal Lobe: Motor and Limbic Functions Primary Motor Cortex Premotor Cortex Prefrontal Cortex Broca’s Area Motor speech Central sulcus Separates frontal and parietal lobes

12. 12 Frontal Lobe: Primary Motor Cortex Central sulcus © McKinley et al. A & P 2013

13. 13 Primary Motor Cortex = Precental gyrus - Directs voluntary muscle movement - Contains a map of all skeletal muscles - Pyramidal neurons in this gyrus project via the internal capsule to synapse in the brainstem or spinal cord; they talk to the neurons that contact the muscles (they do NOT directly synapse on the muscles!!) Frontal Lobe: Primary Motor Cortex

14. The internal capsule contains Pyramidal neuron axons leaving the cortex (motor info) AND the axons of neurons bringing sensory info into the cortex 14 Internal Capsule © McKinley et al. A & P 2013

15. 15 Neurons in the primary motor cortex are arranged according to the muscles they control

16. 16 Frontal Lobe: Premotor Cortex

17. 17 Frontal Lobe: Premotor Cortex * learned motor activities planning of motor activities Directs neurons in the primary motor cortex; therefore, less discrete topographic map Contains two specialized regions: - Frontal eye fields - Broca’s speech area

18. 18 Frontal Lobe: Frontal Eye Fields The purpose of this region is to keep the eyes directed forward. The right frontal eye field forces both eyes to the left while the left frontal eye field forces both eyes to the right. In a unilateral lesion, both eyes will deviate TOWARDS the side of the lesion.

19. 19 Frontal Lobe: Broca’s Speech Area Primarily located in left hemisphere - produces speech Expressive (motor, non-fluent) aphasia - anomia (inability to name objects) - anomia (inability to name objects) Patient aware of deficit Broca's Aphasia http://www.youtube.com/watch?v=f2IiMEbMnPM&feature=related

20. 20 Frontal Lobe: Prefrontal Cortex

21. 21 Frontal Lobe: Prefrontal Cortex Largest part of the frontal lobe Many connections to other areas Vague limbic functions (e.g., personality)

22. 22 © McKinley et al. A & P 2013

23. 23 Parietal Lobe: Somatosensation (the sense of touch, awareness of body) Primary Somatosensory Cortex Somatosensory Association Cortex

24. 24 Parietal Lobe: Primary Somatosensory Cortex Central sulcus © McKinley et al. A & P 2013

25. 25 Primary Somatosensory Cortex = Postcental gyrus Receives somatic sensory information from skin receptors, joints and muscles: – Touch, pressure, vibration – Pain and temperature – Taste Parietal Lobe: Primary Somatosensory Cortex

26. 26 Neurons in the primary somatosensory cortex are arranged according to the body region they receive information from

27. The maps in the primary motor and somatosensory cortices are the same, just the amount of cortex devoted differs! 27

28. 28 Parietal Lobe: Somatosensory Association Cortex

29. 29 Parietal Lobe : Somatosensory Association Cortex Interpretation of sensations –Shape and texture of object –Orientation of object (where an object is in space) –Relationship of body parts stroke to right parietal association cortex results in a fascinating syndrome in which the patient disregards the left side of their body = syndrome of hemineglect

30. 30 Syndrome of Hemineglect

31. 31

32. 32 © McKinley et al. A & P 2013

33. 33 Primary Auditory Cortex Wernicke’s Speech Area Lateral fissure Separates frontal, parietal & temporal lobes Temporal Lobe: Hearing, Limbic Function, Visual Association

34. 34 Temporal Lobe

35. 35 Primary Auditory Cortex –Receives sound information, sorts by frequency (tonotopic map) –Pitch, rhythm Temporal Lobe: Primary Auditory Cortex © Bear et al. Neuroscience 1996

36. 36 Primarily located in left hemisphere Speech comprehension Receptive (sensory, fluent) aphasia - language comprehension affected - language comprehension affected - nonsensical speech, but patient unaware of deficit - nonsensical speech, but patient unaware of deficit - anomia, impaired repetition, non-fluent reading - anomia, impaired repetition, non-fluent reading - apraxia (inability to execute motor activity based - apraxia (inability to execute motor activity based on verbal command) on verbal command) Wernicke’s Area Temporal Lobe: Wernicke’s Speech Area

37. 37 Temporal Lobe: Auditory Association Cortex Wernicke’s Speech Area Wernicke's Aphasia http://www.youtube.com/watch?v=aVhYN7NTIKU

38. 38 Temporal Lobe: Limbic System (will be discussed later in the course)

39. 39 © McKinley et al. A & P 2013

40. 40 Occipital Lobe: Vision Primary Visual Cortex Visual Association Cortex

41. 41 Occipital Lobe: Primary Visual Cortex

42. 42 © McKinley et al. A & P 2013

43. 43 © McKinley et al. A & P 2013

44. 44 © McKinley et al. A & P 2013