The Brain

1. The Brain • 3 primary divisions: • Forebrain • cortex (folded stuff) • limbic system, etc (stuff around brain stem) • Midbrain (top of brainstem) • Hindbrain (bottom of brainstem + cerebellum)

2. Hindbrain Medulla Pons Cerebellum Pons Medulla Cerebellum http://www-unix.oit.umass.edu/~psyc335c/lectures/hindbrain.gif

3. Medulla: Controls vital reflexes: breathing, heart rate, vomiting, salivation, coughing, sneezing - Via cranial nerves Damage to medulla can be fatal Large doses of opiates can be fatal b/c suppress activity of medulla…why…?...b/c receptors there!

4. Pons: Also has cranial nerves Location of axon decussation (where axons cross from one side of the brain to the other…so left brain controls right body and vice versa) Reticular formation: motor control, arousal, consciousness

5. Midbrain: Cerebral aqueduct More cranial nerves Superior colliculus (visual info) Inferior colliculus (auditory info) Substantia nigra: dopamine-producing cells, structure that is lost in Parkinson’s Disease http://en.wikipedia.org/wiki/Midbrain

6. Brainstem Medulla Pons Midbrain Some forebrain structures

7. Senses: Information comes in the cranial nerves and eventually ends up in the cortex

8. Cranial Nerves Table 4.4, page 87 Olfactory nerve: Smell http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

9. Cranial Nerves Table 4.4, page 87 Optic nerve: Vision http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

10. Cranial Nerves Table 4.4, page 87 Occulomotor nerve: Eye movement, pupil constriction http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

11. Cranial Nerves Table 4.4, page 87 Trochlear nerve: Eye movement http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

12. Cranial Nerves Table 4.4, page 87 Trigeminal nerve: Skin senses from face Jaw muscles for chewing and swallowing (muscles of mastication) http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

13. Cranial Nerves Table 4.4, page 87 Abducens nerve: Eye movements http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

14. Cranial Nerves Table 4.4, page 87 Facial nerve: Taste Facial expressions Crying Salivation Dilation of head’s blood vessels http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

15. Cranial Nerves Table 4.4, page 87 Acoustic nerve: Aka vestibulocochlear or statoacoustic Hearing Equilibrium http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

16. Cranial Nerves Table 4.4, page 87 Glossopharyngeal nerve: Taste Swallowing Salivation Throat movements during speech http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

17. Cranial Nerves Table 4.4, page 87 Vagus nerve: Sensation from neck and thorax Control of throat, esophagus, larynx Parasympathetic nerves to stomach, intestines, etc http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

18. Cranial Nerves Table 4.4, page 87 Spinal accessory nerve: Aka Accessory nerve Neck and shoulder movements http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

19. Cranial Nerves Table 4.4, page 87 Hypoglossal nerve: Muscles of tongue http://www.besthealth.com/besthealth/bodyguide/reftext/images/cranial_nerves.jpg

20. Cranial nerve signs help determine the location of a lesion in the brain • Essential element in clinical neuroanatomy • Neurological exam: http://www.vhct.org/case1799/neurologic_examination.shtml • Example: patient is asked to stick out tongue. If the tongue deviates to the left, the lesion involves the nucleus of the left hypoglossal nerve.

21. Nerve key Nerve Type of function On Optic Some = sensory Old Olfactory Say Olympus Occulomotor Marry = motor Towering Trochlear Money Tops Trigeminal But = both (S&M) A Abducens My Fin Facial Brother And Acoustic* Says German Glossopharyngeal Bad Viewed Vagus Boys Some Spinal accessory** Marry Hops Hypoglossal Money * Acoustic-vestibulocochlear, stateocochlear ** Spinal accessory = accessory

22. Forebrain • Thalamus • Hypothalamus • Pituitary gland • Basal ganglia • Basal forebrain • Hippocampus • Limbic system

23. Thalamus: Relay station for all sensory info on its way to brain (except olfactory info) Many specialized nuclei (ex: LGN, MGN…don’t have to know these!)

24. Hypothalamus Communicates with pituitary gland to alter hormone release Involved in feeding, drinking, temperature regulation, sexual behavior, fighting, arousal (activity level)…4 Fs

25. Pituitary gland Endocrine gland (hormone producing) Attached to base of hypothalamus by stalk Makes and releases hormones into bloodstream

26. Basal Ganglia Motor control, but also memory and emotional expression Lose dopamine neurons in SN  Parkinson’s Disease Lose dopamine neurons in caudate & putamen  Huntington’s chorea http://www.uni.edu/walsh/basalganglia-2.jpg Don’t memorize image!!! Just understand that this is a very complex system! thalamus.wustl.edu/ course/cbell6.gif

27. Basal forebrain Anterior and dorsal to hypothalamus Important for arousal, wakefulness, attention Lose cells in nucleus basalis  decreased attention & intellect (AD, PD) http://memorylossonline.com/summer2003/glossary/basalforebrain.jpg

28. Hippocampus Memory formation HM: temporal lobes removed for intractable epilepsy  no longer formed new memories http://www.hermes-press.com/Perennial_Tradition/hippocampus.gif http://www.umassmed.edu/bnri/graphics/crusiofig1.gif

29. Limbic System important for motivated & emotional behaviors (eating, drinking, sexual activity, aggressive behavior)

30. Ventricles Contain cerebrospinal fluid (CSF) CSF reabsorbed into blood vessels, so continuous turnover Protective Reservoir for hormones, nutrients http://mywebpages.comcast.net/epollak/PSY255_pix/ventricles.PNG

31. Ventricle size can indicate problems • Enlarged ventricles as in Alzheimer’s patients (cell loss). • Lack of ventricles due to tumors etc.

32. Cortex • 2 hemispheres • Communicate via corpus callosum & anterior commisure • 4 lobes http://pegasus.cc.ucf.edu/~Brainmd1/brmodelc.gif http://www.urmc.rochester.edu/neuroslides/slides/slide201.jpg http://trc.ucdavis.edu/mjguinan/apc100/modules/Nervous/grosscns/images/brain10.jpg

33. 6 laminae (layers of cells)

34. The lobes of the cortex • Frontal • Thinking • Prefrontal cortex • Planning • Working memory • Socially appropriate behavior • Delayed-response task • Lobotomies • Primary motor cortex • Broca’s aphasia

35. The lobes of the cortex • Parietal • Sensing • Primary sensory cortex

36. Homunculus

37. The lobes of the cortex • Temporal • Spoken language comprehension • Wernike’s aphasia • Hearing • Vision • Movement perception • Face recognition • Emotional motivational behavior

38. The lobes of the cortex • Occipital • Vision • Primary visual cortex • Damage causes “cortical blindness”

39. Evolution of Gene Related to Brain's Growth • A gene that helps determine the size of the human brain has been under intense Darwinian pressure in the last few million years. • It has changed its structure 15 times since humans and chimps separated from their common ancestor. • Evolution has been particularly intense in the five million years since humans split from chimpanzees Changes in the architecture of the ASPM protein over the last 18 million years are correlated with a steady increase in the size of the cerebral cortex (2002) Dr. Bruce T. Lahn at U. Chicago. A disrupted form of this gene was identified as the cause of microcephaly (people born with an abnormally small cerebral cortex).

40. Functions • Forebrain • the cool stuff (thinking, perceiving, big part of emotion) • Midbrain • sensory pathways • Hindbrain • motor control, reflexes (breathing, heart rate, etc)