Bioperspectives neuroanatomy 1

585 views

Published on

Published in: Health & Medicine
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
585
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
19
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Bioperspectives neuroanatomy 1

  1. 1. Biopsychological Perspectives Lecture 1 Functional Neuroanatomy
  2. 2. “I said in Dorian Gray that the great sins of the world take place in the brain: but it is in the brain that everything takes place.... It is in the brain that the poppy is red, that the apple is odorous, that the skylark sings…” (Oscar Wilde)
  3. 3. Aims and Objectives • Basic divisions and sub-divisions of the human nervous system • Gross neuroanatomy of the human brain • Localization of function in the brain (especially the cortex)
  4. 4. The Human Nervous System
  5. 5. Peripheral Nervous System Sense organs and muscles ↓↑ Peripheral nervous system ↓↑ Spinal cord ↓↑ Brain (sensory / motor specific areas)
  6. 6. Somatic Peripheral Nervous System • Nerves that convey information: – Sense organs / muscles → spinal cord → brain (Afferent) – Brain → spinal cord → muscles /glands (Efferent) • Primarily involved in voluntary muscle control
  7. 7. Autonomic Peripheral Nervous System Nerves that control involuntary muscles (heart; intestines; lungs, etc) The two branches of the ANS ↓ ↓ Sympathetic Parasympathetic Adapt the bodies internal / metabolic activity to meet environmental / perceived needs
  8. 8. Autonomic Nervous System Sympathetic ↓ Expends energy in “fight or flight” situation Parasympathetic ↓ Conserves energy in non-emergency situations
  9. 9. ANS Control of Organs • Most organs controlled by both sympathetic and parasympathetic nerves • Usually active at the same time – dynamic relationship between the two • Relative balance dependent on immediate needs of individual
  10. 10. Example of Psychological Application of ANS Investigation • Lie detection • Lie → increase in sympathetic activity → increased sweating → picked by electrodes as increased electrical conductance • Lie detected (as deflection in a waveform)
  11. 11. Central Nervous System - Brain
  12. 12. Central Nervous System • 3 major divisions • Hindbrain – most posterior and oldest part • Midbrain – in centre of brain • Forebrain – most anterior and prominent part – outer portion = cerebral cortex
  13. 13. Hindbrain • Medulla • Pons • Cerebellum
  14. 14. Medulla Location - Just above spinal cord (extension of spinal cord) Function – Controls (via cranial nerves) vital functions: breathing; heart rate; salivation; coughing; sneezing. Damage fatal.
  15. 15. Pons Location - above and in front of medulla Function – sensory relay station
  16. 16. Reticular Formation • Medulla and pons (and other structures) form Reticular Formation • Raphe system and Locus Coeruleus • Networks of neurons sending axons up to forebrain; involved in arousal and sleep
  17. 17. Cerebellum • “little brain” – large convoluted structure behind pons and medulla • Function - coordination of muscles and maintaining balance
  18. 18. Cerebellar Functions • Planning movement • Developing newly learned motor programmes (slow, deliberate) into rapid automated “habits” (driving) • Lateral cerebellar regions contribute to language development – Dyslexics – often have cerebellar damage
  19. 19. Midbrain • Middle of brain (under convoluted outer bit) • Superior Colliculus • Inferior Colliculus • Substantia Nigra
  20. 20. Superior and Inferior Colliculi • Two pairs of swellings at top of midbrain section • Superior Colliculus - route for visual sensory information from eyes (to visual processing areas) • Inferior Colliculus – route for auditory sensory information from ears (to auditory processing areas)
  21. 21. Left Auditory cortex Right Auditory cortex Cochlea Medial geniculate nucleus Inferior colliculus Superior Olivary nucleus Ipsilateral Cochlear nucleus Auditory nerve fiber
  22. 22. Substantia Nigra • Area implicated in control of movement • Abnormality in SN nerves in Parkinson’s disease (movement / tic disorder)
  23. 23. Forebrain • Most anterior and prominent part of mammalian brain • Cerebral Cortex (outer portion – visible) • Subcortical structures - limbic system (set of structures forming a border, encapsulating the brain stem)
  24. 24. Limbic System • Structures heavily involved in motivated and emotional behaviours: eating drinking sexual behaviour anxiety aggression
  25. 25. Larger Structures of the Limbic System • Olfactory Bulb • Hypothalamus • Thalamus • Hippocampus
  26. 26. Olfactory Bulb • Detection and perception of smell • Through links with rest of limbic system and cortex (higher brain) – association of smell with previous events
  27. 27. Hypothalamus • Just below thalamus • Contains several distinct sets of nuclei • Each relates to a specific “motivated behaviour” • 4 Fs – Feeding – Fighting – Fear – Sex
  28. 28. Hypothalamus • Damage to a specific nucleus → specific deficit • Ventromedial and Lateral hypothalamic nuclei → eating disorders (in rats) • Works in conjunction with pituitary gland to alter / regulate release of hormones according to need – Aggression / testosterone
  29. 29. Hippocampus • Implicated in memory (I.e. storing “new” information) • Infant amnesia - – cant remember much of first 5 years of life – due to relatively slow hippocampal maturation • Age-related memory loss – gradual loss of hippocampal neurons
  30. 30. Thalamus • Resembles two small round pillows (side by side) • Sits on top of hypothalamus / under cortex / centre of brain
  31. 31. Thalamus • Function - Main source of sensory input to cortex • Not just passive relay station – further processes info already processed by midbrain structures
  32. 32. Thalamic Nuclei • Like hypothalmus has distinct nuclei • Each nucleus synapses onto a sensory-specific area of the cortex • E.g. Lateral Geniculate Nucleus (LGN) → visual processing areas of cortex.
  33. 33. The Cerebral Cortex • Most important part of the the brain to psychologists • Divided into two hemispheres (covers all the other forebrain structures)
  34. 34. Contralateral Control • Each hemisphere receives sensory information from contralateral (opposite) side of body • Each hemisphere controls movement on opposite side
  35. 35. Each hemisphere controls movement on opposite side
  36. 36. Each hemisphere receives sensory information from contralateral (opposite) side of body
  37. 37. • Two hemispheres are connnected (communicate/ integrate info) by two bundles of nerve fibres • Corpus Callosum • Anterior Commisures
  38. 38. Commisures • Corpus Callosum • Anterior Commisures
  39. 39. “Areas” in the Cerebral Cortex – The Cortical Lobes • Can distinguish 50+ areas within the cortex (thickness / appearance of cells) • Usually divided in 4 cortical lobes • Occipital • Parietal • Temporal • Frontal
  40. 40. Occipital Lobe • Located – back of head • Function – Main recipient of visual info • Very posterior part = Primary Visual Cortex – damage → “cortical blindness” (normal eyes but cannot see)
  41. 41. Occipital Lobe • Also involved in spatial orientation (e.g. maze learning) • Damaged in rats – no ability to maze learn
  42. 42. Parietal Lobe • Located – between occipital lobe and central sulcus – (deep groove from top of head down sides of each hemipshere)
  43. 43. Parietal Lobe • Functions: • Somatosensation - immediately behind central sulcus = somatosensory cortex • Mediates “body information” – Touch – Muscle stretch – Joint movement
  44. 44. Parietal Lobe • Direct electrical stimulation → “feeling” or sensation in particular part of body represented • RH → left side of body sensation • Representation of body parts based on species needs (hands)
  45. 45. The sensory homunculous This model shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its sensory perception.
  46. 46. Other Parietal Lobe Functions • Relating visual information to spatial information (object constancy) • Ability to draw and follow maps and describe how to go somewhere • Ability to identify objects by touch (damage → loss of Braille ability) • Body image (what the body looks like and how it is functioning)
  47. 47. Temporal Lobe • Located – side of each hemisphere (near temples) • Functions – Hearing – Balance – Auditory attention – Complex visual processing (faces) Tumours → visual hallucinations
  48. 48. Other Temporal Lobe Functions • In majority - left temporal lobe contains language comprehension area • Wernickes Area • Damage → receptive aphasia
  49. 49. Frontal Lobe • Located – anterior to central sulcus (front of brain) • Posterior part of lobe = precentral gyrus • Motor cortex (control of fine movement) • As with somatosensory cortex – Contralateral contro – Different parts responsible for different body parts
  50. 50. Primary motor cortex (M1) Foot Hip Trunk Arm Hand Face Tongue Larynx
  51. 51. Motor homunculus This model shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its movement.
  52. 52. Prefrontal Cortex • Anterior to motor strip • Large area • Function – receives information from all sensory areas and “integrates” and “represents” receives sensory information • Understanding / thinking • Memory
  53. 53. Prefrontal Cortex and Language Ability • In humans (most) left hemisphere contains language production area • Brocas Area • Damage → difficulty producing spoken language (“telegraphic speech”) • Comprehension ok
  54. 54. Summary • The main divisions of the nervous system are the Central Nervous System and the Peripheral Nervous System • The CNS consists of the spinal cord and the brain (hindbrain, midbrain and forebrain) • The PNS consists of the somatic and autonomic NS (sympathetic and parasympathetic)
  55. 55. Summary • Aspects of functioning (sensory, motor and “cognitive”) are localized to particular cortical areas and sub-cortical structures.
  56. 56. Summary • BUT brain areas and structures work together and integrate their processing to achieve global functions
  57. 57. 3D Brain Anatomy http://www.pbs.org/wnet/brain/scanning/inde x.html

×