Neuroscience chapter 2

  1. Divisions of the CNS
    • 1. Cerebral Hemispheres
    • 2. Diencephalon
    • 3. Midbrain
    • 4. Pons and cerebellum
    • 5. Medulla
    • 6. Spinal cord
  2. Lobes of brain
    • Frontal--central sulcus
    • Parietal--postcentral gyrus
    • Occipital
    • Temporal-- Superior temporal gyrus, lateral fissure

    • Sulci--prominent grooves, used as landmarks to identify grooves
    • Gyri--elevated regions (crests)
  3. Frontal Lobe

    Planning and sequencing of behavioural acts
  4. Parietal Lobe
    Processing of somatosensory information

    Important for recognizing spatial locations of objects

    Position of limbs, touch, temperature, pain.
  5. Occipital Lobe
    Important in processing visual signals
  6. Temporal lobe
    Hippocampus and Amygdala
  7. What are the functions of the Prefrontal Cortex
    Temporal organization of behaviour

    Lesions produce difficulties in initiating and executing new, goal directed behaviour, working memory, but not in ordinary motor routines, IQ

    Required for remembering specific sensory cues that are linked to performance of motor actions
  8. Working memory
    temporary memory store used for planning and guiding future motor actions
  9. Frontal lobes and behavioural control: Phineas Gage
    Had his left frontal lobe damaged--personality became altered

    Case played a major role in developing our understanding of the localization of brain functions

    Behavioural control= identifying with feelings and emotions, predicting consequences of future actions
  10. Two pathways for visual analysis
    • Dorsal stream: vision for action
    • - striate cortex--> extrastriate cortex --> posterior parietal lobe
    • - damage to posterior cortex disrupts visuomotor tasks that involve actions linked to the location of
    • objects
    • - optic ataxia--disorder in translating vision onto action

    • Ventral stream: vision for perception
    • - striate--> extrastriate--> inferior temporal lobe
    • - processes info to assess what an object is
    • - visual form agnosia-- damage impairs the ability to recognize the forms of objects
    • (can see fine, just can't identify)
  11. Patient RV
    Bilateral damage to posterior partietal lobe= damage to dorsal stream

    Poor performance in reaching out to grasp the object, but could position hand to manually estimate the size of the object (no motor actions involved)
  12. Patient
  13. Patient DF
    Hypoxia from carbon monoxide posioning

    Diffuse cortical damage with large lesions in the ventrolateral occipital region

    Had visual form agnosia--issues in translating vision to hand movements to communicate size/orientation

    • Tested with the slot task, had to 1)manually move hand to estimate orientation of slot and 2) reach out and put card in slot
    • - DF did good at reaching out and inserting the card, but was not good at estimating the orientation
    • of the hole
    • - Could not identify common objects, like she had no visual experience with the object, but she
    • could draw a fairly good approximation from memory
    • - deficit in visual awareness and perception, difference between awareness and consciousness
  14. Hemineglect
    From unilateral damage to the parietal lobe

    Causes neglect of one side of body and visual space
  15. Temporal Lobe
    Hippocampus--important for our ability to lear and remember facts and events

    Amygdala--plays key role in emotional expressions, and in forming associations between emotions and events
  16. Amnesia
    Memory loss that results from disease or injury to the brain, caused by concussions, brain tumors, stroke, Alzheimer's disease

    Damage to the hippocampus--necessary for turning STM into LTM (consolidation)

    Retrograde-- memory loss for events occurring prior to the trauma, very old memories remain intact

    Anterograde-- inability to form new memories
  17. Patient HM
    Temporal lobe, entorhinal cortex and surrounding tissues (hippocampus) removed to treat epilepsy, had recurring severe seizures

    • Inability to form lasting memories, sever anterograde amnesia
    • - cannot remember anything that occurred recently, no new memories of events of facts enountered after surgery
    • - intact short term memory and procedural memory
    • - hippocampus required to make memories but not to maintain them--childhood memories intact
    • - main contribution--discovered the difference between explicit and implicit memories

    - demonstrated that the neural structures underlying explicit and implicit memory are not the same
  18. Multiple Memory Systems: declarative vs nondeclarative
    • Declarative/explicit-- concerned with facts and events
    • - requires conscious recall
    • - unlimited capacity

    • Nondeclarative or implicit memory -- deals with skills and motor behaviours
    • - recall is automatic
    • - does not need conscious recollection
  19. Patient SM
    Bilateral lesions to amygdala

    • Had urbach weithe disease-- calcification of amygdala and medial temporal lobes
    • - failure to process fearful facial expressions, couldn't even sketch facial expressions of fear
    • - genetic basis--german descent from S.Africa

    • Amygdala-- rostral part of hippocampus
    • - helps us adapt to situations of danger
  20. Parkinson's Disease
    Treated with deep brain stimulation--tip of electrode is placed in the talamus, CP or subthalamic nucleus

    Can help eleviate the symptoms, blocks nerve impulses that cause irregular movements

    Not permanent effects
  21. Spinal Cord
    • Cable of axons to and from brainstem and periphery
    • 8 Cervical
    • 12 Thorasic
    • 5 lumbar
    • 5 sacral

    • Grey matter--cell bodies of neurons and glia
    • White matter--axons grouped into tracts of pathways

    • Dorsal horm--sensory nuclei
    • Dorsal Column--cary somatosensory info to the brain stem
    • Ventral horm--motor nuclei
    • Ventral columns--contain axons that transmit pain and temperature and descending motor axons that
    • control axial muscles
    • Lateral columns--contain axons that ascend to higher levels of the CNS as well as descending axons
  22. Ventral vs Dorsal
    Ventral--motor neuron cell bodies

    Dorsal-- Cell bodies of sensory neurons
  23. Dorsal Root Ganglion
    • Adjacent to the spinal cord
    • contain sensory cells which convey info from skin, muscles and joints
    • central branch--enters dorsal horn and projects to grey matter and brain stem (to Thalamus)
    • Peripheral branch--for sensory trasnduction, terminates in skin or muscles
  24. Function of brain
    Process signals, integrate sensory signals and produces motor output

    regulates movements and behaviour
  25. Psychiatry
    • Disorders-- explained by disruption of signals somewhere
    • - need to know cell signalling (electrical and chemical) within a cell and between cells
    • - drgus used in treatment--modify some form of chemical transmission
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Neuroscience chapter 2