Neuroscience chapter 2

• 1. Cerebral Hemispheres
• 2. Diencephalon
• 3. Midbrain
• 4. Pons and cerebellum
• 5. Medulla
• 6. Spinal cord

• 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)

STM

Planning and sequencing of behavioural acts

Processing of somatosensory information

Important for recognizing spatial locations of objects

Position of limbs, touch, temperature, pain.

Important in processing visual signals

Hippocampus and Amygdala

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

temporary memory store used for planning and guiding future motor actions

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

• 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)

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)

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

From unilateral damage to the parietal lobe

Causes neglect of one side of body and visual space

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

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

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

• 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

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

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

• 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

Ventral--motor neuron cell bodies

Dorsal-- Cell bodies of sensory neurons

• 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

Process signals, integrate sensory signals and produces motor output

regulates movements and behaviour

• 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