6.2 Regions and organization of CNS Flashcards
What is the cerebral hemisphere composed of
Copmosed of
- Cerebral cortex
- thi layer of superficial gray matter
- grey matter = where all synapses occur, collection of cell bosies *city where everythign is happening)
- site of conscious mind: awareness, snsory perception, voluntary motor initiation, communication, memory storage
- hemospheres have contrallateral connections with body
- thi layer of superficial gray matter
- White matter
- assoication, commissural and pojection fibers (just what connects)
- Subcoritcal nuclei
- basal ganglia.nuclei
- some limbic structures
What are the functional areas of the cerebral cortex?
- Motor areas
- control bolunatry movement (frontal lobe)
- Sensory areas
- conscious awaremenss of sensation (incoming info)
- Association areas
- integrate diverse informatino (take diff types into and bring togeher
*conscious behavour involes the whole cortex
describe the primary motor cortex
- Precentral gyri of frontal lobe contains pyramidal neurons
- Long axons form upper motor neuron of corticospinal/pyramidal/direct tracts
- Allows conscious control of precise, skilled, voluntary movements
- Somatotopic arrangement (body map)
*anterior to central sulcus
describe the premotor cortex
- Anterior to precentral gyrus in frontal lobe
- Sends information to primary motor cortex to coordinate muscle groups for simultaneous or sequential actions
* secind into to plan and coordinate movement NOT EXECUTE
- Controls learned, repetitious, or patterned motor skills • Involved in planning of movements that depend on sensory feedback
- Direct connection with corticospinal tract (15%) *motor pathway
*this if when you think about raising our hand but dont actually do it
What is Broca’s Area?
- Anterior to inferior region of premotor area in frontal lobe
- Present in one hemisphere (usually left, bc where language is dominant)
- Motor speech area, directs tongue muscles
- active as one prepares to speak
- Area in right hemisphere controls non-verbal communication (facial expression, gesticulation & modulation of speech rate, rhythm & intonation)
What is the frontal eye feild
Anterior to premotor cortex in frontal lobe; superior to Broca’s area
• Controls voluntary eye movements
What is primary somatosensory cortex
In postcentral gyri of parietal lobe
- Receives sensory information from skin, skeletal muscles, & joints
- Capable of spatial discrimination: identification of body region being stimulated
* doesnt do integration, wont know what it is touching
Somatosensory Association Cortex
Posterior to primary somatosensory cortex
- Integrates sensory input from primary somatosensory cortex
- Determines size, texture, & relationship of parts of objects being felt
*puts into together
Describe visual areas
*posterior tip of occipital lobe: (most of it is buried medially in calcarine sulcus)
Primary visual (striate) cortex
– Receives visual information from retinas (special senses lecture)
The visual Assocaition area
- surrounds primary visual cortex
- uses past visual experiences to interpret visual stimuli (colour, form and movement)
- complex processing involces entire posterior hald of cerebral hemispheres
doral vs ventral stream of visual assocation area
- Doral stream: where pathway
- ventral streme: what pathway (travels to temproal lobe, area with memory systems)
What are audiotry areas
- Primary auditory cortex
- Superior margin of temporal lobes
- Interprets information from inner ear as pitch, loudness, & location
- Auditory association area
- Located posterior to primary auditory cortex
- Stores memories of sounds & permits perception of sounds
Olfactory corex
Medial aspect of temporal lobes
• Conscious awareness of odours
Gustatory Cortex
In insula (deep to temoral lobe)
Involved in perception of taste
Visceral Sensory Area
Posterior to gustatory cortex
Conscious perception of visceral sensations
What are multimodal association Areas?
(Sensory receptors -> primary sensory cortex -> sensory association cortex -> multimodal association cortex
- Receives inputs from multiple sensory areas; sends outputs to multiple areas
• Allow us to give meaning to information received, store as memory, compare it to previous experience, & decide on action(s) to take
what are the 3 parts of the multimodal association area?
Anterior Association Area (aka Prefrontal Cortex)
– Posterior Association Area
– Limbic System (deep)
Describe teh posterior association area
- Large region in temporal, parietal, & occipital lobes
- recognizing patterns, faces & localizing us in space (why we can look at our face and recognize that its a face) prosopagnosia, unilateral neglect
- understanding written & spoken language (Wernicke’s area)
how does speaking a written word work? how does speaking a heard word work?
- SPeaking a written word
- Read words (visual cortex) -> Wernike’s area (understanding written/spoken language) -> Boca’s area (speech region) -> motor cortex (sigal sent to muscles to move)
- Speaking a heard word
- Auditory cortex -> wenickes area (gives meaning) -> Broca’s area (speech region) -> motor cortex
what is limbic associan area
Part of limbic system
• Provides emotional impact that helps establish memories
*gives emotional enrichment to life
What is cerebral white matter?
Myelinated fibers & their tracts
*connects regions of grey (white is the highways, grey is the cities)
*how they project dictates the class of fibers
• Responsible for communication between regions:
- Commissural fibers: connect gray matter of two hemispheres
- Association fibers: connect different parts of same hemisphere
- Projection fibers: connect hemispheres with lower brain or spinal cord (leaves cortex and goes far away)
Describe lateralization of cortical function
Lateralization: division of labour between hemispheres
• Cerebral dominance: designates hemisphere dominant for language (left hemisphere in 90% of people)
*left brain controls right body
- Left hemisphere controls language, math, & logic
- Right hemisphere is insight, visual-spatial skills, intuition, & artistic skills
*conected by corpus callosum
What is Basal Nuclei
aka subcortical nuclei
*grey matter, not part of cortex but still part of cerebrum
- consists of corpus striatum:
- > caudate nucleus (tadpole, hugs lateral ventricle
- > lentiform nucleus (has putamen (more superficial) and globus pallidus (more medial/internal))
- functionally associated with subthalamic nuceli (diencephalon) & substantia nigra (midbrain)
*substalamic muclei assocaited with movement patterns
What are teh regions of the diencephalon
describe the thalamus, structure
- 80% of diencephalon
- superolateral walls of 3rd ventricle
- connected by interthalamuc adhesion
describe the thalamus, functoin
Contains several nuclei that project & receive fibers from cerebral cortex
• Sorts, edits, & relays information
Describe the hypothalamus, structure
what nuceli does it contain
*is the beak on the bird
Forms inferolateral walls of 3rd ventricle
• Contains many nuclei:
- Mammillary bodies (memory, limbic & smell) (looks like boobs @ bottom of brian)
- Supraoptic & Paraventricular Nuclei→ Posterior Pituitary
- Suprachaismatic nucleus → Pineal gland
Hypothalamus, function
Autonomic control centre for many visceral functions
- Regulates body temperature, food intake, water balance, & thirst
- Regulates sleep & sleep cycle (Supra-chiasmatic nucleus)
- Produces posterior pituitary hormones (Paraventricular & Supraoptic nuclei)
- Controls release of hormones by anterior pituitary
- Centre for emotional response: feeding, fearing, fighting, fornication
What is the epithalamus?
Most posterior of diencephalon & roof of 3rd ventricle
• Pineal gland: secretes melatonin (pineal -> pinecorne)
* Age 17+, appearance of calcareous concretions (corpora arenacea), gets very hard -> brian sand
describe the midbrain, location
Located between diencephalon & pons
• Cerebral aqueduct (CSF pathway that travels through midbrain)
- has Crus Cerebri of Cerebal paduncles: contains pyramidal motor tracts
*note cereballar ones are different, sound the same
- has corpora quadrigemina: Superior colliculi (visual refelx centers), Inferior colliculi (auditory relay center -> why you head a bang and look at it)
parts of midbrain nuclei
Substantia nigra: functionally linked to striatum (dopamine)
• Red nucleus: relay nuclei for some descending motor pathways & part of reticular formation
• Periaqueductal gray: suppresses pain (around cerebral aquaduct)
Describe the Pons
- Forms part of anterior wall of fourth ventricle
- Pyramidal tract: connects higher brain centres & spinal cord (motor)
- Some nuclei of reticular formation
- Nuclei that help maintain normal rhythm of breathing
Describe the medulla Oblongata
*occupies most of inferior of brain structure
- joint spinal chord at foramen magnum
Forms part of ventral wall of 4th ventricle
• Pyramids: 2 ventral longitudinal ridges formed by pyramidal tracts (motor) • *Decussation of pyramids: crossover of corticospinal tracts
Nuclei of medulla oblongata
Inferior olivary nuclei: relay sensory information from muscles & joints to cerebellum
• Several nuclei (nucleus cuneatus & nucleus gracilis) relay sensory information (not shown)
what is cerebellum
Posterior to pons & medulla
- Subconsciously provides precise timing & patterns of skeletal muscle contraction (ipsilateral to body) -> forms “blueprint” for coordinated movement
- Plays a role in nonmotor functions such as word association & puzzle solving
What are cerebellap peduncles
*relay centers
-All cerebellar fibers are ipsilateral
• 3 paired fiber tracts connect cerebellum to brain stem:
-> Superior cerebellar peduncles: connect cerebellum to midbrain
-> Middle cerebellar peduncles: connect pons to cerebellum
–> Inferior cerebellar peduncles: connect medulla and cerebellum
*makes sense bc of anatomical postion
