CH3- brain anatomy Flashcards
neuroplasticity
NS can grow new branches on dendrites and change # of receptors and NT (changing neuron activity if neuros are damaged or as we grow) we lose neuros as we get older (the ones we dont need)
neocortex (new brain)
- the new brain (neo = new)
Most of your cerebral cortex is considered to be the neocortex. - In humans, 90% of the cerebral cortex is the neocortex.
- association cortex: adjacent to lobes, further processes info and inetgrate with other sensory info
- share characteristics with primates (new brain)
- wrinkly appearence due to gyri (ridges) sulci (valleys) and fissures(spaces)
map of nervous system
peripheral + central
-peripheral: autonomic + somatic
- autonomic: sympathetic + parasympathetic
- somatic: sesnory input + motor output controls
PNS: SOmatic NS
- neurons for voluntary motion
- sensory infro from body to brain
- if spinal cord injured, segment below, can no longer be controlled volunatririly
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PNS: Autonomic NS
- automatic functions (involuntaty movemnt)
- sympathetic and parasympathetic NS
parasympathetic and sympathetic system
parasympathetic:
- rest and digest/ sexually arousal
- nerves originate in lower brains and bottom of spinal cord
sympathetic
- fight or flight
- nerves in length of spinal cord (main)
- sex stimulates this as well
Pons + Medulla
- connect teh PNS to teh CNS
- pons above medulla, make up brainstem
Medulla
- lowest part of brainstem
- controls involuntary movements (heart rate, breathing, digestion, swallowing)
pons
- above medulla
- bridge
- regulate arousla
- COORDINATE Snsory info with info from cerebellum
- controls facial expressions, movement of the eye
Reticular Activating System (RAS)
- network spamming center of medulla and pons
- bridges functions of body + brain via connections to spinal cord and thalamus
- regulates elvels of excietment and energy
- regulates focus of our attention on tasks, peopel or objects
- filters irrelevant stimuli
- dysfunctional: posible ADHD contributor
the limbic system
- system that cooridinates movemnet
amygdala (emotion) :
- increases electricl activity in neurosn when under threat.
- forms memoires associated with strong emotions.
- recieves sensory input from all senses.
- connects with hippothalaums with thalamus
- damage here: causes loss of awareness of emotion and inapproprate responses in situations that normally trigger emotional responses.
hippocampus (memory):
- neurons activated when forming memories
- new memories and imigation
- connected to amygalda for memory of emotionally important events (for survival)
- important for spacial navigation
cingulate gyrus (pain-social exclusion):
- ventral to neocortex
- increase activity in this area in response to apin and social exclusion
- focuses attention on unpleasent experiences
hypothalamus (mainteneance of internal systems + endocrine system):
- directs several maitenance activities (body temp, sex, hunger) homeostaiss
- helps govern endocrine system via pituitary gland
Basal Ganglia
- consists of dorsal stritum (caudet nucleus and putamen) , ventral striatum, substantia nigra, subthalamic nucleus globus pallidus,
- recieve info from midbrain (above pons)
- responsibile for volunatry moovemnt (starting and stopping abrupt movemnts)
- helps make complex movements automatic
striatum (learning to make movments more automatic):
- where inputs to basal ganglia come in (from ALL OVER CORTEX)
- how nuclei work togetehr to help us learn movemts from practice (make complex movemnt easier for us)
- dorsal stiatum (caudet nucleus and putamen):
- ventral stiatum neurons connect to limbic system (emotion = motivation to learn)
Globus Pallidus + subsantia nigra
- send inhibitory outputs to thalamus (integrate sensory and motor info with motor planning)
- helps with starting and stopping motion
- substantia nigra: neurons secrete dopamine . in parkinsosn disease, tehse cells die off, lose part ability to stop and start motion.
Pathways in Basal ganglia:
- direct pathway: excitatory effect on thalamus that drives motor behaviours. increase motor plans that are appropriate for present situation
- indirect pathway: inhibitory effect. helps basal ganglia shut down motor pathways taht are not right for task at hand
- if dmaaged: parkinsosn disease
parkinsons disease
- progressive disease resulting in imparied movement
- cogwheeel rigidty: touble initialiting and terminating movemnts
- substantia nigra: neurons secrete dopamine . in parkinsosn disease, tehse cells die off, lose part ability to stop and start motion.
Cerebellum
- rhythm and timing machine
- looks like little brain
-neuronal circuits connected to rest of brain to modify what thet do (movement and cognition) - recieves input from periphery, spinal cord and brain regions and partienal cortex.
spinocerebellar divison:
- match sensory input with motor plans in order to fine tune movemnt patterns
Vestibulocerebellar division:
- process information from inner ear to help adjust posture and balance
cerebrocerebellar division:
- manaes connectiosn with pons + thalamus to adjust timing and planning of movements
damage to cerebellaum:
- loss of balance uncoordination
- no paralysis tho
- planning timing is affected
- maybe problem solving is affected and emotional repsonse (neocortex and hypothalamus)
Thalamus
- relay station
- cortex uses to choose which thing we pay attention to
- all senses (except smell) must pass through thalamas beofre going to respective areas of neocortex for interpretation
- right and left lobes of thalamus sit above cerebellum
- contain bands of myelinated axons.
Frontal lobes
-output tends to be inhibitory
- decsion making and movemnt
- phineas gage - his frontal lobe destroyed (became irritable and vulgar)
motor cortex:
- two major pathways: corticospinal and corticobular tracts. contorl movment in spinal and head respectively
prefrontal cortex (PCP):
- advanced decsion making. if….then
- recieves input from all cerebreal cortex
- inhibitaory and excitatory
- dysfunction here: presence of negative symptoms of schytophrenic patients
- mylenation occurs here (oligodendrocytes do it)
- ventromedial prefrontal cortex (vmPFc): modulate behavior based on fear (bottom inside part)
- dorsolateral prefrontal cortex (DLPFC): maintain info in working memory and change how we do things depending on task
pariental lobes
- sensation navigation, motor action, numbers
- lobe at back of head
- procesing numbers and calculations
- sensory cortez: recives input from contralater part of body (nerves cross at brainstem so youc an do crosslateral movemnt)
temporal lobes
- above ear
- memories, sound processing, smell association
- lesions: focues areas where cells have died. memory loss and loss to form new memories (antegrade amnesia)
- connect to hippocampus (smell and memory)
auditory cortex:
- caudaul part of lobe
- if damaged: lose all ability to percieve sound wtho damage to ear
Wernicke’s area
- in left temporal lobe
- processing language
- if stroke: unable to comprehend speech
olfactory cortex
- smell is processed and percieved
- smell (olfactory) only sense that doesnt go to thalamus
- memory + olfactory = nostalgic smells
Occiptial lobes
- light stimuli processing
- optic nerves end here
- visual info from right visual field processed in left occipital lobe and left thalamus
sensory info for eyes crosses at optical chiasma - damage: loss of sight, or ability to see specfic things liek faces
Brain laterality
- idea that one hemishphere of the brain preforms different functions than other
- half true half not
- we use both sides regularly (no one is completley laterialized)c
corpus callosum
- helps cross infro from one side of brain to other
- thick bundle of fibers inside of brain
- all sensory info excpet smell croses from one side to another
- epilepsy: cut corpus which helps calm seizures. “split brain” pateints have trouble seeing stuff in left visual field and naming it
Endocrine system
- glands that secrete hormones
- hormones can act as NT
hypothalamus
- secretes hormones and control pituitary glands. secrete oxytocin hormone (love hormone)
pineal gland
- secretes melatonin hormone that helps regulate sleep
pituitary gland
- secretes hormones that affect sexual behaviours, reproduction, circulatory function, hunger, repsosnes to agression
HPA axis and Stress
- stress, chornic stress, endocrine + brain connection
- Hypothalaums-pituitary-adrenal axis
- hypothalamus –> pituitary gland –> adrenal gland
- chronic stress = increase hypothalmus neurons activated = pituitary gland to tell adrenal gland up increase cortisol production (stress hormone)
- chornic stress = to much cortisol, deeling tired, alterness drecreases over time (affecting RAS)
- increase cortisol = decrease immune system function
Ct scans
- x rays that pass through body to generate body image slices
- fast cheap non invasive
- harm: radiation exposure
- detect change in structure from disease
MRI and fMRI
-magnetic fields image alighnemts of H+ ions
MRI
- noninvaseive, no radiation, great precissonn
-con: expensive, no biomedical devices or metal in pateint
- can detetc change in structure from a disease
fMRI
- noninvaseive, no radiation, no ingestions/injections
- Cardiovascular diseases or compromised functions can make meausrements unreliable dely between stimulus and output
- can meausre activation of neuron during a task or follow stimulation
PET scan
- photon emmisoion tomography
- ingest radioactive compound to tracj molecural change
- see molecular change in real time
- con: radioactive exposures
- can visualize activity of NT or measure binding
DTI
- diffusion tensor image
- images water movemnt along neural pthways and meausres density of neural tracts
- non invasive, no ingestions/ injections
- con: interpreation can be difficult in tracts with different fibers
- can study white matter degeneration in a disease
how did we develop current research methods in brain imaging
- ancent egyptian scrolls about brain (1600 bce)
- experiemental studies on brain (1700)
- otto friedrich and karl ditrs (seperate neurons in late 1800s)
- staining method: dye to viszualzi neurons in dead tissue - camillo golgi
- 1990’s stained neurons in living tissue
- 1700, frog leg dippied in electrical stimulation, energy make muslces move (luigi galvani)
Patch clamp technique
- ervin neher and bert sakmann
- patch clamp to record electrical activity from individual neurons
- glass lctrode is placed on membrane of enuron using suction
-membrane oulled into electrode - stimulate and record patch of membrane see how recpetors and channleles influence electrical activity
