Lecture 12-13 Outline Flashcards
CNS develops from a…
hollow tube
At the 3rd week of development, the human brain starts as a…
hollow tube
- the egg has been fertilized, it’s a ball of cells starting to organize
- called neuralation
By the 4th week it (hollow tube)…
specializations in the anterior end
Human brain at ~4 weeks
Hollow tube with
- forebrain
- midbrain
- hindbrain
- spinal cord
Human brain at ~4-6 weeks
- MASSIVE increase in the # of cells & they are starting to move/migrate around these new structures
- forebrain –> cerebrum & diencephalon
- midbrain –> midbrain
- hindbrain –> pons & cerebellum, medulla oblongata
- spinal cord
Human brain at ~11 weeks
all of this has really started to enlarge & start to bend & there is a massive increase in the # of cells in the cerebrum
- cerebrum expands so much that it wraps around the diencephalon
Pons is found _____, & cerebellum is _____
ventrally
dorsally
The medulla oblongata is the
transition into the rest of the spinal cord
What does the Sagital Section/Slice show
if someone cut from the nose straight through the back of the head & right down the middle so it’s bisecting the left half & right half of an adult
Cerebellum is called this b/c
it looks like a little brain
Early names for the brain sections
- forebrain
- midbrain
- hindbrain
Late names for the brain sections
forebrain –> cerebrum & diencephalon
midbrain –> midbrain
hindbrain –> pons/cerebellum & medulla
Derivatives for the brain sections
Cerebrum –> cerebral hemispheres, basal ganglia, lateral & 3rd ventricles
diencephalon –> thalamus & hypothalamus
midbrain –> superior, inferior colliculi & substantia nigra
pons/cerebellum –> pons & cerebellum
medulla –> medulla (nucleus of the solitary tract)
What does the medulla play a huge role in?
in regulation of homeostasis (nucleus of the solitary tract)
Define Ventricles
fluid filled cavities within the brain, remnants of the “hollow tube” from which the brain developed
- fact that their filled with fluid is imp. for part of the protection of the brain
Central Canal
hollow tube in the spinal cord; continuous with the ventricles
What are the ventricles & central canal lined by?
ependymal cells (glial cells)
- ventricles & central canal are aligned by these
- glial cells that form a water tight barrier b/t the fluid filled cavity of the ventricle & the central canal & the rest of the brain tissue
- specialized for transport
How are the ependymal cells (glial cells) specialized for transport?
- allow the MOVEMENT of certain SOLUTES across
2. PROTECT the NEURAL CELLS on one side from the constituents within the CSF
Lateral ventricles
1 on each side
1st & 2nd
Lateral ventricles
1 on each side
1st & 2nd
Third ventricle
around the area of the hypothalamus
Fourth ventricle
found in the hindbrain
Where is the central canal formed?
in the spinal cord
Grey matter
UNmyelinated cell bodies, axon terminals & dendrites
- neuronal cell bodies are most often found clustered together in groups called nuclei, or on the outer surface of the brain as the cerebral cortex
What does nuclei imply?
implies that groups of neurons that do similar things are grouped together & that group of neurons is called a nucleus
White matter
myelinated axons
- kind of like wires - sending info from 1 place to the other (lot of processing being done)
Ganglia
knot of cells (often used for collections of neurons outside the CNS, but there are some within the brain & spinal cord)
- kind of the same as nucleus (mean the same)
- “groups of neurons”
What is a coronal slice?
sliced from one side of the head straight through the other
Where is there a lot of grey matter in the brain?
in the pons & cerebellum
In the BRAIN, grey matter is found ______
outside
In the BRAIN, white matter is found ______
inside
- axons from neurons that have their cell bodies in the grey matter
- myelinated axons in the white going to various places
What is used as support & protection for CNS?
- bony skull & vertebral column
- wrapped by 3 protective & nourishing membranes called MENINGES
- Cerebrospinal fluid (CSF)
- Blood-Brain barrier
What is the bony skull & vertebral column?
- both made of bones
- very hard structures
- 1 of the main jobs is to form a protective layer over the CNS (b/c CNS is fragile & needs to be protected)
Meninges
3 protective & nourishing membranes that wrap the CNS to support & protect it
What is a CAT/CT Scan?
- specialized X-ray that takes pics sequentially (so 1 after the other)
- X-rays are digitalized & a special computer program assembles them & allows us to get an idea of the 3-D structure
- series of images starting from back of someones head, moving to the front
Describe Dura Matter
- “HARD mother” in Latin
- tough, leathery layer
- immediately inside the skull
- helps HOLD your brain & spinal cord IN PLACE/hold still
- also a PHYSICAL protection
- if someone has a skull injury (fractured skull), this is helping PREVENT that object that hit their head from PENETRATING into the brain itself
- FORMS RESERVOIRS which is important for the circulation of your brain
OUTER MEMBRANE OF THE MENINGES
Describe Emissary Vein
- lots of veins that are draining blood that collects in the dural sinus (so blood thats been circulating in your brain), & some of that is pushed out through the skull through these these emissary veins
If you’ve hit your head & it causes a small cut in your scalp, it will bleed a lot more then you’ll expect. Why?
b/c your skull is one of the places where some of your blood vessels/veins draining your brain are actually collecting that blood & will eventually get recirculated back to the rest of your body
Describe Dural sinus/cavity
- middle of Dura Matter
- part of the circulatory system
- it’s venous - so it is continuous with the veins that are draining the blood from the brain
- a reservoir where blood is collecting after being drained from the brain itself
- a # of small veins that exit from the Dural Sinus & will eventually go out through the skull (exit) & out through your scalp
Describe Pia Matter
- soft & delicate
- directly ontop of the surface of the hemispheres of the brain of the cerebrum
- another 1 of the meningia layers
- very tightly & closely associated with the neural tissue underneath
Arachnoid Membrane
- called this b/c the hashes on diagram look like spider webs
- layer in middle
- connected to the Pia matter by very fine fibrous structures
THE MIDDLE MEMBRANE LAYER OF THE MENINGES
Describe Arachnoid trabeculae
- bits connecting Arachnoid membrane to the Pia
- fine spider web like processes that hold the Arachnoid to the Pia
Describe Arachnoid Villus (villi)
projections from the Arachnoid membrane, into the dural sinuses & other sinuses within the dura matter that will play an imp. role in the movement of CSF
Getting a cut on your scalp could be dangerous if it’s deep & bleeding. Why?
b/c if you get an infection there it is a really good pathway for bacteria to make it into your CNS, causing a life threatening infection
A deep cut in the scalp can be dangerous:
some veins pass thru the skull (b/c you can get bacteria in there)
What is meningitis?
is a contagious bacterial, virus or fungal infection of the meninges cause swelling & pressure on the brain
- which is bad b/c neurons don’t like to be subjected to pressure (bad implication for circulation & the way they fire APs)
- gets bad fast
- if untreated can end in death
- concern in young adults (hs or uni)
- more common in large groups of people
Traumatic head injury can cause:
- epidural bleeding (b/t the skull & dura)
- subdural bleeding (b/t the dura & arachnoid)
- subarachnoid bleeding (b/t the arachnoid membrane & the pia matter)
What is epidural bleeding?
b/t the skull & dura
- Natasha Richardson had this from skiing injury & died
What is Subdural bleeding?
b/t the dura & arachnoid
What is Subarachnoid bleeding?
b/t the arachnoid membrane & the Pia matter
Cerebrospinal fluid is secreted into the…
ventricles (lateral–>3rd–>4th) & flows throughout the subarachnoid space (& subdural space) where it cushions the CNS (b/t the brain & skull)
- stops the brain from smashing up against the side of skull where it gets tossed around (think egg in water vs egg no water in jar)
Choroid plexus of 3rd ventricle (also in 4th & 2nd lateral)…
- secretes CSF
- within the neurons, there are specialized cells derived from the ependymal cells
Arachnoid villi
pushing through dura & into dura sinus (like a blister)
The CSF that is…
circulating around the brain is getting collected up the venous drainage of the brain & from there its going to make it back out into your blood stream
Why would the CSF move out through these arachnoid villi?
b/c it keeps the fluid in constant motion
- in that way the CSF can collect up some of the waste from the brain & bring it out & dump it into the circulation to be dealt with appropriately
What are the 4 steps of CSF circulation?
- Produced by CHOROID PLEXUS in the ventricles
- Exits brain thru (2 pores) foramen of MAGENDIE & foramen of LUSCHKA (median & lateral)
- Some CIRCULATES around the SPINAL CORD, some circulates INTO SUBARACHNOID SPACE
- Enters ARACHNOID VILLI (granulations), & crosses into VENOUS BLOOD
Why is CSF important?
- Helps MAINTAIN proper SOLUTE CONCENTRATIONS in the interstitial fluid surrounding neurons
ex: if there is high concen. of K+; some can get mopped up by glial cells & some make its way out into the CSF & carry away from the brain) - Helps REMOVE WASTE
ex: metabolic waste - Provides a CUSHION for the brain
- most anatomical function
- so when your head moves around; your brain & spinal cord don’t bang into the side of your skull *neural tissue is delicate & easily damaged & so it PREVENTS IT FROM PHYSICAL DAMAGE OF BRAIN & SPINAL CORD
Describe the blood-brain barrier
barrier b/t the interstitial fluid (that surrounds neurons) of the brain & the plasma
- due to the specialized anatomy of blood vessels in the CNS
- keeps UNwanted materials OUT, keeps WANTED materials IN (the brain)
Describe Circulation IN THE BODY (skeletal muscle for ex)
Endothelial cells are NOT connected & have pores (called fenestrations - small holes) connecting luminal to extraluminal side:
What happens:
- liquid portion of your blood (plasma) carrying solutes is free to diffuse OUT of a BLOOD VESSEL & come into CONTACT with SKELETAL MUSCLE CELLS for ex & similarly, material can diffuse INTO these blood vessels (very, very leaky)
Describe circulation IN THE CNS
endothelial cells (within blood vessels) joined by TIGHT JUNCTIONS - means cells itself are connected by proteins that DON'T permeate the movement of solute or liquid b/t those 2 cells
surrounded by ASTROCYTE (within CNS) ENDFEET
- form structures called endfeet that are lil projections that surround all the blood vessels
- joined by tight junctions –> solute is NOT free to move b/t those joints - it forms a protective layer (blood vessels are wrapped)
end result of that is, hydrophilic substances (water soluble - even glucose) in the blood, must be transported across those cellular layers to make it into the interstitial fluid & eventually into the neuron
- same goes for signalling molecules - like peptide based hormone - have to be transported from blood to interstitial fluid
- likewise any materials secreted by neurons/glial cells must be transported to get into the circulation
- hydrophilic molecules (like ex ethanol) is fat soluble & can diffuse across those cell membranes & directly contact neurons
Describe which type of molecules can diffuse across the blood brain barrier
only LIPOPHILIC (fatty - fatty soluble) molecules can diffuse across (freely pass from the circulation into the interstitial fluid surrounding neurons) - steroids, ethanol, nicotine, Benadryl
POLAR, HYDROPHILIC molecules can only cross via transporters
- insulin, glucose, Na+
Describe Benadryl
- the antihistamine in this can diffuse across those cell membranes & contact neurons
- allergy medicine (meant to have a proiferal effect)
- but b/c it is lipophilic it can move from the circulation & come into contact with neurons therefore it can actually inhibit the activity of neurons by acting @ histamine receptors
- if you’re effecting those histamine receptors in the brain that is 1 of the reasons why benadryl causes drowsiness b/c the histamine antagonist is actually acting on neurons where its not meant to act
Spinal cord
- major pathway b/t the brain & skin, muscle, joints, & organs (parts of the body we call the periphery)
- 4 levels
- organized into segments
- spinal cord has its own internal circuitry to mediate simple reflexes & generates complicated control programs, such as rhythmic patterns used for walking
What are the 4 levels of the spinal cord?
- cervical (parts of the spinal cord in your neck), thoracic (“” check), lumbar (“” lower back), sacral (also coccygeal) (“” very lower back, near pelvis)
- 31 pairs of spinal nerves in total
- after L1-L2, the SC consist of thick elongated nerve roots called CAUDA EQUINA
What are the 4 levels of the spinal cord?
- cervical (parts of the spinal cord in your neck), thoracic (“” check), lumbar (“” lower back), sacral (also coccygeal) (“” very lower back, near pelvis)
- 31 pairs of spinal nerves in total
- after L1-L2, the SC consist of thick elongated nerve roots called CAUDA EQUINA
What is cauda equina?
after L1-L2, the SC consists of thick elongated nerve roots
- “horsetail” - connection of nerve roots
- there are a lot of axons that have diverged from the spinal cord up higher & by the time you get to this lower region there isn’t a whole lot left
What are the segments that the spinal cord is organized into?
each segment has bilateral (2) sets of roots
- dorsal (sensory)
- ventral (control/motor)
Ex: Pateller reflex
the circuity req for this doesn’t req your brain @ all, it ONLY requires the axons that are innerating those muscles, neurons in the spinal cord & the axons exiting the spinal cord
- doesn’t req anything above the level of your spinal cord
For simple rhythmic movements:
all the circuity for that is located in the spinal cord - so walking for ex
- the circuity req for the act of walking (simple rhythmic movement of your legs - coordinated movement of your legs) all of that is in place with the spinal cord itself
- the input that’s needed for the control of walking comes from your brain & levels above your spinal cord
The meninges surround the _____ _____ as well so it gets protected
spinal cord
Roots
nerves that contain #’s of axons
- can differentiate which is which simply by the presence of this enlargement
Ventral root
- carrying Efferent axons
- those axons will control skeletal muscle, function of some of the organs etc.
Dorsal root
carry sensory axons, carrying info into the CNS
- ENLARGED is ALWAYS the dorsal root (found in your back)
Autonomic ganglion
contain neurons that regulate the ANS or are an intrenget part of the ANS
Spinal nerve
point that they (roots?) join up
Dendrites
- found in the periphery
- contains various kinds of sensors for (temp, touch etc)
Axon
a bunch of these will come together to form these spinal nerves
Pseudounipolar sensory neurons
- b/c they only have 1 process that’s exiting the cell body
- have an axon neuron that is specialized for carrying info over long distances
White matter in the spinal cord
formed by myelinated axons
- REVERSED outside now (opp. from brain)
Grey matter in the spinal cord
formed by neuronal cell bodies, dendrites & unmyelinated synapses, etc
- REVERSED now, inside (opp. from brain)
Dorsal root the spinal cord
carries sensory (afferent) info to CNS - enlargement that contains CELL BODIES of those sensory neurons
Ventral root in the spinal cord
carries motor (efferent) info to muscles & glands
2 roots will merge & form a…
spinal nerve
What is each segment of the spinal cord gonna have?
each segment of the spinal cord is gonna have a pair of dorsal roots & a pair of ventral roots & these will merge together & eventually form a spinal nerve
Dorsal root ganglion
enlargement that contains sensory neuron cell bodies
Visceral sensory nuclei
neurons part of a local processing circuit - meant to process sensory info that is coming from your viscera (from various ORGANS for ex)
Somatic sensory nuclei
2nd order sensory neurons (means they receive a synapse from the 1st order primary sensory neurons)
- cell bodies in there receive some of the sensory info
Autonomic efferent nuclei
- send axons out through ventral roots
- contribute to the autonomic control of your organs
Somatic motor control nuclei (skeletal muscle)
- in the very ventral aspect
- control SKELETAL MUSCLE
What are the 2 white matter tracts?
Ascending tracts:
- on dorsal surface
- carry sensory info
Descending tracts:
- info on axons that will control skeletal muscle & organs
What makes up the brainstem?
- Midbrain
- Pons, &
- Medulla
cerebellum NOT considered brainstem
Brainstem
(phylogenetically) oldest region of the brain
transition to the SC
consists of
- midbrain
- pons
- medulla
- (NOT CEREBELLUM!!!)
most of cranial nerves (10/12 pairs of nerves) arise from brain stem
- pairs of nerves emerging from CNS that carry SENSORY INFO (from eyes, ears, sense of balance, taste - some carry info that controls your mouth, tongue, movement of your eyes etc)
- sensory, motor (that control the functioning on your organs), or both (either carry sensory info back & motor info out & some are mixed - carry both)
Reticular formation (part of brainstem)
- receives & integrates incoming sensory input
- plays critical role in AROUSAL (wakefulness - whether or not your awake & whether or not you can focus on certain kinds of info)
- gives rise to groups of DIFFUSE MODULATORY NEURONS
- means diffused, so there is no real structure to this part
- diffused collection of cell bodies
Medulla (part of brainstem)
contains neuronal clusters (nuclei) that control (these bodily functions) HEART & BLOOD VESSEL function, RESPIRATION, & many DIGESTIVE functions
- better organized
Pons (part of brainstem)
acts as a RELAY station for CEREBELLUM & CEREBRUM: plays role in regulating MUSCLE REFLEXES involved in EQUILIBRIUM & POSTURE
Cerebellum
key part in brain for your ability to maintain POSTURE, sense of BALANCE & EQUILIBRIUM
Cerebrum
integrating station
- info flows back & forth between this & cerebellum - allowing a sense of equilibrium in your posture
Midbrain
- critical relay for visual (from eyes) & auditory (from ears) info
- governs movement of the eyes (dilation & constriction of your pupils)
- gives rise to groups of DIFFUSE MODULATORY NEURONS
Diffuse modulatory systems
long, slow regulation of behaviour of neurons & its usually through the actions of GPCR
for norepinephrine, dopamine, & serotonin
- group of neurons in here (only a few 1000 of those neurons - but they send axons nonetheless through the brain, through the cerellum & down through the spinal cord)
- don’t act to directly stimulate AP’s, but they have subtle modulatory influences on the electrical behaviour of the way neurons work
for acetylcholine
- similarly, several 100 000 but these diffuse modulatory neurons that spread their axons all throughout the brain - don’t just project to a single location
Cerebellum
processes sensory info from muscles, joints, vestibular system, eyes
- integrates POSITION & MOVEMENT of body with intent to move body
- important in maintaining BALANCE & CONTROLS EYE MOVEMENTS (if you close your eyes & stand on 1 foot - sense of balance is inhibited drastically & that is b/c of info coming through your visual system & being integrated within your cerebellum)
- enhances MUSCLE TONE & COORDINATES skilled, VOLUNTARY movements (reach across table to grab a pencil)
- plays a role in planning & initiating VOLUNTARY activity by providing input to cortical motor areas (preplan a coordination before you do it)
- STORES PROCEDURAL MEMORIES (motor learning - learn how to do something, ex: learning to shoot a puck in top shelf (practiced) these procedural memories are stored in the cerebellum)
also has recently discovered function in cognition (ability to think) & emotional processes
derives from same developmental tissue from the pons (even though it is NOT part of brainstem)
POSITION OF THE BRAIN THAT COORDINATES THE EXECUTION OF MOVEMENT
Thalamus
- main relay centre for most types of info
- receives info from almost every area of the CNS, & sends info to these same areas
- sensory, emotional, motor, arousal
- all have a synaptic relay or synapse at the level of your thalamus
PORTION OF THE BRAIN THAT SERVES AS A RELAY STATION FOR INFO GOING TO & FROM HIGHER BRAIN CENTERS
Why do we need a synapse there? Why do we need a relay?
- you might think it will be more efficient if you just send an axon from point A to point B, instead of sending it to from a relay in the thalamus 1st or from the synaptic connection there
- whole point of having more synaptic connections is yes there is a loss of speed b/c there has to be a synapse, but you get info processing/integration, so you allow info that’s going to the cortex to be integrated with other info from other areas (helps contextualize your info)
Hypothalamus
below thalamus
brain area most involved in directly regulating internal environment (internal)
REGION OF THE BRAIN THAT CONTAINS CENTERS FOR BEHAVIOURAL DRIVES & PLAYS A KEY ROLE IN HOMEOSTASIS
Hypothalamus functions
- controls body temp
- controls thirst & urine output
- controls food intake
- controls anterior pituitary hormone secretion
- produces vasopressin & oxytocin (neuroendocrines)
- controls uterine contractions & milk ejection
- serves as a major ANS coordinating center
- plays role in emotional & behaviour patterns, including reproduction, SEXUAL ORIENTATION?
Hypothalamus & sexuality
in 1991 Simon LeVay published a paper indicating a morphological difference in a nucleus of the hypothalamus b/t gay & straight men (INAH3 - small area of hypothalamus)
- the area in gay men was anatomically more similar to females
suggested “sexual orientation has a biological substrate”
- often misinterpreted
- very controversial findings
- LeVay accused of being biased (b/c he is gay)
Cerebrum
LARGEST & most DISTINCT part of human brain (makes up about 80% of total brain weight)
- our intelligence really comes about b/c of a massive enlargement of our cerebrum - compared to other animals (especially other mammals)
folded, showing gyri & sulci (peaks & valleys)
- these are used as landmarks
evolutionarily, the newest
several parts
- cortex
- white matter
- basal ganglia
- limbic system
LARGEST REGION OF THE BRAIN
What are the several parts of the cerebrum?
- cortex
- white matter
- basal ganglia
- limbic system
Cortex
OUTER surface is highly convoluted cerebral cortex
- HIGHEST, MOST COMPLEX INTEGRATING area of the brain
- plays key role in most SOPHISTICATED neural functions (math, language, music)
each half of cortex divided into 5 major lobes
LITERALLY, BARK; THE OUTER OR SURFACE PORTION OF AN ORGAN
What are the 5 major lobes that each half of cortex is divided into?
- occipital
- temporal
- parietal
- frontal
- insular*
What is “special” about the insular lobe?
for 2 reasons:
- it’s not obvious looking @ the brain from the surface view
- sometimes textbooks don’t include it at all
Frontal Lobe
Skeletal muscle movement
- primary motor cortex
- motor association area (premotor cortex)
prefrontal association area
Describe premotor neurons
are critically involved in PLANNING OF MOVEMENT
- get info from BG, cerebellum & somatic sensory cortex
- activation of these neurons is what triggers activation of neurons within your SC; sends neurons down into SC to those motor neurons & ultimately let you grab your coffee cup
thinking of picking up coffee mug then activate these
- these neurons become activated & fire APs & process info that they need to do to help coordinate movement
- proper signals will get sent from neurons to SC to activate right set of motor neurons to grab cup
Sulci
fold
Gyri
Humps
Central Sulcus
frontal & parietal lobe are differentiated by this one major groove (central sulcus)
- anterior to that is gonna be the frontal lobe
- posterior to that is gonna be the parietal lobe
Parietal Lobe
processing textures, touch, temp info from your skin
primary somatic sensory cortex
& sensory association area
Primary somatic sensory cortex
sensation of processing of sensory info from you body
- have the ability to discriminate b/t a smooth surface & a rough surface
- 1st area of processing
Sensory association area
adjacent area
- understand more of the properties of what you’re touching
- 2nd area of processing
- able to associate smooth/rough surface with other simultaneous stimuli & make a judgement as to what that particular stimulus is
- different properties of keyboard your touching
Occipital Lobe
vision
visual cortex
- 1st area of processing
- “this item is red” or “this item is round”
visual association area
- 2nd area of processing
- “oh, it’s a red ball”
allow increase level processing of the info acquired in the visual cortex
Temporal Lobe
Hearing
Auditory cortex
- 1st place where auditory info is transmitted
Auditory association area
- then goes here to understand & process
Insular Cortex
“insulated” - it’s hidden, it’s sheltered
taste - gustatory cortex
smell - olfactory cortex
What is the Ideal of lateralization?
2 halves of the brain are NOT identical,
- left-handed persons brain is NOT a mirror image of right-handed person’s
- for most people language processing, math processing occur on the left side
- 95% right handed people left dominant for language (means their language is processed on the left side of the brain - this doesn’t necessarily mean that theres language processing on the right side - in fact there is very little on the right side of most peoples brain & its not reflective in whether or not your left handed or right handed)
- but only 20% left handed people right dominant for language; many lefties process language on both sides (i.e. it’s complicated)
**Take home message: often many functions are localized to one side of the brain, not always bilaterally localized
- for most people spatial recognition (if you were blind folded & someone put you into a building & you recognized where you were), face recognition, aspects of emotion processing & artistic functions occur on the right side (1 side of the brain) - not always true
Is right & left brain person a thing?
lateralization does NOT refer to right brain person (creative, artistic) vs left brain (logical & analytical): this idea from 1960’s is considered scientifically unsound
Explain how NOT every function is lateralized
some things are localized to one side or the other, some things are found on both sides
ex’s on page 56
What is one of those things that is lateralized?
the process of language
Areas are connected by reciprocal connections…
- are axons that go from W’s to B’s & vice versa
- those 2 areas communicate to each other
Where does input for language processing come from?
audio (listening to language) or visual (reading language) info
Describe the path of sensory input
sensory input goes from audio or visual cortex to Wernicke’s, then to Broca’s
- following integration b/t these 2 areas, info from Broca’s to motor cortex to initiate spoken or written action
Aphasia
inability to comprehend or formulate langauge
Damage to Wernicke’s area:
- difficulty understanding spoken or visual language (Receptive aphasia)
- -> understanding when someone is speaking to you or writing or both or 1 or the other
- speech may be nonsensical b/c of trouble connecting words with meaning (word salad, Jargon aphasia)
- have real words & the real words can come out of their mouth perfectly formed, but they can’t string them together in a proper sentence
- a bunch of words will just come out of their mouth, but there is no logical meaning for any of that
Damage to Broca’s area:
- often can interpret simple words or sentences, but may have trouble with more complicated ones with several elements
- -> might have trouble with the “red cat ran up the big tree to catch a squirrel” - with numerous elements in this sentence
- difficulty expressing ideas: “can’t get a sentence out” (Expressive aphasia)
- -> know what they want to say inside their head, but just cannot get those words out, either spoken or in writing or both
- words (come out) “distorted”
- -> (mangled sounds of the words)
- just a disconnect b/t the ability to form those words into a language & what happens with their mouth, can’t connect how to make a word & make that particular sound
Damage to Broca’s area:
- often can interpret simple words or sentences, but may have trouble with more complicated ones with several elements
- -> might have trouble with the “red cat ran up the big tree to catch a squirrel” - with numerous elements in this sentence
- difficulty expressing ideas: “can’t get a sentence out” (Expressive aphasia)
- -> know what they want to say inside their head, but just cannot get those words out, either spoken or in writing or both
- words (come out) “distorted”
- -> (mangled sounds of the words)
- just a disconnect b/t the ability to form those words into a language & what happens with their mouth, can’t connect how to make a word & make that particular sound
Basal Ganglia
- “Ganglia” are collections of cell bodies (=nuclei)
- there are several components of the basal ganglia
- the neurons within basal ganglia communicate with each other, & with other brain areas
Components of the basal ganglia form a complex circuit b/t the…
motor cortex, premotor cortex, cerebellum, thalamus, & other areas
Explain the 2 main diseases of basal ganglia
loss of any parts of the basal ganglia is devasting
Parkinsons disease: loss of dopaminergic neurons in BG
- causes tremors, loss of ability to move (initiate a movement - difficulty getting up from a chair), cognitive deficits
- MJF (Micheal J Fox, Rush Limbaugh)
- if you overstimulate/overmedicate you can cause Huntington like symptoms
Huntington’s disease is loss of cholinergic neurons in BG (this activates the neurons that are lost in Parkinson’s)
- causes uncontrollable movements (chorea - Latin to dance), loss of coordination, dementia (similar to PD)
Limbic System
considered phylogenetically oldest part of the cerebrum
- includes amygdala, hippocampus, cingulate gyrus
- strongly connected with other areas, such as thalamus, hypothalamus, & parts of the midbrain & brainstem
- links higher processing with primitive emotions such as fear, aggression, reward, social & sexual behaviour - “animal brain”
Ex: See a bear in the woods
- Sensory stimuli
- Cerebral Cortex - integration occurs within the association areas of the cerebral cortex
- Bear! - see bear (visual) - Integrated info
- Limbic system creates emotion
- critical component for regulating basic emotional responses
- Fear!
- processes & integrates - sends info back “OMG that’s a bear, if i don’t move it will eat me!)
- feedback creates awareness of emotions - Hypothalamus & brain stem
- homeostatic response - Initiate
- Somatic motor responses (both voluntary & unconscious - irresistible urge to run)
- Autonomic responses (fight or flight)
- Endocrine responses
- Immune responses (if there is a long term stress)
Diseases & lesions of the CNS: damage to frontal lobe
Phineas P. Gage
- worked on the railroad
- his job was to put dynamic down with the pole
- tamped down dynamic & it sent steel rod through his head
- abolishes large part of frontal cortex
- doctor was surprised he was alive
- made the recovery
- before he was smart, easy to get along with
- *after personality completely changed
- swore, not easy going, angry, difficult to get along with, changed jobs lots
- historically imp. case
- things we learn from a single patient stimulate a whole area of resource (like H.M. hippocampus)
