psyc 301

midterm 1

describe spinal cord

inside: grey matter (outward signal). Outside: white matter (up and down signal). The dorsal horn and root are afferent, the ventral horn and root are efferent.

what is Central NS

Control center , includes brain and spinal cord

what is Peripheral NS

Communication between CNS and everything else. Includes somatic NS and Automatic NS

what is somatic NS

Communicate with the outside world. Afferent-sensory, Efferent-motor(CNS to muscle)

What is Automatic NS

Regulates the inside world. sympathetic ns- fight or flight. Parasympathetic NS-rest and digest.

grey matter

tissue made up of cell bodies and small blood vessels

white matter

cells wrapped in myelin

rostral/caudal

towards the nose/towards the tail

dorsal/ventral

towards the top/towards the back

anterior/posterior

towards the front/towards the back

directions for the head and spinal cord

Lateral/medial

Towards the outside/towards the inside

horizontal plane

coronal Plane

sagittal plane

Unilateral

only one side

Bilateral

both sides

ipsilateral

2 points on the same side

contralateral

2 points on different side of body

5 brain facts

2-3% of body weight

Soft tofu

20% of the body’s energy

Made up of neurons, neural stem cells, glia, and blood vessels

60-100 billion neurons, half in the cerebellum

divisions of the brain

3 divisions: hindbrain, midbrain, forebrain

hindbrain

myelencephalon, metencephalon

myelencephalon

medulla: Mostly white matter tracts carrying signals between the regions of the brain and the body

• Most life-preserving functions travel through this place

• information sent to the right places

metencephalon

pons: connection btw brain and spinal cord

• part of the reticular formation

cerebellum: little brain

• contains half of neurons here

• needed for coordination

• highly connected to the cortex

midbrain

mesencephalon

mesencephalon

Tectum

• Roof

• which contains nuclei that receive and send out:

  • visual information (superior colliculi)

  • auditory information (inferior colliculi)

Tegmentum

• Floor

• Which contains nuclei related to:

  • motor function (substantia nigra and red nucleus)

  • pain (periaqueductal grey)

Reticular formation

Reticulum means “little net”

• In the myel-, met- and mesencephalon (midbrain + hindbrain)

• Many nuclei that play roles in arousal, attention, cardiac and respiratory reflexes, and other jobs

Forebrain

diencephalon, telencephalon

diencephalon

the thalamus 

• 2 lobe structures(looks like balls)

• Many different types of Nuclei

  • some process and relay info between receptors and cortex

• Nuclei may be specific to one sense or non-specific and involved in multimodal integration

• Important for consciousness cuz connected to cortex

  • Ex. anesthetics work on nonspecific nuclei of the thalamus

• Abnormal synchronization in the thalamo-cortical network can cause absence seizures

the hypothalamus

• Important for behaviours like feeding, sex, sleeping, temp, emotion, movement

• Works with hormones 

• Closely related to the pituitary gland and signals it to regulate behaviour

• If problems, hormonal changes 

  • Headache, seizures

  • Feeding and weight changes: Failure to thrive, loss of appetite, weight gain or loss

  • Energy and mood changes: euphoria, hyperactivity, fatigue, aggression

  • Cognitive changes: disrupted attention, memory problems

  • Hormonal changes like early puberty, sexual problems

brainstem

medulla(myelencephalon), pons(metencephalon), midbrain(mesencephalon)

telencephalon

Cortex

• Outer wrinkly portion of the brain

• Normally 6 layers

  • Except Hippocampus, olfactory (piriform) cortex

  • Different neuron types at different layers

  • Input layers and output layers

Basal ganglia

• Lower knots

• Collection of nuclei connected to the cortex, thalamus, and midbrain

• Involved in movement and learning

Limbic systems

• Hippocamnpus

  • Seahorse

  • Role in spatial memory

• Amygdala

  • Almond

  • Emotion processing

gyrus

Top of wrinkle

sulcus

Bottom

Sulci deep enough to indent the ventricles are also called fissures

All fissures are sulcui but not all sulcui are fissures

cortical lobes

• Frontal lobe

• Parietal lobe

• Occipital lobe

• Temporal lobe

central sulcus

between frontal and parietal

lateral sulcus

Between frontal, parietal, temporal

longitudinal fissure

between 2 hemispheres

cerebrospinal fluid

Contained in ventricles in the brain, outside the brain,spinal cord

1. Buoyancy

• the dense brain is suspended in fluid, reducing its effective weight

• does not interfere with blood supply or put pressure on lower structures

2. Protection

• reduces injury upon head impact

• if brain does hit skull: hemorrhaging, brain damage, death...

3. Chemical stability

• CSF flow rinses waste through the blood-brain barrier

• Maintains appropriate levels of hormones, pH

hydrocephalus

If CSF flow is partially/gradually blocked, ventricles become enlarged and pressure builds in the skull

• Treated via surgical shunt 

• Most common in the very young and very old

• large head baby

Chiari malformation

Compression and distortion of cerebellum due to skull shape

Symptoms

• Headache

• Neck pain

• Coordination issues

• Swallowing issues

Pontine tegmental Cap Dysplasia

A rare genetic disorder of pons and cerebellum formation due to a developmental error in axon growth and guidance

Systems affected:

• Hearing, gaze, swallowing, facial movements

neurons and types

Electrically conductive.

• Pos and neg ions inside idff from outside

Process: axons and dendrites

Unipolar = one process leaves cell body

Bipolar = two processes leave cell body

Multipolar = 3+ processes extend from cell body

Interneuron = no axon or short axon (in between other neurons)

fluid inside and outside neuron

3 paths to pass into neuron

NO energy needed, following gradients

• Passive diffusion: Pass through the membrane

  • Made of fat so fat molecules can pass

• Facilitated diffusion through channels

  • Allow only some molecules to enter

    • Ex. sodium channel let sodium

Active transport: moves against gradient

• This is a pump that gets energy by atp

resting membrane potential

Maintain charge -60 mV and -80mV

When sodium and potassium move, they change the potential(charge)

Maintained by sodium- potassium pumps

• 3 Na+ out: 2 K+ in

• Uses 2/3rds of the brain’s total energy (ATP)

• Inside is more negative.

• More Na+ outside the cell

• More K+ inside the cell

Each has dedicated channels (doors that only they fit through) that are closed at rest but open at predictable voltages

• Neither can cross the membrane when channels are closed

Initiation of AP

In a sensory neuron and is sensing something

• Outside stimulus 

Inputs from other cells

• At the end of the axon is the terminal button

  • Designed to send signals

• There are vesicles filled with neurotransmitters

• Presynaptic neuron: When AP reaches the terminal button, neurotransmitter are released into the synapse 

• Postsynaptic neuron has diff receptors that fit with some NTs (lock and key)

• Once binded, they trigger a change that push the charge up or down

  • Excitatory: make the post more likely to fire, push charge up

  • Inhibitory: make less likely fire, push the charge more negative

  • Modulatory: trigger other changes

action potential

rising phase, repolarisation phase, hyperpolarisation phase

rising phase

At rest, it is negative, but when the charge changes and exceeds -55mv the channels changes

• The sodium channel open and it stars rushing in cuz gradient

• Inside is becoming more positive

• Then the potassium channels open and starts rushing out at -40

• Works against eachother but there is more sodium total so the charge continues to go up.

repolarization phase

• Pecks at +50

• Sodium channels are closing

• No new sodium but potassium is still leaving

hyperpolarization phase

• -70mv potassium channels close

• Cell is hyperpolarized

• The pumps catch up and return to resting potential 

Clean up

Neurotransmitters

• diffuse away

• Broken down by enzymes

• Reuptake 

  • By presynaptic neuron 

  • By glia

all or none principle

An action potential travels down the axon and does not decay

Only moves in one direction, down the axon

unmyelinated axons

have Na+ channels all along surface

myelinated axons

Na+ channels only at nodes of Ranvier

agonist

Activating receptor effects

• Methadone - simulate opioid receptors

antagonist

Blocks the receptor from being turned on

• Prevents NTs from binding 

• No drugs can bind to the receptors

Reuptake inhibitors

Act upon reuptake channels 

• Serotonin and norepinephrine 

Used to treat depression, anxiety, and pain

• By blocking reabsorption of serotonin into the pre-synaptic cell, the drug lengthens the time serotonin is available in the synapse to act on the post-synaptic cell

Glia

Glia do everything else

oligodendroglia, Schwann cells, microglia, astroglia

Glia likely play an underestimated role in many neurological conditions given their immune and “clean-up” roles

Oligodendroglia

• Wrap around axons of neurons in CNS (forming many myelin sheaths per cell)

Schwann cells

• Wrap around the axons of neurons in PNS, forming one myelin sheath per cell

microglia

• Respond to injury and disease, engulfing debris and triggering an immune response

• Only in CNS

astrogila

• Largest glial cells , also only in CNS

• Support endothelial cells of the Blood-brain barrier

• Provide nutrients to neurons

• Maintain ion balance in CNS

• Repair after injury

• Communicate with neurons and glia

• Control and maintain synapses

Why do a neurological exam

• Differential diagnosis

  • To distinguish b/w 2 diff diagnosis

• Monitor disease progression

  • Judge new medication, new needs, new methods

• Clarify impact of injury/disease

• Determine rehabilitation needs

• Capacity for ADLs, work, study

  • Can they return to life

• Surgical candidacy

• Triaging

  • Determining who needs to be seen first

• Legal

  • Determined how they will be tried 

locations that could be affected, detected by exam

• 5 divisions of brain

• Internal capsule (internal tract connecting brain+spinal cord)

• Spinal cord

• Cranial nerves

• Neuromuscular junction

• Muscle

Common Components of exams

1. Patient history

2. Cranial nerves

3. Motor system

4. Somatosensory

5. Coordination

6. Mental status

• Follow-up neuropsychological testing

patient history

• Age, education, and handedness (which hand they use changes where something are)

• Past and family medical history

• Use of medication or drugs

• Disease process

  • Timing: sudden v gradual; acute v chronic

  • Change over time: static, improving, worsening

  • Triggers or relievers of symptoms

  • Severity of symptoms

what are the Cranial nerves

1. olfactory

2. optic

3. oculomotor

4. trochlear

5. trigeminal

6. abducens

7. facial

8. vestibulocochlear

9. glossopharyngeal

10. vagus

11. accessory

12. hypoglossal

Olfactory(what does it do, is there a condition related to it, is it sensory or motor)

• Smell, see if person can smell things through one side at a time and compare strength

• Sensory nerve

• Bilaterally abnormal 

  1. Anosmia = loss of smell 

  2. Possible damage to ethmoid ridge via trauma/TBI > CSF leakage

sensory

Optic(what does it do, is there a condition related to it, is it sensory or motor)

• Standard visual tests 

• Visual field confrontation: how much space you can see

• Pupillary light reflexes 

• Fundoscopy (looking at back of the eyes

  1. Looking for optic disc swelling (blurred DM margins

  2. Possible causes of increased intracranial pressure  

     1. TBI 

     2. Brain tumour 

     3. Encephalitis (inflammation) 

     4. High blood pressure 

     5. Bleeding

sensory

oculomotor, trochlear, abducens(what does it do, is there a condition related to it, is it sensory or motor)

Control eye position via paired muscles that move and hold the eye

Gaze palsy = weakness or loss of certain eye movements

can be nystagmus(dancing eye), voluntary/reflexive/both, one/both eyes

motor

Trigeminal(what does it do, is there a condition related to it, is it sensory or motor)

3 parts

1. Motor: feel activation of muscles when biting down, holding mouth open

2. Sensory: detection of location, sharp/dull, hot/cold

3. Trigeminal neuralgia 

   1. A severe chronic pain condition 

   2. Feeling of electric shock to one side of the face, triggered by light touch or sometimes spontaneously

   3. Causes: pressure on trigeminal nerve by a blood vessel; MS(deterioration of myelin), tumour, stroke

   4. Treatment: anticonvulsant drugs, surgery to move blood vessels

both

facial (what does it do, is there a condition related to it, is it sensory or motor)

Test for asymmetry and strength:

1. Face: drooping, sagging, facial creases

2. Raise eyebrows

3. Smile

4. Puff out cheeks

5. Close eyes hard

Bell’s Palsy = paralysis of facial nerve causing weakness on one side of face

Both

Vestibulocochlear (what does it do, is there a condition related to it, is it sensory or motor)

balance and hearing

Whisper test

1. Can they detect them

2. Test hearing with tuning fork touching + not touching skull bone

1. Unilateral hearing loss = peripheral lesion

2. Bilateral hearing loss = more central damage

both

Glassopharyngeal, Vagus(what does it do, is there a condition related to it, is it sensory or motor)

Mouth and throat

Assess voice, swallowing, gag reflex, cough 

Pseudobulbar palsy = bilateral central lesions

1. (pseudobulbar/corticobulbar tracts = cortex +medulla) 

2. Strained, strangled voice 

3. Emotional lability (up and down)

4. Gag normal or increased

Bulbar palsy = bilateral peripheral lesions (bulbar =medulla) 

1. Nasal speech

2. No emotional lability 

3. gag absent

motor

Accessory(what does it do, is there a condition related to it, is it sensory or motor)

1. Neck muscles

2. Shrugging of shoulders

3. Head resistance

4. Looking for weakness + location

motor

Hypoglossal(what does it do, is there a condition related to it, is it sensory or motor)

1. Tongue

2. Stick out tongue, lateral movement

3. Looking for direction deviation + strength

motor

How to test Motor function

Appearance of muscle 

Muscle tone, strength

• Strength: How much force can be exerted

• Tone: baseline tension at rest 

Trying to determine upper or lower

• Upper motor neurons originate in motor cortex or brainstem and use glutamate

  • Weakness

  • Spasticity  (abnormal muscle tightness)

  • Hyperreflecia (exagreateted relect

  • Retains primitive reflexes

    • Infancy reflexes, should be turned off 

• Lower motor neurons originate in spinal cord or brainstem, innervate muscles or glands, and use acetylcholine (incl. motor cranial nerves)

  • Weakness

  • hypotonia (low tone)

  • Hyporeflexia

  • Atrophy 

  • Fasciculations

    • Muscle spasms/twitches 

    • Not enough input from nerve, so muscles become more sensitive  

• Brain -> upper neuron -> lower neuron

How to test Somatosensory Function

Detect without looking

• Temperature

• Pain

• Vibration

• Proprioception

Touch

• Astereognosis = inability to recognize objects by touch

• Agraphesthesia = inability to recognize letters/numbers by touch

  • both point to sensory cortex of parietal lobe

How to test Coordination

Quick, alternating movements

• Dysdiadochokinesia: multiple sclerosis in adults; cerebellar tumours in kids

Point-to-point movement

• Dysmetria: impairment performing accurate movements

• Points to cerebellar damage

Heel-to-shin test

• Dysmetria > likely cerebellar (ipsilateral or bilateral)

Standing/sitting 

Gait/walking (natural, heel-to-toe)

• Looking for asymmetries,

• poor timing, width of steps, especially when turning & stopping

Abnormalities may point to 

• Ethanol Inebriation

  • Consumed alcohol 

• Cerebellum

Romberg’s test: balance with eyes open vs closed 

• Romberg points to cerebellum damage

Pronator drift = rotation and vertical motion of arm

• Points to damage to the pyramidal tract (efferent fibres from cortex to brainstem or spinal cord)

Mental status

Standardized Mental status exam: brief for screening

Comprehensive neuropsychological battery: lengthy for profiling 

General components 

• Level of consciousness > awake vs asleep, stimulus needed to wake

• Attention & orientation

• Language

• Memory

• visuospatial function

• executive functions

Attention & orientation

Observe the patient’s alertness

• Spelling a word backwards

• Counting backwards from 20

• Current whereabouts, time

regions involved:

• Lots of regions and origin may be large too

problems:

• Contralateral neglect

• Anosognosia

  • Cant recognize doing smth wrong

language

Tasks like naming body parts and reading, writing, and repeating simple phrases

• Prosody (pattern of stress & intonation)

• Praxis (e.g., use this pencil to “slice bread”)

Region:

• Focal or diffuse damage to left hemisphere language network

Problems 

• Aphasia = problems with language production and/or comprehension

• • Alexia = problems with reading

• • Agraphia = problems with writing

Memory

Digit span or pointing span

Short-term memory (“remember these 3 words” for 2-5 min)

Long-term memory: past public or personal events

Regions: 

• Medial temporal structures (e.g., hippocampus)

• Prefrontal cortex

• Left parietal lobe

Problems 

• Dementia

• Amnesia

Visuospatial function

Determining the spatial processing and recognition

Regions

• Right hemisphere attention network

Problems

• Agnosias (recognition difficulties)

• Apraxias (motor performance difficulties)

Executive functions

Cognitive control of behaviour

• Luria’s 3 step test. fist , edge, palm

Perseveration

• Going past where to stop

Regions 

• Prefrontal cortex and/or associated projections

Problems 

• Dementia

• Mood disorder

• Stroke

how does time without blood effect the brain

• Sec= neurological symptoms

• mins=irreversible damage

Cerebral arteries

Posterior cerebral artery

Middle cerebral artery

Antenior cerebar; artery

posterior cerebral artery

occipital lobe and temporal lobe

middle cerebral artery

temporal and parietal

Anterior cerebral artery

parietal and frontal

stroke

Death of brain tissue cuz of injury/disfuntion of blood vessels: Irreversible damage

Infarct/infarction

Dead or dying tissue

penumbra

Dysfuntional area surrounding infarct but unknown fate

Acronym for stroke detection

F- face

A- Arms

S- speech

T-time

Consequences for stroke

• Memory - amnesia

• Language - aphasia

• Motor funtion - paralysis

• Consciousness

• sensory symptoms

Risk increase for stroke

• High blood pressure

• High cholesterol

• Diabetes

  • High sugar damge blood vessels

• Smoking

  • Cuzes inflamation and accumulating in blood vessels 

• Cardiovascular conditions

• Drinking

• Stress

  • Lack of quality food

  • No health education

  • discrimiation

• Lifestyle 

Ischemic

Blocking of blood vessel

Thrombosis

• Being plugged by smth 

• Can be blood cells, tumor

Embolism

• A moving thrombosis

• Moving plug until to big to pass

Arteriosclerosis

• Arteries thickening, hardening, and narrowing of arteries due to fatty plaque build up

Tissue plasminogen activator (tPA)

• Injection that breaks up blood clots