Motor Speech

Posterior inferior left frontal lobe

BA 44, 45

Pars Opercularis, Pars Triangularis

Inability to talk- nonfluent

Paralysis on right side of arm/face because organs not receiving appropriate brain signals

Comprehension ok

Agrammatical

Short quick nouns, sounds

Understanding speech

Superior posterior temporal lobe

BA 22 + 42

no inability to talk, but cannot understand speech

Poor comprehension

Word salad- eager to talk but meaningless

Horizontal (transverse/trans-axial)

Coronal- front and back

Sagittal- left and right

Ventricles enlarged

Increased CSF production, decreased CSF absorption (communicating), or CSF ventrivular blockage (obstuctive)

disruption/stroppage of blood to brain

Results: decreased oxygenation, mass or pocket of blood (intracranial pressure), blood spills out of artery

Blocking vs Bleeding

Ruptured blood vessel, heavy spilling of blood into cerebral tissue

Examples:

Aneurism

Hematoma

Intracerebral Hemmorhage

Subarachnoid hemmorhage

Hematoma

(subdural  hematoma)

large accumulation of blood at spot of aneurism

Subdural- below dura external to arachnoid membrane

"within brain"

artery bursts within brain

Ischemia

Infarction

Thrombosis
Atherosclerosis

Cerebral Embolism 

Temporary insufficient blood supply

ischemic stroke that causes necrosis

Blockage (or narrowing) of cerebral artery caused by a clot (thrombus)

clot in heart= heart attack

Narrowing of artery by fatty plaque build-up

Clots can build up around these plaques, further constricting

Another source of focal brain lesions

Compresses brain tissue (herniation) and invades

morbid enlargement or new growth of tissue in which cell multiplication is uncontrolled and progressive

stabilize/control bleeding- maybe through surgery

anti-coagulants- warfarin- for clots

vasodilators- dilate or expand vessels

bp medication and steroids- edema (swelling)

"clip" aneurisms

Heredity

Sex- men more likely

ethnicity- african american

hypertenson, diabetes, cholesterol

Necrosis

Disinhibition- unable to inhibit, increased behavior

Disconnection syndrome

Attention deficit

motor/sensory impairment

Memory problems

abstract reasoning problems

Left- language impairment, aphasic- depression

Cognitive defects

Right- impairment in ability to process and execute behaviors in visual-perseption, spatial, rhythmic, nonverbal processing

Right brain damage in right brain CVAs- contralateral motor and sensory impairment- indifference to euphoria

Infiltrative- take over neighboring areas of brain and destroy tissue

noninfiltrative- encapsulated and differentiated but compresses surrounding brain tissue

gliomas

GBM

astrocytomas

oligodendroglioma

meningiomas

acoustic neuroma

computed transaxial tomography

360 degree x-ray beam

20 degree angle of cuts

bone (dense)-white

CSF (low density)- dark

good bc no radiation

super magnet creates flux and aligns H protons in body- turn off RF, hydrogens spin back, as measured by magnetic field

shows H density

magnetic relxation times- intervals necessary to magnetize and delay before magnetic relaxation

T1- black lesion

T2- white damage

good for demyelination, hemmorhage, and tumor

EXPENSIVE 

detect frequencies from species other than water

i.e. glucose, blood

no radiation

better resolution than PET

measure relative CBF

BOLD imaging- blood oxygen level dependent

pros: no cylcotron, no injection, no radiation, no co-registering

cons: noisy, speed only as fast as blood flow

record electric activity of nerve cells through electrodes attached to scalp

investigate distinct pattens of electical activity in order to correlate behavior and personality- doesn't show what they are thinking, just if they are thinking

more sensitive to "forest" than "tree"

Cheaper than CT/MRI

Use: diagnose seizure disorder (epilepsy), sleep disorder, level of coma, or brain death

Cons: false positives, negatives

radioactive isotopes to measure glucose, oxygen metabolism

isotopes have short t1/2 (vs SPECT) and can attach specifically- but still only 1 read/day

glucose rate more direct measure of neuron function than CBF

pros: quiet, measures brain biochemistry and metabolism

cons- more expensive than SPECT, need to co-register with structural MRI, need cyclotron

subtract blood in area of brain- control while doing activities

estimates CBF and blood volume

long t1/2= only 1 exposure

inexpensive

does not require cyclotron

x-ray of arteries

examine brain through vascular system

aphasia- language problem

dys= articulation issue due to motor cortex damage

similar to angiogram

inject sodium amytal into left or right internal carotid

temporary anesthesizes one hemisphere

to study functions of one hemisphere while other one sleeps

magnetic equivalent of EEG

computer calculated 3D magnetic field of brain, which accompanies the electrical activity of neurons

expensive

subtract control conditions (background) from damage (or performing a meaningful activity)

ex. name numbers with no meaning, then do math, measure with PET. subtract meaningless from meaning

compares signal strength in many different areas- boxes- t-test

20 Voxd rule- area significant to function

connectivity analysis- correlate brain activities in different areas of brain

Viewing a separate and independent field by each eye

Right visual field projected onto left hemisphere and left visual field projected onto right hemisphere

Retinal nerve fibers at back of eye divide at optic chiasm

Left and right communicate through corpus callosum

If callosum cut and eyes and head kept from moving, each eye can only see half visual field

Each ear stimulated simultaneously by different sounds

Left projected on right hemisphere and vice versa

Left parietal damage- bilateral effects

trouble miming- can't motor express

would use finger as key, fist as hammer

bilateral diffuse damage

trouble sequencing- know motor steps but can't sequence

think- lighting a cigarette

occipital or parietal damage (or connections between)- can be bilateral damage

trouble constructing, drawing, or dressing

example- ask people to put 3 matchsticks in a triangle- they know what a triangle is, understand language, but can't spatially arrange

right parietal

Can't recognize by sight

Left parietal-occipital or right occipital

recognize object but not meaning

· place 3 things in hand (key, chalk, dime and ask them to give you key with eyes closed)- can’t recognize things by touch, but can recognize visually

"word deafness"

reading and writing ok

disconnect Wernicke's from auditory areas

inability to recognize or differentiate bewteen sounds

can physically hear sounds and describe using unrelated terms, but cannot recognize them

Outer ear directs sound to eardrum

Middle ear acts as a lever, increasing force and pressure

Inner ear- wave moves through cochlea, change in pressure detected by hair cells of organ of Corti, transduced into neural signals sent to brain

Brocas area- left ventral lateral frontal area

Wernicke's- left posterolateral temporal area

Left and right dorsal inferior frontal cortex

Left dorsolateral prefrontal cortex

Right posterolateral temporal cortex