PSYB65 Cumulative Lecture Notes Weeks 1 11
LEC 1 - Sep. 13
- Critical basic life processes occur in the brainstem mostly in medulla
- Reticular formation plays a role circadian rhythm; sleep and wake cycles
- Thalamus is the relay center to convey information into neocortex
- Hypothalamus controls hunger, thirst, territoriality and sexual behaviour (if it feels good its there, 4Fs)
- Limbic system plays a role in learning and memory, and emotion
- Size of a structure directly related importance of use and function in particular species
- Ontogeny recapitulates phylogeny what an individual goes through in development (ontogeny)
from conception to maturity is similar to process of species evolution
- Macleans Triune Theory has 3 basic component, the human brain is 3 in 1
Reptilian brain (the oldest and consist of brain stem up to thalamus), it still exists. Controls
breathing, heart beat, eating, reproducing and territorial behaviour
Old mammalian (paleo) consists of the limbic system, in human it is more evolved and can process
complex emotions; aside form the basis, humans have the ability to emote.
New mammalian (neo) processes intellectual functioning; read, write, talk, plan and was added to
older parts of the brain.
LEC 2 Sep. 20
- Forebrain is smooth in animals. There is evolutionary pressure for humans to be smarter. Human
brains have sulcis (grooves) and gyri (convolusions)
- Brain has 2 hemispheres connected by a fiber pathway called corpus callosum.
2 hemispheres are contralateral: right hemisphere (RH) controls and gets info form left side and left
hemisphere (LH) controls and gets info from right side
- 3 main sulci (called fissures):
longitudinal fissure separates right and left
central fissure separates anterior and posterior parts of the brain
Sylvian fissure separates frontal and parietal lobes
- Every lobe consists of primary function and primary cortex along with the associational cortex
(receptive area for each love from external/sensory modality)
Sensory input comes in to the sensory cortex (i.e. motor cortex receives input from sensory and
output is in the muscles)
Associational cortex: computing power of the brain; processing more complex info
Human have higher proportion of association cortex relative to overall cortex; primary cortex
More evolved species have more associational cortex
- Lobes according to Brodmanns cytoarchitectural map (BA):
Frontal lobe (BA 4, 6)
Occipital (BA 17) primary receptive area for vision
Parietal (BA 1, 2, 3)
Temporal (BA 41) primary receptive area for audition
- Frontal lobe
start at the anterior of the brain up to the central sulcus
controls motor movement, planning, inhibiting inappropriate behaviour
primary area in frontal cortex is motor strip (precentral gyrus)
motor output and control
- REVIEW HOMUNCULUS DIAGRAMS! (Stimulate the top of the cortex, leg is stimulated; as you
move lower it stimulates from the lower half of the body and moves upwards)
1 - Parietal lobe
Starts at central sulcus and moves back until the occipital lobe
No clear boundary between the 2 lobes
Somatosensory input: receives input from the bodys non-specialized senses (i.e. skin)
Primary area: post-central gyrus which is the somatosensory strip (BA 3, 1, 2) everything is else is
associational cortex and is of higher order functioning
- Occipital lobe (Posterior)
Primary function: receive info form eyes into the primary visual cortex (BA 17)
- Temporal lobe (Ventral/bottom)
Primary function: receives info from ears into the primary auditory cortex (BA 41)
Blood Supply to Brain
- Ventricles are spaces in the brain containing cerebrospinal fluid (CSF)
Connects to the central canal of the spinal cord
4 main ventricles: lateral ventricles (right and left), third and fourth ventricles (deep inside thalamus)
and cerebral aqueduct (CSF exits the brain through this)
- Blood is supplied to the brain by 2 internal carotid arteries and 2 vertebral arteries at the base of the
- Circle of Willis: connection of arteries that form circle (basilar and carotid arteries)
It is important because it ensures equal distribution of blood to the brain
- Cerebral arteries supply blood to the cortex.
- Brains has 3 layers of covering called meninges
Dura mater: tough, fibrous layer; thick membrane
Arachnoid mater: spongy, blood vessel run in subarachnoid space
Pia mater: innermost, very thin and follows all the convolutions of the brain and adheres to its
- Meningitis is infection/inflammation of the meninges. Symptoms include headache, neck pains, fever.
Its common among young people, can go unnoticed and result in death.
LEC 3 Sep. 27
Blockage of blood flow
1. Cerebrovascular accident (CVA) or stroke: severe interruption to the brains blood supply. Results in
ischemia (lack of oxygen/not enough blood). Ischemia can cause dead/dying tissue which results in
2. Encephalomalacia: lack of blood supply which occurs very slowly. Very slow reduction in blood supply
softening of brain tissue (some death)
3. Transient Ischemic Attack (TIA): temporary lack of oxygen/blood; sudden onset or attack. Restricts
blood flow. Musculature of particular blood vessels contracts and wont let blood flow in certain parts
of the brain.
- 3 Major causes:
Thrombosis: locally formed blockage
Embolism: blockage that breaks off from somewhere else; block of plague from anywhere can get
loged in the artery in the brain
Arteriosclerosis: seen more in the elderly, slow reduction of blood supply, caused by thrombosis
and embolism, results in ischemia and hardening of arteries.
Blood Vessels Burst
- Cerebral hemorrhage: massive bleeding into the brain itself; can be fatal, most often associated with
high blood pressure. Maintaining good BP is essential method for preventing hemorrhage.
Sub-dural Hematoma: bleeding into space between skull and brain itself.
- It doesnt kill brain tissue directly if caught in time. It only puts pressure; if pressure is relieved theres
no permanent brain damage.
2 - Massive bleeding into the brain will kill the tissue where its bleeding.
Angioma: collection/mass of enlarged abnormal blood vessels
- Usually congenital
- Shunts blood in wrong direction, inherently weak
- Can lead to a stroke
Aneurysm: is a vascular dilation
- Expanded blood vessel caused by localized problem in elasticity
Closed Head Injuries
- Blow to the head that causes injury but doesnt open the brain (i.e. automotive accidents)
- Most commonly affects frontal/temporal lobes
- Contracoup effect: brain is hit on one side (coup) and ricochets and hits the other side.
- Cancer: mass of groin tissue independent of surrounding tissue
- Major types:
Glioma: cancer of glial cells; 45% of brain tumors. Range form benign to highly malignant (refers to
rate of spreading
Meningioma: tumours formed in meninges; its generally benign, NOT life threatening. Puts a lot of
pressure on the brain.
- Relatively rare and can cause inflammation and swelling
- Encephalitis: inflammation of the brain as a result of infections
- Causes: viruses, bacteria, fungus and parasites
- Affects myelin
- There are 2 main types of cells in the brain: neurons (dendrite, soma, axon) and glia cells (helper
Oligodendrocyte make up myelin within the CNS only meet with axon and wraps around it
Schwann cells make up myelin in the PNS only
- Diseases of NS that affect people who are relatively young
- Chronic disease of CNS myelin
- Generally results in partial paralysis and depends upon where the myelin in the brain the disease
- Results in the myelin destroyed in motor (muscle) control system most debilitating
- Can be sensory as it may affect balance, vision, haptic (feel)
- Crippling, indirectly fatal, shorter life expectancy body degenerates and is more susceptible to
- Effects begin at 20-40 years, bad prognosis if you get it before or after those years
- More commonly occurs in colder climates
- More common in families, not genetic
- Slow progressing virus
- Initital onset is rapid, no symptoms; within a few days symptoms can disappear.
- May be mild/severe. Can be so weak that a person may never know they had M.S.
- Initiated by trauma, illness, change in body temperature.
- Degeneration in myelin sheath occurs in small localized areas (plagues) can be scattered around NS
- Treatment: steroids relieve inflammation
- Myelin can regenerate but this regrowth is slow (effective in long term)
Causes: Virus, along with autoimmune disorder (immune system attacks your body)
LEC 4 Oct. 4