Brain Anatomy

Study of neurological patients
Brain imaging
Animal models

+ Detailed analysis of single subject
+ Study of human behaviour
+ Can potentially relate to brain function
- Limited generalisation
- Rare
- Low stats power (i.e. n=1)
- Lack of control over extent of damage

EEG
MEG
fMRI

+ Good temporal resolution
- Bad spatial resolution

+ Better spatial resolution
- Measures haemodynamic response (blood O2 level dependent response) so activity is inferred
- Lower temporal resolution than EEG (counter by looking at specific areas of the brain, faster)

+ Better temporal and spatial resolution than EEG
- Expensive
- Very few mobile systems

Correlative results
Can't show causation
Very little control of pps outside of the lab

+ Can conduct experiments including invasive procedures
+ Can monitor over long periods of time
+ Greater control over experimental situation
+ Similar brain anatomy and neurochemical systems (depends on animal)
- Difficult to translate tasks between humans and animals (human tasks are often language based eg. questionnaires and interviews)
- Differences in specific brain regions (eg. rats and mice may not even have a prefrontal cortex)

Soma (cell body)
Dendrites
Axon hillock
Axon
Axon terminal

Support cells that make up 50% of the brain

Astrocytes
Microglia
Oligodendrocytes

Anchor neurons to blood supply
Clear neurotransmitters from synaptic cleft

Specialised macrophages (white blood cell) activated by brain damage

Form insulating sheaths around neurons to improve conduction speed

Occipital
Temporal
Parietal
Frontal
Cerebellum

Primary visual cortex of brain (V1)

Blindsight
Consciously blind in affected visual field
Can 'guess' correctly when asked about stimuli in the 'blind' part of their visual field

Involved in:
Auditory perception
Understanding language
Memory formation

Visual agnosia
Can still visually perceive objects but can't relate visual input to the object (can with other modes, eg. touch)

Integrates info from different senses to give us a coherent view of the world
Heavily implicated in functions like attention
Updates representation of where things are predicted to be as a result of movements you are about to make (predicts)

Unilateral spatial neglect
One side of space no longer consciously perceived
Occors across all senses and affects memory

Supports higher cognitive functions including:
Voluntary attention
Decisions making
Long term planning

Prefrontal lobotomis in 1940s and 1950s
Rosemary Kennedy

Necessary for motor coordination and motor learning
Involved in cognitive functions
Contains >50% brain's neurons

Ataxia and other movement errors

Brainstem
Hypothalamus
Thalamus
Hippocampus
Amygdala
Striatum

Includes pons, medulla and midbrain
Maintains autonomic functions (eg. breathing and heart rate)
Coordinates simple motor behaviours

Contains a number of nuclei which release chemical NETs that modulate cortical function

Often fatal
Survivors = locked in syndrome

Regulates motivated behaviour
Integrates info from brain and body, and coordinating neuroendocrine, autonomic and behavioural responses
Made up of many different nuclei

Kallman syndrome (puberty doesn't begin)

Connects sensory systems to cortical regions processing info
Different nuclei process info from different sensory systems
Other nuclei process movement info and communicate this to spinal cord

Range of disorders
Eg. auditory-tactile synaesthesia

Encodes spatial info
Stores episodic memory

HM
Hippocampi bilaterally removed
No longer formed episodic memories

Relates enviro cues with their emotional and motivational significance
Eg. fear

Patient SM
Lost amygdala bilaterally
Doesn't feel fear
Unable to draw fear in faces

Consist of the caudate and putamen
Found within basal ganglia
Basal ganglia contributes to action selection (voluntary, such as voluntary movement of arm)

Parkinson's disease (loss of movement) - pic
Huntington's Disease (excessive movement)

Cell body is grey
Myelin sheat is white
Grey matter = not insulated cell bodies
White matter = insulated axons with myelin sheath

Optic chiasm

Dorsal stream - where, vision for action (goes towards motor cortex)
Ventral stream - what, vision for perception

Hemispatial / unilateral spatial neglect
Simultagnosia
Optic ataxia

Prosopagnosia
Visual agnosia
Cerebral achromatopsia

Representation of info from fovea goes here
Retinotopic
Encodes colour, edges etc.

Tonotopically

From basilar membraine in cochlea, via medial geniculate nucleus of the thalamus

High frequency sounds vibrate basilar membrane at base
Low frequency sounds vibrate basilar membrane at apex

Somatotopically
BUT all somatotopic representations are plastic to some extent

Somatotopically
BUT all somatotopic representations are plastic to some extent

Primary motor cortex (has somatotopic representations)
Cerebellum (has somatotopic representations)
Parietal cortex
Prefrontal cortex (goal representation)

Primary motor cortex (difficulty executing movement)
Premotor areas (difficulty planning movement)
Posterior parietal cortex (difficulty planning movement)
Basal ganglia (difficulty in movement selection - too much/too little)
Cerebellum (difficulty coordinating movement)

Hypothalamus
Rest of the body - blood sugar levels can affect motivation to eat

Amygdala (Patient SM)
Prefrontal cortex (Phineas Gage)
Hypothalamus

Broca's area (speech production)
Wernicke's area (speech comprehension)
Usually in left hemisphere

Explicit (declarative)
Implicit (non-declarative)

Episodic
Semantic

Procedural
Conditioning (emotional)

Prefrontal cortex - working memory
Striatum - procedural memory
Neocortex - perceptual memory, semantic memory, priming
Amygdala - emotional memory
Cerebellum - conditioning
Hippocampus - declarative memory (episodic, semantic)

Involved in:
Planning
Decision-making
Error correction/trouble shooting
Novel sequences of actions
Strong habitual responses/suppressing temptations
Working memory
Problem solving