cognitive neuroscience

study of the relationship between neuroscience and cognitive psychology

Why the influx of cognitive neuroscientists?

1. demand for physical support of theoretical structures
2. need for meaning behind physical structures
3. clinical goal to find connection of brain pathology and behavior
4. involvement of neurological functions in mind models
5. work of computer scientists

resting potential

a negative electrical charge in neurons

inhibitory neurotransmitters

cause charge to go down (become more negative)

excitatory neurotransmitters

cause charge in neuron to go up (become less negative)

action potential of a neuron

when a neuron recieves enough excitation, it can go from negative to positive for a short time.

the charge is carried down the neuron and cause release of more neurotransmitters by the terminal buttons

neuron firing

neuron experiencing action potential

summation

cell adds up excitation, and if its high enough the cells will fire

can operate in 2 ways:

1. Spatial summation: neuron summing up all inhibition and excitation at 1 point in time
2. Temporal summation: summing up activity over time

***THRESHOLD IS UNRELIABLE***

rate of firing is influenced by...

1. size of neuron (bigger=faster)
2. how information is incoded...so faster if it's more difficult

phrenology

held that character and personality were localized in the brain

could be examined by measuring bumps on the head

scientific support

localization

different parts of brain have different functions

began with phrenology

aggregate field theory

motor and sensory functions are not just localized, but also distributed in other parts of the brain.

traumas and injuries seem to affect all higher functions equally

thalamus

takes in sensory information

contralateral

left hemisphere controls/takes in sensory input from right side, and vice versa

sulci/sulcus

grooves in cerebral cortex

gyri/gyrus

ridges in cortex

used for landmarks in brain (along with sulci)

frontal lobe (including central fissure)

rear part controls motor action

broca's area (only on left) - speech production and grammar

broca's aphasia

*aphasia is a general term for a speech problem

broca's means speech is very halting and gramatically incorrect

prefrontal lobe

• abstract thinking
• working memory
• planning
• social skills
• inhibit inappropriate behavior

occipital lobe

• vision
• from rear forward, type of visual processing becomes more complex - very rear is for corners and lines...next to temporal lobe is for recognizing faces

parietal lobe

• touch
• spatial orientation
• nonverbal thinking

somatosensory cortex

body sensing

temporal lobe

• primary auditory cortex
• front and below gray area: sound distinction and other basic auditory sound processing
• hearing
• Wernicke's Area: speech comprehension

Wernicke's (or receptive) aphasia

problem in understanding language. usually they can speak fluently but sometimes speech doens't make sense. it's difficult to understand meaning behind speech.

hippocampus

• no technically part of cerebral cortex
• runs adjacent to inside surface of temporal lobe
• critically important for memory, esp. long-term

medial temporal lobe

inside surface of temporal lobe, where hippocampus is

anterograde amnesia

damage to hippocampus or temporal lobe

difficulty learning new things, but memory is fine for things before injury

fissures

deep and prominent sulci

association areas

anything that's not sensory/motor cortex

cognition, memory, language processing, etc

mass action

importance of individualized neurons is minimized and memories seem to be distributed throughout the brain

"there are no special cells for special memories"

Karl Lashley

how does a brain survive damage?

• many functins are generally localized, but not completely
• neurons work in big groups so if part of a group gets hurt, they can make new pathways (paralell/series processing)
• higher-order functions occur less compartmentally

CAT (or CT) scans

computerized axial tomography

• of modern types, this is most basic and limited
• x-ray taken from many angles of the head which are joined together to make 3D image
• gives idea of physical structure
• static: doesnt tell us how brain might change from one moment to next
• shows where physical damage may have occurred

MRI or fMRI

magnetic resonance imaging

• still images put together
• detects increased blood flow to certain areas of brain, thus displaying structure and function

PET scan

positron emission tomography

• scans for glucose in the brain
• use detectors to find radioactive particles in bloodstream
• color coded map with red meaning most active