Cognitive Neuroscience Quiz 1 (only outline)

Cognitive Neuroscience integrates what 4 disciplines

neurology

neuroscience

cognitive psychology

computer science/artificial intelligence

neurology

function and pathology of the nervous system

neuroscience

study of the structure and function of all aspects of the nervous system

includes:

• cellular (neurons, glial cells)

• molecular (neurotransmitters, genes, hormose)

• systems (vision, motor)

Each studied in terms of anatomy, physiology, and chemistry

cognitive psychology

how the mind processes information

provide detailed analysis of how information is processed when we perform a complex task

cog psych models can be proposed without considering biological issues

computer science/artifical intelligence

how can computers perform tasks?

can we simulate cognition with neural-like models?

Behavioral Neurology

• emphasis on linking regions of the brain with different behaviors and cognitions

• important for clinical eval and treatment

• accomplished through task-based approaches to characterize the precise nature of deficits

• GOLD STANDARD for testing which brain regions are critical for testing which brain regions are critical for a given function

Cognitive Neuroscience

interdisciplinary effort to uncover the neural mechanisms of cognition

interaction is bidirectional

Cognitive Neuroscience Goal

Characterize how various cognitive processes are implemented in the brain

• What brain areas are important for converting visual words in phonological representations?

• How does it do this?

• How does the brain buffer the contents of working memory against distraction?

Cognitive Neuroscience has emerged from these developing methods:

• Electrophysiology

single unit recordings in awake monkeys

electroencephalograpy (EEG, ERP)

• Neuroimaging

PET

fMRI

• Lesion

experimental in monkeys

treatment/accidents in humans

transcortical magnetic stimulation (TMS)

• Computational Models

Camillo Golgi

1873: developed a silver stain that allowed visualization of individual neurons

• believed vrain was a continuous mass of tissue with a common cytoplasm

Santiago Ramon y Cajal

The Neuron Doctrine (1889)

Used Golgi’s stain to show that the brain was made up of individual nerve cells linked together by long extensions

Soma

cell body

Axon

transmitting

dendrite

receiving process

Synapse

gap between neurons where transmission takes place

In vertebrates, neurons receive inputs from ___ and pass information down the ___ towards the ___

dendrites

axon

nerve terminals

Glial cells roles

1. structural and metabolic support

2. produce insulation of axons (myelin)

3. scavengers; remove debris after injury or cell death

4. aid in the maintenance and clean up of extracellular ions and neurotransmitters

5. during development, guide the migration of neurons

6. form tight junctions with endothelial cells that line capillaries and venules

Neuronal Communication

• electrical impulses carry signals within a neuron

• chemical transmitters carry signals between neurons

Membrane potential

difference in electrical charge between the inside and outside of a neuron

around -70mV in a resting neuron

postsynaptic potential

a temporary change in the electrical polarization of a neuron's membrane caused by the flow of ions when neurotransmitters bind to receptors on the postsynaptic cellr

receptor potential

a type of local electrical voltage change that happens in a sensory cell when it detects an outside stimulus like light, sound, or touch

Summation of post synaptic potential leads to action potentials

Action potential is conducted better in myelinated axon

unmyelinated axons allow leakage of voltage

output neuronal signaling

neurotransmitters

• neurons can produce several NTs

• synthesized in cell body or synaptic terminals

• released from synaptic vesicles by presynaptic neuron

• binds to receptors on postsynaptic neuron

excitatory neurotransmitters

glutamate (Glu)

acetylcholine (Ach)

Inhibitory neurotransmitters

Gamma-aminobutyric acid (GABA)

Glycine (Gly)

Neuromodulators

modulate activity in large regions rather than strictly exciting/inhibiting specific postsynaptic neurons:

• dopamins (DA) - origin ventral tegmental area (VTA)

• norepinephrine (NE) - Locus coeruleus

• serotonin (5-HT)

originate from cell bodies in the midbrain

action potential

a brief, rapid change in the voltage across a cell membrane that lets neurons and muscle cells send electrical signals

common neuromodulators

• acetylcholine - facilitates learning and memory

• norepinephrine - enhances vigilance and preperation for action

• dopamine - facilitates movement, reinforces behaviors, helps keep information in short term (working) memory

• serotonin - inhibits some behaviors, many other effects

brain orientation

anterior/rostral - front

posterior/caudal - tail, back

medial - middle

lateral - side

dorsal/superior - above

ventral/inferior - below

Dorsal view

Ventral view

lateral view

medial view

4 lobes of the cerebral cortex

frontal. parietal, occipital, temporal

sulci and gyri

sulcus - depression in brain

gyrus - folds

gray matter and white matter

gray matter - cells make it gray, processes information

white matter - myelin makes it white, routes signals between gray matter

gyral anatomy

ce

central culcus

a landmark

boundary of motor and sensory cortices

sylvian fissure

separates the temporal lobe from parietal and frontal lobes insula is buried within it

6 cortical layers

layer 4 - main input layer

layer 5 - main output layer

Line of gennari

a visible white stripe of nerve fibers running through the primary visual cortex of the human brain

in the fourth layer of cerebral cortex

Brodmann’s Map

a system that divides the mammalian cerebral cortex into distinct regions based on cell morphology, density, and layering (cytoarchitecture)

retinotopy in primary visual cortex

injected radioaztive glucose into bloodstream developed a photograph in the brain

map of retina produced in brain

tonotopy

the organized mapping of sound frequencies

Motor cortex topography

movement

Somatosensory cortex topography

the conscious or unconscious process of perceiving bodily inputs such as touch, pain, temperature, vibration, and body position

experimental lesions in animals

• tissue removal

• tissue destruction

  • electrical current

  • excitoxins

  • neurotoxins

• reversible leasions

  • cryogenic depression

  • injection of drugs

tissue destruction with excitoxins

kainate, ibotenic acid, and NMDA

advantages - controlled extend of spreading (very precise) and selectively kill neurons while sparing fibers

disadvantages - non reversible

tissue destruction with neurotoxins

6-hydrpxydopamine (6-OHDA)

advantages - selective destruction of dopamine neurons, reduces dopamine in specific brain areas up to 90% for up to 18 months

disadvantages - non reversible

cryogenic depression (cooling)

advantages - fully reversible, can be applied many times, dulls synaptic activity near 20 degrees C, but does not affect fiber tracts in vicinity until below 10 degrees C

disadvantages - cooling spreads, not very localizable, prolonged exposure can damage tissue

pharmacological inactivation

• Na+ channel blockers - block action potential conduction. only type that can affect fibers

• inhibitory neurotransmitters - hyperpolarize neurons and drastically reduce probability of firing. Inactivate neuronal cell bodies, where the receptors are located and NOT passing axons

  • state of the artn

neurological patient studies

used to make inferences about brain behavior relationships

especially to test for necessity

stroke

arteriosclerosis - thickening walls of arteries

aneurysms - ballooning in wall of artery

coup brain injury

a type of trauma where the brain is damaged directly below the exact point of impact

contracoup trauma

damage to the brain that occurs on the side opposite the initial point of impact, caused when the moving brain slams against the inner wall of the skull

design flaws of skul?

ethmoid ridge and sphenoid ridge are sharp. brain often injured under these ridges because they get shredded

single dissociation

happens when brain damage or a lesion disrupts one cognitive function (Function A) while leaving another function (Function B) intact

double dissociation

method used to identify specialized functions by comparing two patients

TMS

transcranial magnetic stimulation

a non-invasive medical treatment that uses magnetic pulses to stimulate nerve cells in specific areas of the brain