Cognitive Neuroscience Exam 1

Syncytium (Golgi)

Brain is one mass of tissue

Neuron Doctrine (Ramon y Cajal)

Nervous system is made up of individual cells

Montreal Procedure (Brodmann & Penfield)

Neurons that produce seizures are destroyed in epilepsy patients

James

Father of American Psychology

Law of Effect (Thorndike)

If an action is rewarded, the likelihood of its occurrence will increase

Behaviorism (Watson)

Mental processes that can’t be observed should be avoided

Miller

Rejection of behaviorism & birth of cognitive neuroscience

Golgi staining

shows neuron structure & function

dead cells

Calcium flashing

light flashes = calcium influx into neurons

live cells

Neuron components

dendrites

cell body

axon

axon terminal/synapse

Cell body to axon terminal

Single travels from/to

Oligodendrocytes (CNS)

Schwann cells (PNS)

Myelin is made in

charged ions from leaking out of axon

signal degrading

Myelin provides insulation which prevents

regenerates charge via voltage-gated Na+ channels

Nodes of Ranvier function

loss in myelin

inefficient neural communication

Multiple Sclerosis (MS) has to do with

K+ out

Na+ in

Ca2+ in

Semi-permeable phospholipid bilayer allows flow of what ions through ion channels

3 Na+ out

2 K+ in

net deficit in positive charge

Sodium-Potassium Pump hydrolyzes ATP to ADP to allow

receive inputs

Dendrites function

Send outputs

Axon function

short distances

long distances or fast reflexes

Myelin sheath is not needed for ___ and only needed for

action potential jumping from node to node along an axon

Saltatory conduction is

Passive

Ligand-gated

Voltage-gated

Three types of ion channels

Always open

Passive ion channels

Closed, open when ligand binds

Ligand-gated ion channels

Closed, open when voltage is more negative relative to inside cell

Voltage-gated ion channels

Maintain blood brain barrier

Astrocytes function

\-70 mV

Neuron is at rest at what voltage

\-55mV

Neuron reaches threshold at what voltage

\+40 mV

Neuron fires an action potential at what voltage

\-85 mV

Neuron is hyperpolarized at what voltage

Passive K+ channels

Passive Na+ channels

Sodium-potassium pump

At rest, what channels are open

Ligand-gated Na+ channels

Voltage-gated Na+ channels

Voltage-gated K+ channels

At rest, what channels are closed

Concentration gradient (more Na+ out, more K+ in)

Electrical gradient (inside more negative)

At rest, sodium-potassium pump creates what

Diffusion - K+ enter, Na+ enter

Electricity - K+ leave, Na+ enter

At rest, concentration & electrical gradients create

Na+ to enter cell

Membrane depolarizes

Neurotransmitters open ligand-gated Na+ channels which causes

Voltage-gated Na+ channels in axon hillock causing membrane to reach threshold

When membrane depolarizes, what channels begin to open

All-or-none response

Once threshold is reached, neuron fires an action potential & there is a huge Na+ influx. Why?

firing rates

Neuron action potentials always reach same amplitude but have different

Directly following action potential (repolarization)

Voltage-gated Na+ channels close

No action potentials can fire

Explain absolute refractory period

During hyperpolarization

Neuron can fire an action potential but is more difficult

Voltage-gated K+ channels are open

Explain relative refractory period

Few Na+ passive channels are present in membrane

At rest, why doesn’t Na+ rush into the cell

Ca2+ channels

Action potential causes what channels to open in presynaptic nerve terminal

Vesicle fusion & neurotransmitter release from presynaptic nerve terminal to synaptic cleft

Ca2+ entry into presynaptic nerve terminal causes what

Na+

Receptor channels open following neurotransmitter release into synaptic cleft & what enters postsynaptic cell

Reuptake of neurotransmitters

Enzymes breakdown neurotransmitters

What happens to excess neurotransmitter in synaptic cleft?

brain & spinal cord

CNS consists of

White matter = myelinated axons

Gray matter = neuronal cell bodies

CNS contains white & gray matter which are

Cushion between brain & skull

Dura mater, arachnoid, pia mater

CNS has meninges which function is what & consists of what

ventricles & central canal of spinal cord

CSF is located in

Cushion for acceleration

Produces astrocytes

Waste disposal

Provides nutrients to brain

CSF functions as

Receives auditory/visual inputs

Posture, walking, coordinated movements

Cerebellum functions

Relays sensory info (except some olfactory info)

Thalamus functions

Homeostasis

Metabolic control

Hypothalamus functions

Links nervous system to endocrine (hormone)

Pituitary gland functions

Communication between left/right hemispheres

Corpus callosum functions

folds

Gyri

Valleys

Separate lobes

Sulci

Basal ganglia

Amygdala

Hippocampus

Subcortical structures

motor movement

reinforcement learning

Basal ganglia functions

Long-term memory

Hippocampus function

Sensory info

Body to dorsal horn

Afferent nerves

Motor info

Ventral horn to body

Efferent nerves

Medulla oblongata

Pons

Midbrain

Brainstem consists of

Pyramidal decussation: crossing of inputs

Medulla oblongata functions

Connects brain & cerebellum

Eye movements, auditory info, REM sleep, arousal

Pons functions

Automatic/uncontrolled orienting

Superior colliculus: vision

Inferior colliculus: audition

Midbrain functions

Frontal

Parietal

Occipital

Temporal

Cerebral cortex lobes

Largest

Movement, language, higher level cognitive functions

Frontal lobe

Auditory info

Memory

Temporal lobe

Sensory perception/integration

Parietal lobe

Visual processing

Occipital lobe

Caudal

Another word for posterior

Rostral

Another word for anterior

Left to right

Sagittal brain slice

Back to front

Coronal brain slice

Bottom to top

Axial (horizontal) brain slice

Increase surface area

Neurons closer together

Purpose of folded cerebral cortex

Superior temporal gyri

Middle temporal gyri

Inferior temporal gyri

Important gyri located in temporal lobe

Central sulcus: separates temporal & parietal lobes

Sylvian fissure: separates frontal & temporal lobes

Important sulci

Birth of new neurons

Almost all neurons generated during gestation

Neurogenesis

Hippocampus

Olfactory bulb

In adults: neurogenesis occurs in

1. Proliferation & differentiation of neuronal stem cells into neuroblasts & glial cells


1. Ectoderm forms neural plate
2. Incorrect closing of neural tube leads to anencephaly (absence of major portion of brain) OR spina bifida (missing vertebrae)
3. 5-6 weeks: cells divide symmetrically then asymmetrically
2. Radial Unit Hypothesis


1. radial glial cells help neurons migrate toward brain surface
2. neurons born near each other radiate out towards same layer of cortex & have similar functions -- based on when cell is born
3. Cortical organization into 6 layers


1. Synaptogenesis begins during 2nd semester

Neurogenesis steps

Anencephaly -- absence of major portion of brain

Spina bifida -- missing vertebrae

Incorrect closing of neural tube leads to

Radial glial cells help neurons migrate toward brain surface

Neurons born near each other radiate out towards same layer of cortex & have similar functions

Radial Unit Hypothesis

Peak density \~15 months after birth, again in adolescence

Birth of synapses & connections based on experiences

Synaptogenesis

Occurs alongside synaptogenesis

Axon grows & becomes myelinated to enable cross regional communication

Myelination

Follows peak synaptogenesis

Removal of synapses that aren’t used, slower than genesis (toddlerhood)

Synaptic pruning

Primary input layer

Layer 4 of cortex

Primary output layer

Pyramidal cells

Layer 5 of cortex

Most neurons

Layer 6 of cortex

Ganglion & nerves outside CNS

PNS consists of

Voluntary muscle controls

Somatic nervous system

Involuntary action of smooth muscles, heart, & glands

Automatic nervous system

Rest & digest

Neurotransmitter acetylcholine

Constricts pupils, stimulates salivation, slows heartbeat, contracts bladder

Parasympathetic nervous system

Fight-or-flight

Neurotransmitter norepinephrine

Dilates pupils, inhibits salivation, accelerates heartbeat, relaxes bladder

Sympathetic nervous system

Hypothesis

Experiment

Prediction

Result

Conclusion

Scientific method involves

A guess about how something works

Hypothesis

Used to test hypotheses

Experiment

Expected outcome of test

Prediction

Actual outcome of test

Result