Neuroscience 105 Final Exam

Free Radical

An atom or group of atoms that has an unpaired (extra) electron and is therefore unstable and highly reactive

Reactive Oxygen Species (ROS)

Chemically reactive molecules containing oxygen

Superoxide Dismutase (SOD)

Enzyme that is part of the detoxification of reactive oxygen species; SOD1 gene is muted in some ALS cases

Oxidative Stress

An imbalance between the production of reactive oxygen species species and the bodies ability to detoxify the free radicals or repair damage

EAAT2

Excitatory Amino Acid Transporter 2 - clears glutamate from the synapse; EAAT2 gene is expressed in astrocyte cells. EAAT2 gene is muted in some ALS cases

Excitotoxicity

Cell death resulting from the toxic actions of excitatory amino acids such as glutamate

Astrocyte

One of the three major classes of glia in central nervous system, controls the ionic environment of neurons and can be involved in neurotransmitter reuptake

Hemorrhagic Stroke

Ruptured blood vessel in the brain

Ischemic Stroke

Blocked blood vessel in the brain

Transient Ischemic Attack (TIA)

Symptoms of a stroke that resolve in 1-24 hours - “mini stroke’

F.A.S.T

Facial drooping, Arm weakness, Speech difficulties, Time

Penetrating Arteriole

Blood vessel that branches from a surface artery and projects into the brain

Astrocyte

Make broad contacts with blood vessels; respond to neurotransmitters too; leading to uptake of oxygen, water, and glucose from an arteriole or capillary

Blood Brain Barrier

Combination of endothelial cells and astrocyte acting as a filter allowing only certain substances to pass from the blood into the brain

3 proteins involved in neurodegenerative diseases

Senile Plaque: Amyloid Beta

Neurofibrillary Tangles: Hyperphosphorylated Tau

Lewy Bodies: a-synclien

Senile Plaque

Amyloid Beta

Peptide in amyloid plaques

Primary marker of Alzheimer’s Disease

Neurofibrillary Tangles

Hyperphosphorylated Tau

Common marker of Alzheimer’s disease

Lewy Body

a-synuclein

Common marker of Parkinson’s disease and Lewy Body Dementia

3 Brain Regions affected

Alzheimer’s Disease: hippocampus, cortical and limbic structures

Parkinson’s Disease: substantia nigra & linked cortical regions

Amyotrophic Lateral Sclerosis (ALS) (Lou Gehrig’s Disease): spinal cord and precentral gyrus (primary cortex)

Unconditioned Stimulus

A stimulus that produces a natural, automatic reaction

Conditioned Stimulus

A previously neutral stimulus that, after repeated association with an unconditioned stimulus, elicits the response produced by the unconditioned stimulus itself

Command Neuron

A single neuron (or small number) whose stimulation triggers a specific naturally occurring behavior

Trp Channels

Activated by changes in environmental temperature

Synaptic Pruning

Process of synapse elimination

Proliferation

Rapid growth of brain matter and formation of new connections

Long Term Potentiation

Induces gene expression that produces proteins that strengthen the synapse

Plasticity

Structural or functional changes in the nervous system

Neuroplasticity

Experience driven reorganization of neural pathways in the brain, forming new connections, strengthening or discarding old ones

Increases in Myelination speed up nerve conduction velocities-strengthening circuits-allows signals to arrive synchronously-stabilize neural circuits

Epigenetics

The study in the field of genetics of cellular and physiological phenotypic trait variations that are caused by external or environmental factors that switch genes on and off and affect how cells read genes instead of being caused by changes in the DNA sequence

What functions does the Hippocampus carry out?

Memory and emotion

What functions does the Substania Nigra carry out?

A nucleus in the basal ganglia involved in initiating voluntary movement. Contain a lot of dopaminergic neurons

What functions does the Limbic System carry out?

Emotion and mood

What functions does the Amygdala carry out?

A nuclear complex in the temporal lobe whose major functions concern autonomic, emotional, and sexual behavior. Most often connected with the major emotions such as fear and avoiding situations that induce fear

Resting Potential

The electrical difference across the cell membrane of -70mV that results from the action of the Na+/K+ pump

Polarized Cell

There is an electrical difference across the cell membrane

Depolarization

Displacement of the cell’s membrane potential to a less negative value

Hyperpolarization

Displacement of the cell’s membrane potential to a more negative value

Concepts

Resting membrane potential (-70mV), effects that neuronal depolarization (less negative/closer to 0) and hyperpolarization (more negative) have in terms of numerical values. Threshold of -55mV is usually when action potiental is triggered

What are the primary functions of the dendrite, soma, and axon?

How do the ions Na+, K+, and Ca++ function in generating an action potential?

What is an action potential? How does it propagate through myelinated and unmyelinated regions?

What is the order of the opening of voltage sensitive channels during an action potential?

Na+,K+,Ca++

How can the same neurotransmitter excite or inhibit post-synaptic neurons?

The same neurotransmitter can have opposite effects depending on what receptor type it binds

What happens if you inhibit to synaptic signaling if you inhibit the atonal voltage sensitive channels (Na+, K+, Ca++)

Receptors

Proteins on the post-synaptic membrane that senses the neurotransmitter

Ionotropic Receptor

Receptors in which the ion channel is an integral part of the receptor molecule (as of course is the ligand binding site). Ionotropic receptors are also called ligand gated ion channels

Metabotropic Receptor

Receptors in which the ligand binding site is an integral part of the receptor molecule but the receptor is only indirectly linked to an ion channel. Also known as G-protein-coupled receptors - intracellular signaling pathways use G-proteins. Also known as 7 transmembrane receptors

Ionotropic

Direct effect on ion flow, effects fast and brief

• ions flow through the receptor

• Most fast receptors are of this type

Metabotropic

Indirect effects on ion flow, effect slow but longer lasting

• conformational change transmits information across the membrane

• Often involve biochemical cascades that can affect many processes

• Can be longer lasting

Frontal Lobe

Executive Function

• all of neocortex from front to the central sulcus

• Planning, emotional expression, problem solving, memory

• Includes primary cortex

Central Sulcus

Fissure that separates the frontal and parietal lobes

Parietal Lobe

Sensory Information

• includes somatosensory

Occipital Lobe

Vision

• processes visual input

• Size indicates importance of vision to humans

Temporal Lobe

Memory, Listening

• includes hippocampus: critical in forming long term memories

• Primary auditory perception/processing (hearing)

• Visual memories

Pons

Relay station (like thalamus). Initiates dreams

Medulla

Controls involuntary functions such as breathing

Cerebellum

Regulates motor coordination, posture, balance

Brainstem

Midbrain, pons, and medulla

Neurotransmitter GABA

Major inhibitory neurotransmitter that hyperpolarizes target neuron; GABA allows Cl- influx

Thalamus

Relay station for almost all sensory information

Neurotransmitter Glutamate

Predominant excitatory neurotransmitter that depolarizes target neuron in the brain; glutamate allows Na+ and Ca++ influx

Neurotransmitter Acetylcholine

Small molecule (usually) excitatory neurotransmitter that acts as motor neuron synapses (neuromuscular junction). Also acts in the autonomic nervous system

Axon

The neuronal process that carries the action potential from the nerve cell body to a target-passes info

Cell Body

Integrates incoming signals and generates outgoing signal to axon

Dendrite

A neuronal process arising from the cell body that receives synaptic input-receive info

Soma

Where in a neuron synaptic inputs are summed

Gray Matter

Cell bodies, uninsulated axons

White Matter

Myelinated axons

Synapse

Specialized apposition between a neuron and its target cell for transmission of information by release and reception of a chemical transmitter agent

Synaptic Bouton

A swelling specialized for the release of neurotransmitter that occurs at the end of (or along) an axon - pre-synaptic (before the synaptic cleft)

• also known as axon terminal or terminal boutons

Neurotransmitter

Substance released by synaptic terminals for the purpose of transmitting information from one nerve cell to another

Synaptic Vesicles

Spherical, membrane-bound, organelles in presynaptic terminals the store neurotransmitters

Presynaptic

Referring to the component of a synapse specialized for transmitter release. Upstream of a synapse

Postsynaptic

Referring to the component of a synapse specialized for transmitter reception. Downstream of a synapse

Sensory Neuron

Are nerve cells within the nervous system responsible for converting external stimuli from the organism’s environment into internal electrical impulses

Motor Neuron

A nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland

Interneurons

A neuron that innervates other neurons

• technically links a primary sensory neuron to a primary effector neuron (reflex arc)

Optogenetics

A method in which the combination of genetic manipulation and optical stimulation can be used to elicit either gain or loss of function events in specific cells. Expression of algal ion channels that are activated by specific wavelengths of light - can depolarize or hyperpolarize neurons

GCaMP

Genetically encoded calcium indicator that emits (green) fluorescent light when calcium is present. Indicates synaptic activity in living organisms

Positron Emission Tomography (PET)

Radioactive sugar or glucose injected which is taken up by active neurons. Emitted positrons annihilate and convert to gamma rays which are detected

Magnetic Resonance Imaging (MRI)

Imaging technique that uses a combination of radio waves and magnetic fields to scan the or a body part. Generates a static image

Functional Magnetic Resonance Imaging (fMRI)

Uses MRI technique to image blood flow, which reflects neuronal activity. Multiple images are taken over time to generate a dynamic view, albeit at much lower resolution than a standard MRI

Diffusion Tensor Imaging (DTI)

Variation of MRI - measures movement of water molecules along axon. Allows tracing of brain wiring

Long Term Potentiation (LTP)

A persistent strengthening of synapses based on recent patterns of activity

Long Term Depression (LTD)

A persistent weakening of synapses based on recent patterns of activity

NMDA Receptor (NMDAR)

A ligand-dependent AND voltage-sensitive Ionotropic glutamate receptor. Allows Ca++ ions into the neuron only if both the glutamate ligand and membrane depolarization are present. A Mg++ ion blocks the channel when inactive. NMDA is the major receptor that mediates long term changes at the synapse

Synaptic Strengthening

Increase in the number of receptors or vesicles full of neurotransmitter, greater size of synapse, along with other structural features are all mechanisms for strengthening a synapse

Hebbian Learning

Simultaneous activation of cells leads to pronounced increases in synaptic strength between those cells

• neurons that fire together, wire together

Concepts

Neuronal circuits can change overtime. These changes can be structural (size of synapse/number of receptors) and function (strength of signal at synapse) - see Kandel

Astrocyte

Makes broad contact with blood vessels and B.B.B

Ionotropic

Offer direct effect on ion channel flow. The effects are fast and brief. Ions flow through receptor. Most are fast receptors

Metabotropic

G- protein receptors that have indirect effect on ion flow. Longer lasting.

G-Proteins

7 transmembrane domaines (wiggly line)

Fast Excitatory Neurotransmitters

Binds to an Ionotropic receptor on the post-synaptic membrane activating a single neuron. Deals with glutamate in the brain and acetylcholine in neuromuscular junction

Fast Inhibitory Neurotransmitters

Rapidly inhibit target neurons via ion channels. GABA (main) in the brain and Glycine in the spinal cord.

Slow Neuromodulators Neurotransmitters

Typically metatropic receptors that change neural activity for longer periods, often in multiple neurons.

Channel Opening Order

Na+, K+, Ca++

Plasticity

Structural or functional changes in the nervous system