Lecture Content Flashcards
What is a CT scan?
CT scan is a structural scanner that takes images of the human brain by taking multiple X-ray images that then are combined with a computerized algorithm in order to makeup a complete brain image. Non-invasive.
In vivo vs In vitro
In the first, studies are performed within the organism, whereas in the latter, tissue/sample has been extracted to be studied in a Petri dish (in glass).
Evolutionary conservation
The presence of similar genes and phenotypes, chromosomes, proteins in different species, pointing to a commonality of origin.
What is homology? Types?
Homology is similar characteristics between different species. It could be molecular, structural, or functional (processes).
Phylogenetic Tree
First drawn by Darwin, prior to his Origin of Species. It represents the evolutionary relationships and patterns between different biological species: their similarities and differences.
What is “Glucose on”?
A gene has been turned off in experiments.
What is “Galactose”?
A gene has been turned on in experiments.
Forward genetics
Molecular genetics approach that aims to determine the genetic origin of a phenotype.
- Identify a mutant strain based on a phenotype
- Recover a wild-type gene by complimentation
—> using a mutant phenotype to identify (clone) the gene
Reverse genetics
- Start with a cloned gene
- Make directed mutations in the cloned gene
- Reintroduce into the organism and investigate the phenotype
—> using the gene to identify the mutant phenotype
What is mitochondria responsible for?
Metabolizing energy from food, through an oxidation process, mainly within the muscles, brain, liver, heart, and gastrointestinal tract.
*Switching off the mitochondria in dopaminergic neurons has been linked to Parkinson’s.
Neural circuit
A population of neurons interconnected by synapses that carry out a specific function when activated.
Electrophysiology
Branch of neuroscience that explores the electrical activity of living neurons and investigates the molecular and cellular processes that govern their signaling. A dynamic, functional, SI unit-based, real-time, hi-fidelity and high temporal resolution approach. Many electrophysiological approaches can be used vivo. Electrophysiology can be used simultaneously or in conjunction with optical, molecular, biochemical and pharmacological techniques
How do neurons communicate? (Types of signals)
Electrically and chemically
Extracellular recording
The electrode is placed just outside the neuron of interest.
Intracellular recording
The electrode is inserted into the neuron of interest.
Patch clamp recording
The electrode is closely apposed to the neuronal membrane, forming a tight seal with a patch of the membrane.
Concentration gradient
The difference of ion concentration inside the cell compared to outside the cell.
What is chemical gradient? (See image below)
The ion separate which occurs right at the membrane of the neuron: more K+ (potassium) ions on the inside of the membrane and more Na+ (sodium) ions on the outside.
What is electrical gradient? (See image below)
The difference in charge across the cell membrane. Ions have an electrical charge. At rest, there are more positive ions on the outside than the inside of the cell membrane.
Electrochemical gradient
The ionic imbalance represented by the electrical and chemical gradients at the membrane of the neural cell.
Measuring unit for the electrical potential of the neural cell?
Voltage
What’s the voltage of the Resting Potential of the membrane?
-70mV
How do we call the movement of charge over time?
Current (I)
What limits the movement of ions across the membrane?
The membrane Resistance (R)
How is Resistance generated?
By properties of the membrane, such as how many channels are open or closed.
What is Ohm’s law?
V=IxR. It represents the relationship among the membrane potential (V), the current flow (I), and the membrane resistance (R).
Resting membrane potential
The voltage difference across the membrane of a neuron when it is at rest (non-signalling). In a neuron, the inside of the cell is about 70 mVs (millivolts) less than the outside, so the resting membrane potential is said to be -70 mVs.
Depolarisation
A change in a neurons membrane potential that make it more positive (less negative).
Hyperpolarization
A change in a neurons membrane potential that makes it more negative. It is the opposite of depolarization.
Ionotropic receptors
Transmembrane proteins that form a channel allowing ions to travel in or out of a cell. These channels are opened when the receptor binds a ligand, like a neurotransmitter. Glutamate receptors and GABAA receptors are examples of ionotropic receptors.
Voltage-gated ion channels
Transmembrane proteins that form ion channels whose opening and closing is regulated by the membrane potential near the channel.
Action potential
The process by which a neuron sends information down its axon. Also referred to as a spike, is an all-or-none, rapid, tran- sient depolarization of the neuron’s membrane
At what V do these occur?
What is graded potential?
Local voltage change. Small charge.
How do we call a membrane potential that is more positive?
Excitatory postsynaptic potential (EPSP)
How do we call a membrane potential that is more negative?
Inhibitory postsynaptic potential (IPSP)
Field potential
This is the electric potential in the extracellular space around neurons.
What is the nerve comprised of?
A bundle of axons.
Compound axon potential
The sum of the activity in a number of nerve fibers (or axons).
Ways in which Extracellular recording (ER) is applied:
.field potentials
• whole nerve activity
• multi-unit activity
• single unit activity
• multi-electrode arrays (MEAs)
*in each case:
• the electrode is outside but close to the neurons
• the electrodes pick up only field potentials and low frequency filtered action potentials
• it is not possible to record Vm rest or post-synaptic potentials
Ways in which Intracellular recording (IR)is applied:
• activity within single cells
• sharp electrodes
• patch suction electrodes
Ways in which Single channel recording (SCR)is applied:
• recording activity of single ion channels
• patch clamp-type electrodes