Week 2 Flashcards
Memories from the brain’s view are _____
the changes in connectivity among the collection of neurons responding to an experience
The strengthening of neuronal connections happens at the ____
synapse
Who discovered the phenomenon of long-term potentiation?
Bliss & Lomo
Neurons in the entorhinal cortex connect to ____ by the _____
- A region of the hippocampus called the dentate gyrus
- perforant path
Neurons in the dentate gyrus connect to ____ by ____
- the CA3 region
- mossy fibers
Neurons in the CA3 region connect to ____ by _____
- the C1 region
- Schaffer collateral fibers
What is the most common method of studying LTP?
In vitro preparation
To study LTP, Bliss & Lomo stimulated _____ and recorded _____
- The axonal fibers in the perforant path
- The synaptic response in the dentate gyrus
What is EPSP, and what is it also known as?
- Excitatory postsynaptic potential - what researchers measure after stimulating an area in the brain
- Also known as field potential
What is long-term potentiation?
A persistent strengthening of synapses
A neuron is which 4 types of ‘devices’?
- input
- integrative
- conductive-output
- representation
What are the three components of a synapse?
- presynaptic terminal
- postsynaptic dendrite
- synaptic cleft
The terminal ending of the sending neuron contains _____, which are packaged in ____
- packages of molecules called neurotransmitters
- synaptic vesicles
What are action potentials?
Spikes of electrical activity that travel along the axon
After neurotransmitters are released, they _____
Bind to receptors located on the dendrites of the receiving neuron
When enough receptors are occupied, ____ is generated in the _____
- a post-synaptic potential
- receiving neuron
Fluid inside neurons is called _____ and fluid outside neurons is called _____, and they are separated by the ______
- intracellular fluid
- extracellular fluid
- cell membrane
Both intracellular and extracellular fluids contain _____
Positively and negatively charged molecules called ions
What is a membrane potential?
The difference between the electrical charge inside the neuron’s body compared to outside
There are more negatively charged ions _____
in the intracellular fluid
What is resting membrane potential?
The membrane potential in an inactive state, typically -50 to -80 mV
What is the difference between depolarization and hyperpolarization?
With depolarization, the membrane potential gets less negative, while with hyperpolarization, it gets more negative
Depolarization drives the neuron ____ action potentials, while hyperpolarization drives it ____ action potentials
- towards
- away from
What is postsynaptic depolarization?
- The electrical stimulation used to produce LTP in the hippocampus generates action potentials in the axons of the sending neurons
- positive ions flow into postsynaptic neurons, causing them to depolarize
Synaptic strength is measured by ______
The amount of postsynaptic depolarization produced by the stimulus
What is the fiber volley?
The action potentials produced by an electrical stimulus
How is field potential detected?
The downward slope of the waveform, which reflects the amount of post-synaptic depolarization
What are the functions of the test stimulus in generating LTP?
- establish a baseline level of synaptic activity
- determine if the inducing stimulus changed the strength of connections between the presynaptic fibers and postsynaptic neurons
What is long-term depression?
When synaptic activity weakens the strength of synaptic connections
What can cause LTD?
Many (~900) low-frequency pulses over ~15 minutes
The synaptic cleft is occupied by the _____, which is composed of _____
- extracellular matrix
- molecules synthesized and secreted by neurons and glial cells
Changes in synaptic potentials produced by an LTP-inducing stimulus are primarily the result of _____
Modifying excitatory synapses
A major feature of excitatory synapses is ____
A thickening of the postsynaptic membrane called the postsynaptic density
How does postsynaptic density contribute to glutamate receptors responding to glutamate from dendritic spines?
- aligns the postsynaptic receptors with the presynaptic neurotransmitter release zones
- position signalling molecules near the glutamate receptors so they can be activated
What do endosomes do?
Translate internalized receptors to and from the plasma membrane
What do ribosomes do?
Translate new protein
The molecular composition of synapses constantly ____
Changes
Excitatory synapses are modified by synaptic activity that begins when ____
Glutamate is released by the presynaptic neuron
What is the structure of signaling cascades?
First messenger –> second messenger –> proteins –> kinases/phosphatases –> structural/functional proteins
A protein kinase is an _____ that modifies other _____ by ____
- enzyme
- proteins
- chemically adding phosphate groups to them (phosphorylation)
What do phosphatases do?
Remove phosphates from proteins
What are the three principles of synaptic connections?
- The duration of LTP can vary
- The duration of LTP depends on the set of molecular processes engaged by synaptic activity
- Synapses are strengthened and maintained in a sequence of temporal, distinct but overlapping processes
Grey matter corresponds to _____ and white matter corresponds to _____
- cell bodies
- axons
What is the main function of microtubules in neurons?
Provide structural integrity
What produces neurotransmitters in the neuron?
Ribosomes
What is tau and what gene codes it?
- A microtubule-associated protein
- Coded by the MAPT gene
What does tau do, and what happens to it with AD?
- maintains the stability of microtubules
- forms inside the neuron as tangles
Sensory neurons carry information ______, and motor neurons transmit signals from ______
- PNS to CNS
- CNS to PNS
Saggital cuts go from ______ and coronal cuts go from _____
- front to back
- side to side
What are the main functions of the frontal lobe?
- Executive functions
- Personality
- Attention
- Impulse control
What are the main functions of the temporal lobe?
- Episodic memories
- integrating memories with sensory information
What is the main function of the parietal lobe?
Processing somatosensory information
What is the main function of the frontal lobe?
Vision
Neurodegeneration in the temporal lobe is associated with _____ and in the frontal lobe is associated with _____
- Alzheimer’s disease
- Frontotemporal dementia
A lumbar puncture may be done to ____, and injection into ventricles allows _____
- Extract cerebrospinal fluid
- Diffusion throughout the brain
What is the representational hierarchical theory?
The complexity of neural representations differ across brain regions in the ventral stream
____ receive information and _____ send information
- Dendrites
- Axons
What did Hebb propose about memories?
Modified ensembles of neurons called cell assemblies could provide a substrate for memories
Memories from the brain’s POV are _____
Changes in the connectivity of the collection of neurons responding to a particular experience
What two things need to happen for NMDA channels to open?
- Glutamate binds to the receptor
- Cell depolarizes
