ELM 11 Synaptic integration Flashcards
How does a motor neuron integrate excitatory and inhibitory inputs to decide whether to fire an action potential (AP)?
The decision to fire an action potential depends on the net sign of combined inputs, the strength of synaptic input, and the location of synapses relative to the firing frequency of the presynaptic neuron. Excitatory inputs lead to EPSPs (small depolarizations), while inhibitory inputs lead to IPSPs (small hyperpolarizations). Spatial and temporal summation of these inputs determine whether the neuron reaches threshold and fires an AP.
What is spatial summation, and how does it influence neuronal behavior?
Spatial summation occurs when postsynaptic potentials (PSPs) from multiple synapses influence the behavior of a neuron simultaneously. PSPs closer to the initial segment have more influence, and multiple inputs to one neuron from PSPs fired around the same time can have a cumulative effect, with inputs closer to the initial segment having a greater influence.
Describe temporal summation and its significance in neuronal signaling.
Temporal summation occurs when multiple PSPs from a single synapse, fired in quick succession, are additive and compound their effects. This phenomenon allows neurons to integrate signals over time and determine whether to fire an action potential.
How does shunting inhibition regulate neuronal activity?
Shunting inhibition occurs when single inhibitory synapses close to the soma can shut off all excitatory inputs from that dendrite. This mechanism allows precise regulation of neuronal activity, as inhibitory synapses located close to the soma can effectively cancel out excitatory inputs.
Explain how the nervous system encodes information using amplitude modulation (AM) and frequency modulation (FM) signals.
The nervous system uses both AM and FM signals for encoding information. While producing an action potential is a single-sized event (AM), the firing frequency (FM) can vary, allowing neurons to convey different types of information through changes in frequency and pattern of action potentials.
What is the significance of the reward pathway in neural signaling?
The reward pathway, involving neurotransmitter dopamine from the ventral tegmental area to the nucleus accumbens, plays a crucial role in reward processing. High dopamine release is associated with rewarding experiences, influencing behavior and motivation. Different routes of dopamine administration can affect reward processing, with faster and higher concentrations leading to more rewarding experiences.
What’s the refractory period due to?
inactivation of Na current + activation of K current.
Absolute vs relative refractory period?
absolute = cant produce another ap.
relative = cell less excitable - larger stimulus needed.
