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Question 1

What are the two main outcomes of neurotransmission involving glutamate and GABA?

Answer 1

Glutamate results in excitation, while GABA results in inhibition.

Question 2

What determines whether a neurotransmitter is excitatory or inhibitory?

Answer 2

The type of neurotransmitter and the receptor it binds to determine whether it is excitatory or inhibitory.

Question 3

How do ionotropic and metabotropic receptors differ in neurotransmitter response?

Answer 3

Ionotropic receptors respond directly to neurotransmitter binding by opening ion channels, while metabotropic receptors trigger intracellular signaling cascades.

Question 4

What is a “quanta” in neurotransmission?

Answer 4

A quanta refers to the release of neurotransmitter from a single vesicle.

Question 5

Name one strategy to increase quantal release in neurons.

Answer 5

Extensive innervation, as seen in Purkinje cells, or the presence of a large presynapse like the Calyx of Held.

Question 6

What is synaptic integration?

Answer 6

It is the summation of postsynaptic membrane potentials from multiple synaptic inputs.

Question 7

How does inhibition influence spontaneously active neurons?

Answer 7

Inhibition can sculpt the discharge patterns of these neurons by suppressing certain action potentials.

Question 8

What are the two types of inhibitory neurons in the neocortex mentioned in the document?

Answer 8

Low-threshold spiking (LTS) cells and fast-spiking (FS) cells.

Question 9

What neurotransmitter do both LTS and FS cells release?

Answer 9

GABA.

Question 10

What is the role of climbing fibers in the cerebellar network?

Answer 10

They regulate the low discharge of Purkinje cell complex spikes through extensive synaptic contacts.

Question 11

Define sensory transduction.

Answer 11

It is the conversion of a physical stimulus into a change in membrane potential.

Question 12

What are the four key events in sensation?

Answer 12

1. Stimulation of the sensory receptor.
2. Transduction of the stimulus.
3. Generation of nerve impulses.
4. Integration of sensory input.

Question 13

What is the difference between general and special senses?

Answer 13

General senses include touch, pressure, temperature, pain, and proprioception, while special senses include smell, taste, vision, hearing, and balance.

Question 14

What is lateral inhibition, and how does it help in sensory perception?

Answer 14

Lateral inhibition exaggerates differences in stimulus intensity between adjacent neurons, improving localization.

Question 15

What principle is used to estimate stimulus location in sensory systems?

Answer 15

Topographic mapping, such as somatotopy in the somatosensory system.

Question 16

What is the relationship between the distance of a synapse and its influence on a neuron’s trigger zone?

Answer 16

The influence of a synapse decreases as the distance to the neuron’s trigger zone increases.

Question 17

What are the two main types of synaptic contacts in neurons?

Answer 17

Axosomatic (axon to soma) and axodendritic (axon to dendrite).

Question 18

What does the term “network architecture” refer to in neuroscience?

Answer 18

It refers to the arrangement of excitatory and inhibitory neurons and their physiological properties, such as firing patterns

Question 19

What are the primary functions of sensory systems?

Answer 19

Sensory systems detect signals and discriminate aspects of sensory input, such as modality (what is it), intensity (how much of it), location, and duration.

Question 20

What is the function of sensory receptors?

Answer 20

Sensory receptors detect specific stimuli and perform transduction, converting physical stimuli into electrochemical signals.

Question 21

How does adaptation affect sensory coding?

Answer 21

Adaptation reduces the frequency of action potentials during sustained stimuli, modulating the perception of intensity.

Question 22

What is a receptive field (RF)?

Answer 22

An RF is the region of sensory space where stimulation changes the firing rate of a neuron.

Question 23

How does the brain identify the modality of a sensory input?

Answer 23

Through labeled lines, where specific neural pathways are dedicated to particular sensory modalities.

Question 24

What neurotransmitter is released by granule cells and inferior olivary cells in the cerebellar network?

Answer 24

Glutamate.

Question 25

What is the role of Purkinje cells in the cerebellum?

Answer 25

They integrate inputs from parallel and climbing fibers and regulate motor coordination.

Question 26

How do parallel fibers influence Purkinje cells?

Answer 26

Parallel fibers, originating from granule cells, contact Purkinje cells to generate high-frequency simple spikes.

Question 27

What is the role of climbing fibers in motor learning?

Answer 27

Climbing fibers mediate complex spikes in Purkinje cells, essential for motor learning and timing.

Question 28

What is the significance of LTD (long-term depression) in Purkinje cells?

Answer 28

LTD at parallel fiber-Purkinje cell synapses decreases Purkinje cell activity, disinhibiting the interposed nucleus for motor learning.

Question 29

How do mechanoreceptors and nociceptors differ in function?

Answer 29

Mechanoreceptors detect physical deformation, while nociceptors respond to painful stimuli.

Question 30

What is the principle of topographic mapping in sensory systems?

Answer 30

Points close together on the sensory surface are represented close together in the brain, such as somatotopy in the somatosensory system.

Question 31

What is the function of lateral inhibition in sensory systems?

Answer 31

It sharpens sensory perception by exaggerating differences in stimulus intensity between adjacent neurons.

Question 32

What is the difference between graded potentials and action potentials?

Answer 32

Graded potentials vary in amplitude and are not propagated, while action potentials have a fixed amplitude and are propagated along the neuron.

Question 33

What is feedforward inhibition in neural networks?

Answer 33

Feedforward inhibition occurs when an excitatory neuron activates an inhibitory interneuron, which then suppresses the activity of a downstream neuron. This mechanism ensures precise timing and prevents overexcitation.

Question 34

What is the primary role of feedforward inhibition in neural circuits?

Answer 34

It enhances signal precision by limiting the duration of excitatory signals and shaping the timing of action potentials in target neurons.

Question 35

How does feedback inhibition function in neural networks?

Answer 35

Feedback inhibition involves an excitatory neuron activating an inhibitory interneuron, which then inhibits the original excitatory neuron or its neighbours, creating a regulatory loop.

Question 36

What is the main purpose of feedback inhibition?

Answer 36

Feedback inhibition maintains homeostasis in the network by preventing runaway excitation and stabilizing neuronal activity.

Question 37

How do feedforward and feedback inhibition differ in their timing and control?

Answer 37

Feedforward inhibition occurs early in the signal pathway, acting as a filter for incoming signals, while feedback inhibition occurs later, regulating ongoing activity within the network.

Question 38

What is the significance of convergence in feedforward inhibition?

Answer 38

Convergence ensures that multiple excitatory inputs can collectively activate inhibitory neurons, providing robust suppression of downstream targets.

Question 39

How does divergence influence feedback inhibition?

Answer 39

Divergence allows a single inhibitory neuron to suppress multiple excitatory targets, amplifying the inhibitory signal across the network.

Question 40

How do inhibitory interneurons sculpt excitatory neuron firing patterns in feedback loops?

Answer 40

Inhibitory interneurons selectively suppress spontaneous or excessive excitatory neuron activity, creating rhythmic or patterned firing in the network.

Question 41

What is the role of feedforward and feedback inhibition in sensory processing?

Answer 41

Feedforward inhibition enhances signal specificity and prevents overstimulation, while feedback inhibition regulates gain control and adapts network responses to sustained inputs.

Question 42

How does the balance of excitation and inhibition affect network function?

Answer 42

Proper balance ensures optimal signal transmission and prevents pathological states like epilepsy (overexcitation) or hypoactivity (overinhibition).