Neuroscience PSYC 369 & 375 Overview

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Questions and Answers

What characterizes the principle of the All-or-None Law in neurons?

Action potentials can be triggered by continuous low-level stimulation.

Neurons can fire at varying degrees depending on the stimulus intensity.

Stronger stimuli result in a larger action potential.

Neurons fire entirely or not at all, irrespective of stimulus strength. (correct)

Which component of the neuron is primarily responsible for receiving information?

Axon

Dendrites (correct)

Cell Body

Myelin Sheath

What occurs during the depolarization phase of an action potential?

K+ exits the neuron, restoring the negative charge.

Na+ enters the neuron, making it less negative. (correct)

Action potential is completely diminished.

The neuron reaches a resting potential of -70 mV.

How do glial cells contribute to the function of neurons?

They outnumber neurons and provide structural support Signup and view all the answers

What is the role of excitatory postsynaptic potentials (EPSP)?

They increase the likelihood of an action potential by making the inside of the neuron more positive. Signup and view all the answers

What distinguishes the absolute refractory period from the relative refractory period?

The relative refractory period allows for firing only with significantly stronger stimulation. Signup and view all the answers

Which type of neuron is responsible for transmitting signals from sensory receptors to the central nervous system?

Sensory Neurons Signup and view all the answers

Which of the following correctly describes the myelin sheath's function?

It insulates the axon and speeds up signal transmission. Signup and view all the answers

What is the main difference between agonists and antagonists in their effect on neurotransmitters?

Agonists mimic or enhance neurotransmitter effects, whereas antagonists block those effects. Signup and view all the answers

What phenomenon describes a reduced response to a repeated, non-threatening stimulus?

Habituation Signup and view all the answers

What is a key example of plasticity observed in professional musicians?

Enlarged motor and sensory cortex due to repetitive practice. Signup and view all the answers

Which brain disorder is characterized by inattention to objects in the left visual field due to damage in a specific lobe?

Hemineglect Signup and view all the answers

What aspect of synaptic plasticity allows for the brain to adjust and improve based on learning experiences?

Changes in neurotransmitter release and synapse structure Signup and view all the answers

During split-brain experiments, what happens when the corpus callosum is severed?

Different behaviors can arise depending on which hemisphere processes information. Signup and view all the answers

Which of the following statements about synaptic plasticity is incorrect?

Neural reorganization occurs only during childhood. Signup and view all the answers

Which of these statements best describes neurogenesis?

It refers to the brain's ability to generate new neurons, even in adulthood. Signup and view all the answers

Study Notes

Two Perspectives on Behavior

Materialism believes behavior is fully explained by the brain and nervous system.
Mentalism explains behavior as a function of the mind.

Key Courses in Neuroscience

PSYC 369: Sensation & Perception focuses on the physiological explanation for perception.
PSYC 375: Brain & Behavior explores how the brain affects behavior and vice versa.

Cells of the Nervous System

Neurons are the basic functional units of the nervous system.
Glial Cells support neurons, outnumber them 10:1, and make up 50% of brain volume.

Three Types of Neurons

Sensory Neurons carry signals from receptors to the central nervous system (CNS).
Interneurons connect sensory and motor neurons within the CNS.
Motor Neurons carry signals from the CNS to muscles and glands.

Neuron Anatomy

Dendrites receive information from other neurons.
Axon transmits signals away from the cell body.
Myelin Sheath insulates the axon, speeding up signal transmission.
Myelin Sheath degeneration can lead to multiple sclerosis, muscle control loss, weakness, and paralysis.

The Neuron at Rest

Resting Potential is about -70 millivolts due to different ion flows (Na+ and K+).
Action Potential is a brief voltage spike when the neuron is stimulated, traveling down the axon.

Depolarization & Repolarization

Depolarization occurs when Na+ enters the neuron, making it less negative.
Repolarization follows after reaching +35 mV, with K+ exiting to restore the negative charge.

Refractory Periods

Absolute Refractory Period prevents another action potential for 1-2 milliseconds.
Relative Refractory Period allows firing again but requires stronger stimulation.

All-or-None Law

Neurons either fire completely or not at all.
Stronger stimuli result in more frequent firing, not larger action potentials.

Synaptic Transmission

Synapse is the connection between the axon terminal of one neuron and the dendrite of another.
Excitatory Postsynaptic Potentials (EPSP) increase the likelihood of an action potential.
Inhibitory Postsynaptic Potentials (IPSP) decrease the likelihood of an action potential.

Neurotransmitters

Neurotransmitters are released into the synaptic cleft, bind to receptors on the postsynaptic neuron, initiating a response.
Some are reabsorbed by the presynaptic neuron (reuptake), while others are deactivated.

Agonists vs Antagonists

Agonists mimic or enhance neurotransmitter effects (e.g., amphetamine and cocaine).
Antagonists block neurotransmitter effects (e.g., Chlorpromazine for schizophrenia).

Synaptic Plasticity

Synapses can change in response to experience.
Learning affects neurotransmitter release, synapse growth, and synaptic structure.

Plasticity in Action: Habituation and Sensitization

Habituation is a reduced response to repeated, non-threatening stimuli due to decreased neurotransmitter release.
Sensitization is an increased response to repeated, threatening stimuli due to prolonged action potentials and more neurotransmitter release.
Example: Aplysia (sea snail) withdraws its gill less after repeated water jets (habituation), but exhibits a hypersensitive withdrawal response to an electric shock (sensitization).

Plasticity of the Brain

Neural Reorganization allows brain areas to take on new functions after damage.
Neurogenesis enables the brain to generate new neurons even in adulthood.

Examples of Brain Plasticity

London Taxi Drivers: Enlarged hippocampus due to extensive navigation training.
Professional Musicians: Enlarged motor and sensory cortex due to repetitive practice.
Bilinguals: Enlarged parietal cortex from managing multiple languages.

Brain Disorders

Hemineglect: Damage to the right parietal lobe can cause inattention to objects in the left visual field.

Split-Brain Studies

Corpus Callosum connects the two hemispheres of the brain.
Split-Brain Experiment: When the corpus callosum is severed, the hemispheres cannot communicate.
This results in different behaviors depending on which hemisphere processes information.
Example: A patient may see a chicken claw and point to a related image (e.g., chicken), but when asked about a different image, the explanation may not match the action.

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Description

Explore the foundations of Neuroscience with a focus on the two perspectives of behavior: Materialism and Mentalism. Delve into the types of neurons and their anatomy, as well as key courses like Sensation & Perception and Brain & Behavior. This quiz ensures a comprehensive understanding of how the brain and mind influence behavior.