CH. 2: Neuroscience Flashcards

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1
Q

What we will learn about the nervous system

A
  1. The organization of the human nervous system
  2. The components of the nervous system
  3. The functioning of the nervous system
  4. The role of hormones and neurotransmitters in behavior
  5. How the brain is studied
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2
Q

Phineas Gage

A

Phineas Gage’s traumatic accident allowed researchers to investigate the functions of the frontal lobe and its connections with emotion centers in the subcortical structures.

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3
Q

How Many Neurons Are in the Brain?

A

86 Billion! (Previous estimates were around 100 million)

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4
Q

Components of the Neuron

A

Cell body: Coordinates information-processing tasks and keeps the cell alive

Dendrite: Receives information from other neurons and relays it to the cell body

Axon: Transmits information to other neurons, muscles, or glands

Myelin sheath: Provides insulating layer of fatty material

Glial cells: Support cells found in the nervous system (makes up myelin sheath)

Synapse: Junction or region between the axon of one neuron and the dendrites or cell body of another

Axon> Synapse> Dendrite> Axon

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5
Q

Psychologist Donald Hebb’s “assembly theory”

A

Theory of how the brain achieves the feat of keeping neurons together, best summarized by the idea that “neurons that fire together wire together.” The idea is that neurons responding to the same stimulus connect preferentially to form “neuronal ensembles.”

The glial cells of Myelin also help keep the neurons physically together

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6
Q

Myelin and Nodes of Ranvier

A

Myelin is formed by a type of glial cell, and it wraps around a neuron’s axon to speed the movement of the action potential along the length of the axon. Breaks in the myelin sheath are called the nodes of Ranvier. The electric impulse jumps from node to node, thereby speeding the conduction of information down the axon. Myelin is white while grey matter is unmyelinated

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7
Q

Myelin

A
  • Made up of Glial cells
  • The glial cells help hold neurons in place
  • Surface of brain is cell bodies and hence gray matter
  • Inside is pinkish or white and myelinated axons
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8
Q

3 types of Neurons Specialized by Function

A

Sensory neurons, motor neurons, and interneurons

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9
Q

Sensory Neurons

A
  • Receive information from the external world; convey this information to the brain via the spinal cord
  • Receive signals for light, sound, touch, taste, and smell
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10
Q

Motor Neurons

A
  • Carry signals from the spinal cord to the muscles to produce movement
  • Often have long axons that reach to muscles at our extremities
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11
Q

Interneurons

A
  • Connect sensory neurons, motor neurons, or other interneurons
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12
Q

Electrochemical Action

A

Communication of information within and between neurons proceeds in two stages: conduction and transmission

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13
Q

Conduction

A

Movement of electronic signal within neurons

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14
Q

Transmission

A

Movement of electrochemical signal from one neuron to another due to signaling across the synapse involving (chemical) neurotransmitters to the dendrites.

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15
Q

The action potential direction

A

a. In response to a signal, the soma end of the axon becomes depolarized.

b. The depolarization spreads down the axon. Meanwhile, the first part of the membrane repolarizes. Because Na* channels are inactivated and additional K* channels have opened, the membrane cannot depolarize again.

c. The action potential continues to travel down the axon.

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16
Q

Resting Potential

A

Balance of positively charged and negatively charged ions

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17
Q

Action Potential

A

All or none strength electrical impulse along axon to synapse

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18
Q

Refractory Period

A

Period of time until the nerve cell can fire again

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19
Q

Chemical Signaling: Transmission Between Neurons

A

Information is passed between neurons through chemicals called neurotransmitters.

Terminal buttons: Knoblike structures that branch out from an axon

Neurotransmitters: Chemicals that transmit information across the synapse to a receiving neuron’s dendrites

Receptors: Parts of the cell membrane that receive the neurotransmitter and initiate or prevent a new electric signal

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20
Q

Synaptic Transmission

A

(1) The action potential travels down the axon and (2) stimulates the release of neurotransmitters from vesicles.

(3) The neurotransmitters are released into the synapse, where they float to bind with receptor sites on a dendrite of a postsynaptic neuron, initiating a new action potential.

The neurotransmitters are cleared out of the synapse by (4) reuptake into the sending neuron, (5) being broken down by enzymes in the synapse, or (6) binding to autoreceptors on the sending neuron.

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21
Q

Acetylcholine (ACh)

A
  • Enables muscle action, learning, and memory
  • With Alzheimer’s disease, ACh-producing neurons deteriorate.
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22
Q

Dopamine

A
  • Influences movement, learning, attention, and emotion
  • Oversupply linked to schizophrenia. Undersupply linked to tremors and decreased mobility in Parkinson’s disease.
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23
Q

Serotonin

A
  • Affects mood, hunger, sleep, and arousal
  • Undersupply linked to depression. Some drugs that raise serotonin levels are used to treat depression.
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24
Q

Norepinephrine

A
  • Helps control alertness and arousal
  • Undersupply can depress mood.
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25
Q

GABA (gamma-aminobutyric acid)

A
  • A major inhibitory neurotransmitter
  • Undersupply linked to seizures, tremors, and insomnia.
26
Q

Glutamate

A
  • A major excitatory neurotransmitter; involved in memory
  • Oversupply can overstimulate the brain, producing migraines or seizures (which is why some people avoid MSG, monosodium glutamate, in food).
27
Q

Endorphins

A
  • Neurotransmitters that influence the perception of pain or pleasure
  • Oversupply with opiate drugs can suppress the body’s natural endorphin supply.
28
Q

How Drugs Mimic Neurotransmitters

A

Drugs that affect the nervous system operate by increasing, interfering with, or mimicking neurotransmitters.

29
Q

Agonists

A

Drugs that increase the action of a neurotransmitter

  • Examples of full agonists are heroin, oxycodone, methadone, hydrocodone, morphine, opium and others.
30
Q

Antagonists

A

Drugs that block the function of a neurotransmitter

  • An antagonist is a drug that blocks opioids by attaching to the opioid receptors without activating them. Antagonists cause no opioid effect and block full agonist opioids. Examples are naltrexone and naloxone.
31
Q

Nervous System

A

Nervous system –> Peripheral and Central (brain and spinal cord)

Peripheral –>

  • Autonomic (conveys commands that control internal organs and glands)
  • Somatic (conveys information into and out of the central nervous system; controls voluntary movements of skeletal muscles)

Autonomic –> Sympathetic (arousing) and Parasympathetic (calming)

32
Q

Sympathetic Nervous System

A
  • Dilates pupil
  • Relaxes bronchi
  • Accelerates heartbeat
  • Inhibits digestive activity
  • Stimulates glucose release
  • Stimulates secretion of epinephrine/norepinephrine
  • Relaxes bladder
  • Stimulates ejaculation in male
33
Q

Parasympathetic Nervous System

A
  • Contracts pupil
  • Constricts bronchi
  • Slows heartbeat
  • Stimulates digestive activity
  • Stimulates gallbladder
  • Contracts bladder
  • Allows blood flow to sex organs
34
Q

Vagus Nerve

A
  • Connects brain to parasympathetic nervous system
  • Main nerves of the parasympathetic system
    160,000 nerve fibers
    80,000 on each side of your neck
  • Involuntary but can be classically conditioned
  • Also controls the immune system
35
Q

Spinal Reflex: The Pain Withdrawal Reflex

A

Many actions of the central nervous system don’t require the brain’s input. For example, withdrawing from pain is a reflexive activity controlled by the spinal cord.
Painful sensations (such as the heat of fire) travel directly to the spinal cord via sensory neurons, which then issue an immediate command to motor neurons to retract the hand.

36
Q

Four Main Regions of the Spinal Cord

A
  • Cervical nerves
  • Thoracic nerves
  • Lumbar nerves
  • Sacral nerves
37
Q

Endocrine System

A

Glands that secrete hormones into the bloodstream.

Thyroid - Body temperature, heart rate
Pancreas - Digestion and regulates pineal gland controlling sleep and wake
Adrenal - Stress related responses
Sexual reproductive - ovaries and testes
Pituitary gland - Overall control
Hypothalamus - a region of brain releasing hormones to control the pituitary gland

38
Q

Mass action vs Specialized function: Generally the brain is not specialized by hemisphere
Exceptions include:

A

Broca’s Area - Left hemisphere if right handed - Speech Production

Wernicke’s Area - Left hemisphere if right handed - Speech Comprehension

39
Q

Brain Lateralization

A

Two hemispheres connected by the Corpus Callosum

Typically acts as a whole as long as the corpus callosum is operational as shown by split brain procedures (to resolve intractable epilepsy).

40
Q

Split Brain experiments

A

SLIDE 32: https://docs.google.com/presentation/d/1fhsMFUUhqQevBDYPvizY36e6ibyphKXxVj9UKxpXEZw/edit#slide=id.geba474a15d_80_18

41
Q

Structure of the Brain
There are three major divisions of the brain:

A

Hindbrain: Coordinates information coming into and out of the spinal cord; also controls the basic functions of life
Medulla, reticular formation, cerebellum, pons

Midbrain: Important for orientation and movement
Tectum, tegmentum

Forebrain: Highest level of brain; critical for complex cognitive, emotional, sensory, and motor functions
Cerebral cortex, subcortical structures

42
Q

The Hindbrain

A

Brainstem: lower base which connects the spinal cord to the brain; is the oldest part of the brain responsible for automatic survival functions.
Medulla: controls heartbeat and breathing

43
Q

Functions of the Cerebellum

A

SLIDE 36: https://docs.google.com/presentation/d/1fhsMFUUhqQevBDYPvizY36e6ibyphKXxVj9UKxpXEZw/edit#slide=id.ga02a28d162_0_6

44
Q

The Midbrain and Forebrain

A

SLIDE 37: https://docs.google.com/presentation/d/1fhsMFUUhqQevBDYPvizY36e6ibyphKXxVj9UKxpXEZw/edit#slide=id.g5bd0554773_0_62

45
Q

The Limbic System

A

Hypothalamus
Links brain and endocrine system; regulates hunger, thirst, sleep, and sexual behavior

Thalamus
Processes and integrates sensory information; relays sensory information to cerebral cortex

Amygdala
Involved in memory and emotion, especially fear and anger

Hippocampus
Involved in forming new memories

46
Q

The Cerebral Cortex

A

The cortex has four lobes (in each hemisphere).
The cortex is the highest level of the brain.
Three functionally distinct areas

47
Q

Association Areas of the Brain

A

Provides sense and meaning to inputs - Most developed areas of the brain

48
Q

Mirror Neurons

A

Imitation, observation

49
Q

Feature detectors

A

Shapes, movement detectors, auditory interpretation

50
Q

Default Mode Network

A

Relaxed, daydreaming

51
Q

Visual Imagery Network

A

The mind’s eye

52
Q

Semantic Network

A

Language meaning

53
Q

Visual Perception Network

A

Perception of visual stimuli

54
Q

Brain Plasticity

A

The brain is plastic: Functions that were assigned to certain areas of the brain may be capable of being reassigned to other areas of the brain to accommodate changing input from the environment.
Greater use of a function may command greater space in the cortical map.
Physical exercise can benefit the strength and connections of synapses in the brain.
Forms: Synaptic, functional adaptation, neuronal creation and loss

55
Q

Neuroplasticity: What is it?

A

Increased or changed synaptic connections

New neuron creation (neurogenesis) and /or loss (pruning)

Change in the function of brain structures

56
Q

Gut Brain Communication

A

After the brain the gut contains the most neurons

The gut consists of the intestines, the esophagus, the pancreas, the liver, the gallbladder

57
Q

Postnatal Neurogenesis

A

New neurons?

Hippocampus

Glial Cells - make up 1/2 of the brain mass

58
Q

Studying the Brain’s Electrical Activity

A
  • Study the link between brain structures and behavior through the recording of electrical activity in neurons.
  • Electroencephalograph (EEG): Device used to record electrical activity in the brain
  • Hubel and Wiesel: Inserted electrodes into the brains of anesthetized cats; made discovery of feature detectors by mapping visual cortex
59
Q

Using Brain Imaging to Study Structure and to Watch the Brain in Action

A
  • Neuroimaging techniques use advanced technology to create images of the living, healthy brain.
  • Structural brain imaging shows underlying brain structure.
  • CT scan, MRI

Functional brain imaging shows brain activity while someone engages in a cognitive or motor task.

  • PET - Observe radioactivity in areas of the brain
  • fMRI - Observe blood flow to areas of the brain

Insights from Functional Imaging

  • Insights into the types of information processing that take place in specific areas of the brain
  • Confirmation of theories derived over last century is possible
  • Need to be cautious about how evidence from fMRI obtained
60
Q

Transcranial Magnetic Stimulation

A

Scientists have studied the effects of brain damage for centuries.

  • Brain damage may be related to particular patterns of behavior in people with brain injuries, but the relationship may not be causal.

Transcranial magnetic stimulation (TMS) methods can (ethically) mimic brain damage.

  • Temporarily deactivates neurons in the cerebral cortex
  • Can be combined with fMRI techniques
  • Manipulation can provide causal explanations
61
Q

Optogenetics

A

Directed light to control neurons

62
Q

Neuro Core Concepts

A

Communication

Emergence

Evolution

Gene-Environment Interactions

Information Processing

Nervous System Functions

Plasticity