Rochet CNS Lecture 1

Question 1

Key structures of the brain

Answer 1

-Hindbrain
-Midbrain
-Forebrain

Question 2

Key structures of the hindbrain

Answer 2

-Medulla
-Pons, cerebellum

Question 3

Key structures of the midbrain

Answer 3

-Substantia nigra

Question 4

Key structures of the forebrain

Answer 4

-Cerebral cortex
-Basal ganglia: striatum (caudate and putamen), globus pallidus, subthalamic nucleus
-Limbic system: hippocampus, amygdala
-Diencephalon: thalamus, hypothalamus

Question 5

Functions of the medulla

Answer 5

-Autonomic functions
-Includes centers for controlling respiration, cardiac function, vasomotor responses, reflexes

Question 6

Functions of the pons

Answer 6

-Bridge
-Relays signals from the forebrain to the cerebellum

Question 7

Functions of the cerebellum

Answer 7

-Little brain
-Governs motor coordination for producing smooth movements
-Undergoes neurodegeneration in spinocerebellar ataxias

Question 8

Functions of the substantia nigra pars compacta

Answer 8

-Provides input to the basal ganglia, supplies dopamine to the striatum
-Involved in voluntary motor control (movement with intention) and some cognitive functions (e.g. spatial learning)
-Undergoes neurodegeneration in PD

Question 9

Functions of the substantia nigra pars reticula

Answer 9

Has an output function, relays signals from the basal ganglia to the thalamus

Question 10

Functions of the cortex (cerebrum)

Answer 10

Involved in processing and interpreting information

Question 11

Functions of the basal ganglia

Answer 11

Voluntary motor control, some cognitive functions

Question 12

Functions of the limbic system

Answer 12

Emotions (amygdala), memory (hippocampus)

Question 13

Structures of the diencephalon

Answer 13

-Thalamus
-Hypothalamus

Question 14

Functions of the thalamus

Answer 14

Relay station to and from the cortex

Question 15

Functions of the hypothalamus

Answer 15

-Regulates internal homeostasis, emotions
-Hormonal control (through the pituitary gland) and direct neural regulation

Question 16

Functions of the cortex

Answer 16

-The cortex is involved in decision making, higher level functions
-Our senses receive information about the environment, which is passed through the thalamus, to the cortex and back
-Decisions are made in these cortico-thalamic loops about how to interpret and act on the incoming sensory information
-Damage to the cortex can affect movement, speech, personality
-Schizophrenia is considered a disease of the frontal cortex

Question 17

Role of astrocytes

Answer 17

-Provides neurons with growth factors, antioxidants
-Remove excess glutamate (excitotoxic neurotransmitter)
-Support the blood brain barrier

Question 18

Role of oligodendrocytes

Answer 18

Produces myelin sheath that insulates axons

Question 19

Role of microglia

Answer 19

-Provide growth factors
-Clear debris (e.g. myelin debris) by phagocytosis
-Role in neuroinflammation

Question 20

What is neurotransmission?

Answer 20

-Neurotransmission involves a release of synaptic vesicles from boutons into the synaptic gap (cleft)
-Neurotransmission is triggered by electrical depolarization of the neuron (influx of Na+ ions that changes the charge polarity of the membrane)

Question 21

How long do action potentials last?

Answer 21

0.2 - 0.5 msec

Question 22

What is a refractory period?

Answer 22

Period after action potential (hyperpolarized phase) during which a neuron will not fire again

Question 23

What is an EPSP?

Answer 23

-Excitatory postsynaptic potential (subthreshold depolarization peak)
-Induced by excitatory neurotransmitters
-Excitatory neurotransmitter acts on ionotropic receptor, allowing Na+ ions to cross the membrane
-An increase in the strength of the stimulus will increase the magnitude of the depolarization, so that the threshold depolarization to trigger an action potential is achieved

Question 24

What is an IPSP?

Answer 24

-Inhibitory postsynaptic potential
-Induced by inhibitory neurotransmitters
-Inhibitory neurotransmitter induces hyperpolarization by allowing Cl- ions to cross the membrane
-An IPSP can decrease the magnitude of a subsequent EPSP

Question 25

Common amino acid neurotransmitters

Answer 25

-GABA (gamma aminobutyric acid)
-Glycine
-Glutamate

Question 26

What is the GABA amino acid?

Answer 26

-Major inhibitory neurotransmitter in the brain
-Depresses neuronal excitability by increasing the flux of Cl- ions into the neuron
-There are GABA-A and GABA-B receptors
-Drugs that interact with GABA pathways are generally CNS depressants

Question 27

What is the glycine amino acid?

Answer 27

Similar to GABA, but acts in the spinal cord

Question 28

What is the glutamate amino acid?

Answer 28

-Major excitatory aa neurotransmitter in the brain
-Excess glutamate can cause neuronal damage by allowing excessive Ca2+ influx into the neuron
-Glutamate receptors are metabrotropic (GPCRs) or ionotropic (NMDA and AMPA)

Question 29

Common non-amino acid neurotransmitters

Answer 29

-Acetylcholine
-Dopamine
-Norepinephrine
-Serotonin; 5-hydroxytryptamine (5-HT)

Question 30

What is acetylcholine?

Answer 30

-Both muscarinic (M1-M5) and nicotinic receptors (as in the periphery)
-Examples of drugs targeting this form of neurotransmission are cholinesterase inhibitors (e.g. Aricept, used to treat Alzheimer’s disease)

Question 31

What is dopamine?

Answer 31

-Drug targets include the D1-D5 receptors (GPCRs) and the dopamine transporters (DAT)
-DA neurons arise from the ventral tegmental area (VTA) and the SN
-Drugs that block DAT and thus increase extracellular DA can produce euphoria leading to addiction
-Excessive dopaminergic signaling may be involved in schizophrenia
-Loss of DA neurons in the SN is responsible for PD

Question 32

What is norepinephrine?

Answer 32

-Drug targets include alpha and beta-adrenergic receptors and the norepinephrine transporter
-NE axons arise form the locus coeruleus in the pons region
-NET inhibitors are used to treat depression

Question 33

What is serotonin