Brain and Behavior Exam 2

Pray for Me

Potassium (K+)

Cation (Positive Charge)

Sodium (Na+)

Ion

Chloride (Cl-)

Ion

Calcium (CA2+)

Ion

Graded Potentials (Local Potentials)

Graded Signaling

Hyperpolarization and Depolarization typically take place on neuronal dendrites and the soma (cell body) membrane

Areas contain gated channels that can open and close, thereby changing the membrane potential

Potassium Ungated, Chloride Channels, Gated Sodium Ion Channel

Depolarization

Graded Signaling

Hyperpolarization

Graded Signaling

EPSP (Excitatory Postsynaptic Potential)

Graded Signaling

Associated with the opening of sodium channels, allows influx of Na+

Depolarized neuron is more likely to produce an action potential

Temporal Summation

Graded Signaling

Pulses that occur at approximately the same time on a membrane are summed

Spatial Summation

Graded Signaling

Pulses that occur at approximately the same place on a membrane are summed

Chemical Synapse

Junction where messenger molecules (neurotransmitters) are released from one neuron to excite or inhit the next neuron

Electrical Synapse

Synapses

Vesicles

Round granule that contains neurotransmitter

Exocytosis

Synapses

Voltage-Gated Ca²+ Channels

Synapses

Synaptic Cleft

Small space separating presynaptic terminal and postsynaptic dendritic spine

Postsynaptic Receptor

Site to which a neurotransmitter molecule binds to

Presynaptic Receptor

Synapses

EEG

Techniques

Microelectrode

Techniques

Oscilloscope

Techniques

Optogenetics

Techniques

Combines genetics and light to control targeted cells living inside tissue

Channelrhodopsin responds to blue light by allowing Na+ ions to enter the cell, depolarizing it

Halorhodopsin repsonds to yellow light by allowing Cl- ions into the cell, hyperpolarizing it

Threshold Potential

Action Potential Signaling

Voltage on a neural membrane at which an action potential is triggered

Opening of Na+ and K+ voltage-activated channels

About 40 mV relative to extracellular surround

Action Potential

Action Potential Signaling

All-or-none, about 1 ms: size and shape remain constant along the axon

Voltage-Gated Na+ Channel

Action Potential Signaling

Voltage-Gated K+ Channel

Action Potential Signaling

Depolarization

Action Potential Signaling

Decrease in electrical charge across a membrane (more positive)

Usually due to the inward flow of sodium

Repolarization

Action Potential Signaling

Hyperpolarization

Action Potential Signaling

Increase in electrical charge across a membrane (more negative)

Usually due to the inward flow of chloride ions or outward flow of potassium ions

Refractory Period (Absolute)

Action Potential Signaling

The state of an axon in the repolarizing period, during which a new action potential cannot (usually) be elicited because gate 2 of sodium channels, which is no voltage activated, is closed

Refractory Period (Relative)

Action Potential Signaling

The state of an axon in the later phase of an action potential, during which stronger electrical current is required to produce another action potential

Potassium channels a re still open

Saltatory Conduction

Action Potential Signaling

Myelin: produces oligodendroglia in the CNS and Schwann cells in the PNS

Speeds up neural impulse, energetically cheaper

Nodes of Ranvier: Part of an axon that is not covered by myelin

Enables it

Resting Membrane Potential

Action Potential Signaling

Electrical charge across the cell membrane int he absence of stimulation

A store of negative energy on the intracellular side relative to the extracellular side

Inside of the membrane at rest is -70 mV

A- ions and K+ ions have higher concentration inside the axon

Cl- and Na+ ions are more concentrated outside the axon

Voltage Gated Ca2+

Voltage Gated Ion Channels

Voltage Gated K+

Voltage Gated Ion Channels

Voltage Gated Na+

Voltage Gated Ion Channels

Transmitter Activated Receptors

Receptor Types

Ionotropic Receptor

When activate by a neurotransmitter the receptors change shape

Metabotropic

When activated by a neurotransmitter, the receptors alter chemical reactions in the target cell

Autoreceptor

Receptor Types

Acetylecholine (ACh)

Role of the vagus nerve

2 enzymes combine the dietary precursors of it within the cell, and a third breaks them down in the synapse for reuptake

Acetate Choline

ACh

Nicotinic

ACh

Muscarinic

ACh

Amines

Tyrosine → L-Dopa → Dopamine → Norepinephrine → Epinephrine

Dopamine

Amine: Tyrosine → Dopamine

Norepinephrine (NE)

Amine: Tyrosine → Dopamine → Norepinephrine

Increases heart rate in mammals

Tyrosine

Amine

Dopamine Receptor D1-Like

Dopamine Receptor D2-Like

Epinephrine (EP)

Amine: Tyrosine → Dopamine → Norepinephrine → Epinephrine

Serotonin

5-HT

L-Tryptophan

Amine → Serotonin

Melatonin

Amine

No synthesis

Histamine

Amine

No synthesis

Glutamate

Amino Acid

Ionotropic Glutamate Receptors

NMDA, AMPA, Kainate

Metabotropic Glutamate Receptors

mGluRs

GABA

Amino Acid

Ionotropic GABA Receptors

GABA A and 

Metabotropic GABA Receptors

GABA B

Peptide Transmitters

Amino Acid

Synthesis at the Soma

Opioids

Lipid Transmitters

Synthesis at postsynaptic neuron

Endocannabinoids

2-AG, Anandamide

No Synthesis

Cannabinoid Receptors

Lipid Transmitters → Endocannabinoid

CB1, CB2

Retrograde Signaling

Lipid Transmitters → Endocannabinoid

Gaseous Transmitters

Nitric Oxide (NO)

Gaseous Transmitter

Diffusion from blood/inhalation

Carbon Monoxide (CO)

Gaseous Transmitter

Diffusion from blood/inhalation

Retrograde Signaling

Gaseous Transmitter

Hormone Tolerance

Neurotransmitter

Chemical released by a neuron onto a target with an excitatory or inhibitory effect

Sensitization

Endogenous Ligand

Exogeneous Ligand

Endothelial Cells of Vascular System

Blood Brain Barrier

Cholinergic (ACh)

Basal Forebrain and Brainstem Nuclei

Alzheimer’s Disease

Dopaminergic (DA)

Mesostriatal Pathway

Motor Control

Parkinson’s Disease

L-Dopa, Substantia Nigra

Mesolimbocortical Pathway

Reward, addiction

Schizophrenia vs. ADHD

Noradrenergic (NE)

Locus Coeruleus

Mood, Arousal, Sexual Behavior

Depression/Mania

Serotonergic (5-HT)

Raphe Nuclei

SSRIs, MAO Inhibitors, Tricyclics

Depression, OCD, Schizophrenia

GABAergic (GABA)

Benzodiazepines, alcohol

Sedation continuum, FASD

Glutamatergic (Glutamate)

NMDA, AMPA, Kainate Receptors

Katamine, PCP, memantine

Opioidergic (Endorphins, Enkephalins, etc.)

Morphine, Heroin, Fentanyl

Naloxone (Narcan)

Cannabinergic (Endocannabinoids, THC, CBD)

Cannabis, Anandamide, 2-AG

Adenosinergic

Caffeine (Adenosine Antagonist)

Refractory Period

Produce a single discrete impulse that travels along the axon in one direction only

Uses: Action potential is prevented from reversing direction and returning to the point of origin

Sensitivity of voltage-activated channels affects firing frequency 

Timing and frequency of action potentials, not size, conveys variations in information