Midterm #1 Flashcards

Question

What are ions and what are they called when they are negative or positive?

Answer 1

charged atom or molecule Cations are positively charged Anions are negatively charged

Answer 2

Attractive force between molecules that are oppositely charged OR repulsive force between molecules that are similar charged

Answer 3

Ion channels Specialized protein molecules that sit in the cell membrane. Pore (hole) in them through which specific ions can enter or leave cells Leak channel An ion channel protein that is in the membrane and has a pore that is always open (e.g., potassium leak channel – only potassium is comfortable using this).

Answer 4

Monovalent cations: sodium (Na+) (more in extracellular space), potassium (K+) (more in intracellular space) Divalent cations : calcium (Ca2+)(more in extracellular space), magnesium (Mg2+)(more in intracellular space)

Answer 5

Sodium-Potassium transporter Leak-Potassium Channel

Answer 6

Requires ATP, concentrates sodium and potassium outside and inside the cell, respectively Pump Na+ atoms out of the cell and K+ atoms in. Concentration gradients K+ ions to be 30x more concentrated inside the cell than out Na+ ions to be 15x more concentrated outside the cell than in. These concentration gradients never change, ever, unless the cell dies Membrane potential = 0 (no electrical charge difference)

Answer 7

Always open, the number of these channels largely determines the resting membrane potential The cell membrane of neurons contains K+ leak channels, which are selectively permeable to K+. If K+ was the only ion that could cross the membrane, the electrical potential of the membrane would settle at -90 mV, because this is when the force of diffusion encouraging K+ to leave is equal and opposite to the electrostatic pressure driving K+ in. The resting membrane potential of most neurons is less negative than -90 mV because other ions can move across the membrane through other types of leak channels. The more K+ leak channels a neuron has, the more permeable it will be to K+ relative to other ions and the closer its membrane potential will be to -90 mV. Potassium leak channels are always open. Potassium can always flow through them (in either direction).

Answer 8

Voltage-gated sodium channel Voltage-gated potassium channel Voltage-gated calcium channel

Answer 9

To initiate and propagate the action potential These ion channels are found all over the axon, along its entire length. Open – The gate opens whenever the membrane potential becomes less negative than -40 mV. The initial cause of this depolarized state is usually the activation of receptor protein ion channels that let in sodium Have electrical charges on their doors, such that they open or close when the charge difference across the membrane is greater or smaller than some number

Answer 10

To restore the resting membrane potential Ending the Action Potential Voltage-gate K+ channels open when the membrane potential is more positive than 0 (no difference in charge between inside and outside of the cell). The opening of the voltage-gated K+ channels helps bring the membrane potential back down to -70 mV Voltage-gated potassium channels open in the middle of an action potential, when the membrane potential is around 0 mV.

Answer 11

Located in the axon terminal, triggers the release of neurotransmitters Synaptic transmission Voltage-gated calcium channels open when the axon terminal becomes depolarized (i.e., in response to an action potential). Calcium is 1000x more concentrated outside the cell than in. The calcium that enters through these channels activates vesicle release machinery When an action potential reaches the end of an axon (the axon terminal), it causes voltage-gated calcium channels to open. The influx of calcium into the axon terminal triggers the release of signaling molecules (neurotransmitters) into the synapse.

Answer 12

If there is a concentration gradient and no forces or barriers to prevent free movement of molecules, then molecules will move, on average, from regions of high concentration to regions of low concentration

Answer 13

Neuronal membranes are filled with K+ leak channels. Given the ability to travel freely, K+ ions leave the cell on account of the force of diffusion

Answer 14

All cell membranes are full of proteins that act as sensors (receptors). These proteins are sensitive to specific features of the extracellular environment. For example, cells use proteins to detect and pull in nutrients from the extracellular space. (Nutrients include proteins, fats, sugars, vitamins and minerals.)

Answer 15

The presence of certain molecules (e.g., neurotransmitters) Physical pressure (movement, touch) Electrical pressure (voltage) Temperature pH (acidity, basicity) Electromagnetic radiation (light)

Answer 16

Membrane potential of a cell becomes less negative than it normally is at rest When positive sodium ions enter a cell through a receptor protein ion channel, they might depolarize a neuron from -70 to -60 mV If this happens – they immediately close back up Potassium leak channels are always open - potassium can flow in either direction through them

Answer 17

The opening of one Na+ channel allows Na+ ions to rush in, propelled by both diffusion and electrostatic forces. This influx of Na+ depolarizes the membrane further, which in turn causes additional voltage-gated Na+ channels to open. Soon there is an avalanche effect as all voltage-gated Na+ channels open causing the membrane potential to shoot up to +40mV At the peak of the action potential, the membrane potential is +40 mV. All voltage-gated Na+ channels are now inactivated. When voltage-gated potassium ion channels open, the outflow of K+ ions driven now by diffusion and electrostatic forces restore the resting membrane potential in about a millisecond.

Answer 18

The value of the membrane potential that must be reached to produce an action potential

Answer 19

transmission of messages from one neuron to another via the release of signaling molecules (neurotransmitters) into the synapse. These signaling molecules activate receptor proteins on downstream neurons

Answer 20

Region of DNA that initiates transcription of a particular gene They indicate what kind of cells should read the gene and when Typically located just before the gene

Answer 21

Found al around neurons and physically encapsulate some parts of them They help traffic nutrients and maintain molecular (ionic) stability in extracellular space Support any functions of the Nervous system Glial : Neuron = between 2:1 and 5:1

Answer 22

Glial cell providing physical support and cleans up debris in the brain through phagocytosis Control chemical composition of surrounding environment and help nourish neurons

Answer 23

Smallest of glial cells Provide immune system for the brain Protect the brain from invading microorganisms

Answer 24

Produce the myelin sheath that encapsulate axons Sheath is a series of segments – not continuous Exposed axon – Node de Ranvier During the development of the CNS, oligodendrocytes form processes shaped something like canoe paddles Each of the paddle-shaped processes then wraps itself many times around a segment of an axon and, while doing so, produces layers of myelin that make up part of the axon’s myelin sheath.

Answer 25

The conduction of action potentials by myelinated axons Action potential appears to jump from one Node of Ranvier to next – at each one the strength of the signal is regenerated with additional voltage-gated Na+ channels Slow processing of pain and temperature

Answer 26

The only place where a myelinated axon comes into contact with extracellular fluid is at nod of Ranvier, where the axon is naked In myelinated areas there are almost no ion channels and those that are there are of no consequences because there is no extracellular fluid outside the membrane

Answer 27

Junction between axon terminal of the sending neuron and the cell membrane of the receiving neuron Communication across the synapse is achieved by the release of a molecule from an axon terminal

Answer 28

A molecule that can have a simple excitatory or inhibitory effect or a complex modulatory effect on the receiving neuron.

Answer 29

Contain molecules of neurotransmitter. They attach to the presynaptic membrane and release neurotransmitter into the synaptic cleft

Answer 30

The space between the pre- and postsynaptic membranes. It is filled with an extracellular fluid.

Answer 31

The membrane of the terminal button (the sending cell). This is where neurotransmitter is released from.

Answer 32

The membrane of the receiving cell that is opposite the axon terminal.

Answer 33

Allows us to see small anatomical structures (e.g. synaptic vesicles and details of cell organelles) using a special electron microscope.

Answer 34

Signaling molecules that bind to protein receptors Most cell signaling and cell communication occurs through ligand-receptor interactions.

Answer 35

ion channels

Answer 36

G protein coupled receptors that can open ion channels through an intracellular signaling cascade. Receptors can be found on the cell membrane (surface receptors) or inside the cell (intracellular receptors).

Answer 37

on postsynaptic membrane

Answer 38

on presynaptic membrane.

Answer 39

near to but outside the synapse

Answer 40

ligands binding sites post-synaptic receptor ligand-gated ion channel/ionotropic receptor

Answer 41

General term for a signaling molecule (chemical) that binds to the binding site of a receptor. Neurotransmitters are ligands

Answer 42

Location on a receptor protein to which a ligand binds

Answer 43

Receptor protein in postsynaptic membrane of a synapse that contains a binding site for a neurotransmitter

Answer 44

A receptor that is an ion channel. The ion channel opens when the ligand (e.g., the neurotransmitter) binds to it

Answer 45

Destruction of a neurotransmitter by enzyme after its release (example: destruction of acetylcholine by acetylcholinesterase

Answer 46

Reentry of a neurotransmitter just liberated by a terminal button back through its membrane, thus terminating postsynaptic potential

Answer 47

Alterations in the membrane potential of a postsynaptic neuron, produced by neurotransmitter release into the synapse and receptor activation. Excitatory – influx of positive sodium ions depolarize the cell Inhibitory – influx of negative chloride ions hyperpolarize the cell

Answer 48

Less negative than normal Excitatory When the membrane potential of a cell becomes less negative than it normally is at rest influx of positive ions (Na+) can depolarize a neuron from -60 to -50 mV

Answer 49

Less positive than normal Inhibitory When the membrane potential of a cell becomes more negative than it normally is at rest influx of negative ions such as Cl- can hyperpolarize a neuron from -60 to -70 mV

Answer 50

Excitatory postsynaptic potential (EPSP) Excitatory depolarization of postsynaptic membrane caused by neurotransmitter binding to a postsynaptic receptor protein. Mediated by receptor proteins that open ion channels permeable to sodium. (Making the membrane more permeable to sodium will depolarize the cell.) Brief depolarization of the membrane potential, typically caused by neurotransmitter activation of ionotropic receptors that let in positively charged sodium ions.

Answer 51

Inhibitory postsynaptic potential (IPSP) Inhibitory hyperpolarization of postsynaptic membrane caused by neurotransmitter binding to a postsynaptic receptor protein. They are mediated by receptor proteins that open ion channels permeable to chloride (Making the membrane more permeable to chloride will hyperpolarize the cell.) Brief hyperpolarization of the membrane potential, typically caused by neurotransmitter activation of ionotropic receptors that let in negatively charged chloride ions

Answer 52

The interaction of the excitatory and inhibitory synapses on a particular neuron When EPSPs and IPSPs occur at the same time, the influx of negatively charged chloride ions diminish the impact of the positively charged sodium ions. IPSPs decrease the likelihood that the cell will fire.

Answer 53

Can be depolarizing or hyperpolarization Receptor – determines the direction of the postsynaptic potential Ex. Some serotonin receptors sauce exhibitory and others cause inhibitory potentials

Answer 54

A neurotransmitter receptor that is an ion channel. The properties of the pore of the ion channel (the hole) will determine if it causes EPSPs or IPSPs (i.e., if it lets in sodium or chloride ions)

Answer 55

Protein that is sensitive to and capable of communicating some signal.

Answer 56

Neurotransmitter binds and can change shapes to accept/bind Turn towards IONS to mediate their effect A receptor protein that is an ion channel. The properties of the pore of the ion channel (the hole) determine if it will produce EPSPs or IPSPs (i.e., if it lets in sodium or chloride ions). The direct effect of ionotropic receptor activation is always an immediate change in the permeability of the membrane to specific ions (i.e., whatever ions pass through the receptor).

Answer 57

Proteins but not ion channels – they also change shapes but they don't have automatic reaction like the ionotropic receptors Turn towards METABOLISM to mediate their effect A receptor protein that is not an ion channel. These receptors typically trigger an intracellular signaling cascade that involves g proteins, which can produce a variety of cellular effects such as a change in gene expression or the opening/closing of g protein-gated ion channels. The effects of metabotropic receptor signaling can be quite large, but they are often delayed (because they rely on signaling cascades and diffusion). Metabotropic receptor activation can cause the opening of many ion channel

Answer 58

G proteins are a family of intracellular proteins that are involved in intracellular signaling cascades. All G protein coupled receptors are METABOTROPIC "G proteins" are proteins that use GTP molecules instead of ATP molecules for their energy to perform chemical reactions

Answer 59

it turns it "ON" and can trigger chemical reactions A g protein turns GTP into GDP. This process turns the protein "OFF"

Answer 60

They do so by finding an activated metabotropic receptor and use the intracellular side of an activated metabotropic receptor to pry off their GDP molecule. After prying off the GDP molecule, they bind to another GTP molecule and the process starts over again

Answer 61

Some ion channels are gated by g proteins. They all use the GTP molecule for energy. Generalized illustration of a metabotropic GPCR receptor causing ion channel opening Neurotransmitter binds to a metabotropic receptor. Activated g proteins transmit the message intracellularly. Some ion channels are gated (directly or indirectly) by activated g proteins.

Answer 62

opening g protein gated ion channels changes in gene transcription secretion of substances from the cell really anything the cell wants.

Answer 63

Between axon terminals Dendrites (dendritic shafts) - cause action potential Dendritic spines – cause action potential The soma (cell body) - cause action potential Other axon terminals (axoaxonic synapses)

Answer 64

Regulate amount of neurotransmitter that the second neuron will release when it has an action potential

Answer 65

Axoaxonic synapse can HYPERPOLARIZE the axon terminal of the downstream neuron, so that its voltage-gated calcium channels WILL NOT OPEN at all or for very long when an action potential arrives. The net effect is to REDUCE neurotransmitter release from the red cell when it has an action potential.

Answer 66

Axoaxonic synapse can DEPOLARIZE the axon terminal of the downstream neuron, so that its voltage-gated calcium channels are MORE LIKELY TO OPEN when an action potential arrives. The net effect is to INCREASE neurotransmitter release from the red cell when it has an action potential.

Answer 67

A receptor located on presynaptic membrane that gets activated when the cell releases its own neurotransmitter. They are gated by the neurotransmitter that the cell releases. They are generally metabotropic and inhibitory. Main source of presynaptic inhibition.

Answer 68

A receptor located on the receiving neuron (the one that is not releasing the neurotransmitter).

Answer 69

Neuraxis – imaginary line that runs along the length of the CNS Animals and Human head Anterior – in front Posterior – behind Superior – above Inferior – below Rostral – towards the beak Caudal – towards the tail Dorsal – towards the back Ventral – towards the belly Human spinal cord Lateral – away from the midline Medial – towards the midline "Geography" of the brain Transverse plane (frontal section, cross section, coronal section) Sagittal plane – A mid-sagittal cut means the exact middle (between the eyes) Horizontal plane – looking down at horizontally cut brain

Answer 70

Contralateral – structures on the opposite side of the body e.g., the motor cortex controls movements of the contralateral hand. Ipsilateral – structures on the same side of body e.g., taste information is processed ipsilaterally, which means that taste receptors on the left side of your tongue are processed by your left cerebral hemisphere. Taste and smell are the only sensory systems that do not have contralateral organization. Superficial – located close to the surface, close to the exterior of the animal Deep – located far away from the surface, deep in the interior of the animal Proximal – nearby Distal – far away Brain nuclei – in the brain, the word nuclei means a collection of neurons that are clustered together that all work together to serve some function. E.g., there are many different brain nuclei in the hindbrain. One controls breathing, another controls vomiting, etc.

Answer 71

CNS Everything in the brain AND spinal cord Myelin created by oligodendrocytes A neuron located in the CNS is considered an interneuron Interneuron is only used for CNS neurons whose axon STAYS LOCAL (it only makes synapses on nearby neurons). The term projection neuron to used when the axon of a cell goes outside the area where its soma is located

Answer 72

PNS Any part of the nervous system outside the brain and the spinal cord Myelin created by Schwann Cells PNS communicates with the rest of the body with NERVES (cranial and spinal nerves)

Answer 73

EFFERENT fibers – fibers that bring information AWAY from (the CNS), the OUTPUTS Motor neurons control muscle contraction and gland secretion. The soma of motor neurons is located within the spinal cord (the CNS).

Answer 74

AFFERENT fibers – fibers that bring information TOWARDS… (the CNS), the INPUTS. Sensory neurons detect changes in the external and internal environment. They send this information to the CNS.

Answer 75

31 pairs of spinal nerves attach to the spinal cord (like 1 pair per vertebrae) 12 pairs of cranial nerves attach to the ventral surface of brain

Answer 76

All the cranial nerves (except the 10th) serve sensory and motor functions of head and neck region

Answer 77

The 10th cranial nerve is called the vagus (“wandering”) nerve because its branches wander throughout thoracic and abdominal cavities. It regulates functions of the heart, lungs, upper digestive track, and other organs in that area.

Answer 78

Somatic NS and Autonomic NS

Answer 79

Interacts with external environment Afferent nerves – carry sensory signals from eyes, ears, skin, etc TO CNS Efferent nerves – carry motor signals FROM CNS to skeletal muscles

Answer 80

Regulates body's internal environment Afferent nerves – carry sensory signals from internal organs, etc TO CNS Efferent nerves – carry motor signals FROM CNS to internal organs The efferent ANS consists of two anatomically separate systems: Sympathetic and parasympathetic divisions

Answer 81

Part of efferent autonomic nervous system that primes the body for action, particularly in life threatening situations (e.g., it mediates the flight-fight-freeze response when animals are threatened).

Answer 82

Part of efferent autonomic nervous system that supports activities that occur when the body is in a relaxed state and all is well. It is generally involved with increasing the body's energy stores (i.e., digestion). Its functions also include sexual arousal, defecation, urination, and salvation. For simplicity, people often say the parasympathetic system is involved in "feed and breed" and "rest and digest" activities.

Answer 83

Semipermeable barrier between the blood and the brain The blood capillaries that pass through the brain and spinal cord do not have gaps in them. This property is known as the blood brain barrier. Interstitial fluid in the body and brain Outside the brain and spinal cord, all extracellular fluid comes from blood. Blood vessels in the body have small holes in them, which allows the liquid part of blood (blood plasma) to continually leak out.

Answer 84

The blood that leaks out becomes lymph Lymph – the extracellular fluid of the body. Flows around cells providing nutrients and collecting waste. It is then collected into lymph vessels and brought to lymph nodes / lymph organs. These structures detect and destroy any invading organisms or foreign particles, and then they return the lymph back to the blood to start the process again. Rather than letting blood leak out, the brain simply makes its own extracellular solution by actively picking out exactly what it needs from the blood. The solution it makes is called cerebrospinal fluid (CSF).

Answer 85

Tough, protective connective tissues that surround the brain dura matter arachnoid membrane pia matter

Answer 86

The outer layer: thick, tough, unstretchable tissue

Answer 87

The middle layer: soft and spongy and has a web-like appearance

Answer 88

The third layer that sits closest to the brain: This layer and the space above it has blood vessels in it.

Answer 89

cerebrospinal fluid (CSF) and blood vessels.

Answer 90

A long conical structure approximately as thick as an adults little finger. Principle function – collect sensory information to be passed on to the brain and distribute motor fibers to effector organs throughout the body (glands and muscles) Has a certain degree of autonomy from the brain: various reflective control circuits are located there.

Answer 91

Production of new neurons Neural progenitor cells produce neurons (and glia) when they undergo asymmetrical cell division. Human neurogenesis largely stops four months after conception when neural progenitor cells undergo apoptosis.

Answer 92

Process of programmed cell death that occurs in a multicellular organism Apoptosis is a highly regulated and controlled form of cell suicide that ensures a dying cell does not cause problems for its neighbors. Human neural progenitor cells undergo apoptosis 125 days after conception

Answer 93

Forebrain Midbrain Hindbrain

Answer 94

Cerebral cortex Basal ganglia limbic system Thalamus Hypothalamus

Answer 95

Tectum Tegmentum

Answer 96

Cerebellum Pons Medulla oblongata

Answer 97

Known as the "LITTLE BRAIN" Plays an important role in motor control. The cerebellum does not initiate movement, but it contributes to its coordination, precision, and accurate timing. Integrates sensory information and motor commands to exert a coordinating and smoothing effect on movement (and cognition). Plays an important role in motor learning, particularly when parts of the body grow and change (which necessitate adjustments in sensorimotor integration).

Answer 98

Cerebellar damage primarily results in jerky, poorly coordinated, exaggerated movements. Extensive cerebellar damage makes it impossible even to stand.

Answer 99

Large bulge in the brain stem that relays information between the cerebrum and cerebellum. Contains part of the reticular formation as well as several cranial nerve nuclei, which participate in hearing, balance, taste, and sensations and movements of the face.

Answer 100

Most caudal part of the brain stem. It contains a collection of brain nuclei that regulate different autonomic (involuntary) functions, such as heart rate and blood flow, breathing, vomiting, sneezing, etc. Area postrema is a famous part of the medulla, as the blood–brain barrier is noticeably weak here. The medulla also contains part of the reticular formation, which plays an important role in sleep and arousal.

Answer 101

"roof" Appear as two pairs of bumps on the dorsal surface of the midbrain Top 2 bumps – superior colliculi Involved in orienting the animal to things seen in peripheral vision Bottom 2 bumps – inferior colliculi Involved in orienting to unexpected sounds

Answer 102

Several structures that coordinate and motivate complex species-typical Some areas process pain and orchestrate behavioral responses to threats

Answer 103

Sensory information enters conscious awareness. It is where our understanding of the world is formed and where we decide how to purposefully move in the world. The cerebral cortex is not made up of distinct nuclei (except in birds). Rather, it is a multi-layered structure (6 layers in mammals, 3 layers in reptiles). Neurons are interconnected between layers in a way that gives rise to cortical columns, which are thought to be partially distinct functional units.

Answer 104

sulci (small grooves) fissures (large or major grooves) gyri (ridges between sulci or fissures). These convolutions increase the surface area of the cerebral cortex. The outermost portion of the cerebral cortex is called gray matter. The color is because of the high concentration of cell bodies there. The white matter (beneath the gray matter) has a large concentration of myelinated axons. There are very few neurons in this area

Answer 105

Dorsal, Lateral, Ventral and Medial view Longitudinal fissure - separates the two hemispheres Lateral fissure - separates frontal from temporal lobes Central sulcus - provides a good landmark separating the rostral and caudal divisions of the cerebral hemisphere

Answer 106

The corpus callosum large band of axons connecting corresponding parts of association cortex for left and right hemisphere.

Answer 107

Frontal lobe Parietal lobe Occipital lobe Temporal lobe

Answer 108

controls movement

Answer 109

touch information

Answer 110

visual information

Answer 111

auditory information

Answer 112

primary motor cortex somatosensory cortex primary auditory cortex primary visual cortex

Answer 113

Frontal lobe Motor neurons synapse in the spinal cord

Answer 114

Parietal lobe Touch information enters cerebral cortex

Answer 115

If this damaged - you know you are touching something but you do not know what

Answer 116

Temporal lobe Auditory information enters cerebral cortex

Answer 117

If this damaged - you hear something but do not know what (ex. You hear a dog barking but don’t recognize it is a dog)

Answer 118

Occipital lobe Visual information enters the cerebral cortex

Answer 119

If this damaged - you do not recognize faces (not even family)

Answer 120

Perception takes place and memories stored Areas of sensory association cortex nearest to primary sensory areas receive information from one only sensory system

Answer 121

Adjacent to sensory association cortex Where movements are planned

Answer 122

Previously called the primitive « reptilian » brain Collection of nuclei in the forebrain Regulate intentional movements, motivation, reinforcement learning and habits

Answer 123

Come from all over the forebrain especially the frontal lobe

Answer 124

Some descend to midbrain and hindbrain nuclei that regulate movements Others descend in cerebral cortex (via thalamus) that regulate sensory processing and decision making

Answer 125

Collection of subcortical brain areas that regulate emotions and the formulation of episodic memories

Answer 126

Hippocampus Critical for explicit memory formation Hidden in the temporal lobe Amygdala Critical for emotional processing especially for fear Hidden in the temporal lobe Cingulate cortex Large area that overlies the corpus callosum Cingulate = encircling This region interconnects with many lambic areas of the brain

Answer 127

Bilateral structure that is divided into several nuclei, many of which relay ascending sensory information to different regions of the cerebral cortex. Ex; visual information from the eye passes through the thalamic lateral geniculate nuclei, whereas sound information from the ear passes through the thalamic medial geniculate nuclei. Many nuclei of the thalamus have widespread cortical projections.

Answer 128

Bilateral structure made up of several nuclei that regulates ANS activity Involved in behaviors that directly relate to survival (i.e. the four F’s: feeding, fighting, fleeing and mating) Involved in behaviors that directly relate to survival (i.e. the four F’s: feeding, fighting, fleeing and mating) One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system (release of hormones into the blood stream) via the pituitary gland.

Answer 129

chemical substance that is released by an endocrine gland and that has effect on target cells in other organs

Answer 130

gland that secretes chemical signals (hormones) into the bloodstream. Much of the endocrine system is controlled by hormones produced by cells in hypothalamus

Answer 131

A protein that senses some signals

Answer 132

A receptor that is an ion channel Activation has an immediate consequence on the membrane potential, causing a depolarization or hyper polarization (more or less spiking)

Answer 133

A receptor that is not an ion channel Typically signal through G proteins on the intracellular side. Activation can produce any effect from a change in the membrane potential to a change in gene expression

Answer 134

Main EXCITATORY neurotransmitter All ionotropic glutamate receptors let sodium in Typically excitatory - the gas pedal Ionotropic glutamate receptors let in sodium ions causing excitatory post-synaptic currents (ESPCs) and membrane depolarization

Answer 135

Agonists Often cause seizures and excitotoxicity Antagonists Dissociative anesthetic (ketamine, PCP)

Answer 136

Main INHIBITORY neurotransmitter All ionotropuc GABA receptors let chloride in Typically inhibitory - the brakes Ionotropic GABA receptors let in chloride ions, causing inhibitory post-synaptic currents (IPSCs) and membrane hyper polarization

Answer 137

Agonists Anaesthetics, anticonvulsants, muscle relaxants, sleeping pills, anti-anxiety (alcohol, barbiturates, benzodiazepines) Antagonists Often cause seizures

Answer 138

Dopamine Norepinephrine Acetylcholine Serotonin These neurotransmitters primarily act on metabotropic receptors and tend to exert a modulatory influence on cell activity *in contrast to glutamate and GABA, which often causes fast EPSPs or IPSPs via their respective ionotropic receptors) Are released from small collections of neurons that send their axons out widely

Answer 139

Most of their receptors are g-protein coupled receptors, not ion channels They typically don’t produce simple excitatory or inhibitory effects in CNS They can diffuse short distance outside of the synapses and influence the activity of neighboring neurons.

Answer 140

conventional neurotransmitters neuropeptides lipid-based signaling molecule

Answer 141

Mostly amino acid derivatives (modified amino acids) Main players - glutamate, GABA, Dopamine, Norepinephrine, Acetylcholine, Serotonin Synthesized locally in axon terminals Usually secreted from small synaptic vesicles that dock very close to the site of Ca+ entry in axon terminal Generally active ionotropic AND metabotropic receptors Typically recaptured after secretion and REUSED Usually binds receptors directly across the synapse. Even when they diffuse, they only influence activity of neighboring neurons

Answer 142

Short string of amino acids (ex. A protein formed with only 10-30 amino acids) Ex. Of >70 : oxytocin, vasopressin, enkephalin, prolactin, NPY, ghrelin, CRH Synthesized in cell soma, transported down axon while undergoing additional processing and release just once Usually secreted from large dense core vesicles that dock a ways back from the site of Ca2+ entry in the axon terminal Only activates METABOTROPIC receptors No synaptic recycling occurs of either the neuropeptides or their immediate precursors May diffuse long distances long distances and exert action at a distance (non-synaptic communication)

Answer 143

Ex. Cannabinoids, anandamide, arachidonoyl glycerol synthesized and released on demand as needed Secreted in non-vesicular manner, typically from postsynaptic neurons Only activates METABOTROPIC receptors, typically located on the presynaptic axon terminal

Answer 144

Serotonin, dopamine, norepinephrine and epinephrine are all monoamines

Answer 145

Dopamine, norepinephrine and epinephrine are further classified as catecholamines as they have exceptionally similar chemical structures epinephrine and norepinephrine are synthesized from dopamine

Answer 146

contain substances that interfere with neurotransmitter signaling. Many interfere with neurotransmitter signaling at the neuromuscular junction

Answer 147

Neurotransmitter

Answer 148

Primarily acts as a neuromodulator often as axoaxonic synapses

Answer 149

Released by motor neurons at the neuromuscular junction where it activated the fast excitatory ionotropic receptors on muscle cells that cause muscle contraction. Motor neurons Generally release ACETYLCHOLINE as their main neurotransmitter Sensory neurons Generally release GLUTAMATE as their main neurotransmitter

Answer 150

BWSV Poison triggers the release of acetylcholine Botox Produced by bacteria that grow in improperly canned food. Acetylcholine system agonist since it prevents the release of acetylcholine Causes muscle paralysis

Answer 151

Drug that inhibits the activity of acetylcholinesterase Acetylcholinesterase – enzyme that breaks down acetylcholine in synaptic cleft Causes acetylcholine to stay around longer in synapses causing more muscle contraction

Answer 152

Hereditary autoimmune disorder Your own immune system attacks their healthy acetylcholine receptors

Answer 153

INCREASES activity of postsynaptic receptor protein

Answer 154

DECREASE activity of postsynaptic receptor protein

Answer 155

Drugs that affect postsynaptic receptor activity by directly binding to postsynaptic receptors

Answer 156

Drugs that affect postsynaptic receptor activity in an indirect manner (proteins they bind to are not postsynaptic receptors)

Answer 157

Direct dopamine receptor antagonists (receptor blockers) Class of drug used to treat psychosis

Answer 158

Psychosis is an abnormal condition of the mind that results in difficulties determining what is real and what is not real Affects approximately 1% of the population

Answer 159

They all directly block dopamine D2 receptors Inhibitory metabotropic receptor expressed by neurons all over the brain

Answer 160

Some drugs are use to treat mental illnesses and others are used recreationally Most popular drugs are the ones that directly activates serotonin 2A receptors (inhibitory metabotropic receptors expressed by neurons all over the brain) Not all drugs that activate serotonin 2A receptors cause hallucinations Some 5HT-2A receptor agonists cause massive hallucinations

Answer 161

Mescaline (hallucinogen) Psilocybin (hallucinogen) LSD (hallucinogen) *Lisuride* (not a hallucinogen)

Answer 162

When these agonists bind and activate this metabotropic receptor, they launch an intracellular signaling cascade that starts with the g protein Serotonin normally activates this receptor in this manner When hallucinogenic drugs bind to this receptor, we also see activation of the g protein Hallucinations result from serotonin 2A receptor activation of G proteins. But we do not yet know why this g protein signaling cascade causes hallucinations

Answer 163

Metabotropic receptor ligand causes receptor to preferentially activate one type of intracellular g protein, whereas another ligand at the same receptor might preferentially activate a different g protein

Answer 164

A competitive AGONIST acts similarly to the endogenous neurotransmitter. It activates the receptor by binding where the neurotransmitter normally binds. Direct receptor agonists can be full agonists or partial agonists A competitive ANTAGONIST attaches to the same binding where the neurotransmitter normally binds, but it doesn’t activate the receptor. Competitive antagonists are full antagonists.

Answer 165

When a drug binds to a receptor at a site that does not interfere with the binding site of the principal ligand it is called non-competitive binding. It is possible for a neurotransmitter to bind on one site of a receptor while a drug binds on another. Non-Competitive AGONIST Fully or partially activates the receptor Non-Competing ANTAGONIST Fully blocks receptor activation. It doesn’t compete for the neurotransmitter binding site. It “wins” without competing by binding to an alternative site

Answer 166

Non-competitive drugs that only influence receptor activity when the neurotransmitter is also bound to the receptor.

Answer 167

Negative Reduce the effect of the primary ligand. Positive Amplify the effect of the primary ligand.

Answer 168

Neurological disorder Characterized by tremors, rigidity of limbs, poor balance, and difficulty initiating movements. Caused by the degeneration (death) of dopamine neurons in the midbrain.

Answer 169

The amino acid L-Dopa is often used as a drug to treat Parkinson’s disease because it increases dopamine production in the brain and thus acts as an indirect dopamine receptor agonist.

Answer 170

in the axon terminals made from precursor molecules (generally from amino acids).

Answer 171

Can be administered as drugs since They can increase the amount of neurotransmitter that is made and released. In such cases, the precursors acts as receptor agonists.

Answer 172

Some antagonists work by blocking these enzymes, thus reducing production of the neurotransmitter so there is less in each vesicle

Answer 173

Some antagonists work by blocking the transporter proteins that package neurotransmitter into vesicles. When this occurs, the synaptic vesicles can remain empty, so nothing is released when they fuse with the presynaptic membrane

Answer 174

Some antagonists work by blocking the vesicular release machinery, so no neurotransmitter is ever released (e.g., botox). Some agonists work by activating the vesicular release machinery, causing neurotransmitter release (e.g., black widow spider venom).

Answer 175

Some agonists block the enzymatic deactivation of neurotransmitter in the synaptic cleft (e.g., neostigmine). Some agonists block neurotransmitter reuptake proteins. Some agonists can even reverse the reuptake transporters, so that neurotransmitter is pushed into the synapse as soon as it is made (without ever getting packaged into a synaptic vesicle).

Answer 176

Methylphenidate, Cocaine

Answer 177

Adderall, Crystal meth [Ecstasy (MDMA) does a similar thing to all the monoamine reuptake transporters (i.e., causes them to run backwards).]

Answer 178

Drugs are exogenous chemicals that at low doses significantly alter the function of certain cells. Drugs can be categorized in different ways: According to their behavioural effects (e.g., upper, downer, stimulant) According to their physiological effects (e.g., action potential blocker) According to their actions on specific proteins (e.g., serotonin reuptake blocker) According to their effects on postsynaptic receptor activity

Answer 179

Easily crosses the blood-brain barrier An enzyme in the blood makes it VERY LIPID/ fat soluble

Answer 180

Less easily crosses the blood-brain barrier Less lipid soluble

Answer 181

Does not cross the blood-brain barrier

Answer 182

All very strong opiates (opioids) All cause constipation 3 main types of opioid receptors All inhibitory, metabotropic receptors found throughout the body and the brain Normally get activated by endogenous opioid peptides that function as hormones in the body and as neuropeptides in the CNS

Answer 183

When a drug effect gets smaller with repeated administration. The body becomes used to the drug and actively counteracts its effects. After tolerance develops, in the absence of the drug the user will suffer withdrawal symptoms, which are opposite the effects of the drug (e.g., euphoria vs dysphoria; constipation vs diarrhea).

Answer 184

Occurs when a drug effect becomes larger with repeated use

Answer 185

Occurs when a drug effect becomes larger with repeated use

Answer 186

STEP 1 Relatively cheap and fast The resolution is not great for soft tissue like brain. A computer assisted X-ray procedure used to take a “photograph” of the brain. Patient lies with his or her head positioned in the centre of a large cylinder. X-ray beam (i.e., high energy electromagnetic radiation) is projected through the head to an X-ray detector X-ray beam is delivered from all angles. A computer translates the information received from the X-ray detector into a series of pictures of the skull and brain.

Answer 187

STEP 2 Uses strong magnetic fields (instead of X-rays). The patient lies in the centre of a large cylinder (like CT Scan) When a strong magnetic field is applied to the body, the spin of every hydrogen atom proton assumes a particular direction inline with the magnetic field. Radiofrequency waves (i.e., low energy electromagnetic radiation) are administered to the body. This energy is absorbed by protons, changing the direction of their spin. These protons then emit their own radio waves when their spin immediately flips back to that determined by the magnet By triangulating where the emitted radio waves came from, the scanner can provide an estimate of the relative density of protons (hydrogen atoms) in each area of the body.

Answer 188

STEP 3 A variation of the MRI technique Measures the direction and speed of the diffusion of water molecules Used to identify axon tracts Colors indicate the direction of water molecule diffusion

Answer 189

fMRI uses a rapid series of MRI scans The amount of oxygen in blood distorts the local magnetic field. With a series of MRI scans, it is possible to detect changes in blood oxygenation, which reflects blood flow and correlates with neural activity. When a brain area is active, blood flow to that region quickly increases (~5s lag). Popular BECAUSE: Doesn’t involve needles Doesn't involve surgery Doesn’t involve radioactivity It provides both structural and functional information with decent spatial resolution (1 to 5 mm) and temporal resolution (several seconds).

Answer 190

PET scans involve injecting a person with a radioactive compound. Radioactive sugar molecules (like 2-DG) are commonly used to detect changes in energy use in the brain. Sugar broken down too quick and used by cells so was hard to track (slightly modified sugar) 2-DG is similar to glucose, in that it is taken up by energy consuming cells in the body. However 2-DG is not broken down as easily as sugar is, so it stays around for hours.

Answer 191

The scanner identifies where radioactive 2-DG molecules are located over time. The MAIN DISADVANTAGE of PET scanners is their operating COSTS For safety reasons, the radioactive molecules are designed to decay rapidly (over hours), thus they have to be made on site the morning of the experiment.

Answer 192

Radioactive L-Dopa is picked up by dopamine neurons, converted into dopamine, and released as normal. There are fewer dopamine neurons in the brains of people with Parkinson’s disease. PET is also used to measure changes in the expression levels of neurotransmitter receptors across weeks. These studies use radioactive agonists/antagonists.

Answer 193

An electroencephalogram is a measure of electrical activity in the brain that uses macroelectrodes (metal discs) attached to the scalp. Records the summed population-level activity of millions of neurons Can be used as a diagnostic tool – specific patterns of EEG activity are associated with different states of: Consciousness Stages of sleep Types of cerebral atrophy

Answer 194

If you want to know what an area of the brain is good for, lesion it in an animal and see how their behavior changes Involves the removal or destruction of a portion of the brain Presumably, the functions that can NO LONGER be performed following the surgery are the ones the brain region NORMALLY controls.

Answer 195

Radiofrequency Lesions Excitotoxic lesion SHam lesion reversible lesion

Answer 196

Radiofrequency Lesions Small lesions can be made by passing radiofrequency current THORUGH A METAL WIRE that is insulated everywhere but the tip. This ELECTRIC CURRENT produces heat that burns cells around the tip of the wire. The size and shape of the lesion is determined by the duration and intensity of the current. A DOWNSIDE to this approach is that axons just passing through will also be burned.

Answer 197

“Placebo” procedure that duplicates all steps of producing brain lesion except for one that actually causes extensive brain damage

Answer 198

Brain lesion produced by intracerebral injection of a glutamate receptor agonist, such as kainic acid. These drugs cause so much excitation (and calcium influx) that the affected neurons often undergo apoptosis, while axons passing through (fibers of passage) are usually spared.

Answer 199

A temporary brain “lesion” can be achieved by injecting drugs that block or reduce neural activity in a given region. Common drugs include Voltage-gated sodium channel blockers (stops all action potentials) GABA receptor agonists (which hyperpolarize cell bodies)

Answer 200

Most direct measurements of neural activity Made with thin metal wires placed in the brain They have a fine tip that can record electrical activity of individual neurons (single-unit recordings) Record every action potential from a given neuron

Answer 201

made over an extended period of time

Answer 202

Made over a relatively short period of time Often during surgery when the animal is anesthetized

Answer 203

Involves passing an electrical current through a wire inserted in the brain. Affects EVERYTHING in the area Cell bodies and fibers of passage Some electrical simulation patterns Often very high frequencies Tend to produce the same behavioral effects as lesioning in the area

Answer 204

Achieved with DRUGS In rodents: Drugs administered through guide cannula (hollow tube) implanted in particular brain area Anesthetics can be injected to shut down all neural activity Receptor agonist/antagonist can be used Should not affect fibers of passage since there are no neurotransmitter receptors on the membrane in the middle of an axon (axons passing through)

Answer 205

The use of light to control neurons which have been made sensitive to light through the introduction of foreign DNA. Foreign DNA encodes light-sensitive proteins known as opsins

Answer 206

Proteins that are sensitive to light Opsins in our eyes are metabotropic receptors that operate with a 30-millisecond delay Opsin used for optogenetics are often ion channels that open and close instantly in response to light Original ones were discovered in bacteria in different parts of the world Can design and modify opsins for research purposes

Answer 207

Lots of different photosensitive ion channels evolved in bacteria and algae. POPULAR EXCITATORY one named channelrhodopsin-II (ChR2) Permeable to sodium ions Depolarizes neurons Causes spiking when activated by blue light. Other opsins, like IC++ Designed by humans Inhibitory Light sensitive ion channels (pass chloride and hyperpolarize neurons when activated by blue light)

Answer 208

Type of DNA delivery system Normally replicate by injecting viral DNA into a host organism Contains instructions on how to make more virus. We know how to remove the DNA from a virus – renders the virus "replication-deficient". Can add foreign DNA to the virus (DNA that encodes – ex. fluorescent proteins or optogenetic proteins.) Once the virus gets its DNA into the infected cell’s nucleus, that cell will start to transcribe it and make the foreign protein.

Answer 209

Where their soma are located (e.g., neurons in the amygdala) Where their axons are located (e.g., neurons that form synapses in the amygdala) The proteins they express (e.g., neurons that make serotonin or dopamine) Whether they recently had more action potentials than normal (e.g., active neurons) Almost all lab-made viral constructs contain a section of DNA that encodes a fluorescent protein (e.g., GFP). Fluorescent proteins are used to later identify the infected cells.

Answer 210

Discovered in Jellyfish They modified it Causing it bind calcium and fluoresce much brighter when it does. This protein is called GCaMP. Since a little calcium influx always occurs during action potentials (even in the cell body), monitoring GCaMP fluorescence is GOOD WAY TO MEASURE NEURAL ACTIVITY (in cells made to express GCaMP protein).

Answer 211

Tracing AFFERENT axons What brain areas send their axons here? Retrograde labeling is used to label the cells that innervate (project to) a given region. Various chemicals, such as fluorogold can be used as a retrograde tracer. Fluorogold molecules are taken up by axon terminals and transported back to the cell body.

Answer 212

Tracing EFFERENT axons Where do the axons from these cells go? Anterograde labeling is used to label where axons from a particular location go to. Various chemicals, such as PHA-L, can be used as an anterograde tracer. PHA-L molecules are taken up by cell bodies and transported down to axon terminals.

Answer 213

Surgical intervention Uses stereotaxic apparatus Device that permits a surgeon to put something into a very specific part of the brain Used to inject things into the brain, such as Drugs and Viruses Tracer molecules (dyes) Used to permanently implant things like Cannula and Electrodes

Answer 214

The junction where pieces of skull fuse together Often used as a reference point in stereotaxic surgery

Answer 215

Lesion a brain area e.g. excitotoxic lesion Lesion a specific type of cell in a particular brain area e.g. inject a compound that specifically kills dopamine neurons Change gene expression e.g. to remove a gene needed for serotonin synthesis or to deliver DNA that encodes a foreign protein Typically accomplished with viral-mediated gene delivery.

Answer 216

Used in behaving animals to measure changes in neurotransmitter levels in a given brain region

Answer 217

refers to the use of a semipermeable membrane to either deliver molecules to or measure the amount of molecules in some solution or brain area.

Answer 218

Small metal tube that holds dialysis tubing. These can be placed in the animal’s head

Answer 219

Histological method that is used to label proteins and peptides in biological tissue Classify neurons by the protein they possess Only serotonin neurons express serotonin reuptake proteins. Only glutamate neurons express vesicular glutamate transporter proteins. Most common technique for identifying cells that make a specific protein (takes advantage of antibodies - proteins made by the immune system of mammals Where specific neurotransmitter receptors are located What neurons in the amygdala express serotonin receptors? Where are dopamine D3 receptors located in the brain?

Answer 220

Antibodies, by nature, are designed to selectively bind to a single type of protein. Researchers have made fluorescent antibodies that selectively bind to all different types of proteins. When these fluorescent antibodies are washed over a brain slice, the protein of interest will become fluorescently labeled, and under a microscope it is easy to identify which cells contain these proteins.

Answer 221

Often used to IDENTIFY PROTEIN EXPRESSION PATTERNS, which in turn tells us WHERE neurotransmitters are RELEASED and WHAT RECEPTORS are there.

Answer 222

often use antibodies against the enzymes that make these neurotransmitters. For example, cells must first make serotonin if they plan to release it. In order to do so, they must express the enzyme tryptophan hydroxylase, which converts the amino acid tryptophan into serotonin. Therefore, the antibodies that label tryptophan hydroxylase are used to identify serotonin neurons.