Exam 1 Notes (complete)
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This 42 page Study Guide was uploaded by Michael Ekdall on Wednesday February 18, 2015. The Study Guide belongs to PSY425 at University of Miami taught by Dr.McCabe in Spring2015. Since its upload, it has received 404 views.
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Date Created: 02/18/15
Psychobiology 02192015 11513 our behavior determined by physical and chemical reactions goal of psychobiologyunderstand behavior and explain it separates it from physiology and biology and chemistry no one approach is suf cient to understanding how brain works 0 late 60 s people nally worked together to understand the brain need to train new scientists interdisciplinary come at the problem from multiple perspectives 0 hence eld of neuroscience is born 0 fastest growing area psychobiology has now merged with neuroscience 0 can also be considered cognitive neuroscience behavioral neuroscience History of Psychobiology 0 Ancient greeks interested in the mind had no way of studying it 0 18005 people started wondering if functions were localized to particular brain regions localization of functions Franz GaI proposed brain was specialized o Looked at surface of headpeope had different bumps 0 When people used certain parts of brain they grew and created these bumps o Phrenology is the study of the brain via the bumps 0 Public ate this up people went and got their brain bumps read to hear about their personality 0 Scienti c community hated it 0 Pier Fourens 0 Does experiment with cats removed certain parts of brains thought to be associated with certain traits to see whether they could still show that trait 0 Basically disproved Gail s theory 0 Had people thinking how to study this 0 1860 Paul Broca published report of patient with brain injury who developed aphasia lack of speech 0 patient name TA 0 Broca studied Ta s brain Had damage in region of frontal lobe con ned to left hemisphere of brain Damage on right side of brain caused no change in speech or language 0 First evidence of localization Began developing tools and methods of productively studying the brain Staining techniques able to see particular neurons and what they look like Ramon y Cajal look at tissues and tell you about the function in dead people using staining 0 Tools to detect tiny levels of chemicals in the brain Neuron Doctrine the neuron cell is basic function of the nervous system and all behavior Darwinism was developing at the same time we must share certain neurological functions with other animalsbegan studying animal physiology Walter Cannon and Ivan Pavlov both are pysiologists studying nervous system and gastrointestinal system respectively Understood physiology and behavior were closely linked Carl Lashley rst to publicaly admit he was a psychobiologist Interested in learning about memory how the brain stores and retrieved information Psychobiology is new eld only about 90 years old Neuroscience is rather new discipline as well about 70 years or so How we study the brain 0 No sophistication in experimental design thsiolooical intervention manipulate physiology and observe changes in organisms behavior dependant variable 0 Behavioral intervention manipulate organisms behavior and observe changes in physiology 0 Ex put in stressful environment and measure blood pressure and heart rate 0 This is noninvasive study 0 Used a lot with humans 0 Psychopysiologists Correlational approach take two dependant measures physiology and behavior and compare them and see how they vary 0 No causality simply able to determine correlation Tools we use Stereotaxic instrument xes organisms head in particular orientation and there are manipulators in different directions can attach probes and other things 0 Atlas of the brain helps you nd particular regions of the brain Ex Move two mm left and 3 mm down Techniques Ablation destroy tissue by burning hole in the tissue 0 Observe how behavior changes 0 How does brain react without that region not exactly learning what that region does Destroy nerve cells and axons that pass through that region 0 quotfibers of passagequot 0 may skew results and think you found the region when really you just destroyed the pathway Electrical stimulation Activate nerve cells with pulses of energy 0 How far is current spreading You may be stimulating completely different region than you think Recording 0 Put electrodes on brain and pick up electro activity that nerve cells are producing Able to record activity of single nerve cell 0 Multiple unit recording look at large region of cells lntercellular recording electrode into cell EEG Large recoding electrode and record from scalpsimultaneous activity of many many cells in brain 0 Allows you to correlate some behavior with activity Biochemical analysis pharmological approaches 0 Measure chemicals in local enviroment insert uid then suck up back up in region 0 Can inject drugs in discrete region of brain and see how they affect neurons in an area Neuroanatomical approach 0 Go in and stain tissue in different ways 0 1 Nissl stain stains ribosomes found in nucleus of cells basically staining cell bodies 0 tell you where cell bodies are 0 2 Golgi Stain stains ll the entire cell able to look at structure of cells 0 only stains about 1 of neurons 0 3 Intracellular stain Electron Microscopy gives very high magni cation of cells How do you know where neuron projects to 0 Can inject chemicals and neuron will transport all the way to receptors Anterograde tracers injected into neuron and see where they end upshows the pathway Retrograde tracers injected into area taken up by terminals and taken backwards to the neuron 0 Ex Horseradish peroxidase lmmunocytochemisty use antibodies that recognize speci c molecules attach uorescent tracer that will show where in the brain the molecule will be Confocal microscopes allow you to look at tissue in three dimensions Brain imaging good pictures without opening up the skull 0 Brain angiogram able to see arteries and veins in the brain by injecting a dye o Detect aneurism blood clot etc CTCAT scan 1st imaging technique gives anatomical picture of the brain 0 Doesn t give great special resolution 0 MRI scan uses magnetic properties of cells and what now 0 Able to see grey matter and white matter much better resolution Want tools that allow us to see the brain and view it while its functioning 0 Most active cells in brain will take up the most sugar 0 Attach radioactive dye to sugar and see what regions are being activated in the brain 0 l development of PET scan positron emission o imaging functional activity in brain 0 problem is no spacial regocnition takes a long time to do this 0 FMRI image the uptake of oxygen most active cells will take up most oxygen 0 Get spacial details in a quick matter Cells in culture grow cells from brain in dish Manipulate the genome use tools to manipulate the gene 0 Go in and knock out particular gene Able to knock in a gene 0 Can knock down a gene decrease its activity 11713 Neuroanatomy the more you study the brain the more you realize that function is more tied to structure and organization 0 Knowing where major areas are is very important 0 Things are interconnected 0 Connections are just as important as placement Brain is three dimensional structure 0 ln anatomy you cut it and look at it two dimensionally creating different planes 0 C Down middle quotmidlinequot between eyes through the nose saggital directly down the middle mid saggital only looking at one hemisphere at a time o B Slice the front frontalcoronal plane See both hemispheres at the same time o A take the top off horizontal plane See both hemispheres Terminology Lateral v Medial Medial toward the midline 0 Structure that is near the midline is said to be medial Lateral towards the side 0 Can use these terms to compare to another area also relatively Dorsal v Ventral Dorsal top Ventral bottom 0 In human s spinal chord the dorsal is near the back and ventral is near the belly 0 Imagine a four legged animal which is simple that stands up Anterior v Posterior Anterior front rostral towards the nose Posterior back caudal towards the tail 0 In two legged animals it stays the same anterior is same as ventral posterior is same as dorsal o Rostral is towards brain stem 0 Caudal is lower towards the quottailquot or bottom Organization Peripheral nervous system Somatic nervous system skin and muscles Autonomic ns nerves for organs and guts the vicera o Sympathetic and parasympathetic systems Somatic nervous system nerves in body that inervate somatic part of body 0 Skin skeletal muscles tendons joints Sensation and movement Begins at level of spinal chord nerves come out of both sides 0 31 pairs of nerves quotspinal nerves quot 0 each is responsible for discrete part of body dermatome area of skin that corresponds to particular pair of nerves 0 provide muscle commands o myotome area of muscle corresponds to area of skin spinal nerves contain muscle bers and sensory bers Grey matter v White matter 0 Grey is made of nerve cell bodies dendrites and un myelinated axons White matter is myelinated axons o lnsulates nerve cells and speeds conduction Right near spinal chord spinal nerves split 0 One pair going towards dorsal other towards ventral part of spinal chord Dorsal root part of spinal nerve that deals with sensory input 0 Sensory nerves then go into dorsal horn of gray matter in spinal chord Dorsal horn is purely sensory Interneurons connect sensory and motor neurons 0 Project towards ventral horn of spinal chord Contain cell bodies for motor neurons 0 Ventral root purely motor function Dorsal root ganglion Swelling is area for cell bodies of sensory nerves Re ex arc have a sensory element an interneuron and a motor element Sensory motor integration 0 As you move up into the brain its all about sensory motor integration Taking in info about the world and deciding what to do about it Re ex something unlearned hardwired circuits that produce stereotypical response 0 Ex Blinking coughing Autonomic nervous system peripheral nerves that innervate internal organs Considered to be output system only 0 Referring only to motor neurons the sensory neurons are another system 0 Dealing with efferents o Afferents neurons project information towards a target Typically sensory neurons o Efferents neurons projecting away from target Usually motor neurons First neuron central nervous system preganglionic cell l ganglion post ganglionic cell goes to target organ l heart Sympathetic nervous system increase breathing heart rate goes up adrenaline increases 0 Originates in the spinal chord kind of in the middle 0 Within thorasic and lumbar area 0 lntermediolateral nucleus IML Contains preganglionic region for sympathetic system Send axons out ventral root Sympathetic chainparavertebral chain chain of ganglia o Interconnected by longitudinal bers 0 Lies right nect to spinal column on either side 0 Able to transfer info very quickly all organs prepare at one time Preganglionic neurons are mylenated postganglionic ones are not 0 Generally slow system Acetyl choline is a major neurotransmitter that conveys info between preganglionic cell Norepinephirne is transmitter between postganglionic cell and target organ 0 Can use drugs to mimic these neurotransmitters 0 Ex Beta blockers Adrenergic system Parasympathetic system brings things back to normal 0 Originates in brain stem cranial region and bottom of spinal chord sacral region Bypass sympathetic chain and go towards target organs 0 Ganglion is very close to target organ l long preganglion cells that are myelinated this is fast system Newer system 0 10th cranial nerve aka vagus nerve quotthe wandererquot 0 major input to body cholinergic system 0 uses acetylcholine at synapse between post ganglionic cell and target organ Spinal Chord Spinal nerves determine segments of spinal chord really its conUnuous Sit in bony structures aka vertebrate Spongy disks allow chord to bend and rotate Meninges 31 segments of spinal chord o 8 cervical segments neck area inervate upper limbs o 12 thorasic segments base of neck to mid back inervate lower limbs o 5 lumbar segments mid back to lower back o 5 sacral segments lower end of back 0 1 coccygeal near tail bone 0 spinal chord is shorter than vertebrateends somewhere in lumbar region 0 spinal nerves get displaced and go downward in order to exit at the right place ascending v descending tracks ascending towards the brain descending away from the brain central canal contains cerebral spinal uid 12212 Neuroanatomy part II brain is highly metabolic organ receives a large amount of blood owup to 20 job bring in sensory info integrate it in some fashion produce motor out ow organized hierarchal layers added on the lower layers are most basic Higher layers exert control over the lower brain regions 1 Myelencephalon corresponds to medulla 2 Metencephalon pons and cerebellum o myelencephalon and metencephalon together make up the hindbrain 3 Mesencephalon midbrain 4 Diencephalon thalamus hypothalamus o 1 2 3 4 all together make up the brain stem 5 Telencephalon limbic system basal ganglia cerebral cortex 0 45 together make up the forebrain the higher brain structures Myelencephalon Medulla adjacent to spinal chord actually a continuation of spinal chord o Vegetative functions breathing swallowing involuntary re exive behaviors o Damage to medulla is typically fatal not very well protected by cranium Fiber Tracks go up and down medulla o Reticular formation goes through center of brain stem interconnected brain cells Thought of as the brain alarm clock When activated it causes brain arousal n Alertness and consciousness o 12 pairs of cranial nerves that come out of brain stem 0 Xth cranial nervevagus nerve comes out of medulla lnervates all the organs for parasympathetic control Metencephallon Pons has a bolbus shape Similar functions to medulla mostly vegetative Some cranial nerves emerge from pons 0 V trigeminal nerve largest of all cranial nerves lnervates the face and has motor bers that extend to the jaw controls muscles used for chewing n Both sensory and motor 0 VIII acousticvestibular nerve sensory nerve from inner ear 0 Carries info from sound and balance 0 VII facial nerve motor nerve that innervates the muscles of yourface Bells palsy occurs when facial nerve is damaged half of face is paralyzed Cerebellum involved in motor control 0 Involved in sense of balance adjusts muscles to remain standing up 0 Controls posture 0 Motor guidance guiding movements by providing timing and precision to make movements uid and continuous Therefore cerebellum must be able to learn Lots of learned motor control takes place here 0 Every animal with cerebellum has identical circuitry 0 Alcohol inhibits this area Mesencephallon aka midbrain Contains two nuclei sensory relay nuclei 0 Superior colicuus Vision takes info from the eye and passes it on Visual tracking ability to follow visual stimuli 0 inferior colicuus auditionhearing takes info from ear and passes it on to higher area 0 Together these can be called the tectum Motor nuclei found in midbrain 0 Red nucleus has a reddish hue Origin of descending neurons that go down spinal chord and control movements o Substantia nigra black pigments Projects upward into higher parts of brain in basal ganglia Use dopamine These are damaged and die in people with parkinson s disease Symptoms appear when person doesn t receive dopamine 0 III cranial nerve occulomotor nerve controls eye movement Diencephalon thalamus and hypothalamus o Thaamus sits in the heart of the brain 0 2 main functions of thalamus contains many sensory relay nucleiwhen you hear thalamus think sensory Sends the info to the cortex quotgate keeper to the cortexquot a lateral geniculate reay nucleus for vision main visual pathway a medial geniculate reay nucleus for audition a ventral posterior lateral VPL and ventral posterior medial VPM VPL sensory for your body VPM sensory for headface Goes to somatosensory cortex 0 Intrinsic nucei receive input from reticular formation Neurons fan out and activate neurons in cerebral cortex fanning out over area Arousal type system that alerts brain and facilitates higher brain function Hypothalamus about size of thumb nai o Involved in many motivated behaviors behaviors that must be driven ex Eating drinking sexual temperature regulation 0 Sits in position to regulate your whole body 0 Sits above pituitary gland which releases hormones into blood stream Hypothalamus controls what hormones the pituitary gland releases 0 Interacts with many structures above hypothalamusthe limbic system Emotional behavior learning and memory Hypothalamus Uses info from this area to regulate your body Telencephalon Limbic system Hippocampus seahorse like shape Amygdala looks like an almond Fornix Septal nuclei Cingulated cortex Parts of Hypothalamus Parts of Thalamus o Olfactory system smell Basal gangia cluster of nuclei Important for motor function interact with cerebral cortex 0 Damage in this area can cause parkinson s disease l akinesia loss of motor control Caudate Putamen n Putamen and caudate together can be called striatum Globus pallidus Cerebral cortex highest level of nervous systemour advantage over other animals Speech thinking inhibiting behaviors OOOOOOO 0 Thin sheet of cells folded up to t in brain Grooves sulcus a Long deep groove ssure Raised portionridges gyrus Paleocortex 4 or 5 layers Neocortex 6 layers 0 4 major lobes in cerebral cortex 1 Occipital lobe in posterior end of cortex n contains visual cortex 2 Parietal lobe n somatosensory cortex n involved in coding for space internal and external like depth perception 3 Temporal lobe n auditory cortex n olfactory cortex 4 Frontal lobe midfront half a motor cortex n prefrontal cortex OO Corticospinal tract quotpyramidal tractquot 0 Pathways name tells the beginning of path and where they end 0 Starts in cortex ends in spinal chord Pretty direct and discrete system Pathways can go sideways in the brainconnecting right and left sides Commissures the sideway paths 0 Corpus callosum comissure that connects right and left higher areas of the brain Holes in our brain brain develops around series of chambers o VentriCes the holes in the brain 0 Contain cerebral spinal uid CSF o Continues ow of CSF through ventricles and around the brain Blood supply of the brain 4 major arteries 0 2 carotid arteries 0 2 vertebral arteries circle of willis has evolved circuit of arteries 0 arteries dump into the loop before going to whole brain 0 ensures that the whole brain gets some blood ow in case one artery fails blood brain barrier protects the brain forms protective membrane that screens out particular chemicals preventing them from entering the brain 12413 Neurophysiology how do the structures integrate information Need to understand how individual cells neurons produce info and carry it throughout the brain Many different kind of nerve cells Common features 0 Cell body or soma or perikaryon 0 Contains the dna mitochondria o Keeps the cell alive 0 Location of soma is usually what people talk about when they ask where neuron is o Dendrites receptive part of nerve cell 0 Receive information 0 Single nerve Cell can have thousands of dendrites Get info from many different places 0 Dendritic spines swelling or protrusion Part that makes contact with other cell 0 Transmits info back towards soma and then rest of nerve cell a Axon 0 Usually only one axon per cell 0 Axon hillock o Axons can split and form collaterals To make contact with more than one cell 0 Axon terminals ends of axon Boutons swellings at terminals that bonds with other cell and transmits the signal o Hollow tubes composed of microtubules Microtubules help transport chemicals Can provide retrograde transport aso Called axonal transport Hard for nerve cells to replicate themselves Categorizing nerve cells 0 Number of projections off soma o Monopolar ce one projection off soma acts as both axon and dendr e Typically found in invertebrates more basic 0 Bipolar cell 0 Multipolar cells 0 Diameter of soma o 10 uM small 0 75 uM large large mammalian cell 0 300 uM huge found in invertebrates neuropil everything outside of soma dendrites axons other types of cells 0 all nerve cells are bathed in uid extracellular matrix scaffold of proteins all around cells 0 helps in development Vascular tree keeps the brain in shapethe blood vessels another class of cells in the brain Astrocytes see these around blood vessels and lining ventricles of brain 0 Help form part of blood brain barrier 0 Certain ones respond to injury or infection reactive astrocytes Help in repair in ammation haul off garbage Microgia aka phagocytes o Engulfs debris and gets rid of it Glial cells are able to replicate themselves fairly easily Oligodendrocyte satellite cells 0 Often found right next to nerve cells 0 Wrap membrane around axon of nerve cellsinsuates axon Forms myelin sheath Do this in central nervous system Schwann cells insulate nerves in peripheral nervous system 0 Nodes of Ranvier uninsulated areas Signals jump from node to node Salutatory conduction leaping motion signal takes Nerve impulses Greater the difference in charges l greater action potential voltage In nerve cells the charged particles are ions 0 Na K Cl 0 Potential of movement is created by membrane 0 lons on both sides of cell membrane 0 Inside membrane has more negative charge 0 Resting potential 70 mV inside cell 10quot3 V outside Polarized Depolarized ions can move towards each other and membrane potential changes from 70 n Occurs when membrane becomes permeable lon channel made of proteins allows ions to move in and out of cell 0 Different kinds of channels for different ions 0 K found in high concentraion inside cell low concentration outside cell 0 Na and CI in high concentration outside the cell 0 Diffusion creates a want for equality At rest K and Cl channels are open 0 Electrical gradient prevents them from owing in 0 Action potential spike in membrane potential 0 Need to have an excitement to 50 mV l Na channels open Voltage dependant channels 0 At 50 Na no longer wants to go inside and stops 0 All action potentials are the same height 0 All or none phenomenon if it spikes but doesn t get to 50 mV nothing happens 0 Recovery K ef ux k leaves the cell making inside more negative Sodium potassium pump kicks back on n Pumps sodium out of cell and pumps K back into the cell Cell is refractory at this point cant re a Absolute refractory period 0 Pretty fast determines how fast a neuron can re Pysical limit is 1000 times a second a Relative refractory period a Supernormal period very ready to have another excitement and open the Na channels a Subnormal period hyperpolarize the cell pump overpumps o Hyperpolarization Less excitable Neural conduction Passive spread ofcurrent depolarization at one spot moves down and spreads the current depolarizing next chunk of tissue and the next and the next Action potential conducted at xed amplitude because its regenerated each time Action potentials only go in one direction because of absolute refractory periodcan only go forward Feedback signal travels in opposite direction to let cell know that its ring Myelinated action potential goes to spot of low resistance nodes of ranvier 12913 Graded potentials what spark the action potential Found on the dendrites and soma The stronger the stimulus the greater the potential 0 Graded in strength Decremental as it travels down the axon away from point of stimulation they get smaller 0 Very different from action potentials occur in axons only Not graded in strength They are all or none Conducted at xed amplitude Graded potentials depolarize the membrane enough to allow action potential to start Action potential Occurs at the axon hillox 0 From there and on along axon there is an increase in the voltage dependant Na channels 0 Stimulated by summation of many graded potentials Spatial summation potentials occurring at the same place and they add up Temporal summation graded potentials added up over the course of time 0 Has to decide to re or not to re 0 Each cell is constantly making decisions 0 However not all graded potentials are depolarizations some can be a hyper polarization H 0 Drive membrane further away from polarizationinhibits the cell 0 All inputs travel to axon hillock and all and are added up to determine whether or not to re Excitatory postsynaptic potentials EPSP depolarization graded potentials o Inhibitory postsynaptic potentials IPSP the hyperpolarization potentials Signaling between two cells Neurochemistry Space between cells synapse implies that communication is chemical phenomenon o Presynaptic cell and post synaptic cell 0 Synaptic cleft 100300 A A 10quot10 0 Those three things together synapse Chemical synapses allow for more exibility or plasticity 0 Ability to change and adapt 0 See these in more advanced organisms Synaptic Transmission 0 1 Presynaptic cell must create a chemical synthesized in soma o Transported from soma to tubules to arrive at axon terminal o Neurotransmitters stored in synaptic vesicles Vesicles protect neurotransmitters from enzymes I These destroy NT 0 2 Cell res action potential l depolarizes membrane opening up Ca channels 0 stimulates movement of NT toward the membrane 0 vesicles fuse and dump NT into synaptic cleft o Ca is very important step wont release NT if there is no Ca 0 3 NT diffuses across synaptic cleft 0 some NT bind to autoreceptors activating them feedback signallets presynaptic cell know how much NT they released ne tune the amount of neurotransmitter dynamic process constantly being adjusted o diffusion is the slowest part of this process 0 4 NT binds to receptors like lock and key on postsynaptic cell 0 two types of receptors transmittergated ion channels essentially the receptor is an ion channel a binds to receptor and opens up channel allowing ions to go in and out of cell Either IPSP or EPSP o K Cl channel l IPSP o Na channel l EPSP Gprotein coupled receptors a Work a little slower theres an extra step n NT binds to Gprotein receptor l activates g protein2 paths 0 G protein can then open up ion channel 0 G protein activates enzyme which activates another chemical the second messenger o Stimulating chem Reaction in cell that produces important stimulating molecule lst ATP 0 2nCI messenger cAMP can change many things in the cell very important metabotropic effects of neurotransmitter 5 NT breaks off of receptors need to get them out of cleft or it will keep resignalling to the cell 0 3 ways to remove NT 1 NT diffuses away from cleft in the soup 2 Enzyme degradation deactivate or metabolize NT 3 Reuptake transporters molecules suck up NT packages them and brings them back into membrane of presynaptic cell a some drugs inhibit transporters preventing the reuptake l stimulating receptors over and over synapses are always changing based on experience 0 General features of synaptic transmission every NT can have many reactions the receptor molecule essentially determines what happens Dale determines there s only one NT for every nerve cell 0 For the most part he was right Only one true classic NT per nerve cell 0 Nerve cells produce lots of different types of molecules peptides building blocks for proteins coreeased with NT Neuromodulators neuropeptides 0 When we talk about neurochemistry we are really talking about communication 0 Send signals with point to point communication very localized o Broadcast message chemicals travel throughout body and stimulate many cells at one time Endocrine system the hormones of your body 0 Diffuse modulatory systems Broadcast communication through neurons some branch extensively and make contact with hundreds of other nerve cells Ex Arousal emotion attention learning and memory Synapse is sight of most drug effects in the body 0 Drug exodionous agent given in small quantities can greatly affect behavior of ces2 classes Agonist either mimics or enhances action of NT n 1 Stimulate the release of NT n 2 Bind to receptor and activate it mimicking NT 0 similar chemical structure of NT n 3 Inhibits reuptake blocks transporter NT stays in cleft n 4 Inhibits enzyme that metabolizes NT Antagonist opposes or blocks action of NT n 1 Inhibit the production of NT n 2 Binds to receptor and blocks it occupies it without activating it competitive antagonist n 3 Inhibit the release of NT 13113 Neurotransmitters valproic acid depakote Amino acid NT 0 A gaba and gylcine inhibitory NT in brain 0 B Glutamate major excitatory NT in brain 0 In large quantities glutamate is toxic and kills nerve cells glutamate toxicity Excites neurons literally to death Useful in pruning on a singular cell level This can take place when someone has a stroke or head trauma 0 Has different classes of Receptors Use drugs to nd receptors In AMPA receptor NMDA receptor Kainate receptor a Refer to them as NMDA receptors and nonNMDA receptors NMDA channel blocked by Mg at rest when glutamate bonds it attaches to both but only the non NMDA channel l Na comes in l depolarization I knocks Mg out of channel opening up NMDA receptor a Activity dependant receptors only active when cell has been sufficiently depolarized n Synapses modi ed by experience important in learning and memory Acetyl Choline NT Derived from choline First NT discovered Found in autonomic nervous system NT between motor neurons and skeletal musclefound at neuromuscularjunction Found in pons thalamus dreaming o septa nucleus send neurons to hippocampus llearning and memory 0 basal nucleus of meynert nucleus basalis some of rst affected by Alzheimer s work with g protein coupled receptors and point to point transmitters multiple acety choline receptors discovered through drugs hence the name 0 nicotinic transmitter gated ion channels point to point communication 0 muscarininc gprotein coupled receptors diffuse modulatory communication metabolized by Ach esterase AChE enzyme curare drug that comes from plant gets into body and binds to acety choline receptors and blocks it 0 pa ralyzes person 0 snake venoms work in a similar way black widow venom constant release of acetyl choline l depletion of AC I trouble breathing and moving botuinum toxin blocks release insecticides blocks breakdown of transmitter agonist sarin nerve gas weapon of mass destruction 0 Blocks enzyme inhibits breakdown 0 Used by Nazis and afghans Bioamines monoamines NT Derived from amino acids AA precursor that gets chemically altered Diffuse modulatory systems in the brain 0 Modulate activity of brain in whole sail fashion Work with gprotein coupled receptors l changing metabolisms Two classes 0 A Catecholamines All derived from tyrosine enzyme tyrosine hydrocsolace transforms it to dopa precursor l dopamine via dopa decarboxylase Dopamine found in mid brain a 3 pathways 0 1Nigral striatal bundle origin and ending name system motor control 0 neurons die and deteriorate during parkinons disease l akinesia lack of movement 0 2 Mesolimbic o originate in ventral tegmental area 0 reward or pleasure system in brain 0 3 Mesocortical pathway 0 originate in ventral tegmental area o nucleus accumbens o reward or pleasure system in brain Five classes of dopamine receptors D1 D2 D3 D5 Amphetamines stimulate the release of dopamine and inhibits reuptake Cocaine blocks reuptake of dopamine metabolized in 20 minutes a Stimulating the pleasurereward systems explains addiction Enzymes MAO COMT Thorazinem chloropromozine terminates psychotic episode blocks Dopamine receptors I Became antipsychotic drug aka neuroleptic drug a Bad side effects motor problems tardive dyskinesias Designer drugs chemically altered drugs legal n MPTP kills dopamine neurons Advanced parkinson s disease 0 B lndoleamines 2513 dopamine neuron with the addition of one enzyme is transformed into norepinephrine neuron gene for that enzyme is turned on norepinephrine noradrenaline in united kingdom works through the diffuse modulatory connections 0 cell bodies found in locus coeruleus increases activity of nerve cells able to process more quickly 0 system works with gcoupled proteins 0 involved with sympathetic nervous system 0 multiple receptors 0 alpha receptors 0 beta receptors MAO and COMT enzymes that inactivates metabolizes norepinephrine o Amphetamines stimulates release inhibits reuptake o MAO inhibitors inhibits MAO agonist 0 Also works on dopamine and serotonin o Tricyclics elavil tofranil block reuptake of norepinephrine and serotonin o Realize norepinephrine and serotonin deal with people s moods Beta blockers blocks action of sympathetic nervous system in heart l lowers blood pressure Another catecholamine If there is another ezyme present norepinephrine l epinephrine Epinephrine is not major NT in brain and spinal chord Produces by adrenal gland and released into blood stream lndoleamines o Tryptophan l 5 htp l 5 HT serotonin Nuclei of Serotonin known of raphe nuclei Constrains activity of other circuits in the brain at high levels When serotonin levels lower those circuits have chance to work 0 l Aggressive hostile irritable angry behavior agitated depression SSRI s selective serotonin reuptake inhibitor work speci cally on serontonin o Prozac was rst then Zoloft paxil celexa o Serotonin is left in synapse keeping other circuits in control 0 Can be used to treat terrets 0 Can make people manic and cause suicide Gprotein coupled receptors Metabolized by MAO and HIOMT LSD psychotropic effect works on serotonin synapses Retrodrade messenders Moves backwards from dendrite to axon terminal Feedback and in uence the cell Blood vessels create gaseous molecule that can penetrate cell 0 NO nitric oxide Metabolized in seconds hard to discover Chemical structure similar to carbon Monoxide 0 Calcium comes in when cell is excited and activates enzyme NO synthase 0 Can lead to greater release of NT or produce proteins Strengthens the synapse and neuron V Neuromodulators Neuropeptides Brain produces hundreds of peptides coreeased with NT Mechanism of action isn t quite the same as NT Endorphins example of class of neuropeptides 0 Short for Endogenous morphine considered an opiate o Opiates produce analgesia pain relief 0 Morphine chemical synthesis from poppy seed pain reliever Civil war morphine addiction Search for chemicals that provide analgesia without addiction Bayer co produces heroin claiming it to be non addictive lnferred that there must be opiod receptors in the body for these drugs to be binding to o Radioactive tracer Bound to brain and spinal chord Pain and limbic system fear and anxiety Alleviates emotional component of pain Suggests we must have chemicals in body that work just like morphine Enkephains 5 amino acid peptides were the endogenous opiates Endorphins another group of aa peptides 0 Now together endorphins and enkephalins are collectively called endorphins Presynaptic synapse occurs between axon terminal and another axon terminal 0 Changes behavior of cell s messages sent into the synapse o Able to block pain by inhibiting pain pathway Presynaptic inhibition Hormones Pituitary gand releases hormones into blood stream for whole body Hypothalamus controls the pituitary gland Infundibulum ong stalk that connects hypothalamus to pituitary gland Anterior pituitary adenohypophysis o Neurons at bottom of hypothalamus produces peptides caed releasing factors 0 Capillaries travel down infundibulum and enter anterior pituitary 0 Portal blood supply the circuit between anterior pituitart and hypothalamus o Signals release of anterior pituitary hormones travel through body and nd their target Posterior pituitary neurohypophysis 0 Up in hypothalamus there are huge cell bodies which secrete hormones Transported through the axons through infundibulum and enter posterior pituitary then enters blood stream 0 Called neurohypophysis because it uses neurons Negative feedback system ne balances the hormones in body o Hypothalamus and pituitary get signals and determine the levels of hormones currently in blood Adrenal cortex adrenal cortex and adrenal medulla o aCTH works on cortex glucocorticoids o suppress in ammation 0 produce glucose aldosterone works on kidneys Regulates sodium and potassium o thyroxine works on cell metabolism 0 higher level higher metabolism 2713 2 ways that hormones can work 0 1 Peptides amines 2nCI messanger system 0 change internal biochemistry of cell 0 bind to receptor on surface of cell Results in activation of g protein coupled receptor this actives an enzyme ademylate cyclase in cell which produces camp which sends signals throughout cell 0 2 Steroids o steroid binds enters cell and stimulates protein synthesis being lipid soluble allows this to happen 0 takes time to get across membrane reach nucleus and perform protein synthesis steroid hormones are the slowest hormones are means of communication entirely different from nervous system 0 some fundamental differences evolved together and interact o hormones can feedback to the brain and tell it what to do advantageous to have both ways of communication in the body Wiring the Brain Developmental Neurobiology Speci city is best understood by studying development of system 0 How they acquire their identity 0 How they make these precise and speci c connections 0 Most is speci ed by genetic instruction predestination Environmental factors in uence the development also Blastula into three layers 0 Endoderm l internal organs guts o Mesoderm l skeleton bones and muscles 0 Ectoderm l skin and nervous system Blastula attens out and becomes neural plate forms a groove then a hollow tube of ectoderm l neural tube 0 Brain and spinal chord form from neural tube 0 Neural crest gives rise to peripheral nervous system 0 3 swellings form at rostral end of tube 3 vesicles I lst 2 d mid brain 3rOI hind brain development of neurons 0 brain made up of two zones 0 ventricular and marginal zone towards the surface 0 undifferentiated cells extend an arm to marginal zone and nucleus climbs up arm into marginal zone these are the stem cells once it gets to certain position it signals cell to replicate its DNA retracts its arm signaling cell to divide l newly born daughter cell daughter cell moves away to its target destination daughter cells receive chemical signals which program cell to determine what the cell is going to be 0 chemical environment is constantly changing The fate of the cell depends on what time its born 0 cortex is built from inside out 0 early cells born grow and then the next cells form above that and then the next above those etc etc proliferation birth and creation of cells above process Movement Daughter cells wrap around scaffold created by radial glial cells and slither up the pole 0 Once it reaches destination glial cell retracts its pole Differentiation become speci c type of cell Daughter cell reaches particular destination o Sprouts little arm type things called neurites o More form and lead to a differentiated neuron Daughter cell not dependant upon chemical signals once it reaches its de nition 0 Determined by chem Signals right when its born Genesis of Connections pathway development Axon elongation At the tip of every neurite there is a structure called the growth cone It is specialized to help pull growing neuron along and elongate itself Membrance called the lamellipodia is constantly oscillating and moving along 0 Filopodia spikes extend out and grab and anchor onto surface to help pull it along 0 Grabs onto extracellular matrix to pull themselves forward 0 Can secrete protease to thin out extracellular matrix when it sometimes gets too thick Pathway selection l target selection l address selection Speci ed by cell to cell interactions 0 Direct cell to cell contact 0 Cells and cell secretions Molecules embedded in extracellular matrix that act as guide post these are called lamnins 0 Not all lamnins are attractive some are repellant o On the growth cone there are lntegrins which stick to lamnins o Lamnin s locations kind of act like road map determining where axons grow 0 Cell adhesion molecules cams glue the axons together so that they grow together Chemoaffinity hypothesis chemicals determine pathways and development of brain 0 Not everyone believed it Sperry o Rotated frogs eyes 180 degrees and allow frog to recover and have connections form Eye was upside down but connections went back to the same location Saw up as down and down as up 0 Proved that growing connections are making very speci c connections and determined by chemicals NEtrins chemical signal diffusible molecules that retract or attract growing molecules Once axon reaches its destination it stops growing Now you must form synapse Stops growing and produces protein agrin Binds to agrin receptors on target cell 0 Tells cell to start making NT receptors 0 Target cell sends retrograde message to other cell l opening of Ca channels Causes growth cone to collapse becomes axon terminal Now cell gets signal to start producing NT 0 And thus we have a functional synaptic terminal Elimination of extra cells and synapses Brain creates way too many cells and forms too many connections Need to get rid of some natural occurring cell death Neurons compete for life sustaining molecules trophic factors 0 Nerve growth factor NGF o Collectively they are known as neurotrophins When cells don t get trophic factors apoptosis occurs o This is the pruning process Activitydependent synaptic rearrangement Change the wiring pattern through experience important during critical periods or windows of time when the brain is very plastic Hubel and Weisel studied visual system Ocular dominance columns Took kittens and put opaque lens on one eye blocking light went in and looked at ocular dominance columns 0 Columns of closed eye shrink and columns of open eye expand 0 Only makes a difference during the rst 6 weeks of life Has window of opportunity only during the rst 6 weeks 0 Critical periods need to have a cut off in order to have specialization and memory and stability 0 How can we induce critical periods to help repair the brain 0 Stem cells will form totally different things than they would have when they were a fetus because the chemical environment is different
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