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Psychology 425 Dr. McCabe Study Guide Attention & Selective Perception I. Relationship of attention and sensory encoding/perception constantly bombarded by sensory information that gets transduced. We can simultaneously encode many things, we need to focus on something specific to process it better. We tend to pay attention to things that are important, new, possibly dangerous. Attention can be involuntary, a reflex driven by external stimuli. Attention can be voluntary, choose what you want to attend to. You can attend to mental processes, not only sensory information. II. Global states of consciousness vs. selective attention Selective attention is for a single stimulus. Global states of awareness, reticular formation is involved in regulating arousal making yourself attentive or drowsy or asleep. A. Arousal global states of brain. B. Cocktail party phenomenon selective attention, you walk in and stand in one place and even though noise is all coming at you, you can selectively tune in to one conversation. C. Broadbent modellimited capacity system Donald Broadbent started thinking about selective attention and how it happens. He hypothesized that the brain is a limited capacity system, only process a certain amount of info at a time. We receive sensory stimuli, hits nervous system, encoded and registered and enter. At some point there us a gate or filter, which only lets some through. What controls gate? There are higher level parts of brain that analyze incoming info and through executive process controls gate. Attention is about filtering unwanted information. Can gate information right after it enters nervous system, you don’t want to waste energy on it early selection. Consequence is that info does not get fully perceived, so perception of world can change. You can let all info pass go through sensory system and fully perceived and then decide what to continue to focus on and what to ignore late selection, does not affect perception of world. Both are used. III. Early vs late selection late selection would be conscious decisions of what we want to pay attention to and not. Both assume that performance suffers when there is high information load. A limited capacity system. Make errors when there is high information mode. IV.Involuntary vs voluntary attention attention can be involuntary, A. Orienting responseinferior and superior colliculi orienting reflex hardwired, when faced with stimuli, usually important, brain stem automatically controls behavior and turns body and head, dilates pupils and puts in contact with stimulus. “What is it?”. Novel stimulus that may be important. This information feeds into the Tectum the inferior and superior colliculi and control muscles in core of body to track stimulus. B. Voluntary attentionsearchlight analogy Can choose what to attend to. Choose a spatial location to attend to. V. Brain mechanisms in attention and selective perception attention is likely to involve many nerve cells working at once. A. Electroencephalogram (EEG) used to study attention, advantages: can be done in humans, non invasive technique, put electrode on scalp and that picks up signals from brain. Pick up field potentials being generated by millions of nerve cells. Recording as it is happening. Synchronous activity, record summation, you end up with a smooth sine wave. Can get situations where nerve cells are dysynchronous >25 Hz, alert, beta activity. Can look at spontaneous activity sine waves at 814 Hz is known as alpha activity, relaxed, drowsy, inattentive brain. Going to sleep get more activity at slower wavelengths in 47 Hz range, theta activity. When person is in deep sleep usually <1 Hz, delta activity. Can also get beta activity during sleep, paradoxical sleep or REM, which is characteristic of dreaming. B. Evoked potentials (Eventrelated potentialsERPs) look at response of brain to stimulus. Present a stimulus and record EEG. Problem: EEG gives activity of millions of nerve cells, when given stimulus, only a portion of those nerve cells are responding to the stimulus, need to find the response in all of the noise (not interested in). Take multiple recordings to find the response to the stimulus. Over multiple trials, the randomness or noise will be zeroed out and the stimulus will still be there. With this approach, study neurobiology of attention. C. Visual ERPs and attentionextrastriate cortex positive going wave is first wave, P1 component. Then you get a negative N1, next positive is P2 etc. When you see something it takes 70 ms to get processed. Use this to study visual attention. Person loks at dot in middle of screen. Info sent to visual cortex. Stimulus to left visual field is sent to right brain, put recording electrode on right side. Experiment: Tell person whi is staring at dot to focus attention to the left, look at dot still but focus attentin to left field. You will get large P1 component, directing attention towards stimulus enhanes the evoke potential. Show same stimulus on left visual field but attend to the right. P1 component will be half of what it was before. Response is less because you are attending away from stimulus. Stimulus is being filtered. i. Early selectiondescending filtering mechanisms info from optic nerve to LGN in thalamus, to the primary visual cortex V1 and then to V2 and V3 (areas 18 and 19) and from there up the dorsal stream to posterior parietal lobe or ventral stream to inferior temporal lobe. Filter analyzing info appears to be in areas 18 and 19. Case of early selection because info is not fully perceived. After neurons analyze info, learning goes on, neurons from cortex can send descending info back to thalamus. ii. Reticular nucleus of the thalamus descending connections to the reticular nucleus in the thalamus. Reticular nucleus is only nucleus that DOES NOT project TO cortex. Receives input FROM cortex. Within it are nerve cells that project into other thalamic nuclei and these are gabanergic neurons (release GABA) inhibition. Inhibit cells in lateral geniculate, a huge filter of incoming visual info. Really early selection. D. Modulation of visual cortex by other cortical regions visual info to area 18 and 19 and then fully perceived after going through dorsal and ventral. Posterior parietal perceives space. Posterior parietal is involved in spatially shifting attention. i. late selectionfrontal and parietal influences (dorsal stream) Posterior parietal and pre frontal cortex project to thalamus where they project to the pulvinar thalamic nucleus. This then projects to visual cortex and can filter information but allow other info to pass. Thalamic cortical interaction is crucial for attention. E. Attention as a distributed processSupervisory Attentional System wherever there are neurons filtering, there is attention. Different parts of brain are doing this. It is a distributed process. Many attention systems in brain. Must be some source of executive overseeing everything that goes on in organism to regulate attention, Executive attention or supervisory attentional system. If organism is asked to do a task, there needs to be a process that says ok lets focus on this. The Anterior singulate cortex is paleocortex that is associated with limbic system. It connects to many other brain regions, if you record from here it seems like it monitors organisms performance. When you make errors it lights up. Shift attentional resources to different systems. A lot of developmental disorders, ADHD, problem with executive attention; autism, social cognition and attentional disorder, etc. VI.Neurological damage and attention study attention on people with brain injuries. Area of brain that gets injured a lot is the parietal lobe. A. Posterior parietal lobe (asymmetry) easily injured, develop agnosias, perception. Something else that can happen: right parietal lobe damage is that they develop the neglect syndrome not a sensory problem, the do everything on right side (put pants on right side, eat right side of plate, draw right side of image, etc. They can see everything fine, not due to sensory coding or perception, it is an attentional problem, not attending to left part of world. Posterior parietal lobe is involved in attention in spatial world. B. Sensation/perception vs imageryItalian experiments working with patients with right parietal lobe damage. Task: walking into plaza, close eyes and imagine walking into it from the south, tell me what you see. They describe buildings on east but nothing on west. Ask them what they see when they walk in from the north, they describe everything in the west but not east. Ignore what is on the left. They know both sides but the brain chooses to ignore it. Psychology 425 Dr. McCabe Study Guide 4) Neurochemistry I. Synaptic Transmission chemical can be controlled better, adapt and change as a function of experience, malleability, plasticity. Chemical replaced electrical in most ways. A. Synapse First thing to happen, pres must produce a chemical which will be released and bind to posts. NT are generally synthesized in cell body of pres cell. Transported to synaptic cleft, one it reaches axon terminal, it is stored in membrane covered sacs, vesicles. Have membrane to protect from enzymes that can eliminate or modify NT. Cell waits for something to happen. Cell fires action potential, travels down axon and reaches terminal and depolarizes the membrane, opening up the Ca channels. Vesicles move to cell membrane, they are snared by snare proteins to membrane and fuses with cell membrane to release NT. If Ca is depleted, not present, you will not get synaptic transmission B. Presynaptic cell C. Postsynaptic cell D. Neurotransmitter E. Synaptic mechanisms i. Transmitter synthesized ii. Transmitter stored in vesicles iii. Ca++ influxvesicle movement iv. Transmitter diffuses across cleft NT travels by diffusion high to low concentration. Rate limiting step is this diffusion of NT. a. autoreceptorsfeedback mechanism some NT drifts over and binds to pre synaptic cell, feedback to tell cell how much NT is out there. If producing too much, it can trigger cell signal pathway to shutdown production of NT. Some drugs work on autoreceptors and make false feedback. v. Transmitterreceptor binding NT reaches posts cell. On surface there are large protein complexes, receptors. Large proteins that span membrane and NT comes in contact, binds like lock and key. Action of NT is determined by receptor molecule. a. Transmittergated ion channels receptor is an ion channel. with either Cl or K movement (Cl coming in of K going out), produce IPSP, inhibit cell from firing. With Na you depolarize so EPSP. Very quick response. b. EPSPs and IPSPs c. Gproteincoupled receptors different mechanism of action. NT binds to g protein, can be coupled to ion channel and open it up and cause ions to move through and produce EPSP or IPSP. Other way, they can couple to an enzyme inside the cell and when enzyme is activated it causes a chemical to be converted to another. NT is the first messenger, new molecule produced inside cell is the second messenger. NT is not changing potential it is a message to activate an enzyme. cAMP when produced changes how cell works. Metabotropic actions, working through second messenger system. vi. Transmitter breaks off receptor need to release so next message can come along. After NT exerts effect, it drifts off, how to get rid? vii. Transmitter inactivation a. enzyme degradation there are also enzymes in synaptic cleft, they attach to the NT and degrade it. Cleave it or attach molecules to inactivate. Enzyme cant inactivate neurotransmitter that fast. b. diffusion away simply diffuses away, extracellular fluid takes it to low concentration areas. c. reuptake by presynaptic cell most efficient. Using Nt again by taking it up and storing in vesicles. Process, a lot of drugs target this. SSRI’s target this process, serotonin reuptake inhibitor, leave more serotonin in cleft and let it bind to posts. Cocaine works on reuptake. F.Characteristics of receptors determine the response if you are constantly stimulating receptors on posts cell, this cell will down regulate number of receptors, pulls receptors in and can metabolize them. Or if not stimulated enough, it will up regulate, produce more receptors. each NT can have different actions. End result is not due much to NT but characteristics of receptor G. One neurotransmitter per neuron (Dale's Law) for any neuron there is a single NT. For most part he is right, for classic NT, generally only one is found per nerve cell. In last 25 years, hundreds of other molecules found to be released by neurons: neuropeptides. Many molecules are co released with NT and are as important. Neuromodulators, modulate how synapses work Point to point discreet message for a number of cells Broadcast communicaton Communicate with many cells at same time, neuron secretes chemical to bloodstream, this is taken through body and access many cells. Endocrine system Diffuse modulatory systems many cells that branch and contact many cells, can regulate excitability of nerve cells in brain. Necessary for emotional state, fight or flight, higher brain functions. II. Drugs treat psychopathology, modify the systems. Neuropharmacology. Most drugs affect the synapse, exogenous substance, not normally found in body, produced elsewhere, plant, lab. Has to cross blood brain barrier to affect synapses and affect how they work. A. Agonists enhance or mimicks action of NT, facilitates synapse. i. Gets into a synapse and stimulates release of NT ii. Binds to the receptor and activates it, drug has similar chemical structure as NT. iii. Block reuptake iv. Drug can inhibit the enzyme that metabolizes the NT B. Antagonists oppose or block the action of a neurotransmitter. i. Blocks release of NT ii. Binds to the receptor and blocks it iii. Interfere with the synthesis or storage of NT III.Neurotransmitterscommunication in the nervous system A. Amino Acid Transmitters work through transmitter gated ion channels, discreet, localized and quick. Vast majority of synapses in nervous system. i. GABA gama amino buteric acid drugs that bind to receptor and make receptor more susceptible to GABA, allosteric modulator of the receptor, Agonist, increase inibition. ii. Glycine Both GABA and Glycine: Wherever they are found they have inhibitory actions. They hyperpolarize, they bind to receptors that open up Cl or K channels. Over ½ of synapses are these. If we have a chain of inhibition, but the first cell can release the inhibition by being inhibition firing and lead to excitation. Drugs that are sedatives, and drugs that reduce anxiety iii. Glutamateactivity dependent receptors (NMDA) excitatory, binds to receptors that open up sodium channels. Discovered that when it is released in large quantities, it is toxic, kills nerve cells. When brain is injured, stroke, infection, or progressive degenerative disease, glutamate is released from neurons and glial cells and this excites nerve cells to death. Why has this mechanism evolved? during development, when brain is growing, you produce way more nerve cells and synapses than you need, through development and growth there is a scaling of neurons, pruning, to get rid of extras. Glutamate is a natural mechanism that gets activated when brain gets injured, then backfires and kills brain. Other reason it is interesting is due to its receptors. There are different classes of receptors that bind to glutamate, they also bind to drugs specific to them. a. NMDA receptor drug that binds to receptors and activates them. Glutamate is released and binds to receptors. When it binds to nonNMDA, it opens channel and allows Na to enter, depolarizes. Glutamate binds to NMDA, but when it binds, ions do not flow because channel is blocked by MG . For ions to pass, it needs AMDA to sufficiently excite the membrane for Mg to exit NMDA and open NMDA and let Na through and then also Ca through to cell. NMDA receptor is activity dependent receptor. Receptor used when cell becomes excited. b. AMDA and kainate non NMDA receptors. B. AcetylcholineACh not related to aminoacid, first to be identified. At neuromuscular junction, b/w motor neurons and muscles in body. Also found in brain, neurons found in clusters, one in midbrain, goes to thalamus, one of the diffused modulatory systems. Two clusters, one in septal nucleus and another in the base of forebrain. Neurons work through point to point and through transmitter gated ion channels, others are diffues modulatory projections through Gprotein coupled receptors. Works in different ways, there are multiple receptors. i. Nicotinic binds to nicotine, use it to identify these receptors. Transmitter gated ion channels. ii. Muscarin binds to muscarine (from plants) as well. G protein coupled receptors. a. ACh metabolized by AChE (Esterase), sits in synapse and gobbles it up. Drugs that work on ACh synapses: Curare comes from plant, binds to receptors and blocks them, antagonist. Shuts down NT between motor neurons and muscles, paralyzes. Snake venoms, binds to nicotinic receptors, kill somebody quickly. Black widow venom causes continuous release of ACh, agonist, ultimately ACh is depleted. Botulinum toxin, Botox, blocks release of ACh, antagonist. Insecticides contain drugs called collenesterase inhibitors, inhibit AChE, agonist, leave more ACh in synapse so overexcite cells and kilss insects. C. Bioamines monoamines NT derived from aminoacids, aa is precursor and through enzymatic steps converted to these. All work through Gprotein coupled receptors and all are diffuse modulatory systems, small clusters of nerve cells that send axons to brain and branch and make contact with throusands of other cells. i. Catecholamines All are derived from same amino acid, know enzymes involved. All are derived from tyrosine, taken to brain and within nerve cells, Tyrosine Hydroxylase converts them to Dopa. Dopa is not a NT, it is a precursor. Dopa decarboxylase causes Dopa Dopamine. a. Dopamine found in specific pathways in brain, 3 major pathways. All dopamine neurons exist in the midbrain in clusters. First originates in Substantia Nigra, send axons to basal ganglia (striatum) nigral striatal bundle. One bundle to limbic system and another to frontal lobe Mesolimbic and mesocortical pathways. Pleasure and reward system. Cocaine activates dopamine synapses, may be directly stimulating reward pathways. Dopamine with enzymes MAO and Comt inactivate dopamine. Amphetamine causes release of dopamine and also inhibits reuptake, potent Agonist. Designer drugs FDA classifies drugs based on structure. People began modifying them, i.e. ecstasy, 1982 in SF, people started showing up in hospitals with Parkinson’s disease, severe motor disorders, tremors. They had all taken a designer drug produced there. Analyzed it, it was MPTP, highly toxic in small quantities, killed dopamine neurons. b. Norepinephrine If dopamine beta hyroxylase is present, Dopaminenorepinephrine/noradrenaline Nt within sympathetic NS, found extensively in brain, diffuse modulatory systems, bundle in Locus Coeruleus. This system is thought of be helping make forebrain more responsive to salient stimuli. Can have different actions whether it activates alpha or beta receptors. Amphetamine is also an agonist, in a lot of different synapses, jacks up activity. Some drugs inhibit action of MAO, in treatment of depressions, MAO inhibitor was one of the first developed, leaves more Norepinephrine in synapse and moods improved. Tricyclics inhibit reuptake of Norepinephrine and serotonin. Aderall is used to improve attention. Stimulates, enhances release of norepinephrine and improves attention in people. Can become drug of abuse. c. Epinephrine if the cell contains one additional enzyme then norepineprine is converted to epinephrine. Epinephrine=adrenaline in UK. Adrenaline is not a major NT. Produced by adrenal gland, released into bloodtstream more as hormone than NT. ii. Indoleamines a. Serotonin synthesized from Tryptophan. Converted by tryptophan hydroxylase to 5HTP, then converted by 5HTP carboxylase into serotonin (5HT). Serotonin is one of the NT involved in diffuse modulatory projections. The neurons that produce serotonin are found in clusters in brain stem, medulla, pons, etc. Nuclei with cell bodies are Raphe nuclei. Send axons all through brain and modulate activity of other nerve cells. Believed to constrain activity of other circuits, when it malfunctions, loose constraint and other behaviors manifest themselves. Example: impulsivity, emotional behavior, hostility, aggression, irritability. Metabolized by 2 enzymes, MAO (if you inhibit MAO there will be more serotonin, dopamine and norepinephrine because they are not metabolized) and by HIOMT. Tricyclics are drugs that inhibit reuptake of norepinephrine and serotonin, so they become more available for synapse, they are agonists, effective in treatment of depression. SSRI (selective serotonin reuptake inhibitor) specific to serotonin, inhibit reuptake, first developed was Prozac. Can lead to hypomania, not perfect but they are used a lot. New set of SSRI: Zoloft, Paxil, Celexa… Tourrets syndrome problem with impulse control. LSD is a hallucinogen synthesized in a lab, affects serotonirgic neurons in brain, mimics positive symptoms of schizophrenia. LSD can have agonist effect or antagonist depending on where it binds. Serotonin has been implicated in sleep. IV.Retrograde messengers dendrite back to axon as feedback signal, this came about because people who were studying glutamate synapse, axon terminal acted as it knew what dendrite was doing. People looked at blood vessels, they release chemicals that cause vessels to relax. Released NO, nitric oxide, a gas produced by cells in body, easily passes through membranes and quickly metabolized. Wondered if this existed in brain, when glutamate is released and binds to receptors, when NMDA activated, sodium and calcium come in, when Ca enters dendrite, it stimulates nitric oxide synthase which produces NO. When cell is stimulated by glutamate, calcium stimulates production of NO, which leaves and enters previous axon terminal and stimulates to release more: stronger synapse. CO is similar to NO. V. Neuropeptides/Neuromodulators large role in brain regulation. Short chains of amino acids produced in spinal cord, packaged and coreleased with NT. These don’t work like true NT, instead they modify the way synapses work. Can do presynaptic inhibition. A. Endorphins endogenous morphine, molecules found in body and act like morphine, an opiate, similar to opium. Relive pain, analgesia. Morphine is used as analgesic. Highly addictive, treating pain created an addiction in veterans of the civil war. Bayer company in 1890 came up with heroin thinking it wasn’t addictive. 1940s came Demerol, synthetic opiate, addictive as well. i. Opiates ii. Opiate Receptors opium and morphine and heroin bind to, to create these effects. Injected with readioactively labeled and saw they bound to specific targets, in the gut, reproductive organs, most importantly in nervous systen, spinal cord and brain stem in pathways involved in pain perception and in limbic system (fear system). Opiates go to limbic system and shut down feelings of fear and anxiety and alleviate pain by affecting neurons involved in pain perception. Body must be producing chemicals that work just like opiates, must be an endorphin produced in body, that’s why ther are receptors for these molecules. iii. Endogenous Opiates a. Enkephalins 5 amino acid peptide molecules that were found in brain that bound to opiae receptors and acted like heroin and morphine. b. Endorphins broad term for small peptides B. Mechanism of action of Neuromodulators pain is good but then you want to get rid of it, have mechanisms with these molecules to get rid of pain. C. Functions of Endorphins some are found in neurons, neuropeptides released by neurons. In pituitary gland there is a long peptide: betalipotropin, it has small segments with exact sequence as endorphins. In pituitary gland, this peptide is cleaved into smaller chunks which become endorphins. Substance found not only in brain but also dumped in bloodstream as hormones, can affect tissue around body. Psychology 425 Dr. McCabe Study Guide 2) Neuroanatomy General Issues PPT A. Planes 1. Saggital 2. Coronal 3. Horizontal B. Directions 1. medial vs lateral 2. anterior (rostral) vs posterior (caudal) 3. dorsal vs ventral A Horizontal B Coronal C Saggital Dorsal is towards the back or on top Ventral is forward or bottom Since we stand up, nervous system takes a turn and on brain: ventral is in bottom and dorsal on top. On Spinal cord: dorsal is on back and ventral on belly. Anterior vs Posterior •Anterior is front (Rostral towards the nose higher levels of spinal cord) •Posterior is back (Caudal towards the tail spinal cord close to tail) Organization of Nervous System Neurons on top of brain are ultimately connected to tip of toe. Historically it is into divisions, central and peripheral I. Peripheral Nervous System made up of somatic and autonomic A. Somatic Nervous System from spinal cord into skin, muscles and tendons of body, somatic part of body. Consists of nerves that connect to spinal cord. 31 pairs of spinal nerves that start at base of brain into lower back. These nerves contain sensory neurons and motor neurons, sensory innervate skin and muscles and joints and convey info about touch, pain temperature. The motor neurons are those that come out of spinal cord toward muscles and activate skeletal muscles, contraction. Each spinal nerve is responsible for certain part of body. Portion of body by a nerve is called a Dermatome. Order in spine is: Cervical, Thoracic, Lumbar and Sacral. (8,12,5,5). Muscle by a single nerve is a Myotome. Dermatome and myotome usually line up, they overlap, don’t want sensory or motor loss, don’t want dead areas. i. Sensory neurons (dorsal root, dorsal horn) Grey matter has cell bodies, dendrites and unmyelated axons. White matter has myelated axons. Myelin is fatty covering over axons. Myelinated axons conduct faster. The myleinated axons are conduits, cables that carry info long distances, but grey matter is where connections are made. Gray matter is in the middle of spine, while white matter is in the outside. Spinal nerves come in from the sides, they branch and forms to branches, one of them goes to the dorsal cord (this branch is the dorsal root) The dorsal root carries the sensory neurons, purely sensory information, this goes into spinal cord, enters the grey matter in dorsal horn (grey matter). These neurons can make a synapse or bypass, dive into white matter and ascend into brain directly to sensory structures. Dorsal root has a swelling, this is where cell bodies lie Dorsal root ganglion cluster of nerve cell bodies. ii. Motor neurons (ventral horn, ventral root) Ventral horn, this is where cell bodies of motor neurons are located. Motor neuron sends axon out through ventral root out to muscles. Ventral horn and root are purely motor. If you were to pinch a sensory dorsal root, there will be numbness but no problem moving. iii. Interneurons connect sensory and motor neurons. Travels to ventral horn of grey matter. iv. Reflex arc sensory element, interneuron and motor element, basic organization for behavior of body. This organization has another name: Reflex arc. Body is desgined to have reflexes, unlearned behavior. When sensory neuron is activated, produces motor response. B. Autonomic Nervous System (pre, postganglionic cells) nerves in organs of body, viscera or guts. Sympathetic and Parasympathetic fight for control for organs, have antagonistic relationship, net result is due to balance of both. Neurons in body that innervate visceral organs, eyes and salivary glans. Features common to both: both are considered to be output only, motor systems. Organs in body do have sensory innervations but that is separate. Second, both are made up of 2 neuron chains, the first neuron originates in spinal cord, and then there is a ganglion where synapses occurs, the second neuron goes to target organ through synapses. The first neuron is the preganglionic cell, the second is the postganglionic cell. (SO IS IT 1 NEURON TOWARDS THE GANGLION?) i. Sympathetic system (fight or flight) physiological excitation, ready for action, hearts pumps faster and more forcefully, blood vessels dilate, breathe faster, pupils dilate. Originates anatomically in spinal cord. Originate in middle of spinal cord, the thoracic and lumbar segments, between these is an elongated nucleus structure where the cell bodies for first neurons originate, in the Intermediolateral cell column (IML), preganglionic neurons. These project out of spinal cord and line through the ventral root into spinal nerve and (near spinal cord there is a structure which is a chain of ganglia, known as the sympathetic chain (paravertebral chain)) it goes through the sympathetic chain to a second neuron which goes out to target organ. Purpose of this chain of ganglia is to have a widespread effect. Inhalors for asthma have sympathetic like drugs that open up airways. Adrenal Gland is given direct innervation by a pre ganglionic nerve, adrenaline is then released into bloodstream, part of synmpathetic response. Pre ganglionic axons are myelinated, post ganglionic axons are unmyelinated. Preg axons synapse in sympatehtic chain near the spinal cord so these are short, the postg are pretty long, so the movement of info is pretty slow towards organs. a. intermediolateral nucleus b. thoracic and lumbar c. paravertebral chain d. adrenergic system there are different neurotransmitters involved in synapses in the system. The primary NT in preg is Acetylcholine (ACh), at postg it is Norepinephrine (NE) or Noradrenaline, so the system is known as Adronergic system. You can manipulate the system by affecting these NT. Give drug that blocks action of norepinephrine (beta blocker) at heart if heart beats to hard/fast. Epinephrine is produced in adrenal medulla, hormone. Norepinephrine is produced in neurons and used as NT, also can travel as hormone in bloodstream. Can bind to same receptors but have different affinities. ii. Parasympathetic system innervates same organs but it has opposite effect to sympathetic. There is a constant battle between both. Output of organ depends on who wins. Nerves originate in brain stem/cranial and from sacral (bottom of spinal cord). There are cell bodies that originate in both places. These neurons project out of nervous system but do not pass through sympathetic chain, they travel all the way out to target organ and near it there are small ganglia, where there is a synapse and postg neuron is very short. This movement then is very fast because the preg are long and myelinated and the postg are short and unmyelinated. Most important part originates in brain stem, the nerve is one of the cranial nerves, also known as the Vagus nerve, it branches and wanders through body and innervates all kinds of organs. The synapse b/w pre and post ganglionic use acetylcholine as NT. At post g it uses the same. For this reason, this system is known as cholinergic system. Use drugs to manipulate as well. Atropine is used to block this system so eye will dilate. a. cranial and sacral b. cholinergic system Neuroanatomy (Continued) Central Nervous system II. Spinal Cord sits within bony structure, the vertebrae, 31 bones separated by a cushion, disks that can compress and rotate. The cord is not very big, a half inch wide. Spinal cord has membranes covering it, the meninges, if these become infected or inflamed, develop Meningitis. Big thick white fibrous membrane, Dura mater. The core is bathed in cerebral spinal fluid. Spinal cord is shorter than vertebrae, it ends in lower middle back but the nerves travel down to correct vertebrae and exit through there. First 8 are cervical, the next 12 are thoracic, 5 are lumbar, 5 Sacral and 1 coccygeal. A. Divisions B. Grey Matter vs White matter C. Spinal Damage common injuries, compression fractures can stretch spinal cord, have it stunned with temporary dysfunction. Also, can crush the spine and transect the spinal cord with serious problems. Type of injury depends on what kind of fracture and where. Break near neck, loose connection between brain and limbs. **whole in middle of spinal cord has fluid (central canal) which connects to cerebral wholes. Connections from one side of spine to the other LOOK AT PPT More gray matter in cervical and lumbar connections and integration of info from arms and legs III. Brain roughly size of 2 fists, roughly symmetrical, a lot of blood relative to size, mostly becase it requires a lot of oxygen and glucose to burn. 100 billion nerve cells in brain, complex. To simplify actions, major job is to interact with environment, gather sensory info, integrating and producing motor outflow. Brain is organized, areas fairly primitive shared with other animals, layers of tissue have formed on top. We have large mass of cerebral cortex which regulates inner regions. Encephalon in the head. 5 distinct regions: A. Myelencephalon lowest level of brain, the Medulla, continuous with spinal cord i. Medullavegetative adjacent or continuation of spinal curve, no clear separation. Functions are mostly vegetative functions. Its concerned with vital functions that keep organism alive, breathing regulation, regulation of heart and blood pressure, reflexes like swallowing. Damage to medulla is often fatal. Should be very well protected but medulla is out of the cranium so its just muscle and connective tissue, underneath that, a vulnerable spot is where medulla is situated. Medulla carry cable systems towards and away from brain. a. cranial nervesvagus nerve Also in medulla are the cranial nerves, these are analogous to spinal nerves. There are 12 pairs of cranial nerves from brain stem, one important one is the 10 nerve called Vagus nerve, primary component of parasympathetic nervous system. ii. Reticular Formation From medulla to thalamus is a web of neurons. It seems to contain cells and nuclei that play large role in arousal, sleep and dreaming. Regulating states of consciousness, how aroused is brain, alert and active. B. Metencephalon above the myelencepahlon, together they are the hind brain. Embryonic brain before it differentiates has a blump known as this. i. Ponsvegetativeabove medulla, bulb shape, a lot like the medulla in that most functions are vegetative, regulation of breathing, cardiovascular, sleep, etc. Kind of involuntary functions. Sensory and motor pathways also make way to and from brain. a. cranial nervesacoustic, trigeminal Important cranial nerves that come out of pons: 8 nerve is the acoustic vestibular nerve from inner ear, relays acoustic information and vestibular info, about balance. This nerve is purely sensory info into pons. Another nerve, the 7 nerve is the Facial nerve, this one exits the pons and innervates the muscles of face, purely motor nerve, stimulates muscles of face. Another nerve, the 5 nerve is the Trigeminal nerve. This one has 3 branches, one to region around upper face, other to middle, other lower. Two functions, provide sensory information from face and head and also innervates teeth. Other function is it has some motor fibers that innervate jaw, muscles used for chewing. ii. Cerebellumextrapyramidal system, looks like a little brain, but through looks like cauliflower. Primary function has to do with motor control, important for balance, posture, motor guidance, provides precise timing and sequencing information to the rest of the brain to allow movements to be fluid and continuous. When damaged, movements are not as coordinated. Ethanol affects cerebellum. Important for motor learning, motor skills. Wiring is the same in every species of animal. C. Mesencephalon Mes is middle. In animals without evolved higher brain, it is situated in the middle. i. Midbrain contains the same sensory and motor pathways. As does the reticular formation. Also contains sensory relay nuclei, cluster of nerve cells that receive sensory info and relay somewhere else in brain. a. Sensory relay nuclei Inferior Colliculus and Superior Colliculus together they are known as the Tectum. They relay info, superior is for vision and inferior is for audition. b. Red Nucleus and Substantia Nigra also in midbrain are motor nuclei. Nuclei involved in controlling motor functions. Red nucleus sends to control motor. Substantia looks black, motor nucleus but does not project into spinal cord, instead it projects upward to brain to a region called Basal ganglia to supply with neurotransmitter Dopamine, structure affected in parkinsons disease **Cranial nerves 3 nerve: Occulo motor nerve controls eye movement, 3 of the 12 cranial nerves are for eye movement. Mid to fore D. Diencephalon Di means two, made up of 2 structures. i. Thalamus two major functions a. Sensory relay nuclei gatekeeper to cortex. When info needs to get into cortex, it has to project to thalamus first, almost all senses project from outside into thalamus first and then processed and relayed to cortex i. Medial Geniculate sensory for audition, projects to temporal cortex. Lateral Geniculate sensory for vision, info from eye goes to this region, synapses, sends axons to cortex, occipital lobe. ii. Ventral Posterior Lateral (VPL) sensory info from body (touch, vibration, pressure, pain and temperature) and sends uo to thalamus, it has map of body and that info goes to area in parietal lobe in somatosensory cortex. And Medial Nuclei (VPM) receives input from senses of face and head. VPM gets info from trigeminal nerve. b. Intrinsic NucleiElectrocortical Arousal white or gray in pic on PPT. receive info from reticular formation, terminates in thalamus. This region, instead of projecting to discrete parts of cortex, it sends out huge projections to all cortex. Job os this system is to arouse the cerebral cortex. When faced with a task, cortex has to be involved, the system produces electrocortical arousal, to enhance speed of processing. ii. Hypothalamus hypo/ beneath the thalamus. Up through roof of mouth. Powerhouse of activity, involved in motivated behaviors. Regions with different functions. Interconnected to higher circuits, the limbic system, emotional behavior and learning and memory. a. Motivated Behaviors behaviors so important that you cannot leave them to chance, drive organisms behavior to accomplish these goals, eating, drinking, temperature rgulation (put on a sweater, eat food, etc). Sexual behavior, not critical for survival of individual but critical for survival of species. b. Hormonal FunctionPituitary Gland also involved in emotional behavior, rage, aggression. Activate region can elicit rage like behaviors. Neurons that seem to control autonomic system, regulating activity of organs of body and it is connected to the pituitary gland. The pituitary gland is the master gland of body b/c it secretes hormones that regulate other organs. The hypothalamus regulates the pituitary gland. These 4 are referred to as the brain stem th E. Telencephalon 5 level, contains following structures: i. Limbic System interconnected network of brain structures, as brain grows, these structrues form around ventricles of brain. a. Hypothalamus, Hippocampus, Amygdala, Septal Nuclei, Fornix (fiber bundle from hippocampus), Singulate cortex and entorhinal cortex and Olfactory System (smell) Smell is interconnected with structures for memory. Structures are interconnected. ii. Basal GangliaExtrapyramidal System cluster of nerve cells in brain. 3 major structures: Caudate Nucleus, Putamen (called Striatum together with caudate) , Globus Pallidus. Basal Ganglia are important in motor control. Interacts with cerebral cortex, regulate excitability of frontal lobe through circuits or loops that it has. People have always studied ganglia in terms of motor functions and disorders. If disregulated (parkinson’s) will show motor systems Akinesia, lack of movement, Postural abnormalities, rigivity and tremors. Also regulates frontal lobe in terms of cognitive functions. iii. Cerebral Cortex highest level of brain, highly evolved in humans. Allows to speak, reason, think, anticipate consequences of actions. Groove is a Sulcus, a ridge is a Gyrus. Big groove is a Fissure. The cortex is a sheet of cells, folded into itself. Two types of tissue: Paleocortex old, shared with other creatures. It has 4 or 5 cell layers. Associated with limbic system. We have Neocortex, new cortex. Has 6 cell layers. a. Occipital Lobe back of brain, visual cortex b. Temporal Lobe on the sides, auditory cortex and parts of olfactory. c. Parietal Lobe behind frontal, has a strip at the front, which is the somatosensory cortex, receive senses of body. d. Frontal Lobe Front half of brain, dtrip of cortex on the back known as motor cortex, cells that project into spinal cord originate here. Diencephalon and Telencephalon form Forebrain Major Pathways pathway that originates in motor in frontal lobe, axons project from motor cortex through brain into spinal cord. Known as the Corticospinal tract. Nerve cells with axons 23 ft long. Uninterrupted, end up going to the other side of body after the Pons. Pyramidal crossing, Pyramidal tract. Fibers dive into spinal cord and synapse with motor neurons in spinal cord. 1. Pyramidal System 2. Extrapyramidal System 3. Medial Forebrain Bundle CommissuresCorpus Callosum Pathways can also go sideways. Hemispheres are connected by pathways that go sideways Commisures, fiber bundles that interconnect two hemispheres, major one is corpus callosum VentriclesCerebrospinal Fluid fluid travels through brain, can draw off fluid to look for infections or signs of pathology. Blood Supply Brain is highly metabolic organ, needs a lot of blood flow. Supplied by 4 arteries: 1. 2 Carotid and 2 Vertebral Arteries Each artery goes to ¼ of brain, if one does not function loose function.. but, brain has evolved a network of arteries that makes a complete circle: 2. Circle of Willis allows the 4 arteries to send blood into brain, dumped in circle of willis so blood circulates and then goes into brain. When you loose one of the arteries, loose ¼ of blood flow but still have from the others. 3. Blood Brain Barrier at junction between brain tissue and blood vessels there is a barrier to protect the brain. Specialized cells that wrap around blood vessels and protects the brain from harmful chemicals. Hard for pharmacologists b/c it is hard to get stuff into brain. Parkinson’s patients need dopamine but dopamine doesn’t cross the barrier. Give pre cursor to dopamine which then is converted to dopamine inside brain. Psychology 425 Dr. McCabe Study Guide 5) Hormones I. Hormones release of hormones from endocrine glands and broadcast info through bloodstream. A. Hypothalamus sits above pituitary gland. Controls the pituitary gland in many ways. Connected by a long stalk called Infundibulum. B. Pituitary Gland mastergland of body, regulates all other glands, it is controlled by hypothalamus. Divided into 2 sections: anterior and posterior pituitary. Interact in different ways with hypothalamus. Anterior pituitary starts with cells in hypothalamus that produce peptides called Releasing Factors, secreted into capillaries and these go into anterior pituitary (through Portal Blood supply). In anterior pituitary, they releasing factors stimulate cells to secrete hormones into systemic circulation. Hormones go to target body and stimulate release of their hormones. Posterior pituitary: big cells in hypothalamus produce the final hormone, these peptides are transported through the axons of neurons into posterior pituitary (Axonal transport). When stimulus comes along, these neurons fire and release hormone into systemic circulation. i. Infundibulum ii. Anterior Lobe (adenohypophysis) iii. Posterior Lobe (neurohypophysis) iv. Feedback Loops Several levels of control: hypothalamus controls pituitary gland, which tehn releases hormones that stimulate endocrine glands through body, these glands secrete hormone into bloodstream. This hormone feedsback to pituitary gland and back to hypothalamus, negative feedback control. Controls hormones of endocrine system. If you dump hormones into equation, they will get negative feedback signals and shut down. C. Hormonal SystemsAnterior Pituitary i. LHRH, LH, FSH, Estrogen, Progesterone, Testosterone Luteinizing hormone releasing hormone through blood supply to anterior pituitary, affecting LH and FSH gonadotrofic hormones, released and travel to gonads (ovaries and testies). Ovaries release estrogen and progesterone (steroids) and testies produce testosterone. These drive secondary sex characteristics. ii. CRH, ACTH, Cortisol, Aldosterone begins in hypothalamus with CRH, corticotropin releasing hormone, a peptide that travels to anterior pit and causes release of ACTH (adrenocorticotrophic hormone) which travels to adrenal cortex (adrenal gland above each kidney). Adrenal cortex has two kinds of hormones produced: glucocorticoids (Cortisol, a stress hormone, when body is under stress, physical or emotional, it is produced and it helps to provide a source of energy to deal with stressful situation. It also helps suppress inflamation) and Mineralocorticoids (aldosterone, works on kindeys, regulates Na and K reabsorption, critical for muscle and other cell functioning) iii. TRH, TSH, Thyroxine begins in hypothalamus with TRH, thyroid releasing hormone, goes to pituitary and stimulates TSH, thyroid stimulating hormone
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