Lecture 11

• EEG
  
  •  Electroencephalogram:
    
    • It monitors the superficial electrical activity of the cerebral cortex. You can't see what the hypothalamus is doing. Electrodes are placed on the scalp itself.
      
    • ECoG – Electrocorticogram. [NOW: ECG old: EKG (Electrocardiogram)-put electrodes on the head.]
      
      • The electrodes are placed directly on the brain (in the ECoG).
        
    • Electrodes are placed on reference points (landmarks) from the Nasion (where nasal suture meets frontal suture) to the Inion (on the external occipital protuberance).  Standardized so it will work on children and adults.
      
    • We place 11 electrodes from the Nasion to the Inion to divide the scalp into 10 equal spaces. To get this you draw a line from Naison to Inion
      
    • SEE HANDOUT of EEG locations (not given HO)
      
    • In front of the opening to the ear, there is a notch – There are 2 Pre-auricular points. From pre-auricular point to pre-auricular point is divided into 10 equal spaces.
      

       
       

    • Modified Combinatorial system – all the possible placements of EEG electrodes on the head.
      

       
       

      • There are 11 positions.
        
        • z = zero, dead center
          
        • The Right hand side of the person is even numbers
          
        • The Left hand side of the person is odd numbers
          
        • N = Nasion
          
        • FPz = pre-frontal
          
        • AF = anterior frontal
          
        • F = frontal
          
        • FC = frontal, central
          
        • C = central
          
        • A1, and A2 – auricular, hang on earlobes, grounding electrodes (these don't count). 
          
        • T9 and T10 = Temporal, and are the Pre-auricular points. There will be 11 of them (dividing 10 equal spaces)
          
        • FT = frontal temporal
          
        • CP = central parietal
          
        • P = parietal
          
        • PO = Parietal Occipital
          
        • O = occipital
          
        • I = inion
          
      • People who have brain damage, will have different places where you want to put leads for the EEG. If someone got shot in the head and they lose part of their brain and you do EEGs around the area, they might have Strange Montages.
        

       
       

    • The 10-20 System is what they do for a normal person, if you are conscious.  This is the standard set up for EEG (called 10-20 b/c instead of 10%, you are getting 20% in some of the electrodes). It is based on equal spacing so there is no such thing as a child EKG and adult EKG.
      
      • These are for strictly Unipolar Readings
        
      • There are 16 leads.
        
        • We don't put electrodes on Fz, Pz, or Cz.  We don't monitor these
          
          • Because its between hemispheres
            
        • PG1 and PG2 – grounding posts placed on either side of your nose.
          
        • A1 and A2 – there are alligator clips on the ear lobes used for grounding
          

           
           

  • Two Types of Recordings:
    
    • Bipolar Recording – it is hooked to two electrodes and you measure the difference between the 2 (the electrical flow is going in one direction if positive). 
      
      • You can measure the electrical difference from north to south or from east to west (they can't go diagonal).
        
      • Don't do them here, but a lot in Europe
        
    • Unipolar Recording – the electrodes are set up like a bipolar reading.  We have 2 electrodes reading, but 1 is placed on an area where we won't see electrical activity (we are always working against/comparing the electrode with electrical activity to the null/void electrode). Essentially all we see is the unipolar. It is comparing it to a non-electrical event.
      
    • In America we only use Unipolar EEG's because they give nicer waves and are easier to read.
      
    • In Europe they use Bipolar EEG's almost exclusively because they give nicer waves and they are easier to read.
      

       
       

  • If we set up electrodes for this Modified Combinatorial System, they have to go in the same direction. This would mean that all the other electrodes would have to be going across in this plane. They have to go from left to right or front to back.
    

     
     

  • The grounds are put on your nose because it is cartilage, and you won't get excess electrical activity (there is no muscle here)
    

     
     

  • A Montage, is a list of bipolar leads that you actually monitor, which means that they are Bipolar Readings.
    
    • If we have Unipolar readings it is called a Referential Montage, which is referenced to the ground, and the machine is set so it will find the electrode that has the least amount of electrical activity going to it, and it will compare that electrode to the electrode that is grounded (i.e. the reference point being the null or void).
      
  • The Standard Waves of an EEG: (never written in the Greek Sign)
    
    • http://en.wikipedia.org/wiki/Electroencephalography#Wave_patterns
      
    • Alpha Wave 
      
      • 8 – 13 Hz in frequency (how often it goes up and down)
        
      • approximately 50mv in amplitude (how tall it is).
        
    • Beta Wave 
      
      • > 13 Hz
        
      • They have a greater frequency but they usually have a lesser amplitude than an alpha wave.
        
    • Theta Wave 
      
      • 4hz < 8hz
        
      • Higher amplitude than alpha waves.
        
    • Delta Wave 
      
      • < 4 Hz
        
      • Very high in amplitude.
        
    • We have some unofficial waves:
      
      • Gamma Wave – used to be considered greater than 30 Hz but they are now considered part of the Beta Waves.
        
      • Zeta Wave – abnormal wave of some sort, means nothing.
        

         
         

    • Alpha rhythm
      
      • are a series of repeating alpha waves.
        
      • occur when you are completely and totally relaxed, and your mind is blank. This is a non-alert state.
        
        • Resting with your eyes closed, but if someone were to do a stimulus you would go into Beta Waves – you would be relaxed and alert.  This is called Alpha Blocking.
          
        • Alpha rhythm is never found in the anterior of the brain.
          
        • Alpha waves are found over the:
          
          • occipital lobe,
            
          • parietal lobe,
            
          • The posterior half of the temporal lobe
            
        • Once in a while you will find an alpha rhythm in 10% of people called a Central Mu Rhythm, which is over the Pre-central Gyrus where you are getting movement messages – but it goes away when people move.
          

         
         

• Sleep 
  
  • comes in 4 stages (we only have done research on graduate students, so we only know how graduate students sleep)
    
  • http://en.wikipedia.org/wiki/Sleep#Physiology
    
    • Stage 1 –
      
      • you are just lying down, you start in Alpha Rhythm.  You are Awake lying calmly not asleep, just relaxed with a blank mind)
        
      • When the alpha rhythm starts to elongate (slowing to 2 to 7Hz and drops slightly in amplitude), you have moved into Stage 1 sleep.
        
      • You do not go directly in to REM, you come up to REM from lower stages.
        
      • Vital signs– 1.) Pulse, 2.) Blood pressure, 3.) Respiration, and 4.) Temperature – stay normal, and person is easily aroused, but may deny that they were asleep, they have not lost their awareness. This is only true in some people.
        
      • When the alpha rhythm gets very jumpy up and down (lots of noise), it is referred to as a: 
        
      • Sleep Spindle – 7 to 14hz, and it will be higher in amplitude than an Alpha wave.
        
        • The first Sleep Spindle that appears is a sign that the person has gone into Stage 2 sleep.
          
    • Stage 2 –
      
      • Sleep Spindles increase in number slowly
        
      • The person has lost perceptual awareness, and is not easily aroused.
        
      • Vital signs are still normal.
        
    • Stage 3 –
      
      • Sleep Spindles begin to disappear (decrease in number).
        
      • The waves that are between the Spindles start to increase in amplitude and lower in frequency
        
      • Vital signs begin to decline.
        
      • Finally the Spindles disappear all together, and all that is left is a very large Delta wave.
        
    • Stage 4 –
      
      • Once the Sleep Spindles have disappeared completely, all we have are Delta waves.
        
      • The Delta wave is produced by the Thalamus. The thalamus gets its instructions from the RAS system.
        
      • You are going to cycle out of Stage 4 sleep in the middle of the night, and then we are going to get a stair step into REM sleep. 
        
      • Stair step all the way from awake, 1, 2, 3, 4, 3, 2, 1, REM
        
    • REM (Rapid Eye Movement) Sleep is considered to be a more awake pattern of sleep where you are dreaming (more of less we have Beta waves). 
      
      • You can do an EOG, which monitors the muscles of the eye, and your eyes are flipping back and forth.  The EOG can monitor when you are dreaming.
        
      • Then you are going to cycle back down (you might go from Stage 3 to Stage 1 immediately, so it is not always a stair step process)
        

         
         

    • The pattern that is formed is called a Sleep cycle (that is from peak to valley)
      
      • http://www.ultracrepidate.com/wp-content/uploads/2007/01/sleep_cycle.jpg
        
      • You have 4 to 6 sleep cycles a night (for 20 yr. olds),
        
      • Not all of the stages are visited and there are different durations that you stay in a stage for.
        
      • If you are elderly, you have fewer cycles per night, and when you are really old, you stop going into Stage 4 (Stage 4 is needed, and that is why elderly people fall asleep in front of the TV/during the day) – they have fewer sleep cycles.
        
    • You do not remember a dream unless you wake up during REM.
      
    • If a person is deprived of Stage 4 sleep, they will spend more time in Stage 4 the next time they get down to Stage 4.
      
    • If you are deprived of REM sleep, they will go back into REM more quickly the next time the sleep cycle comes around.
      
    • If someone is totally derived of REM sleep – the person will become emotionally unstable and exhibit various personality disorders until they are allowed to get REM sleep again.
      
    • Dreaming 4-5 times per night, but only remember the ones that you wake up to…
      
• Posture and Movement
  
  • Posture:
    
    • Posture is Reflexive. It is maintained by a series of reflexive actions. They are learned reflexes.
      
      • You learned this when you are little kid, now you don't think about what you are doing. You have a learning process (ex. Picking up a Foal to get it to walk faster)
        
      • Static Reflexes for Posture – are sustained muscle contractions to maintain the position of the body (if you extend your arm you have to flex more back muscles to hold something than if you held a weight close to your body – physics)
        
      • Phasic Reflexes for Posture– are movement reflexes, they are short-term movement or stance corrections (ex. If you push someone, they brace themselves in response to being pushed – hop on one foot to readjust)
        
      • Medullary Reflexes – those regulated by the Medualla oblongata.
        
  • Movement:
    
    • Putamen Circuit: (subconscious motion)
      
      • Subconscious Motion – these are motions that you don't think about, you just do them (such as reflexes)
        
    • Pre-Motor  Supplementary Motor --> Somatosensory Area (which goes into the post central gyrus and has to do with proprioception). 
      
      • These 3 make a plan for the motion what they want to do, and then they send this information to the Putamen.
        
      • The Putamen sends the information to the Globus Pallidus.
        
      • The Globus Pallidus sends the information to:
        
        • 1.) The Substantia Nigra (in the midbrain) – doesn't talk back
          
        • 2.) The Subthalamic Nuclei – talks back.
          
        • 3.) The Thalamus
          
    • Globus Pallidus, Substantia Nigra, and Subthalamic Nuclei send info to the Thalamus.
      
      • EVERYTHING Talks to the Thalamus
        
    • The Thalamus sends information back to the:
      
      •  Primary Motor Cortex (in the pre-central gyrus)
        
      •  Pre-Motor Cortex (with supplementary motor and somatosensory)
        
      • The Primary-Motor Cortex initiates the movement and will initiate the cortex.
        

         
         

    • Cognitive Movement (you decide you are going to make a motion)
      

       
       

       
       

      FRIDAYYYY
      

   
   

   
   

   
   

Lecture 10

Autonomic Nervous System 

 
 

1. The Autonomic Nervous System:
   
   1. Sympathetic Nervous System
      
   2. Para-sympathetic Nervous Systems 
      

       
       

• They both have a system of the upper motor neurons going to pre-synaptic neurons and post-synaptic neurons (and then go to the target tissue) in place of the lower motor neuron (note: upper motor neurons went to lower motor neurons in the CNS). 
  
• The Sympathetic nervous system can trace its pre-synaptic neurons to the sympathetic trunks
  
  • This is the anatomical definition of the Sympathetic nervous system
    
• The Para-sympathethic Nervous system cannot trace any of its neurons to the sympathetic trunks
  
  • This is the anatomical definition of the Para-sympathetic nervous system
    

     
     

• The two systems differ in neurotransmitters that they use at the target tissue
  
  • Pre-synaptic neurons in both Sympathetic and Parasympathetic secrete ACh (Acetylcholine)
    
  • The Parasympathetic system uses ACh at both the pre-synaptic and post-synaptic spaces
    
  • The Sympathetic uses Norepinephrine as the post-synaptic on or near the target tissue
    
  • There are 3 exceptions to this rule that the SNS uses Norepinephin
    
    • The SNS post-synaptic neurons, during flight or fight, are going to dilate the blood vessels to the skeletal muscles and use ACH. When you sit down and then stand up – your blood pressure was changed by the SNS – that is called Vasomotor Tone. When it changed the blood pressure it used Norepinephin.???At presynaptic???
      
    • Sympathetic post-synaptic neurons that innervate the Sweat Glands use ACH.
      
    • Sometimes there are no post-synaptic fibers.  When this happens the pre-synaptic fiber goes all the way to the adrenal medulla.  There the pre-synaptic fibers synapse (raining ACH out) on:
      
      • Chromaffin cells
        
        • These are endocrine cells that secrete hormones and they get released into the blood stream
          
        • Secrete things called Circulating Catecholamines - which are 80% epinephrine and 20% norepinephine
          

           
           

• The effect of the Parasympathetic system:
  

   
   

  • Constricts the pupils of the eye
    
    • it is the only one innervating the circular smooth muscles of the iris)
      
    • Contracts the ciliary muscle of the eye, which is attached to the lens of the eye. 
      
    • The lumen is getting smaller since this is a circular muscle. 
      
    • There are suspensory ligaments going to the lens, and it allows the lens to bulge (for close vision) and get fatter. 
      
    • The Sympathetic system does not innervate the ciliary muscle of the eye. 
      
  • It decreases the heart rate
    
    • When you sit down, your heart rate decreases b/c of the PNS b/c it has increased the firing rate to do that.  But when you stand up and increase your heart rate, it increases b/c of a decreasing the firing of the PNS. The SNS kicks in through regulating your heart rate, and there is a constant sending through there.  All you have to do to increase it or decrease it is change the PNS up and down.
      
  • It constricts coronary blood vessels
    
  • It increases the activity of the GI tract
    
    • it relaxes the sphincters to allow movement, it will increase the secretions, and it will increase the smooth muscle contractions in the GI tract.
      
  • It constricts the bronchioles of the lungs 
    
  • It is responsible for the contraction of the bladder, but it does not effect the kidneys (the PNS does not innervate the kidneys) 
    
  • It causes sexual excitation in both males and females
    

     
     

1. The effects of the Sympathetic system
   
   1. It dilates the pupil of the eye. 
      
      1. It innervates the radial muscles of the Iris, making the pupils larger. 
         
      2. During flight or fight, we will dilate your eyes, but when we walk into a dark room your eyes will dilate too, which is not flight or fight.  During the Sympathetic stimulation of flight or fight, if we monitor the lens of the eye, we do find that the lens of the eye does flatten some.  This is probably due to the change in the blood flow/circulation or the changing of the firing of the PNS, b/c there is no ciliary muscle to do that.
         
   2. It constricts and dilates all the necessary arteriole and venous systems for fight or flight (to accommodate for changes in the blood flow)
      
   3. It increases the heart rate, and increases the force of the heart beat. 
      
   4. It dilates the arterioles of the heart and skeletal muscle (you are thinking more about flight or fight when you do this)
      
   5. It constricts the arterioles of the:
      
      1. GI tract
         
      2. Kidney
         
      3. Skin
         
      4. Sex organs
         
   6. It constricts the arterioles to the lungs
      
      1. When running, you are expanding the lungs.  When you start to take deeper breathes, this will drop your blood pressure.  This is why we constrict our arterioles to make the blood pressure rise and stay at the proper pressure of the lungs.  You don't want your blood pressure to drop.  
         
   7. It dilates the Bronchioles of the Lungs (allowing more in)
      
   8. It shuts down the GI tract completely (this is definitely a flight or fight thing), closing sphincters, decreasing secretions, and relaxing the smooth muscle contractions.  
      
   9. It relaxes the bladder (this is not urinating) and closes the sphincter urethra (this is a flight or fight thing too)
      
   10. It increases Renin secretion by the kidney, making more Angiotensin II available giving you increased blood pressure.
       
   11. It increases sweating and pilli muscle contraction (Haripilation occurs – goosebumps)
       
   12. It stimulates fat break down in adipose tissue 
       
   13. It mobilizes glycogen stores of the liver raising blood glucose levels
       
   14. It also contracts the spleen, this does not make much of a difference in humans. 
       
       1. In larger animals, like a horse, if they contract the spleen they raise their Hemoatocrit by 5 points, because they have large stores of RBC's in the spleen. 
          
   15. Causes sexual orgasm in both male and female. 
       

• The Sympathetic system cannot shut down the sexual excitation that the Parasympathetic system created; the only way to end the excitation is through orgasm. 
  

 
 

• The sympathetic system is usually the winner over the parasympathetic system. 
  

   
   

• Sympathetic Tone – is the tonal firing of the sympathetic systems, especially the heart. 
  
  • When we talk about Sympathetic tone we only think of the Sympathetic Vasomotor tone, b/c there are no innervations of the blood vessels that are responsible for blood pressure regulation
    

     
     

• Parasympathetic Tone - is not due to the lack of Sympathetic innervations, it just sits there doing the same thing with the exception of when you have flight or fight.   
  
  • The heart has Parasympathic Tone firing and constant sympathetic tonal firing to blood vessels, increasing and decreasing tonal firing of sympathetic fibers – Sympathetic Vasomotor Tone
    
  • Regulating the blood pressure as you are walking back and forth. 
    
  • This is not in fight or flight. 
    
  • 3 systems of Parasympathetic Tone
    
    • these systems are generally regulated by the Parasympathetic system, except in the case of fight or flight. The Parasympathetic system is the ruler, unless we have fight or flight.
      
    • The heart is run by the parasympathetic system except you are in fight or flight (the PNS tells the heart to slow down and the SNS tells the heart to speed up: they are on both sides of the SA node)
      
    • The GI tract is under parasympathetic control except in fight or flight
      
    • The bladder is controlled parasympathtically except in fight or flight. 
      

   
   

• The Autonomic Nervous system: (we cover EEGs and Sleep)
  
  • Reticular Activating System (RAS): 
    

1. Reticular Formation is comprised of sensory afferents bound for the cerebrum going up to the brain stem (medulla, pons, and midbrain). 
   
2. The sensory afferents are going to have clusters of nuclei in white matter:
   
   1. As they go through the brain stem the more mid-line nuclei are called Raphe Nuclei.  
      
   2. Farther from the midline, but closer than the lateral line we have a medial group called a Large cell group. 
      
   3. Farther out from that we have a lateral group called a Small cell group. 
      
   4. The neurons of virtually all the senses send neurons to this area. (Such as from the eye or ear, they are above and go directly to the brain and talk to it).  They send messages into the reticular formation down into the brain stem.
      
3. The Reticular formation is an integral part of the RAS, but it is only one single part of the RAS system
   
4. The RAS sends a continual stream of impulses to the brain
   
   1. The messages change but the flow is continuous
      
5. It keeps the brain alert or puts the brain to sleep
   
6. The RAS system filters out what it considers unnecessary information. 
   
   1. You don't feel something if you are not paying attention to it.  (ex. Can you feel your socks?)
      
7. The RAS has the cerebral cortex disregarding 99% of the sensory stimuli that are sent to the brain. If we did not have this filter, the brain could not handle all the messages. 
   
   1. The filtering of the RAS system is shut down by LSD, and then you can feel more of the sensory stimuli. 
      
   2. Bad trips – take LSD and something scares you and you stay scared (LSD stops itself)
      
   3. You don't have flash backs, but there is only a sense of flashbacks
      
      

 
 

Pasted from <https://mail.google.com/mail/?ui=2&view=bsp&ver=1qygpcgurkovy>

 
 

Lecture 6

Synapses, continued

 
 

• vesicle has synaptotagmin (synaptic vesicle protein)
  
  • can interact with syntaxin (protein in neurolemma), interact only after priming of vesicle
    
• if put calcium in, it will come down and bind to synaptotagmin, changes the shape of synaptotagmin and can now interact with syntaxin, this causes the vesicle to open and NT is released
  
• synaptotagmin can bind to clathrin which is found surrounding the vesicle, when this binds it causes endocytosis or pulling away of the vesicle and the closing of the vesicle
  
• Ca can be pumped out by ATP-powered pumps, but typically think there is 3 Na in for one Ca out called an antiport
  
  • functions to remove most of the Ca
    
• Ca can also be taken up by mitochondria in the synaptic knob
  

   
   

• Autonomic Varicosities
  
  • receptors all over the cells, varicosities rain there NT around the receptors
    
  • use similar method to synaptic knob to release NT
    
  • takes time for NT to cross the synaptic cleft this delay is called the synaptic delay
    
  • the more synapses between start/end of excitation and wherever sending the impulse, the slower the signal will go
    
  • like reflexes to go through one or two synapses, so they go as fast as possible
    
  • response to NT, is dependent upon the receptor that the NT hits
    
    • Response not based on neurotransmitter
      
• if have excitatory receptor, bringing closer to threshold called Excitatory Post Synaptic Potential (EPSP)
  
  • EPSP's typically Na and Ca channels opening
    
  • Can also get EPSP by K channels closing
    
• if have an inhibitory receptor, bringing further away from threshold called Inhibitory Post Synaptic Potential (IPSP)
  
  • IPSP get closing of Na and Ca channels
    
  • opening of K channels, sometimes also see opening of Cl channels (Cl follows Na around, when Na pumped out Cl went without, have higher level of Cl outside of cell and whne open these channels, Cl flows in and hyperpolarizes the cell)
    
• sometimes see synaptic knob with another synaptic knob on top of it, the synaptic knob on top is regulating the amount of NT coming out of the second one
  
  • Synaptic knob on top is called presyanptic facilitation or presynaptic inhibition
    
• Presynaptic facilitation will increase the amount of NT leaving and it does this by either opening more Ca channels or prolonging how long the Ca channels are held open
  

  -can also close K channels, if it closes K channels, this will enhance action potential and will kick out more Ca
  

• Presyanptic inhibition will close the Ca channels, restrict them so they can't let in as much Ca, dampen action potential (if dampen the action potential, they will then open Cl channels, influx a negative)
  

 
 

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• A wants to get X to fire:
  
  • sends excitation
    
  • Doesn't work…fires again….doesnt work…..
    
  • NEEDED rapid firing
    
    • TEMPORAL Summation
      
• B wants Y to fire
  
  • Needs C to fire at same time to cause firing.
    
    • SPACIAL Summation
      

       
       

• temporal summation = rapid firing of two or more neurons or an individual neurons that causes excitation
  
  • temporal rapid firing can be adjusted, but with temporal firing all you can send is I fired
    
  • temporal summation in bursts used to send messages is called temporal patterning
    

     
     

• spatial summation = not rapid firing, but neurons fire once and then firing across three or more neurons is summed to achieve excitation
  
  • spatial pattern = tells you which neurons are firing
    
    • detect smell through spatial patterning
      
    • 10,000 odors spatially patterned in brain
      
      • when have a twitch fire a summation
        
      • summation in a multipolar neuron is in the axon hillock (where dendritic positives and negatives get summed), multipolar neuron will taper down to become an axon, this is the first initial segment of axon
        
      • unipolar and bipolar neurons summation occurs at the initial segment of the axon
        
      • to send a message regulate firing rate and how often it occurs
        

     
     

   
   

• NT made up in soma
  
  • sent down a microtubule railway microtubules
    
    • have vesicles attached to them which move back and forth
      

       
       

• protein called kinesin moves vesicle towards the synapse
  
  • Calcium combined with calmodulin will cause phosphorolation of vessle and release NT in synapse
    
  • Antegrade transport
    
• protein called dynein moves vesicle back up the microtubule to the soma to be refilled
  
  • Retrograde transport
    
• each of the microtubules have both proteins associated with it but only one works at a time
  
• some neurons have co-transmitters
  
  • don't come out of active sites, can come out anywhere around the synaptic knob
    
  • typically think they facilitate the main NT in some way, but they are not necessarily all the way
    
  • can enhance the NT when excitation high or low it depends on the neuron
    
  • Neuron needs certain firing rate to release co-transmitters (maybe)
    

     
     

NEUROTRANSMITTERS & RECEPTORS

• See Handout!!
  

   
   

• if NT binds directly to receptor and opens the channel  ionotropic receptor
  
  • NT directly opens/closes channel
    
• If NT activates a secondary messenger and is linked to something else 
  metabotropic
  
  • NT can hit a receptor, but it causes a metabolite to increase/decrease and can open/close a channel
    
  • two major metabotropic systems
    
    • cyclic AMP
      
      • See handout...
        
    • IP3-DAG
      
      • See handout...
        

 
 

Name	Chemical	Receptor	Receptor Type
Acetylcholine	Esther	Nicotonic – receptor find on skeletal muscle (5) Muscarinic M1-M5	1. Ionotropic     Metabotropic
Norepinephrine	Catecholamine	α 1-2 β 1-3	Metabotropic Metabotropic
Dopamine	Catecholamine	D 1-5	Metabotropic
Serotonin (5-hydro trptomine = 5-HT))	Indolamine	5-HT 3 5-HT 1, 3, 4-7	2. Ionotropic Metabotropic	Opens non selective channel
Histamine	Indolamine	H1-H3	Metabotropic	H3 in synaptic knob
GABA (gamma amino butyric acid)	Amino Acid	GABA A GABA B	3. Ionotropic Metabotropic	Opens Cl channel = inhib
Glycine	Amino Acid	Glycine Receptor NMDA	4. Ionotropic 5. Ionotropic	Opens Cl channel = inhib Has to bind BOTH gly/glut
Glutamate	Amino Acid	AMPA Kainate Metabotropic Receptor of Glutamate (11 subtypes) NMDA	6. Ionotropic 7. Ionotropic Metabotropic     5. Ionotropic	Opens Na channel Opens Na channels         Has to bind both glycine and glutamate
Endorphins/Enkephalins	Peptides	μ (mu) κ (kappa) δ (delta)	Metabotropic Metabotropic Metabotrpic	All called opiate receptors
Substance P/Neurokinate	Peptide	NK-1 Receptor	Metabotropic
Somatostatin (SST)	Peptide	SSTR 1-5	Metabotropic
NO	Gas	1 receptor	Metabotropic	Increase cyclic GMP
CO	Gas	1 receptor	Metabotropic	Increase cyclic GMP

 

Lecture 9

Audio recording started: 12:04 PM Wednesday, February 04, 2009

 
 

Lecture 9 – More Senses:

 
 

•    The Ear – has 3 closely linked sensors 

o    1.) The Semi-circular canals - detect rotational acceleration

•    They are filled with Endolymph

•    The Capulla (a gelatinous membrane that seals off the Crista Ampularis) sits on top of the Crista ampularis

•    There are hairs that protrude into the gelatinous mass of the Capulla. 

•    When we turn our head, the Endolymph pushes on the Capulla (billows like a sail) and pushes the hair cells to Distortion, and that is what it is detecting

•    Since Semi-circular canals lie in each plane of space, the anterior on one side is the same plane as the posterior on the other side. 

o    2.) Utricle and Sacule – detects head position and linear acceleration

•    They are at right angles to each other

•    Utricle – front to back and side to side – detects head position and linear acceleration

•    Sacule – front to back and up and down - detects head position and linear acceleration

•    The gelatinous mass is sitting on top of the Macula.  There are Calcium carbonate stones called Otoliths (which are acting as weights) sitting on here and they shift in response to gravity or acceleration, and they pull the membrane back and change the hair cells.

•    The induced bending of the cilia (shifting the membrane back and forth) is doing the detection of the motion. 

 
 

• Cochlea – detects Sound
  
  • Hair cells:
    
    • Vestibular Hair Cells-The hair cells are embedded in the Macula and in the gelatinous membrane of the Macula. 
      
      • The hair cells have clumps of Cilia on them (these are Vestibular Hair cells)
        

  There is a single very large cilia called the Kinocilium, this cannot depolarize, it cannot function, other than it is there.  
  

  •    The small away you move from the Kinocilium, the smaller the cilia (the Steriocilia) become shorter and shorter.
  

  •    The rest of the cilia are called Steriocilia – there are rows of the Seriocilia moving away from the Kinocilium, with each row getting smaller and shorter and shorter.  The tallest cilia will be the Kinocilium. 
  

  •    There are Cross-links between the Sterocilia, this is from 
  

  •    The Cross-links make sure that everything bends in the same direction at the same time. 
  

  •    There are Tip-links between the Steriocilia – from the tip of a small Sterocilia to the tip of the next highest one.
  

  •    The Tip-links open channels in the side of the larger cilia
  

  •    When the Sterocilia (the hair cells that are doing the electrical event) bend towards the Kinocilium there is a depolarization of the afferent nerve. 
  

  •    When the Stereocilia bend away from the Kinocilium, there is a hyperpolarization of the afferent nerve. 
  

  •    The hair cells rain out Neurotransmitters, and you are just increasing or decreasing the amount of Neurotransmitter over time
  

  •    The whole thing is considered a hair cell because it has the hairs sticking out of it. 
  

  •    The hairs sticking out of the cell are bathed in Endolymph, and the rest of the hair cell is being bathed in Perilymph. 
  

  •    Endolymph – is high in Potassium, and is much like intercellular fluid.
  

  •    Perilymph – is like extracellular fluid. 
  

  •    When the Sterocilia bends towards the Kinocilium (due to a depolarization) and opens the Distortion channels (a potassium channel), potassium is flowing into the cell. This is very unique because this is the first place where Potassium has a higher concentration gradient outside the cell than inside of the cell. Potassium is going into the cell. This is the only place in the human body where you find this.
  

  •    There is a high level of K in the Endolymph
  

  •    The Potassium (came in from the Endolymph) is going to cause a depolarization and cause the voltage gated Calcium channels to let Calcium into the cell.   The Calcium will flow into the cell from the Perilymph – this influx of Calcium increases the Neurotransmitter output.  The Neurotransmitter will bind to the Potassium channel and the Potassium will go out into the Perilymph.
  

  •    Support cells will pass this to other support cells, and then it will work its way back into the Endolymph and the cycle will restart again
  

  •    Hair cells don't fire action potentials, they just increase and decrease their Neurotransmitter output. Their afferents will fire action potentials.  
  

  •    The Voltage gated Calcium channels kick out Calcium, which binds to a Potassium channel, which kicks the Potassium out into the Perilymph. 
  

  •    The Potassium Distortion channel is pulled open by the Tip-link
  

  •    Endolymph is formed by dark cells. 
  

  •    Potassium is picked up in the Perilymph by support cells, and it is passed along to the dark cells, and then recycled into the Endolymph. 
  

  o    In the Semi-circular canals, the Kinocilium of the Crista Ampularis all face the same direction. 
  

  •    In the Lateral Semi-circular canals – the kinocilia face towards the utricle. 
  

  •    In the Posterior and Anterior Semi-circular canals – the kinocilia face away from the utricle. 
  

  •    In the utricle and sacule, the macula will have hair cells that go up into the gelatinous membrane. 
  

  •    There is an area in the utricle and sacule that does not have any hair cells coming out, and this is called the Striola. 
  

  •    The ridge of Otoliths is above this Striola. This is not the snowy ridge that sits above it. 
  

  •    In the Utricle the Striola is C-shaped 
  

  •    In the Sacule it is S-shaped or hook-shaped. 
  

  •    In the Utricle the Kinocilia face toward the Striola (the Kinocilia will be on both sides of the C)
  

  •    In the Sacule the Kinocilia face away from the Striola (the Kinocilia will be on both sides of the S)
  

  •    There are 2 types of Vestibular hair cells in the Macula of the Utricle and the Sacule. 
  

  o    Type I hair cells – it only connects to 1 afferent neuron, and it sits in a cup, and the axon comes up and wraps right around this cup.  This is a sensory axon. 
  

  •    There is Efferents going down and end on the outside of the cup, but they never actually touch the hair cell.
  

  •    The Afferent neuron is firing Tonally (it is always firing, and it just changes its firing rate based upon how much Neurotransmitter is being released; it speeds the firing up and down). 
  

  o    Type II hair cells – hair cells which directly connect to both efferents and afferents neurons; we have a bunch of efferents coming to it, and we have a bunch of afferents leaving it. 
  

  •    Type II - These cells fire Phasically (they have to be stimulated with enough Neurotransmitter to get a firing rate), they are NOT firing tonally 
  

   
   

   
   

• Cochlea and your Hearing: 
  
  • Sound is comprised of air vibrations. 
    

  o    The air vibrates and vibrates the Tympanic membrane, what we refer to as the eardrum. 
  

  o    The Tympanic membrane vibrates the Ear ossicles. 
  

  o    The Ear ossicles (the Stapes) vibrates the Oval window. 
  

  o    The Round window opens to the air filled middle ear. 
  

  o    See drawing (straightened cochlea). 
  

  •    The role of the Round window is that you cannot compress a fluid.  This is the only way the vibration can come in. 
  

  •    If one part pushes inward, something has to push out. 
  

  •    The Round window pushes out. 
  

  •    The vibrations are entering into the Perilymph and the vibrations get the Scala media to move up and down. (The Scala media has the vibrations going to it)
  

  •    As it moves up and down it causes a lateral movement of the Tectorial membrane. 
  

  •    The hair cells are below the Tectorial membrane
  

  o    There are 2 types of hair cells in the Cochlea:
  

  •    1.) Outer hair cells – there are 3 rows of them, and they stick up into the Tectorial Membrane
  

  •    2.) Inner hair cells – there is 1 row of them, and they don't stick up into the Tectorial Membrane
  

  •    Sometimes you can get up to five rows of outer hair cells in some regions of the Cochlea. 
  

  •    There are 3 rows of Outer hair cells, and they don't have a Kinocilium.  All the rows have Sterocilia.
  

  •    Within each row the Stereocilia are the same size/height. But the rows get shorter and shorter, arranged from tallest to smallest
  

  •    There are also Cross-links and Tip-links present. 
  

  •    Outer hair cells are V or W shaped, and the opening will face the inner portion of the spiral of the cochlea. 
  

  •    Inner hair cells are U shaped, but a flattened U-shape and the opening faces the inner portion of the spiral of the cochlea. 
  

  •    There are NO Type I and Type II cells 
  

  •    The inner hair cells only have afferent connections and they don't sit in a cup. Inner hair cells will have 10 or more synaptic connections, but all of them will be afferent.  
  

  •    Outer hair cells have both efferent and afferent connections.  (like Type II cells with no cillia)
  

  o    Inner hair cells are what we are hearing with
  

  o    Outer hair cells are for Amplification. 
  

  • These are what get damaged to cause deafness
    

   
   

   
   

  •    The Theories of Hearing: A human range of hearing is from 20Hz to 20,000Hz
  

  o    The Place Theory of Hearing (only works in the high notes well)
  

  •    The Basilar membrane that the Organ of Corti sits on is about 100um wide at the base, and about 500um wide at the apex. 
  

  o    The Organ of Corti is what you are hearing with, and it sits on a Basilar membrane 
  

  •    The tension is the same throughout its length, but it is stiffer at the base than at the apex. 
  

  •    This allows waves to travel one direction from base to apex. (there is no echoing and the wave cannot be returned back)
  

  •    If sound is vibrating the Oval window, we get a sigmoid (S) shaped wave in the vestibule, and it passes it all the way up towards the helicotremia, it will grow in size until it quickly disappears. 
  

  •    Where it peaks and dies, it what you hear as a tone. 
  

  •    If it peaks down close to the base, you hear a high note, if it peaks down towards the apex, you hear a low note. 
  

  •    Where the Maximum deflection occurs is where you hear the note. 
  

  •    There is a long flat part where the brain cannot discern the notes anymore. 
  

  •    Below 500Hz the peak of the traveling wave is too broad for pitch discrimination, so this theory does not work below 500Hz. 
  

  •    This theory is only good from about 20,000Hz to 500Hz. 
  

  •    It starts to fade out, as it gets closer to the 500Hz, and then dies. 
  

   
   

  o    The Phase Locking Theory of Hearing
  

  •    Below 500Hz the hair cells will vibrate at the same Hz frequency as the note/sound wave 
  

  •    Listing to the low notes because the hair cells are vibrating at the same frequency as the sound itself.  You are listening with the cells that are vibrating. 
  

  •    This is good from 20Hz to 500Hz. 
  

  •    We have this transition here b/c Phase Locking does not go above 500Hz.   At this 500Hz level the Absolute Refractory Period of the Afferent neurons prevent firing faster than 500 times a second. 
  

  •    The Place Theory is starting and isn't doing a good job of listening, and that's where the Transition Theory kicks in, which we call the Volley Theory of Phase Locking.
  

   
   

  o    The Volley Theory of Phase Locking
  

  •    Rows of hair cells, one hair cell fires, and then the next one up fires, until the first one can fire again. This is a Volley of firing. The brain analyzes and counts (counting how many hair cells that have gone by) the pattern of the Volley and interprets into sounds. 
  

  •    This transition from Phase and Place happens at 500Hz, switching to the Volley Theory, and that is doing a good job of hearing 
  

  •    The Volley Theory starts to phase out between 2,000Hz to 6,000Hz (this is variable between people)
  

  •    This is good from about 500Hz to 4,000Hz. 
  

  o    20Hz to 500Hz – only Phase Locking. 
  

  o    500Hz to 4,000Hz – both Volley theory and Place theory (with the Place increasing its ability as you move up further away from 500Hz towards 4,000Hz)
  

  o    4,000Hz to 20,000Hz – only the Place theory. 
  

  o    Most of the sensory input from the inner hair cells of the ear are sent to the opposite hemisphere of the cerebrum. If you are following the excitation of this, it will go to the opposite hemisphere. A small amount of information will be sent on the same side (Ipsolateral).  (Ex. This is useful for EEGs)                    End of Exam I Material
  

   
   

  Pasted from <https://mail.google.com/mail/?ui=2&view=bsp&ver=1qygpcgurkovy>
  

   
   

   
   

Lecture 8

-EYE

• Detects electromagnetic waves from wavelength of 400-750nm (visible light)
  
• Detects EM waves using rods and cones
  
  • Rods  function in dim light, they're very sensitive, can respond to a single photon of light, doesn't see colors (black and white are colors), all you see is shades of grey with a rod
    
  • Cones  function in bright light, record color images
    
    • White = all colors at once
      
    • Black = none of the colors
      

• a rod has free floating discs in outer segment
  
  • each of these discs has a photopigment in the outer surface of its membrane, this pigmented membrane is going to pinch off the end of the rod and consume discs and and three new discs are made every hour, discs are made at the bottom and migrate upward
    
• photopigment called rhodopsin (is 11 cis-retinale + scotopsin)
  
  • 11 cis-reinale goes through a series of shape changes
    
    • One is the
      

    This opsin is called scotopsin in rods (the opsin of rhodopsin)
    

    -when only looking with rods (not enough light stimulating cones) using scotopic vision
    

  -if we turn up the light to bright light, the rod gets flooded with too much light and can't function and you are only using cones, this is called photopic vision
  

  -when use both rods/cones  mesopic
  

  -which one, rods/cones, is based upon how much light is available
  

  -rod has peak absorption of 505 nm
  

  -in dark the rod fires, ion channels open and Na and Ca flood in
  

  -the ion channels are held open by cyclic GMP and Na/Ca come in
  

  -think of Na as the main thing that causes the release of the NT
  

  -Ca plays a special role in NT release
  

  Cyclic GMP formed by glymulate cyclase, but is inactivated by Ca entering the cell, this causes cyclic GMP to be reduced and the amount of Ca coming in is reduced, when Ca is reduced more cyclic GMP is made
  

  THIS IS A CYCLE, it does not open or close it just finds a happy medium
  

  -when get rid of the light, hitting the rod, this process changes
  

   
   

  ______________________________________________________________________________________________________________
  

  http://en.wikipedia.org/wiki/Photoreceptor_cell
  

   
   

  ONE photon works for rods, not for cones
  

  • CAN change one rodopsin molecule, making one metarhodopsin
    
  • One meta can change 100s of transductions
    
  • One transduction can stimulate 1000s of
    

     
     

  Scotopic vision
  

  • No color, only the rods were working
    

   
   

  Photopic vision
  

  • In normal light, rods are maxed out and not really functioning
    

   
   

  Mesoptic vision
  

  • Transition period between the 2
    

   
   

  Types of cones:
  

  • Long wave cone
    
    • Peaks at 557 nm
      
    • Only one to see red
      
    • In yellow spectrum
      
    • longwaveconeopsin
      
  • Medium wave cone
    
    • Peak at 535 nm
      
    • mediumwaveconeopsin
      
  • Short wave cone
    
    • Peak at 420 nm
      
    • Shortwaveconeopsin
      

       
       

  660 nm - bright red (paper)
  

  410 nm - bright violet - (disk on it)
  

  TINY dot is a hole in disk
  

  Put you in dark room, with strobe light
  

  If we can get DOT in center of foveola, since there are no short wave cones…it disappears!
  

  Analysis AT BRAIN, not receptors - it sees what it wants
  

   
   

  Daishi
  

  € Invar
  

  it
  

  
   

  or
  

   
   

   
   

   
   

   
   

   
   

   
   

   
   

  Light hits Cone A center
  

  hyperpolarizes
  

  Glutamate coming out of A slows down
  

  A bipolar cell Na channels held down by glutamate
  

  Therefore more Na channels open and increase output of A
  

  Therefore ON CENTER
  

   
   

  B hit by light
  

  B bipolar cell Na channels held open by glutamate
  

  Therefore reduction in glutamate closes channels, output is decreased
  

  THEREFORE OFF CENTER
  

   
   

  Center surround antagonism
  

   
   

  ROD bipolar cells are only ON Center
  

   
   

  http://en.wikipedia.org/wiki/Bipolar_cell_of_the_retina
  

   
   

  Ganglion cells
  

   
   

  W - 40%
  

  • Connect mainly via amacrine cells?
    
  • Directional movement
    
  • Important in scotopic vision
    

   
   

  X - parvo cells - 55%
  

  • Color
    
  • Shape
    
  • Firing tonally
    
  • Main transmitter of visual image
    

   
   

  Y - magno cells 5%
  

  • Rapid changes in visual field
    
  • Movement
    
  • Intensity
    
  • Phasic bursts
    

     
     

   
   

  Uri is
  

   
   

  http://en.wikipedia.org/wiki/Visual_system
  

   
   

  Layers of LGN
  

   
   

  End in layer 4
  

   
   

  LGN and cortex have visual maps
  

  • Foveola has largest mapping
    

     
     

  Cortex
  

  • Blobs
    
  • No blobs - layers 2 and 3 - interblob areas
    

     
     

     
     

Parvo blob	Color
Parvo - interblob	Shape
Magno - movement	Depth of field, location

 
 

 
 

 
 

EAR

 
 

• Inner ear has sensors to detect rotational acceleration
  
  • Semicircular canals
    
• Head position and linear acceleration
  
  • Utricle and saccule
    
• Choclea
  
  • Sound
    

Semicircular canals have endolymph

•  
  

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

5

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