Neuroanatomy, Neurophysiology and Neuropharmacology: The Basics

Neuroanatomy, Neurophysiology and Neuropharmacology: The Basics

Lecture Notes

I.  Brief, Basic Chemistry Review (Appendix A- pg 486)
  A. Elements and Compounds

1. As stated in Chapter 1, the Big Bang initially produced 4 forces- 1. gravity, 2. electromagnitism  3. strong nuclear forces and 4. weak nuclear forces.  Chemistry is the study of the weak nuclear forces found in compounds. The weak nuclear forces allow for chemical reactions which are the transfer of ions and molecules to make new molecules and compounds. When wood is burned it turns into ashes and gases and water vapor and also produces heat. These are all chemical reactions. The basis of chemical reactions is the interaction of  elemental chemicals.  The periodic table lists 92 elements of which only are few are found in living organisms. Some of the most important are listed here.

Q. What are the most important elements in living organisms?

2. Compounds are made from molecules which are made from elements. Elements that  are listed on the Periodic Table are comprised of atoms.   For instance, when listed on the Periodic Table, Hydrogen has an atomic number of  #1 and Oxygen is #16. The atomic number corresponds to the number of protons in the nucleus of an atom of that element. It also corresponds to the number of electrons in the neutral atom. When atoms come together, they make molecular compounds. Water is a compound or molecule. Compounds are created  when electrons from different atoms join each other in chemical reactions. For instance, the molecules of water are elements Hydrogen and Oxygen. On each water molecule are two atoms of hydrogen and 1 atom of oxygen (H20). Each atom is composed of subatomic particles, protons, neutrons and electrons, which are positively charged, neutral and negatively charged- in that order.  Protons and neutrons are found in the center of the atom, the nucleus and electrons are found in the space around the nucleus. It is very very difficult to separate protons which is a property of strong nuclear forces. The result of breaking those nuclear bonds is an atomic bomb. In a stable state, an atom will have the same number of protons as electrons. Molecules prefer a stable state to an unstable state and this is what drives ma

Q. What  is the atomic number for Oxygen, Hydrogen and Carbon? What do these numbers mean?

    B. Ions

3. An atom that has gained or lost one or more electron is called an ion.  When the compound salt NaCl (Sodium and Chloride) is placed in water it dissolves or dissociates into ions: Na+ and Cl-.  Sodium atoms lose electrons and become positively charged (has space available to accept an electron).  A negatively charged ion, like Cl- has an extra electron. Thus ions with opposite charges attract each other and ions with the same charge repel each other. This is a property of electromagnitism and contributes to the property of weak nuclear forces.

In some cultures physics and chemistry are taught before biology because these fields underlie the very complex mechanisms necessary for biological systems. The topics above provide an extremely brief background for processes that are involved in synaptic transmission.

Textbook Module 1.2 Genetics and Behavior

Module 1.2 Genetics and Behavior   January 20, 2015

PLEASE READ THE ENTIRE MODULE 1.2 FROM THE TEXTBOOK AND THEN READ THESE NOTES. PAY PARTICULAR ATTENTION TO THE MATERIAL IN RED THAT IS BELOW. THE RED TEXT MAY BE USED FOR QUIZ/TEST QUESTIONS.  

Mendelian Genetics

The book concludes that it is both Nature and Nurture since the Module begins with the statement "Everything you do depends on both your genes and your environment."

The evidence provided for this statement is facial expressions. What kind of observations led to the conclusion about facial expressions?  Other behaviors listed are intelligence, sexual orientation, alcoholism and weight gain.  Could you provide evidence for both genetic and environmental influences on these behaviors?

 I understand that many of you may have taken Biology some time ago, so you may be unfamiliar with Mendelian Genetics. I've tried to provide a brief but effective re-introduction, starting with this video.


A much broader view of Figure 1.7 and Figure 1.9 
Here you will be reminded that living tissue is made up of cells. Every cell has a nucleus, Every nucleus contains materials for the replication of the cell, genes. Genes are made up of DNA.  RNA is used to replicate the gene from the DNA.
 
According to the text, Genes are units of heredity that maintain their structural identity from one generation to another. Genes are defined as a portion of a chromosome which is composed of the double-stranded molecule DNA. Here's a movie to help visualize this.  (Please watch the videos SEVERAL times in order to answer the questions in red below.)

Genes are reproduced through a process of DNA replication and DNA transcription.  A strand of DNA serves as a template for the synthesis of RNA, a process called transcription.

From the Videos above answer the following questions.
1. could you explain how the following terms differ from one another?
DNA,  Chromatin, Chromasomes, Histones, Nucleosome

2. How many molecules of DNA are synthesized by RNA.

Once there is a single strand of messageRNA or mRNA (copied DNA), the strand leaves the nucleus and is joined to ribosomes where amino acids sequences produce proteins. This process is translation.

Genes can be dominant, recessive or intermediate.  Here's an explanation using what Mendel used, peas.

From the Video define- allele, genotype and phenotype.
 The list of traits given at the beginning of the chapter include intelligence, sexual orientation, alcoholism and weight gain. Now that you have a clearer understanding of genotype and phenotype, do you believe there is a genetic basis for intelligence, sexual orientation alcoholism or weight gain.  Be able to explain your answer?


Genetic Changes

Genes can change and therefore the transcription by mRNA will be altered as well as translation of proteins as the final outcome.

Mutations of the gene (incl. duplication and deletion)
Epigenetics- Various experiences can turn a gene on or off.  Evidence of epigenetic effects come mainly from animal studies, several of which were described on pg. 12.

What did Godfrey et al, 2007 discover about obesity and heart disease?
What did Weaver et al, (2004) find out about the effects of maternal care on stress levels of rat pups?

How does an experience modify gene expression?

Heredity and Environment

Evidence about the influence of heredity and environment often come from twin studies. Why?

What does it mean to be a monozygotic or dizygotic twin?

Evolutionary Psychology

Define the terms: altruism, kin selection and reciprocal altrusim

Textbook Module 5.1 Neural Development

Neurogenesis 

Please review the links to help understand the process. 

ONLINE VIDEOS to Visualize Neural Tube

Closer look at neural tube formation

Brain Development video

Fetal Development

Coloring Book Assignment for Neurogenesis (Understand these processes)

CB 4.2 Processes of Early Neural Development

 Stage 1- Proliferation

Stage 2- Migration
      Radial Glial cells

Stage 3-Aggregation
    Growth Cones and Circuit formation

Stage 4- Process Growth and Synapse Formation
     Circuit pruning

Stage 5- Neuron Death

Stage 6 Myelination

CB 4.5 Axon Growth: Correctly Wiring the Nervous System

A. Chemoaffinity theory

B. Blueprint theory
       pioneer growth cones
       fasciculation

CB 4.6 Adult Neurogenesis

Adult neurogenesis and recovery from brain damage.

 

Textbook Module 1.1 Coloring Book Assignments

FROM A colorful Introduction to the Anatomy of the Human Brain 2nd Edition John Pinel and Maggie Edwards (2008)

Neurodevelopment-
   Coloring  Book Unit 4.1 (pg 53) through 4.6 (65) and Review (pg 66 - 69) and 5.2 ( pg 74 )
 Review your paragraph on neurogenesis.


Planes of Section
     CB Chapter 2 (Entire Chapter) and Review Exercises 2.1 through 2.4 (pg 28 - 30)
Exercise done in class.   

Psych 412 FA 2015 COURSE INTRODUCTION

Introduction to the Course

1. Syllabus
    Objectives, Office hours, Office location

2. Types of Assignments
    Blackboard quizzes
    In-class quizzes
    Coloring Book
    Textbook Module

3. Blackboard
       
4. Course blog

5. Exams and Grading Formula

6. Teaching Assistant- Sophia Howard
  

Textbook Module 6.1, 6.2 & 6.3 Vision

I. THE STIMULUS
        A. Getting the image to the retina
Most of the structures of the eyeball are involved in preparing the image that is reflecting visible light into the eye. The visible light range of the electromagnetic spectrum is the frequency of approximately 400-700nm. Humans perceive the shortest visible wavelengths as violet, medium short wavelenths is green; medium long wavelength is perceived as yellow and long wavelenght perceived as red. (see Figure 6.8 on page 160). Once the particular range of the electromagnetic energy is reflected off the image, the pattern of the reflected image enters the eyeball.
  
1. What role do the iris, pupil, lens and cornea (structures of the eyeball) play in getting the pattern of the reflection onto the photoreceptors of the retina?  (pag 156)

 2. In the illustration below draw in the placement of horizontal cells and amacrine cells.(page 169)
 3. Which cell axons leave the eyeball and what is this collection of axons called. Also, why is there a blindspot?






FRONT OF EYE BALL                                                                                BACK of EYE BALL

4. What is the role of the fovea? (pg 157) 
5. What is the functional significance of a midget ganglion cell?
6. What is convergence?


II. TRANSDUCTION (Retinal Processing)
  


IIIa. TRANSMISSION PATHWAYS IN THE EYE
   Ganglion Receptive Fields  (see lecture notes on Blackboard & pg 172 in textbook)

IIIb. TRANSMISSION PATHWAYS IN THE BRAIN
Transmission of visual information actually begins in the retinal layers once the photoreceptors are stimulated. 
1. Trace the transmission pathway from when retinal cell axons leave the eyeball to the destination synapse of MOST of those cells in the LGN .(see pg 168 textbook and pg 134 Coloring Book)

 Lateral Geniculate Nucleus is located in the Thalamus.  (See PAGE 98 of Coloring Book)

IV. SENSATION, PERCEPTION and COGNITION

a. Receptive Fields (Sensation and Perception)
Use this site to help your understand the concept of Receptive Fields. You should understand the sections labeled
THE RETINA
RECEPTIVE FIELDS FROM THE RETINA TO THE CORTEX
You are not responsible for the third section- THE CELLULAR STRUCTURE OF THE VISUAL CORTEX.

b. Cogntion
Shape,
Color Perception
Motion Perception 

V. PUT IT ALL TOGETHER- Stimulus, Transduction, Transmission, Sensation, Perception & Cognition

If you are really understand this material, you should be able to easily read the following webites. Once you are comfortable reading the websites below, your next assignment will be to upload your version of the "Sensory Stories," in which you will be able to explain this sensory modality from start to finish  on a YouTube video.   More about the Sensory Stories assignment in class.

Put it all together site for Vision
 The following terms from this link will help you "put it all  together" in the story of the sensation of Vision. 

THE EYE
retina
*cornea
*lens
*photoreceptors
rods
cones
*amacrine
horizontal
*ganglion cells
*pupil
iris
first visual system synapse

THE TARGETS OF THE OPTIC NERVE
optic disk,
optic nerve
ganglion cell axons
*optic chiasm
*lateral geniculate nucleus of the thalamus
LGN receptive fields

THE VARIOUS VISUAL CORTICES
receptive fields of the cells of the retina
occipital lobe
*primary visual cortex
secondary visual cortex
*posterior inferior temporal cortex
*middle temporal cortex
*medial superior temporal cortex
ventral pathway- "What"
dorsal pathway- "Where"









 

Textbook Module 7.2 Mechanical Senses- Somatosensation

Somatosensory Systems
The somatosensory system monitors the sensations of the body and its movements and include multiple systems.

STIMULUS
The different types of mechanical stimuli are listed in the text in Table 7.1 (pg 205). The stimuli include pain (generated by cell injury); heat or cold (on either side of physiological cell injury range)
Movement of hairs on the skin surface; sudden displacement of skin; light touch; skin stretch or also stretch or injury to joints and muscles.

 What these all have in common is that they are associated with types of receptors that are sensitive to them.

TRANSDUCTION
Receptors associated with the types of stimuli listed above are also listed in Table 7.1 They are
Free nerve endings; hair follicle receptors Meissner's corpuscles, Pacinian corpuscles, Merkel's disks, Ruffini endings and Krause end bulbs.  These receptors are located in the  skin and in the joints and muscles.  Stimulation of a touch receptor opens sodium channels in the axon and thereby starts an actionl potential.

TRANSMISSION
Somtosensory information from touch receptors on the head enter the CNS through the cranial nerves, such as Cranial Nerve V. . Somatosensory information  from receptors below the head enter the spinal cord via the dermatones.   Dermatomes were discussed previously in Module 2.1- cells of the Nervous System on this blog.

Transmission Pathway for Fine Touch and Vibratory Sense-  Dorsal Column Medial Lemniscus
see unit 9.5-9.6 of the Coloring Book (pg 142-145)

• The transmission pathway for touch is carried into the spinal cord via the dorsal roots (see Unit 1.4 Coloring Book pg 10) and then without synapsing ascend ipsilaterally in the dorsal part of the spinal cord to the dorsal column nuclei.  Sensory input from the legs synapse in the nucleus gracilis and input from the arms synapse in the nucleus cuneatus. 
• Axons from the dorsal column nuclei decussate in the medulla and ascend to the the thalamus via the dorsal column medial lemniscus.
• Axons from the dorsal column medial lemniscus ascend to the thalamus.  Fibers from Cranial Nerve 5 join the medial lemniscus enroute to the thalamus
• Most of the axons of the medial lemniscus synapse on neurons in the ventral posterior nucleus of the thalamus.
• Axons from the VPN project to the primary somatosensory cortex (Coloring book unit 7.6 pg 120).
• The primary somatosensory cortex is located on the post central gyri (see coloring book unit 7.1 pg 119) of the parietal lobes (CB unit 7.2 pg 112).

• The output of the primary somtosensory cortex is mostly projected to the secondary somatosensory cortex located just inferior to the primary somatosensory cortex located in the ventral portion of the postcentral gyrus and hidden by the lateral fissure
• Output from the sencodary somatosensory cortex is sent to the posterior parietal association cortex.

The somatosensory cortex is laid out somatopically, a map of the body is on the brain. (Just like there is a retinotopic representation of the visual image represented on the occiptial lobe and a tonatopic representation of frequency represented in the cochlea and auditory cortex).
The somatosnesory body map is called a homonculus. (CB unit 8.6 pg 144).


Transmission Pathway for Pain, Temperature, Crude Touch -Spinothalamic Tracts
Pain and Temperature (lateral spinothalamic tracts) Crude Touch (anterior spinothalamic tract)
 see Textbook figure 7.15 and 7.16 (pg 208-209).

Why is pain information conveyed so slowly to the brain?
What are the neurotransmitters involved in conveying pain in the spinal cord?
How does the pain transmission pathway differ from the touch transmission pathway?

Pain information crosses to the contralateral side of the spinal cord at once. The pathways then continue to the brain via the spinothalamic tract. This axonal pathway begins in spine then ends in thalamus- thus the name spine -o- thalamic.



 

• The spinothalamic tract conveys pain and temperature (lateral spinothalamic tract) and crude touch (anterior spinothalamic tract).
• Primary sensory nerves that register pain have  cell bodies that lie in the posterior dorsal root ganglion. 
• They synapse in in the posterior horn of the dorsal root in the spinal cord.
• Secondary neurons cross the spinal cord contralaterally and ascend to the brain via the  lateral spinothalamic tract in a somatotopic arrangement. 
• Secondary neurons synapse in the VPN of the thalamus,
• From the VPN of the thalamus, tertiary neurons ascend via the internal capsule to the primary sensory cortex  
• These cells also branch off axon collaterals to the limbic system, hypothalamus, and other portions of the CNS such s the amygdala, hippocampus and prefrontal cortex.  These areas react not to the sensation of pain but  to its emotional associations.

SENSATION PERCEPTION COGNITION

Descending Analgesic Circuit
Textbook Figure 7.18 pg 210 and unit 8.7 of the Coloring Book (pg 146)

A centrifugal pathway is a pathway that exerts either a facilliatory or inhibitory influence on a nerve signal.  One example of a centrifugal pathway is the descending analgesia circuit.  During times of intense emotion it is possible to feel little or no pain, even when there is a grave injury.

What is a centrifugal pathway?

The inhibition of pain information in the brain is due to the activation of natural opioids or endorphins in the midbrain structure, the periaqueductal gray (PAG)- gray area surrounding the cerebral aqueduct in the midbrain.

Axons from the PAG synapse back to the spinal cord  and decreases pain signals in the spinal cord. Therefore, even though pain receptors may be firing the signal to the brain has been blocked and therefore the injured individual does not experience pain.

See figure 7.18 in the textbook

• "Certain kinds of painful and other stimuli" send emotional pain information from the cortex to the PAG via endorphine neurotransmitters.  
• The PAG projects to the "area in the rostral part of the medulla" and excites cells that release more endorphine neurotransmitter into the spinal cord. 
• The endorphine neurotransmitter inhibits the primary sensory nerve which is releasing substance P as a neurotransmitter and therefore stops "areas of the spinal cord that receive pain messages" from sending ascending pain messages to the brain
• 'The injured person experiences no pain

More recent research about this pathway can be found here.