1. Nature Versus Nurture Neurons, The Brain and Nervous System Science 2 Fall 2014 Dr. Michael Sneary Neurons, The Brain and Nervous System Science 2 Fall 2014 Dr. Michael Sneary

2. Today’s Topics  The Concept of Nature Versus Nurture  Overview of Function of the Nervous System  Anatomy of a Neuron  Stages of the development of the brain  Developmental Milestones  The Concept of Nature Versus Nurture  Overview of Function of the Nervous System  Anatomy of a Neuron  Stages of the development of the brain  Developmental Milestones

3. What is Nature Versus Nurture?  What determines our physical characteristics? Heredity? Environment? Nature Nature Nurture Nurture

4. Nature, Nurture or possibly both?  Nature(genetic)Nurture (environment)  Eye color (Blue, Brown, etc..)Eye color (Blue, Brown, etc..)  Menopause Hormone replacement therapy  Production of Vitamins DVitamin D pills  AllergiesAllergies  Disease (Diabetes, heart disease, cancer)Disease (Diabetes, heart disease, cancer)  We as a species have lost much of We as a species lost much of our body hair our body hair  Pigmentation or skin colorPigmentation or skin color  Nature(genetic)Nurture (environment)  Eye color (Blue, Brown, etc..)Eye color (Blue, Brown, etc..)  Menopause Hormone replacement therapy  Production of Vitamins DVitamin D pills  AllergiesAllergies  Disease (Diabetes, heart disease, cancer)Disease (Diabetes, heart disease, cancer)  We as a species have lost much of We as a species lost much of our body hair our body hair  Pigmentation or skin colorPigmentation or skin color

5. Function of the Nervous System  Helps Maintain Homeostasis- regulates its internal environment to maintain a stable, constant condition  Responds to internal environment  Responds to external environment  Survival of the Organism  Helps Maintain Homeostasis- regulates its internal environment to maintain a stable, constant condition  Responds to internal environment  Responds to external environment  Survival of the Organism

6. How Do Nerve Cells Communicate to Each Other?  Chemically  Electricity  Chemically  Electricity

7. Nature and Nurture in the Nervous System  The neuron and its synapses are important in nature and nurture 1. http://chemistry.caltech.edu/~fucose/Neural%20Coonections.htm 1

8. What is a Neuron?  A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling  Chemical signaling occurs via synapses, which are specialized connections with other cells.  Neurons connect to each other to form networks  Neurons are the core components of the nervous system which includes the brain, spinal cord, and peripheral ganglia  From Wikipedia : http://en.wikipedia.org/wiki/Neuron  A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling  Chemical signaling occurs via synapses, which are specialized connections with other cells.  Neurons connect to each other to form networks  Neurons are the core components of the nervous system which includes the brain, spinal cord, and peripheral ganglia  From Wikipedia : http://en.wikipedia.org/wiki/Neuron

9. Anatomy of the Neuron  Dendrites  Receive Information  Cell Body  Contains Nucleus and Genetic Information  Axon  Transmits information  Dendrites  Receive Information  Cell Body  Contains Nucleus and Genetic Information  Axon  Transmits information

10. Anatomy of the Neuron  Synapse Site of communication between neurons Site of neurotransmitter (NTX) release (chemicals which transmit signals from neuron to neuron or another cell)  Pre-synaptic Terminal Contains synaptic vesicles (with NTX)  Synapse Site of communication between neurons Site of neurotransmitter (NTX) release (chemicals which transmit signals from neuron to neuron or another cell)  Pre-synaptic Terminal Contains synaptic vesicles (with NTX)

11. Chemical synapses are: specialized junctions through which neurons signal to each other allow neurons to form circuits within the central nervous system, allow neurons to form circuits within the central nervous system, crucial to the biological computations that underlie perception and thought crucial to the biological computations that underlie perception and thought allow the nervous system to connect to and control other systems of the body allow the nervous system to connect to and control other systems of the body From Wikipedia Chemical synapse http://en.wikipedia.org /wiki/Presynaptic Receivers Transmitters surrounded by Myelin (outer coat) Cell body Genetic info & nucleus Site of communication between cells

12. Anatomy of the Neuron  Post-synaptic Neuron Contains receptors for NTX Neurotransmitters are chemicals which transmit signals from a neuron to a target cell across a synapse [1] [1]  Post-synaptic Neuron Contains receptors for NTX Neurotransmitters are chemicals which transmit signals from a neuron to a target cell across a synapse [1] [1]

13. Anatomy of the Neuron  Myelin- a dielectric (electrically insulating) material that forms a layer, around the axon of a neuron. It is essential for the proper functioning of the nervous system. Speeds conduction of action potentials (Nerve Impulses)  Pre-synaptic Terminal Contains synaptic vesicles (with NTX)  Myelin- a dielectric (electrically insulating) material that forms a layer, around the axon of a neuron. It is essential for the proper functioning of the nervous system. Speeds conduction of action potentials (Nerve Impulses)  Pre-synaptic Terminal Contains synaptic vesicles (with NTX)

14. Nature and Nurture in the Nervous System  What are the developmental milestones in the nervous system?

15. The Brain from conception to birth: Slide From Brain Facts: Society for Neuroscience http://www.sfn.org/skins/main/pdf/brainfacts/2008/brain_development.pdf

16. Fetal Development  First trimester  Synapses begin to form  Second trimester  The fetus can move  Third trimester  Sensory pathways form  First trimester  Synapses begin to form  Second trimester  The fetus can move  Third trimester  Sensory pathways form

17. Newborn to 3 Months  Visual and other systems start to mature

18. First Two Years  100 billion nerve cells form  Myelination begins  100 billion nerve cells form  Myelination begins

19. First Two Years  The following systems begin to develop  Motor  Language  Emotional  Memory  Sense of self  The following systems begin to develop  Motor  Language  Emotional  Memory  Sense of self

20. Two to Twelve Years  Synapses are sculpted or strengthened by experience

21. Teen Years  Last big maturation of the brain-a second growth and sculpting spurt-impacted in part by the activities one engages in (use it or loose it)  Brain still developing (mainly the pre frontal cortex)  Reasoning, Planning and Judgment abilities still not fully realized  Emotional systems still maturing  Attention systems still maturing  Myelination continues  Last big maturation of the brain-a second growth and sculpting spurt-impacted in part by the activities one engages in (use it or loose it)  Brain still developing (mainly the pre frontal cortex)  Reasoning, Planning and Judgment abilities still not fully realized  Emotional systems still maturing  Attention systems still maturing  Myelination continues

22. Diseases which manifest during the teen years – 20s  Schizophrenia  Depression  Addiction  Schizophrenia  Depression  Addiction

23. Early Twenties  Memory systems start to decline  Prefrontal cortex continues to mature  New synapses in language and perception centers  Myelination continues  Memory systems start to decline  Prefrontal cortex continues to mature  New synapses in language and perception centers  Myelination continues

24. Up to Thirty-two Years  Myelination continues

25. The Aging Brain  Small loss of cells  Some loss of synapses  Physical activity positively impacts the ability of the brain to remember information  Evidence suggests that if an aging person remains active; doing so will decrease the rate of mental decline and possibly prevent it altogether  Plasticity present through life  Small loss of cells  Some loss of synapses  Physical activity positively impacts the ability of the brain to remember information  Evidence suggests that if an aging person remains active; doing so will decrease the rate of mental decline and possibly prevent it altogether  Plasticity present through life

26. Diseases of the Aging Brain  Parkinson’s disease  Alzheimer’s disease  Both can be treated at this point but neither cured with current technology  Parkinson’s disease  Alzheimer’s disease  Both can be treated at this point but neither cured with current technology

27. Topics Covered Today  The Concept of Nature versus Nurture  Nature and Nurture in the Nervous System  Developmental Milestones of the Brain  The Concept of Nature versus Nurture  Nature and Nurture in the Nervous System  Developmental Milestones of the Brain

28. Dendrite Soma Axon Nucleus Node of Ranvier Axon terminal Schwann cell Myelin sheath