961 lines
24 KiB
Markdown
961 lines
24 KiB
Markdown
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##What is neuroscience?
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Neuroscience is a field of scientific study that seeks to understand how the nervous system carries out its functions and what goes wrong when it doesn’t. While we understand much about nervous system function, there is much to learn. You are the scientists who will figure it all out.
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[President Obama brain initiative](http://abcnews.go.com/Politics/video/obama-says-brain-initiative-will-be-transformative-18861944)
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http://courses.pbsci.ucsc.edu/mcdb/bio125/
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Note:
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Welcome. This class will be an Introduction to Neuroscience– Neuroscience is a field that by necessity integrates information and techniques from many other scientific disciplines— not just biological sciences like genetics, molecular biology, biochemistry, immunology, physiology. But also physics, engineering, computer science, psychology. And these days neuroscience is touching upon fields as varied as sociology, criminology, marketing, ethics, and the law. So what is Neuroscience? Neuroscience is fundamentally a field that…
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Thus it will be you, and your children, and your children’s children that will figure it all out and literally allow human beings to reach the stars or save us from the cylons on battlestar galactica, whichever comes first. And hopefully recent funding initiatives will help in this cause.
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---
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##What are the nervous system’s functions?
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* The nervous system organizes and controls an individual’s appropriate interactions with the environment.
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* Thus, it’s functions are dynamic, vast and wide-ranging – extending to include all thoughts, perceptions, bodily actions, behaviors, and even the very essence of one’s being: consciousness and the mind.
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['Star Trek' Wars](http://on.cc.com/1r4rOE1)
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http://courses.pbsci.ucsc.edu/mcdb/bio125/
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<figure><img src="figs/ScreenShot2016-01-04at12.58.17PM_e1dcf52.png" height="100px"><figcaption></figcaption></figure>
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Note:
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What does the nervous system do? It organizes and controls an individuals interactions with the environment. It does this by processing current or past experiential information and making and executing behavioral decisions.
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Therefore the brain’s functions are dynamic, vast and wide ranging, and extends to include all thoughts, perceptions, and actions and the very core of what it means for each of one us to be us–– consciousness and the mind. It is this complex lump of biological tissue, this emergent computational system that allows us humans to not only imagine the future, but to create it as well.
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---
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##We will focus on a few basic features of the nervous system
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* The mechanisms by which neurons produce signals.
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* The patterns of connections between nerve cells.
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* The relationship of different patterns of interconnections to different types of behavior.
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[http://courses.pbsci.ucsc.edu/mcdb/bio125/](http://courses.pbsci.ucsc.edu/mcdb/bio125/)
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<figure><img src="figs/ScreenShot2016-01-04at3.59.29PM_dea1077.png" height="100px"><figcaption></figcaption></figure>
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Note:
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…
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---
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##The nervous system and its function is the product of both our genes and our environment
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* We are now in a gene-centric “post-genomic” phase of neuroscience
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* Human genome sequenced- approximately 20,000 genes.
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* Most genes are expressed in the brain, either during development or in the adult. It is the spatial and temporal regulation of these genes that builds a nervous system.
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* Mice, flies, and worms have nervous systems and even express many of the same genes as humans. Genetics allows us to correlate gene activity with nervous system function.
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* Neuroscience therefore encompasses many fields, including genetics, cell biology, physiology, and development biology.
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Note:
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…
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---
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##Genome size does not correlate with nervous system complexity
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100,000,000,000
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71,000,000
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302
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10,000,000
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250,000
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Number of
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neurons in whole nervous system
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<figure><img src="figs/Neurscience5e-Box-01A-0_0eadd2b.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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Number of genes is not related to nervous system complexity or size. The nematode c. elegans has just 302 neurons, and yet its genome contains virtually as many genes as a humans. An african elephant brain weighs 3 times more than a human brain and has 3 times the number of neurons.
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The largest brains are those of sperm whales, weighing about 8 kg (18 lb). An elephant's brain weighs just over 5 kg (11 lb), a bottlenose dolphin's 1.5 to 1.7 kg (3.3 to 3.7 lb), whereas a human brain is around 1.3 to 1.5 kg (2.9 to 3.3 lb). Brain size tends to vary according to body size.
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---
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##There are many brain-specific and non-brain specific genes expressed in the nervous system
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<figure><img src="figs/Neurscience5e-Fig-1_d17d3e9.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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There are many genes are expressed only in the brain, but there are many genes expressed in the brain that are not specific to only the nervous system.
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---
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##A single mutation can lead to dramatic brain size defects
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Mutation in a spindle pole gene call ASPM1
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<figure><img src="figs/Neurscience5e-Fig-2_920386b.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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Now mutations in single genes in the right place in our genome can cause drastic effects on the formation of our brain’s wiring.
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For example, shown here is a person with a mutation in ASPM1 a protein used to make spindle poles for mitotic stem cells during embryonic development.
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But most single gene mutations do not cause such drastic effects, with a more subtle and complex set of genetic and environmental risk factors causing neurological disease, similar to and probably exceeding the complex etiology of cancer.
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---
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##Model organisms— C. Elegans
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* It is hard to visualize and monitor neurons and manipulate genes in humans so neuroscientists study a number of different organisms.
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* Worm nervous system highlighted with green fluorescent protein (GFP): 302 cells
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<figure><img src="figs/image_69d9fc5.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Now to do neuroscience research we have to use model organisms of course. Small number of neurons, can be labeled using GFP or other means. Many mutant worms have been isolated that affect nervous system function.
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---
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##Model organisms— Mus. Musculus
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The mouse is a common model in neuroscience research
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[http://www.youtube.com/watch?v=5D7bbyguACI](http://www.youtube.com/watch?v=5D7bbyguACI)
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<figure><img src="figs/image1_fb40934.png" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/image2_920ce96.png" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##Model organisms— squid
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Squids have unusually large axons
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1 mm
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<figure><img src="figs/image3_ce90492.png" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/image4_9435689.png" height="100px"><figcaption></figcaption></figure>
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Note:
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jules verne
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---
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##Model organisms
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Higher mammals are used to study more complicated brain functions
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<figure><img src="figs/image5_a061f83.png" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/image6_57f7719.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Research with cats was critical for work from the 1950s to 1980s that allowed neuroscientist to learn how visual signals are processed in the highests circuits of the mammalian brain.
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And research with monkeys has been really essential for learning about perceptual, attentional, and decision making in the mammalian brain.
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---
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##Brain lesion patients
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* Lesions in brains or degenerative diseases help us understand brain functi* Phineas Gage- Railroad spike through frontal lobes changed his personality.
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<figure><img src="figs/image7_0e1af20.png" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/image8_c3232ea.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Furthermore, studies of patients with brain lesions has historically been key to localizing parts of the brain that affect emotional states and learning and memory.
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e.g. Phineas Gage in 1848 his whole personality changed after the spike went through his brain.
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Harlow wrote: “the equilibrium ... between his intellectual faculties and his animal propensities seems to have been destroyed”
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---
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##What are brains made of?
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<figure><img src="figs/image9_e303503.png" height="100px"><figcaption></figcaption></figure>
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Note:
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So what are brains made of? Is it just a glob of squishy jello?
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---
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##What are brains made of?
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Wikimedia Commons
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<figure><img src="figs/image10_c067a0a.png" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/image11_fbb6fc7.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Yes— but this tissue is some pretty complicated soft tissue. The answer is the brain is made of cells.
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Shown here is a section through a human brain. If we zoom in on a tiny part of it
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---
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##How many neurons in a human brain?
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* 100 thousand
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* 10 million
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* 100 million
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* 1 billion
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* 10 billion
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* 100 billion
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Note:
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---
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##Brains are made up of cells
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* Camillo Golgi (Italy)– believed that cells in the brain were connected forming a continuous network (reticular theory).
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* Santiago Ramon y Cajal (Spain)– Brains made up of single cells-communicate at specialized areas called synapses.
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* Shared Nobel prize in 1906
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Note:
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Cells widely accepted everywhere else in the 1830’s. Neuroscientists last to accept this.
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---
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##The Nobel Prize in Physiology or Medicine 1906
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"in recognition of their work on the structure of the nervous system"
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Camillo Golgi
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Pavia University
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Pavia, Italy
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Santiago Ramón y Cajal
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Madrid University
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Madrid, Spain
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<figure><img src="figs/CamilloGolgi_5c05797.jpg" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/SantiagoRamónyCajal_dd682a4.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##Golgi staining
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Golgi staining: potassium chromate and silver nitrate (1873)
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Golgi's drawing of the hippocampus impregnated by his stain (from Golgi's Opera Omnia).
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Nobel e-museum
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<figure><img src="figs/golgi1_7ba8753.jpg" height="100px"><figcaption></figcaption></figure>
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<figure><img src="figs/image12_666d3e4.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Top golgi stain of a cortex at different magnifications, bottom is a drawing of Golgi’s in the hippocampus
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---
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##Is the nervous system a syncytium?
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* syncytium: a mass of cytoplasm with many nuclei but no internal cell boundries
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* Answer: NO!
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* Camillo Golgi
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* Nobel Lecture December 11, 1906
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* The Neuron Doctrine- theory and facts
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* "...Far from being able to accept the idea of the individuality and independence of each nerve element, I have never had reason, up to now, to give up the concept which I have always stressed, that nerve cells, instead of working individually, act together, so that we must think that several groups of elements exercise a cumulative effect on the peripheral organs through whole bundles of fibers."
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<figure><img src="figs/Figure1copy_dc1b35e.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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Golgi drew the structure of the hippocampos as being all fused together into a reticulum, no free axon endings
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---
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##The Neuron Doctrine
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* Santiago Ramon y Cajal
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* Neurons are cells. Each is an individual entity anatomically, embryologically, and functionally.
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* Neurons have a functional polarity
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<figure><img src="figs/02f17_4b77a87.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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Neurons in culture have specific endings. EM methods, dye filling experiments.
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---
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##Two basic cell types in the nervous system
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* Neurons and Glia
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Note:
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---
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##Glia
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* Outnumber neurons by 10-50 fold
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* myelin sheath
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* blood-brain barrier
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* removing debris and excess neurochemicals
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* structural support for neurons
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* critical role in brain development
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<figure><img src="figs/Fig_6852903.png" height="100px"><figcaption></figcaption></figure>
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Note:
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greek for ‘glue’
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|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Types of glial cells
|
|||
|
|
|
|||
|
|
* Microglia- phagocytes, mobilized after infection, injury, or disease
|
|||
|
|
* Macroglia- three types
|
|||
|
|
* Astrocytes– CNS, most numerous type of glia and contain star shaped long processes.
|
|||
|
|
* Oligodendrocytes– Myelin producing cells of the CNS.
|
|||
|
|
* Schwann cells– Myelin producing cells of the PNS.
|
|||
|
|
* Satellite cells– Support cells of the PNS
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Glial Cell Types
|
|||
|
|
|
|||
|
|
* Microglia
|
|||
|
|
* Astrocytes
|
|||
|
|
* Oligodendrocytes
|
|||
|
|
* Schwann cells
|
|||
|
|
* Satellite cells
|
|||
|
|
|
|||
|
|
<figure><img src="figs/10-01_GlialCells_1_bddb845.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Schwann cells
|
|||
|
|
|
|||
|
|
* Myelinate axons in PNS
|
|||
|
|
* One axon per cell
|
|||
|
|
|
|||
|
|
Cross section through PNS nerve
|
|||
|
|
|
|||
|
|
<figure><img src="figs/48_08SchwannMyelin_902bf3b.jpg" height="100px"><figcaption>[neuralcloud.it](http://neuralcloud.it)</figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
Discovered by German scientist Theodore Schwann. In 1839 he actually stated that all animal tissues are made of cells.
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Astrocytes
|
|||
|
|
|
|||
|
|
* Restricted to CNS
|
|||
|
|
* Maintain a proper chemical environment
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image13_f34a1d6.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image14_a95004a.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Oligodendrocytes
|
|||
|
|
|
|||
|
|
Myelinate axons in CNS
|
|||
|
|
|
|||
|
|
Each cell can myelinate multiple axons
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image15_3f99acf.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image16_d6dfaa7.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neurons
|
|||
|
|
|
|||
|
|
* Main signaling unit of the nervous system
|
|||
|
|
* Polarized– have axons and dendrites
|
|||
|
|
* Communicate by electricity– usually using action potentials.
|
|||
|
|
* Tremendous range of different cell types– categorized by morphology, molecular identity and physiological activity.
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
Now let’s think about the cell type most responsible for the brain’s business of biological computation— the neuron.
|
|||
|
|
|
|||
|
|
It is…
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Which of the following cell structures are found in neurons?
|
|||
|
|
|
|||
|
|
* DNA
|
|||
|
|
* RNA
|
|||
|
|
* Nucleus
|
|||
|
|
* ER
|
|||
|
|
* Mitochondria
|
|||
|
|
* Microtubules
|
|||
|
|
* Golgi
|
|||
|
|
* Cell division machinery
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neurons have a functional polarity.
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
Incoming information arrives
|
|||
|
|
|
|||
|
|
Information is assimilated
|
|||
|
|
|
|||
|
|
Information is sent to next neuron
|
|||
|
|
|
|||
|
|
synapses
|
|||
|
|
|
|||
|
|
<figure><img src="figs/neurons_9b62aa4.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Structures of a neuron
|
|||
|
|
|
|||
|
|
* cell body (soma)– metabolic center of the cell, contains the nucleus.
|
|||
|
|
* dendrites– receive incoming signals from other nerve cells
|
|||
|
|
* axon– carries signals to other neurons
|
|||
|
|
* axon hillock– initiates action potentials
|
|||
|
|
* synapse– site at which two neurons communicate
|
|||
|
|
* synaptic cleft– area between pre and post-synaptic cell
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Cell Body Structure
|
|||
|
|
|
|||
|
|
|
|||
|
|
Figure 12.4
|
|||
|
|
|
|||
|
|
Structures of a neuron
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image_7f746fe.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neuronal Processes: Dendrites
|
|||
|
|
|
|||
|
|
* Dendrites
|
|||
|
|
* Extensively branching from the cell body
|
|||
|
|
* Transmit electrical signals (graded potentials) toward the cell body
|
|||
|
|
* Function as receptive sites for other neurons
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Dendritic spines
|
|||
|
|
|
|||
|
|
Purkinje cell
|
|||
|
|
|
|||
|
|
hippocampal dendrite
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image17_7b9d67f.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image18_5c73b35.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
* 2 billion transistors in an iphone6.
|
|||
|
|
* 100 billion neurons, each receiving up to 10000 synaptic connections
|
|||
|
|
* quadrillion synapses, 10^15 in our nervous system
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Dendritic Spines
|
|||
|
|
|
|||
|
|
spine
|
|||
|
|
|
|||
|
|
dendrite
|
|||
|
|
|
|||
|
|
axon
|
|||
|
|
|
|||
|
|
astrocyte
|
|||
|
|
|
|||
|
|
|
|||
|
|
<figure><img src="figs/ImageDescriptionHere_7859c7e.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
False color of the dendrite of one neuron near an axon from another neuron from an EM image
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neuron Processes: Axons
|
|||
|
|
|
|||
|
|
* Axons (nerve fibers)
|
|||
|
|
* Neuron has only one, but it can branch
|
|||
|
|
* Impulse generator and conductor
|
|||
|
|
* Transmits action potentials away from the cell body
|
|||
|
|
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neuron Processes: Axons
|
|||
|
|
|
|||
|
|
* Axons
|
|||
|
|
* Neurofilaments, actin microfilaments, and microtubules
|
|||
|
|
* Provide strength along length of axon
|
|||
|
|
* Aid in the transport of substances to and from the cell body
|
|||
|
|
* Axonal transport
|
|||
|
|
|
|||
|
|
<figure><img src="figs/2-16_042d7c5.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neuron Processes
|
|||
|
|
|
|||
|
|
* Axons
|
|||
|
|
* Branches along length are infrequent
|
|||
|
|
* Axon collaterals
|
|||
|
|
* Multiple branches at end of axon
|
|||
|
|
* Terminal branches
|
|||
|
|
* End in knobs called axon terminals (also called end bulbs or boutons)
|
|||
|
|
|
|||
|
|
Neuron Structure
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neuron Processes: Action Potentials
|
|||
|
|
|
|||
|
|
* Nerve impulse (action potential)
|
|||
|
|
* Neuron receives and sends signals
|
|||
|
|
* Generated at the initial segment of the axon
|
|||
|
|
* Conducted along the axon
|
|||
|
|
* Releases neurotransmitters at axon terminals
|
|||
|
|
* Neurotransmitters – excite or inhibit neurons
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Neurons are classified in different ways
|
|||
|
|
|
|||
|
|
* Morphology: unipolar, bipolar, and multipolar
|
|||
|
|
* Function: sensory neurons, motor neurons, and interneurons
|
|||
|
|
* Neurotransmitter expression: excitatory, inhibitory, dopaminergic, etc.
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Some nerve cell morphologies found in the human nervous system
|
|||
|
|
|
|||
|
|
<figure><img src="figs/Neurscience5e-Fig-3_a0c1df2.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Some neuronal morphologies
|
|||
|
|
|
|||
|
|
Purkinje cell, cerebellum
|
|||
|
|
|
|||
|
|
Hippocampal neuron
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image19_f5adbad.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image20_124ad72.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Some neuronal morphologies
|
|||
|
|
|
|||
|
|
* Pyramidal neurons: multipolar neurons that contain both apical and basal dendrite. Also contain one axon.
|
|||
|
|
* Most common excitatory neuron in the cerebral cortex.
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image21_d8ed7c5.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image22_3c8b8f9.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Different morphologies of neurons in the retina.
|
|||
|
|
|
|||
|
|
Coombs et al., 2006
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image23_f065820.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image24_a2e8d3e.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Fluorescence Microscopy
|
|||
|
|
|
|||
|
|
* Fluorescent molecules absorb light at one wavelength and emit it at another-longer wavelength.
|
|||
|
|
* Uses optical filters to allow only light of a given wavelength in and out.
|
|||
|
|
* Can detect specific proteins or other molecules in cells and tissues.
|
|||
|
|
* Fluorescein (emits green), rhodamine (deep red) are molecules that can be chemically coupled to proteins to detect their localization indirectly
|
|||
|
|
* GFP, isolated from jellyfish is a protein (encoded by a gene) that has intrinsic fluorescence.
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
Fluorescent molecules can be detected with light in very small amounts. This lets us look at specific molecules within a cell if they are tagged with a probe. Remember that most animal cells are not fluorescent. The fluorophore absorbs light energy of a specific wavelength and re-emits light at a longer wavelength. The absorbed wavelengths, energy transfer efficiency, and time before emission depend on both the fluorophore structure and its chemical environment, as the molecule in its excited state interacts with surrounding molecules.
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Secondary antibodies recognize primary antibodies and are species specific.
|
|||
|
|
|
|||
|
|
<figure><img src="figs/figure25-21_22bac65.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image25_ee9722d.png" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
Can couple many things to antibodies
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Fluorescence Microscopy
|
|||
|
|
|
|||
|
|
<figure><img src="figs/0913_4d3b4cf.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/0912_2075faa.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
Here is the maximum excitation and emission wavelengths of several common flourescent probes. The photon emitted is of lesser energy that the one absorbed. In a microscope a filter set is used to only allow a specfic wavelength in and out to the eye.
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##Immunocytochemistry
|
|||
|
|
|
|||
|
|
If you want to look at a macromolecule inside a cell, but it is not fluorescent...use indirect immuno-fluorescence microscopy
|
|||
|
|
|
|||
|
|
<figure><img src="figs/0916_2c6f5e1.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##GFP is an intrinsically fluorescent protein
|
|||
|
|
|
|||
|
|
[2008 Nobel prize site](http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2008/)
|
|||
|
|
|
|||
|
|
[2008 Nobel prize vid](http://www.youtube.com/watch?feature=endscreen&NR=1&v=90wpvSp4l_0)
|
|||
|
|
|
|||
|
|
<figure><img src="figs/0943_14318d1.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
<figure><img src="figs/image_da3e017.pdf" height="100px"><figcaption></figcaption></figure>
|
|||
|
|
|
|||
|
|
Note:
|
|||
|
|
|
|||
|
|
Freshly translated GFP is not flourescent, but undergoes a self-catalyzed post-translational modification that generates a chromophore inside the barrel.
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
##GFP can be expressed under
|
|||
|
|
|
|||
|
|
##specific gene promoters
|
|||
|
|
|
|||
|
|
Figure 9-25 Molecular Biology of the Cell (© Garland Science 2008)
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Here expressed in fly peripheral neurons
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<figure><img src="figs/figure9-25_2b6a94b.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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Remember that GFP is a gene that encodes a protein. You can put it behind the promoter to detect which cells express a given gene.
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---
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##GFP can be used to create designer pets
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[http://news.nationalgeographic.com/news/2009/05/photogalleries/](http://news.nationalgeographic.com/news/2009/05/photogalleries/glowing-animal-pictures/)
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<figure><img src="figs/image26_594c5d6.png" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##All kinds of fluorescent protein variants these days
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<figure><img src="figs/image27_9fff1ca.png" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##Basic structure of a sensory neuron (afferent)
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skin
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spinal cord
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<figure><img src="figs/image28_d35899e.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Afferent- term meaning to send information from periphery to the CNS or to brain
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---
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##Structure of a motor neuron (efferent)
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<figure><img src="figs/image29_bfd15ce.png" height="100px"><figcaption></figcaption></figure>
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Note:
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Efferent sends info to muscles
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---
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##Neurons communicate by electricity
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* Axons project great distances
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* Neurons do not touch each other directly.
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* Come in close proximity at the synapse
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* Use action potentials to transmit information
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* Action potential causes release of neurotransmitter that is received by post-synaptic cells.
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Note:
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---
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##Title Text
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<figure><img src="figs/image30_268faa4.png" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##Properties of the action potential
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* rapid
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* transient
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* all or none
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* self-regenerating
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* can go long distances. 15 m in a giraffe
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* highly stereotyped
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* discrimination is based on patterns of firing
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Note:
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---
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##Neural Circuits
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* Neurons don’t function in isolation- they are organized into circuits that process specific kinds of information.
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* Direction of information flow is important for understanding the function of a circuit
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* Afferent neurons-carry information toward the brain
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* Efferent-carry info from the brain
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Note:
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---
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##Example of a simple circuit:knee jerk response (myotatic reflex)
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<figure><img src="figs/image31_999ac07.png" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##The “knee-jerk response,” a simple reflex circuit
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[http://www.youtube.com/watch?v=RmKKeI9totE](http://www.youtube.com/watch?v=RmKKeI9totE)
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<figure><img src="figs/Neurscience5e-Fig-4_4de973d.jpg" height="100px"><figcaption></figcaption></figure>
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Note:
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---
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##Ways to measure neural activity
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* Extracellular recording– an electrode is placed near a neuron. Measures action potentials. Useful for detecting patterns of activity.
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* Intracellular recording– an electrode is placed inside a neuron-can measure smaller graded potential changes. Useful for isolating responses to single inputs.
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Note:
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---
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##Relative Frequency of Action Potentials in Different Components of the Myotatic Reflex
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extracellular recordings-action potentials
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|
<figure><img src="figs/PN01060_d9ea863.jpg" height="100px"><figcaption></figcaption></figure>
|
|||
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Note:
|
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---
|
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##Intracellularly Recorded Reponses Underlying the Myotatic Reflex
|
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Neuroscience 4e, Sinauer
|
|||
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|
|
<figure><img src="figs/PN01072_ddd3e36.jpg" height="100px"><figcaption></figcaption></figure>
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|
<figure><img src="figs/PN01071_02ebee2.jpg" height="100px"><figcaption></figcaption></figure>
|
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Note:
|
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---
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