Biopsych Exam 1

Front 1

What is biopsychology?

Back 1

It examines the relationship between the brain and behavior.
- How does the nervous system mediate what we perceive, feel, think, say, and do?
- Uses principles and methods from psychology, biology, physiology, chemistry, pharmacology, and anatomy.

Front 2

Biopsychology v. neuroscience

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Neuroscience is the study of the brain. Biopsychology is the study of the nervous system.
- Biopsychology used to be in the realm of philosophers. It is a discipline of neuroscience that attempts to tie several disciplines (neuroanatomy, neurophysiology, neurochemistry, neuroendocrinology, neuropharamacology, neuropathology) together and to examine how these disciplines affect behavior

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Roots of biopsychology 1

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1. 7000 years ago: there is evidence of trephining (cutting a hole in someone's brain) found in skulls that are 7000 years old.
2. Egyptian hieroglyphics that are 3000 years old talk about the brain, but the brain obviously wasn't too important to the egyptians because they threw it away during mummification

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Roots of biopsychology 2 + philosophers

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3. Hippocrates was the first to suggest that the brain was intellect
4. Galen began to make observations about gladiators who came back from battle. He notices that brain injuries led to behavioral changes
- From that, people began to draw what the brain looked like.
5. Da Vinci later took out the brain and made a cast so that he could see the brain's structures and anatomy
6. Descartes observed garden statues and hydrolics. From that, he hypothesized that it was hydrolics that determined how movement worked and that there was a mind/body interaction in the pineal gland

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Roots of biopsychology 3

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7. Leavenhook - created the light microscope and realized that light could be used to penetrate thin tissue
8. Galvini - came up with the idea that electricity transmits messages in the nervous system.
- Had frog legs hooked up to a weathervane and would make the frog legs jump and dance during a thunderstorm
9. Cajal - discovered that the nervous system is made up of separate cells

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Roots of biopsychology 4

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10. Gall - came up with phrenology (the bumps of your head are indicative of specific characteristics and functions)
- Not accurate, but today we have the idea of brain localization (using a PET scan or fMRI)
11. Broca - came up with the area of the brain responsible for speech production
12. Fritsch and Hitzig - localization of motor function in the cerebral cortex
13. Hughlings-Jackson - came up with the idea that brain functions are hierarchical, with more complicated functions being carried out by higher parts of the brain
14. William James - mind is a function of brain and all human cognition and behavior is the result of physiological processes

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Neuropsychology

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Focuses on the behavioral deficits produced in humans by brain damage. Cannot study these effects by direct experimental manipulations
- uses things like CT and MRI

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Comparative psychology

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Studies the evolutionary and genetic factors of behaviors among and across species, using laboratory research and/or research in a natural environment

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Psychopharmacology

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Studies how drugs affect behavior, favoring pure research and using drugs in experiments to reveal the nature of brain-behavor interactions
- autoradiography, rats, etc.

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Cognitive neuroscience

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Newest division of biopsychology. Focuses on the neural basis of mental processes like learning and memory, attention, and complex perceptual processes. Often uses noninvasive, functional brain imaging techniques, such as fMRI

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Physiological psychology

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Puts physiology first. Focuses on the direct manipulation of the nervous system in a controlled laboratory setting by using techniques such as lesions, electrical stimulation, and invasive recordings, primarily using laboratory animals. Invasive because they want to know about specific parts of the brain first and behavior second

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Psychophysiology

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Put psychology first. Focus on the relation between physiology and behavior by recording the physiological responses of human subjects. Use non-invasive techniques (like EEG) and took at mental processes first.

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Questions/goals of biopsychology

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1. how does the brain function?
2. can we improve normal functioning?
3. what can go wrong in the brain?
4. can disease be prevented/cured?

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Three main approaches

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1. Manipulating the body may affect behavior
--- somatic interventions ----> behaviors affected

2. Experience affects the body
--- somatic interventions <---- behavioral interventions

3. Bodily and behavioral measures covary
--- somatic variables <----> behavioral variables

A biopsychologist attempts to understand it all

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Examples of bad science

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1. Moniz in 1949 won a Nobel prize for frontal lobotomies.
- A chimp named Becky was uncontrollable. To control her behavior, they lobotomized Becky, and she became very calm. Moniz took that idea and started to lobotomize regular people with aggression and other behavioral problems
--- This is bad science because it was based on 1 chimp, inhumane, and assumed what was good for a chimp was good for humans
2. Delgado tried to tame a bull by activating a part of the brain in the bull and make it stop charging. From this, he concluded that the basal ganglia mediated aggression
- Bad science because he assumed that the bull's not charging meant the bull was no longer angry.

Front 16

The neuron doctrine

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Santiago Ramon y Cajal established that the nervous system was composed of separate cells

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Neurons

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cells specialized for communication and information processing

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Glia

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specialized cells that perform a variety of support functions for neurons and outnumber neurons 10/50:1

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Histology

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looking at the minute structures of a cell

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Staining

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1. tissue is acquired (profusion + hardening)
2. tissue is sectioned into thin slices
3. slices are mounted onto slides
4. stain/immunocytochemistry

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Types of staining

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1. staining for architecture
- golgi silver stain
- nissl stain
- myelin stain
2. staining for projections
- horseradish peroxidase
3. immunocytochemistry
4. situ hybridization
5. c-fos

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Golgi silver stain

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Used to characterize the shapes of neurons because not all neurons have the same shape when stained

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Nissl stain

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This stain saturates and binds to Nissl bodies (ribosomes responsible for making proteins in the cell); help detect how many cells are in a particular area
- used to determine the concentration of cells in an area. is the lack of cells causing a disease?

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Myelin stain

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Myelin is the sheath that covers the axons of some (not all) neurons. Used to see how thick/thin/wore down the sheath is

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Anterograde projection

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What a neuron projects to

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Retrograde projection

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What a neuron projects from

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Horseradish peroxidase

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Helps see where a projection comes from (retrograde). HRP is absorbed in the terminals and works its way back into the cell bodies when injected into the brain.

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Immunocytochemistry

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Helps target specific proteins (by creating antibodies that bind to a specific protein) so you know where a particular protein is because it is labeled (to see the antibody)

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Situ hybridization

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looking at the genetic expression (DNA/RNA) which provides signals to a make a specific protein before the protein is present (maybe there are changes but the changes are not complete, so you can't detect the protein with immunocytochemistry; like a precursor)

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c-fos

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an immediate early gene; when we label this, we can see exactly when a gene becomes active and expressed

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Autoradiography

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An early neurotracing technique to see where a projection may go (anterograde)
1. inject a radioactive substance (like tritium)
2. allow uptake by neurons and transport through dendrites and axons (approx 24-72 hours)
3. profuse and slice animal
4. mount on photographic slides
5. radioactive substance will develop the slide (so the darkest parts are where something is most active)

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Electroencephalogram (EEG)

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Non-invasive. Uses surface electrodes. Diagnostic.
- reflects all electrical activity (neurons, skin, muscles, etc)
- does NOT provide a pure view of neural activity
- is a diagnostic tool that can measure certain brain states and pathologies

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Computed Tomography (CT)

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Non-invasive. Uses x-ray. Diagnostic. Shows if something is present or not
- Like an x-ray on steroids. the xray source is rotated around the brain and individual images are reassembled by the computer
- provides a cross-sectional image of the brain, showing only the brain's structure

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Positron Emission Tomography (PET)

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Non-invasive. Functional.
- During a PET scan, the patient receives an injections of a short-lived, radioactive substance. More glucose and oxygen are used by neurons that are active, so the PET scanner records the signal these substances emit as they travel throughout the brain. The computer reconstructs the patterns of detected radioactivity into a 3D picture of brain activity
--- used to detect cancer; cancer cells use glucose more quickly than normal cells

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Magnetic Resonance Imaging (MRI)

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Non-invasive. Diagnostic.
- Elements/protons in our body are magnetic and when you turn a magnet on, they all line up. Then, you shoot a beam and it knocks the protons down. The MRI measures how long it takes the protons to get back up and realign after being knocked down (giving information about how dense materials are)
--- allows us to see mass and how it has changed, density of tissue

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fMRI

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Non-invasive. Functional.
Can see the activity of the brain, and uses contrasts to see where blood is going in a specific area.

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Invasive procedures for examining brain function

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In general, the rat is put on a stereotaxic frame that allows identification of brain structures. Then, an electrode, injection tube, or other device is lowered into the brain at the precise coordinates

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Brain atlas

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used to locate a structure in 3D

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Leison

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To damage of remove a brain structure to assess behavior in the absence of that structure.
- can be electrical, chemical, reversible, cryogenic blockade

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Cryogenic blockade

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a reversible lesion where you freeze the area so that it is no longer functional to see what happens and then the animal returns to normal functioning when the brain thaws.

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Stimulation

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a small electrical current is passed through an electrode in order to activate neurons, causing them to fire

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Unit recording

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electrodes placed within the brain record from individual neurons when they fire (rate and time of firing); 3 types:
1. extracellular - do not penetrate the cell to get a recording
2. intracellular - penetrate the neuron (action potential)
3. patch clamp - recording the activity of a single channel on a neuron

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In vivo microdialysis

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alive; allows sampling of fluid used to analyze concentrations of neurotransmitters or enzymes in a particular region
- with HPLC identifies chemicals in a sample

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Mice

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what type of mice should be used?
1. inbred mice - genetically identical so all of their genes are the same
2. knock out mice - particular genes are KO'd or deleted
3. transgenic mice - one or more genes is added to see if adding the gene causes a specific change

Front 45

Brain cells

Back 45

2 types:
1. neurons
- about 100 billion
- come in many shapes and sizes
2. glia
- much more prevalent than neurons (10x more)
- many types
- play a critical role in neurotransmission

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Glial cells

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"glue"
- first described in 1846 by neuropsychologist Virchow
- glial functioning was largely ignored until recent research showed that glial cells played a role in neurotransmission

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Cell types

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1. stem cells - cells that have to potential to become any type of cell
2. progenitor cells - similar to stem cells but they have a fewer range of things they can become
3. blast cells - even more directed, taking shape of what they may become (neuroblast or glioblast)
4. neuron or glia

Front 48

Stages of neural development

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1. neurogenesis - stem cells start developing in the neural tube
2. migration - cells begin to migrate from ventricular zone on radial glial cells. at this point, you don't know whether something is a stem cell or a progenitor cell
3. differentiation - cells have reached the area and they start becoming blasts
4. synaptogensis - beginning the formation of synapses
5. apoptosis - neuronal cell death (because a lot of the connections made during synaptogenesis were not viable or unnecessary)
6. synaptic rearrangement - makes synaptic connections more directed and more goal-oriented.

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Radial glial cells

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Radial glial cells allow progenitor cells to adhere and bind to them and crawl along the glial cell until they reach their destination (from ventricular zone to marginal zone)

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Ectoderm

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The ectoderm is what will make up the skin and brain. We also have a neural plate. There is a neural crest that forms from the neural plate, and the neural crest eventually forms the brain plate, neural tube, and central canal.
- cerebrospinal fluid is made in the central canal.
- neurogenesis begins in the ventricular zone of the central canal which is in the middle of the neural tube.

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Glial cells + functions

Back 51

1. guide migration of neurons during development (radial glial cells)
2. provide firmness and structure
3. nourish neurons
4. nervous system plasticity (information storage)
- modulate the uptake of neurotransmitters
- regulate extracellular ion concentration
- glial cells have a global effect (whereas neurons have a more local effect)

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Roger Sprry

Back 52

Asked questions about where/when/how neurons know where to know.
- Looked at newts who go through neurogenesis.
1. cut the optic nerve and noticed that the salamanders regained vision
2. cut the optic nerve and rotated the eye ball 180 degrees
- if the newts saw upside down, this means that cells regenerate and go back to their original location
- if the news saw right side up, this means that the cells regenerate to a new site
--- what really happened was that the salamanders saw upside down. So, there is a target cell and the neurons go back to the original location. The target cells give off specific chemicals (chemoattractants and chemorepellants) so that neurons know where to do during neurogenesis.

Front 53

Types of glia

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1. Macroglia
- oligodendrocytes
- schwann cells
- satellite cells
- astrocytes
2. Microglia
- ependymal cells

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Oligodendrocytes

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Have many extensions from the cell bodies
- produce myelin sheaths in the CNS
- form segments of myelin sheaths of numerous neurons at one
- provide structure and support
- have organelles to help grow

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Schwann cells

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Produce myelin sheath in the PNS
- a single schwann cell makes up 1 segment of an axon's myelin sheath in the PNS

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Satellite cell

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Flattened cell arranged around cell bodies of neurons in ganglia in PNS
- usually found around schwann cells
- function to provide support and nutrients to neurons in the ganglia of the PNS
- may stimulate the production of more schwann cells

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Astrocytes

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Most numerous glial cells; star-shaped with long processes
- extensions make contact with blood vessels, pia mater, and neurons
- regulate the exchange of blood/ions/chemicals from neuron to neuron

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Astrocytes + functions

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1. scaffolding to hold neurons in place
2. transports nutrients from blood vessels to neurons
3. influences tightness of blood brain barrier
4. regulates the content of extracellular space
5. removes debris and helps seal off damaged tissue following injury
- harder to regenerate after injury in the CNS because astrocytes are not as good and they leave behind scar tissue on the axon so axons lose some functionality

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Microglia

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represent 10% of all glial cells
- monitor health of brain tissues (and function as the immune cells of the brain, like macrophages)
- better at cell repair than astrocytes

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Ependymal cells

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Squamous, columnar, ciliated cells that line the cavities (like the ventricles) of the CNS
- help to circulate cerebrospinal fluid
- can also produce and reabsorb cerebrospinal fluid

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Reticular theory

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The reticular theory suggests that the nervous system is a syncytium, a network of living material having multiple nuclei and cytoplasmic continuity from one place in the network to another

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Neuron doctrine

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The neuron doctrine suggests that the nervous system, like all other biological tissues, is composed of discrete cells, called neurons, each with just one nucleus and surrounded by a cell membrane

Front 63

Golgi + Cajal + neuron doctrine

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in 1873, Golgi devised the silver nitrate method of staining nervous tissue
- Cajal used Golgi's staining method, greatly improved it, and carried out detailed anatomical studies of the shapes and distributions of neurons in many parts of the nervous system

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Early evidence for the neuron doctrine

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- Neurons are clearly seen as individual cells during embryonic development
- small lesions in the nervous system produced localized discrete degeneration, as if parts of individual cells had been severed
- golgi stains highlighted what appeared to be individual cells

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Irony of neuron doctrine

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Golgi and Cajal share a nodel prize in 1906 for the neuron doctrine, but ironically, golgi was a proponent of the reticular theory

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Neuron + cell body

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the neuron cell body has organelles, integrates synaptic energy, makes energy, and makes neurotransmitters or other proteins

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Organelles + mitochondria

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powerhouse; makes energy (ATP) from glucose

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Organelles + nucleus

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stores DNA and RNA

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Organelles + nucleolus

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makes the machinery to make neurotransmitters (ribosomes)

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Organelles + ribosomes

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made by the nucleolus; used to assemble proteins; made of RNA and other proteins; has the code

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Organelles + rough ER

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rough because it has ribosomes attached to it; like a conveyor belt that puts the parts of a neurotransmitter together

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Organelles + smooth ER

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conveyer belt; transports proteins to the golgi

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Organelles + golgi apparatus

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puts a membrane around the neurotransmitters that the ER manufactures so that the neurotransmitter does not interact with everything

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Neuron + cell membrane

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a double layer of phospholipids separates the intercellular fluid and the extracellular fluid, and this membrane wraps around the cell body and dendrites
- protein ion channels allow movement of molecules across the membrane
- hydrophilic heads; hydrophobic tails

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Neuron + neuronal cytoskeleton

Back 75

The neuronal cytoskeleton helps axons keep its shape
1. microtubules - provide transportation for proteins, neurotransmitters, etc
- tau protein helps keep the structural integrity of the cytoskeleton and microtubules (lack of tau causes alzheimers)
2. neurofilaments - provide structural support
3. microfilaments - may change the structure of the neuron in response to learning
- can change synaptic connections

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Neuron + axons/dendrites

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- axons transmit action potentials
- action potentials originate in the axon hillock
- many axons are insulated by myelin
- axon terminals contain synaptic vesicles (vesicles that contain NT)
- dendrites and dendritic spine receive input from other neurons
--- little protuberances from the dendrites increase surface area to gather as much information as possible. many protuberances are associated with excitatory neurons

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Axon hillock

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the switch; decides if there will be an action potential or not

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Structural variations in neurons

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1. unipolar neurons
2. bipolar neurons
3. multipolar neurons

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Unipolar neurons

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have one process leaving the cell body

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Bipolar neurons

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have two processes leaving the cell body

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Multipolar neurons

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have multiple processes leaving the cell body (usually, this is one axon and many dendrites)

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Ways to classify neurons

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1. according to structure (the number of processes)
- unipolar
- bipolar
- multipolar
2. according to functions
- sensory neuron
- motor neuron
- interneuron
3. according to size (and shape)
- of cell body
- diameter (thickness of branches)
- axon length (projection and local neurons)
4. according to neurotransmitter content
- ex. dopaminergic cell
5. according to the scientist who first characterized it
- ex. purkinje cell

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Sensory neuron

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Afferent neuron; usually unipolar; transmits information about the environment to the CNS

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Motor neuron

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Efferent neuron; usually multipolar; transmits commands from the CNS to the muscles and glands

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Interneurons

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Have cell bodies that are located inside the CNS (smaller cell body with dendritic arborization)
- most are inhibitory
- communicate locally
- act as a bridge between sensory and motor neurons

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Projection neurons

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Also called golgi type 1 neurons
- really long projections going from the brain to the toe
- like motor neurons
- ex. pyramidal

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Local neurons

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Also called golgi type 2 neurons
- like interneurons

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Cortical lamination + cerebellum

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1. molecular layer
- made of stellate (star-shaped) and basket cells, most of which are inhibitory
2. purkinje cell layer
- made of purkinje cells because the cerebellum is responsible for movement
3. granular layer
- made of granule and other cells

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Granule cells

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The granule cells located in the olfactory bulb and the dentate gyrus of the hippocampus are the only places where neurogenesis can occur in human beings after birth

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Cortical lamination + cerebrum

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1. allocortex ("other" cortex")
- 3 layers
- envelopes the olfactory bulb and dentate gyrus of hippocampus
2. neocortex ("new" cortex)
- 6 layers
- has 2 different kinds of neurons - pyramidal and non-pyramidal
- each layer is distinct; consists of either groups of cells of particular sizes or patterns of dendrites/axons
- columnar organization (vertical orientation; mini-circuit that forms a single function)
- relative thickness of layers caries across cerebral cortex, depending on the differences in function

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Electrical neurotransmission within the neuron

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1. postsynaptic potentials (dendrites and soma)
2. action potentials (axons)

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Chemical neurotransmission between neurons

Back 92

with neurotransmitters

Front 93

Membrane potential (Mv)

Back 93

The difference in charge across the membrane
- more positive outside the neuron (recording electrode)
- more negative inside the neuron (reference electrode)

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Concentration gradient

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The membrane potential results from a separation of positive and negative charges across the cell membrane
- primarily bc of the anions that are abundant inside of the cell

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Ion channels

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1. gated
- open and close in response to specific chemical, mechanical, or chemical signals
2. non-gated

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Four factors determining movement across the membrane

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1. force of diffusion
2. electrostatic force
3. selective permeability
4. ion pump

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Force of diffusion

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particles more from areas of high concentration to areas of low concentration.
- when channels open, cations flood in, changing the action potential

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Electrostatic force

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like changes repel each other; opposite charges are attracted to each other

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Selective permeability

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The cell membrane permits some substances to pass through but not others
- anions (-) are completely impermeable
- K+ is moderately permeable; Na+ is kinda sorta not really permeable
- Cl- is very permeable

Front 100

Ion pump

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Maintains concentration differences that create electrical differences across the membrane (3 Na+ leave, 2 K+ come in)

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Action potential

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Revealed in early 1950's by Huxley and Hudgkin's studying a squid's giant motor axons
- stimulation immediately and directly affects mV
--- graded action potential - further from stimulator = weaker effect
- hyperpolarization makes it less negative
- depolarization makes neg for a little bit but after reaching threshold, all Na+ channels open and you see a spike in action potential
--- Once threshold is reached, the action potential is no longer graded. instead, it is just as strong all across the axon

Front 102

Bioelectric properties of neurons action potentials

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Movement (or lack thereof) across the membrane
- at rest: K+ moves across the membrane but the movement of Na+ is blocked
- however, a slight change in the membrane voltage opens Na+ channels
--- first at the axon hillock and then all down the axon

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Refractory period

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A point at which no other action potential can be generated

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Absolute refractory period

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Inactivation gate closes inside Na+ channel, so no action potential can be generated because no Na+ can enter the cell

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Relative refractory period

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Generally, there will not be an action potential, but it could be generated if it was strong enough to overcome the after potential