Unit 1: Intro, History, & Cells Flashcards
1
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Human Connectome Project
A
Initiative to map neural connections in the brain. Static map.
2
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BAM - Brain Activity Map
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Functional map of brain (while active)
3
Q
Brain disorders
A
Schizophrenia, Depression, Anxiety, Addiction, AD, PD, MS, Stroke, Epilepsy, etc.
4
Q
Historical foundation provided in Koch article
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Summarized humanity’s progression as philosophers and scientists of the mind and brain.
5
Q
Aristotle
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Soul: nature of living thing. Vegetative, sensitive, and rational (humans).
6
Q
What big leap in the study of brain/mind occurred during the Enlightenment?
A
The idea of the rational soul as a physical, biological object. Gave rise to fields of psychology, neurology, and psychiatry.
7
Q
Descarte’s dualism
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Explained natural world mechanistically, but believed the mind (nonphysical) and the brain (physical) were separate entities.
8
Q
Hobbes
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Matter can think
9
Q
John Locke
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Idea of soul similar to modern mind; a subjective experience that arises from outside stimuli and experiences. Notion that our ideas and knowledge are not innate.
10
Q
In the end of the 17th c., the idea of the mind as part of nature was important because
A
Mind is fallible and can become ill. Religious explanations and treatments -> clinical ones. (Before, the sickness of the “rational soul” was seen as possession or witchcraft.)
11
Q
Who was Franz Joseph Gall?
A
A physician of the mid 19th c. Did many dissections and concluded that the brain is the sole organ of the mind, and is composed of different parts with different functions, and that varying sizes of these parts explains individual differences.
12
Q
Why was Gall right but wrong?
A
His attention to localization of function was correct, but phrenology is not.
13
Q
Who else contributed to the idea of localization of function?
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Broca (mid 19th c.) had patient with damage to specific area in brain after stroke and could not speak
14
Q
What and where is Broca’s area?
A
Left interior frontal gyrus; responsible for production of speech.
15
Q
What role did Darwin play?
A
Evolution and theory of natural selection suggested that the mind may have evolved from the minds of our nonhuman ancestors, and is an extension of the minds of other animals.
Humans are not the only ones with minds and consciousness.
16
Q
Koch article
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Provided historical foundation of the mind/brain “problem.” Grappled with historical and present understandings of consciousness and the mind
17
Q
Trepanation/Trephining
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Fossil evidence of humans connecting the head with the mind and behavior, ~10,000 ya ->17th c.
Holes drilled into skull to treat disorders caused by “evil spirits in the head.” People survived this procedure (healing evidence.)
18
Q
What is the point of modern day trepanation
A
Supposedly to improve mental functioning by increasing blood flow. “Effects” caused by placebo and gratitude for surviving, nothing more.
Different than in medicine: craniotomy, to release pressure from the brain.
19
Q
Papyri records list…
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disorders (many of the brain) and medications (emetics and purgatives)
20
Q
The priest/physician Imhotep had a religious view of the brain
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Prayer to treat illness, as well as more scientific procedures.
21
Q
Egyptian hieroglyph phrase for brain literally translates to
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Marrow inside the head
22
Q
Egyptian hieroglyph phrase for brain literally translates to
A
Marrow inside the head
23
Q
What are the inconsistencies of ancient Egyptian culture regarding the brain?
A
Buried all organs in vessels, except scooped out the brain and discarded.
24
Q
Where did some other cultures think was the location of the mind?
A
Stomach, larynx, heart
25
Historically there are three prevailing views regarding
the location of the mind
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Cardiocentric view
Mind in the heart. Believed by Aristotle.
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Encephalocentric view
Mind in head/brain. Believed by Plato for the wrong reasons (cosmology) and Hippocrates (a Monist)
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Ventricular view
Mind in the ventricles of the brain. Brain matter was a vessel only. Different ventricles had different functions.
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What are brain ventricles
Compartments filled with CSF
30
Who was Galen of Rome and what view did he hold regarding the location of the mind?
A gladiator physician, believed the mind was everywhere in the body. This view was influential until the 17th c.
31
Who was Descartes?
17th c mathematician and philospher who sought to explicate a unified theory of the mind and brain.
32
What did Descartes believe?
That only humans had a mind, which existed in a spiritual, nonphysical realm and was separate from the physical machine of the body (including the brain.)
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How did Descartes believe the mind and brain/body were connected?
Descartes believed in Interactionism
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Interactionism
Body and mind interact via the pineal gland
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What is the opposing view to Descartes' dualism?
Physical monism: the mind resulted from the function and activities of the brain. Ongoing debate.
36
Who was an early proponent for physical monism?
Willis, but people didn't really pay attention. Then Crick, in 1994: The Astonishing Hypothesis
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What is the opposite of physical monism?
Psychological monism: the world exists only in our minds and there is no physical reality.
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What are some subcategories of pseudoneuroscience
neuromarketing and neuroeconomics (more legit)
neuropolitics
neuromusicology (more legit)
neuroaesthetics
39
How do we attempt to measure consciousness?
Measure changes in neural activity in response to stimuli
40
How has the brain evolved?
Increase in overall size
Increase in size of certain areas
Increase in complexity (more gyri, synapses, tissue, connections)
Increase in flexibility
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What does it mean for our brain to be flexible?
There are ways for the brain to still function despite damage; it is adaptable.
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What restricts our brain from being bigger?
Must be small enough to fit through the birth canal. Already requires 20% of fuel from blood.
43
What did Penfield do?
Performed awake brain surgery. Labeled areas of the brain based on what the output was when the area was stimulated.
44
Why is an analysis of systems important
The brain is not composed of a bunch of disconnected structures, but interconnections between structures. Sensory and motor systems.
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Levels of Analysis
Molecular->synaptic->cellular->circuits->brain regions->organ system->social interaction
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Reductionism
Explaining behavior in terms of smaller things (ions, atoms, molecules)
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Generalization
Explain things from a big-picture perspective, paying attention to connections and systems, and how the brain and entire body interact
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Which analysis levels/views are important in neuroscience?
Analysis from both a reuctionist and generalist perspective
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Using animal models in neuroscience is important because it
Offers many opportunities for experiments and exploration, because we should not experiment on humans
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Problems with animal models in neuroscience
Ethical guidelines
| Can you generalize findings from mice and apply them to humans?
51
Epigenetics
Experiences and environment can change gene expression without altering one's DNA
52
What was the "Decade of the Brain?"
1990s gov funding for research to treat neuro and psych disorders that cost US money and crime. Funding for mapping projects.
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What is Neuroscience?
Study of the nervous system and its role in behavior etc
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What is Biopsychology?
Study of the brain/behavior relationship. How and why do physiological brain mechanisms result in our behavior and experiences?
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What is behavior?
Explicit, external acts as well as internal ones like thinking, emotions, and learning.
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Monism definition of the mind
No entity of "the mind." A constructed concept that includes our experiences that result from brain functions.
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What is a model?
A proposed mechanism or explanation, or the use of a simple system to represent a complex one.
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Descartes' Hydraulic Model
Muscular function due to fluid inflating the muscles. "Animal spirits" flow through hollow nerves.
...flow through brain pores to cause thoughts and memories.
... Are pumped by the pineal gland.
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What is empiricism?
Gathering of information through observation
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Galvani and the frog leg
1700s: leg removed from body twitched when electrically stimulated.
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Fritsch and Hitzig
electrically stimulated a dog's brain to cause movement.
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Helmholtz discovered
Nerves are not wires; the speed of conduction in nerves is much slower
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Research today on localization of function
Brain functions are both distributed and localized, and behavior results from interactions between the parts but integrates into a single experience
64
What is the nature vs. nurture dilemma?
What is the relative importance of heredity and environment in shaping behavior?
65
What is the Human Genome Project?
Map the location of genes on chromosomes and determine those gene's codes. Which genes are involved in what?
66
What makes neurons similar to other tissue cells?
Lipid bilayer cell membrane
Cytoplasm and organelles
Nucleus and genetic material
67
Important organelles in the neuron
Mitochondria
Microtubules
Rough ER and ribosomes
68
What are microtubules?
Rod-like structures in cytoplasm of soma and cell extensions that provide structure and support as well as transport substances throughout cell.
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What disease are microtubules involved in?
Alzheimer's Disease
70
What are the special parts of a neuron?
Soma (where info is integrated)
Dendrites (receive input from neurons or sensory cells)
Axon (carries AP, output)
Myelin (not all neurons; glial cell protects axon in segment with fatty coating)
71
What comes after the axon
The axon branches and terminal buttons
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What happens at the terminal buttons
Release of chemical messengers via vesicles to neuron, muscle, or gland cells.
73
What glial cells provides myelin for the PNS?
Schwann cells
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What glial cells provides myelin for the CNS?
Oligodendrocytes
75
How are neurons visualized under a microscope?
Using stains: golgi stain only stains a portion of the neurons in an area
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Types of neurons
Sensory, motor, and interneurons
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Sensory neurons
carry sensory info to the CNS via cranial and spinal nerves
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Motor neurons
Carry info away from brain and spinal cord to muscle or gland
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Interneurons
Aka local interneuron. Connector neurons; entire neuron in CNS
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Projection neurons
Aka relay interneuron. Carry info long distances, across brain structures. E.g., cell body in thalamus and terminals in cortex.
81
Commissural neurons
Link left and right hemispheres (e.g. corpus callossum)
82
Why would one surgically cut the fiber bundle of the corpus callossum?
To treat some forms of epilepsy
83
What % body weight is the brain? What % blood supply does it require?
2% of the body's weight; 20% of the body's blood supply
84
What makes neurons unique?
They have variety in shapes, do not easily replicate after age 2, and do not store their own fuel
85
How is fuel for neurons stored
Glial cells (astrocytes) store it for them
86
Do neurons replicate?
Not after age two, except for adult stem cells in certain parts of the brain.
87
When does a human have the most neurons?
In utero and after birth
88
What happens to the neurons? What is "pruning?"
Programmed waves of apoptosis to clarify connections.
89
When does a big wave of pruning occur
At the end of adolescence
90
How much of the brain is glial cells?
85-90% of the cells in the brain are glial cells
91
What functions to glial cells serve?
Support, maintenance and repair, metabolic functions, and assistance in the formation of synapses
92
What NS disorders are associated with glial cells
MS, AD, PD, tumors (made of glial cells) and any NS injury
93
What do glial cells do after a NS injury
May help regenerate area of damage, or form scar tissue
94
What happens when human astrocytes are put into mouse brains?
Smarter mice!
95
What do microglia do?
Phagocytosis; get rid of debris
96
Oligodendroglia
Make myelin for the CNS
97
What glia are part of the CNS support system?
Microglia, oligodendroglia, and astrocytes
98
What do astrocytes do?
```
Support and guidance: Form ladders that neurons use to get where they need to be during development
Phagocytosis: remove debris
Store nutrients
Part of filter for BBB
Synaptogenesis: learning and memory
```
99
Gliosis
formation of scar tissue by glial cells; response to NS damage
100
What is the Blood-Brain Barrier?
Don't allow many substances to cross over from the bloodstream to the brain; capillary membrane to membrane of brain cells
101
PNS support cells
Schwann cells
102
Schwann cells
Make myelin for neurons in the PNS
103
How does myelination by Schwann cells and oligodendrocytes differ?
Schwann cells wrap their whole cell body around the axon; oligodendrocytes have projections that extend from the cell body and wrap around axons
104
What role do schwann cells play in damage of axons?
If part of the axon dies, Schwann cells stay in place and form regrowth tubes to guide axons back to targets
105
Why doesn't this kind of regrowth (through regrowth tubes) happen in the CNS?
In the CNS, scar tissue and chemical signals block regrowth
106
What is gray matter?
Gray matter refers to neurons, the communicators of the NS
107
What is white matter?
White matter refers to glial cells, the workhorses of the NS
108
What is Multiple Sclerosis?
A demyelinating disease of the oligodendroglia in the CNS
109
What is the primary neurological disorder of young adults?
Multiple Sclerosis
110
What is characterstic of MS?
Symptoms are separated by time and place (different parts of the NS and body are affected)
MS plaques or Scleroses form (where cells have died)
111
What are early signs of MS?
fatigue, optic neuritis, clumsiness, numbness, tingling, pain
112
Do all people with MS show the same symptoms?
No, symptoms depends on where the lesions are. MS can also cause language, cognitive and emotional problems
113
What is killing the oligodendrocytes?
The body's immune cells are attacking the oligodendrocytes; it is an autoimmune process
114
What are some possible causes of the autoimmune process of MS?
```
A virus that attacks the BBB?
Genetics?
Exposure: Environment/diet?
Lack of sunlight/Vitamin D deficiency?
Toxins?
Hormones?
```
115
What hormones might be involved in MS?
Melatonin (sleep wake cycle), investigating for use in treatment.
Estrogen - high levels during pregnancy-> remission hormone drop after birth -> symptoms
116
What kinds of drugs are used to treat MS?
Immunosuppressives like corticosteroids and interferons which are also antiviral.
Some drugs anti-inflammatory to target the degenerative process.
117
What are the cons of using corticosteroids?
Weakens immune system, many side effects, can't be used for long periods of time
118
What are Interferons
Injection drug for MS; immunosuppressive and antiviral
119
What is Tysabri?
Controversial, anti-inflammatory drug used for MS. It is effective and can be used in early stages of the disease. But it can cause activation of a deadly virus in th ebrain.
120
What determines symptoms of MS?
Which structures are affected by lesions
121
Tecfidera
Anti-inflammatory
Anti-oxidant
Tasha took Tecfidera
Based on a different model of MS
122
What are problems encountered regarding MS and treatment?
Injections are difficult.
Side effects, including those related to immune system suppression.
Disease is relapsing and remitting.
123
What two common neurological disorders often occur in MS patients?
Anxiety and depression
124
What are some ideas of possible future treatments for MS?
Stem cells -> replace dying cells w/ own cells
| CAM (complimentary and alternative medicine) -> Diet
125
What is provigil and why is it used in MS patients?
It is a stimulant, and used to treat fatigue.
126
Who is the subject of the MS case study?
Natasha Gardner, journalist and Smith Grad Class of 2002
127
What symptoms did Tasha have?
Vision abnormalities
Optic neuritis
Numbness, tingling, weakness -> afraid to pick up child
Motor delay/ lack of coordination -> softball incident
Fatigue
Slurring of speech
Pain
128
What is significant about optic neuritis?
Characterized by a shooting pain in head when moving eye. Can be first symptom of Multiple Sclerosis.
129
What were some of Tasha's triggers (common MS triggers)
Hormones, stress, lack of sleep and heat.
130
Signs of MS could have been present in Tasha earlier. What did they attribute them to instead?
Clumsiness, and "mind-tripping"; her mind always seemed to be ahead of her body.
131
What are two types of transmission that neurons perform and how do they differ?
Action potential -> transmission within the neuron
| Synaptitc transmission -> between neurons
132
Why are there so many neural connections in the brain? How many are there?
There are trillions of neural connections in the brain, because each neuron receives and integrates inputs from thousands of neurons and sends output to thousands of neurons.
133
What is convergence?
Many inputs integrated
134
What is divergence?
Many outputs
135
What is the beginning point of neural transmission?
Synaptic Integration: All the inputs to a neuron, both inhibitory and excitatory, are integrated into a single input that may lead to an AP if the excitation exceeds inhibition and passes threshold. (Dendrites, soma)
136
What happens after synaptic integration if the local potential exceeds threshold?
Na+ channels open and stimulates axonal transmission of an AP (axon hillock to terminal buttons)
137
What is synaptic transmission?
Transmission of information via NT between neurons
138
What are the important ions involved in axonal transmission (AP)?
Na+, Cl-, K+
139
What are the concentrations of ions across the axonal membrane at resting potential?
Na+ Cl- mostly outside the cell, K+ and other anions mostly inside the cell
140
What is the membrane potential at rest (mV)?
~-70mV
141
Is it more negative inside or outside the cell at resting potential?
The inside of the cell is more negative; the outside of the cell is more positive (due to more Na+ out than K+ in)
142
What are the three forces that act on the membrane and determine AP?
Diffusion, electrostatic pressure, and membrane permeability.
143
What is diffusion?
The movement of ions across membrane down their concentration gradient.
144
What is membrane permeability?
The axon membrane is selectively permeable. Ions etc. must go through protein channels or pumps in the membrane.
145
What is electrostatic pressure?
Forces of + and - attract; like forces repel.
146
At rest, Na+ is __. It wants to __ because of what forces?
At rest, Na+ is outside the cell. It wants to go in the cell because of diffusion and electrostatic pressure (more - in cell.)
147
At rest, K+ is ___. It wants to ___ because of what forces?
At rest, K+ is inside the cell. It wants to go out because of diffusion, but it wants to go/stay in because of electrostatic pressure.
148
At rest, Cl- is ___. It wants to ___ because of what forces?
At rest, Cl- is outside the cell. It wants to go into the cell because of diffusion, but it wants to go/stay out of the cell because of electrostatic pressure.
149
During rest, do the ions move across the membrane?
No, because the channels are closed.
150
What happensacross the membrane during an AP?
1. Na+ channels open, Na+ goes inside the cell.
2. It is now more positive inside. (Depolarization)
3. K+ channels open, K+ goes out of the cell
4. Causes an undershoot
5. Membrane potential returns to a resting state with help from the sodium-potassium pump.
151
What are the rules of transmission?
Ion movement due to diffusion, electrostatic force, membrane permeability and pump.
All or none law.
Coding of signal strength
Myelin speeds transmission and saves energy
152
What is the All or None law?
Either an AP is generated (if potential reaches threshold) or it is not. AP size remains the same. AP cannot carry info about the intensity of a stimulus.
153
The strength/intensity of a signal is coded by
The number of firing neurons, or frequency of APs (rate law. Firing rate regulation by relative refractory period.)
154
What organelles are numerous in the terminal buttons?
Vesicles and mitochondria.
155
What is the neuron's message?
The AP.
156
APs are affected by drugs such as
alcohol, cocaine/local anesthetic.
157
How does alcohol affect APs?
It destabilizes the membrane (changes rest state) by changing permability
158
How does cocaine/local anesthetics affect AP?
By affecting membrane permeability. Lidocaine/Novocaine blocks transmission of AP and therefore pain signal.
159
What neurological disorders are characterized by abnormal APs?
MS (due to demyelination) and seizure disorders
160
What are three types of seizures?
Tonic Clonic/Grand mal seizures, Multifocal seizures, and Absence seizures (petit mal).
161
What are the three phases of synaptic transmission?
Presynaptic, Postsynaptic events, and Termination
162
What happens in the presynaptic cell?
1. AP arrives at terminal buttons
2. Ca2+ into cell
3. Vesicles move to membrane, dock, and open from fusion pore
4. Exocytosis of NT into cleft
163
What happens in the postsynaptic cell (simple way)?
NT attach to receptors on membrane to open ion channels directly, fast, and locally.
Produces EPSPs and IPSPs.
164
In the simple secondary phase (ionotropic receptors), effects act
Directly, fast, and locally
165
Alternative postsynaptic events using G-proteins
Involve metabotropic receptors. More common.
1. NT act on receptors, which activate G-proteins and many postsynaptic molecules to yield
2. Changes in postsynaptic cell
166
In the Metabotropic/G-protein secondary phase, effects act
indirectly, slow, and long lasting
167
How is synaptic transmission terminated?
1. Diffusion of NT
2. Degradation by enzymes
2. Reuptake into terminal button via pumps or transporters
4. Glial uptake (astrocytes)
168
What happens to ACh in the synaptic cleft?
Mostly degraded
169
What are some classes of NT?
Animo acid NT - most plentiful
Monoamins
Neuropeptides
170
2 common amino acid NT
Glutamate: excitatory, brain
GABA: inhibitory, brain
171
Monoamines
Dopamine, norepinephrine, seratonin
172
ACh
works in the NMJ, ANS (fight or flight) and in the brain (learning, memory)
173
Neuropeptide example
Endogenous opiate. Manage pain. Maintains addictive behavior.
174
Dopamine is involved in
reward (addiction) motor and attention circiuts
175
Norepinephrine is involved in
brain, ANS (fight or flight)
176
Where is seratonin in the body?
1% in brain, 10% blood, rest in gut
177
What is the fight or flight response?
Major activation of the autonomic nervous system
178
How does nicotine affect synaptic transmission?
Acts like ACh at receptors in brain, ANS and muscles. Indirectly at dopamine receptor - > reward and addiction
179
How does Ecstacy/MDMA affect synaptic transmission?
Acts at pump for seratonin - long term might destroy?
180
ACh role
motor function, learning/memory, REM, Autonomic Nervous System
181
What disorders involve ACh
Alzheimer's Disease, MG (Myasthenia Gravis) (-)
182
What drugs involve ACh
Nicotine (+)
183
What is an Action Potential?
An excitatory signal that moves down the neuron's axon and dendrites; caused by a change in the cell's membrane potential.
184
State three core concepts of Neuroscience
1. The brain is the most complex organ in the body.
2. Life experiences change the nervous system.
3. Neurons communicate using both electrical and chemical signals.
