Unit 4: Biological Bases Of Bahviour (Chapter 3) Flashcards
1
Q
Sensory neurons
A
Carry messages from the sensory organs (e.g., eyes, tongue, skin) to the spinal cord and the brain.
2
Q
Neuron
A
Cell of the nervous system specialized for sending and receiving neural messages. There are approx. 100 billion neurons in the brain making 100 trillion connections.
3
Q
Motor neurons
A
Carry messages from the brain and spinal cord to muscles and glands.
4
Q
Interneurons
A
Within the the brain and spinal cord collect, integrate, & retrieve messages from various sources.
5
Q
Dendrites
A
Receive chemical messages from other neurons. Search to increase the surface area of the cell to recieve messages.
6
Q
Cell body/soma
A
Collects neural impulses, contains the nucleus, sustains cell functions.
7
Q
Axon
A
Transports electrical impulses to other neurons via the terminal branches.
8
Q
Axon terminals/terminal branches
A
Convert electrical signals into chemical messages for other neurons.
9
Q
Myelin sheath
A
Fatty layer that insulates the axons & speeds up transmission of electrical signals. Helps speed up the propagation of the action potential by ensuring the electrical messages meet less resistance.
“Underdevelopped prefrontal cortex” = Neurons not all myelated yet! Slower messages sent at 0.5-2 m/s.
10
Q
Glia
A
Nervous system cells that perform variety of critical support functions. Make up the myelin sheath around neurons to insulate, support and nourish neurons and modulate neuronal function.
11
Q
Glial cell functions
A
- Provide structural support & scaffolding for neurons (“guide them”).
- Clean up debris.
- Form blood-brain barrier (prevent blood toxins to enter the brain tissue).
- Facilitating neurons between neurons and pruning unneeded (excess/weak) connections.
- Nutrient supply.
- Insulation (myelin sheath).
12
Q
Action potential
A
Electrical impulses fired off by neurons to “talk” to one another. Generated at the junction between the axon and the cell body. Causes the depolarization (rapid change in voltage) of said area and the opening of sodium channels. Travel down the length of the axon to its terminal, where they signal release of chemical messages to neighbouring cells.
13
Q
Cell membrane
A
Thin fatty “skin” enclosing the neuron:
- Separates the intracellular fluid inside the neuron and extracellular fluid
outside the neuron.
- Intracellular and extracellular fluids contain various electrically charged particles (ions). Ex: sodium (Na+), chloride (Cl-), potassium (K+), calcium (Ca2+).
- Cell membrane is selectively permeable, allowing for passage of certain ions and not others.
14
Q
Resting potential
A
Electrical charge across the membrane (~70 millivolts). In this state:
- More negatively charged particles inside the cell than outside.
- Neuron cannot fire action potential.
15
Q
Ion channels
A
“Gate-type structures” in the cell membrane at the end of the axon, adjeacent to the soma. Open when the neuron is sufficiently stimulated by other neurons, and allow positively charged Na+ ions to enter. Electrical charge then begins to reverse.
I.e. the channels that allow chemical ions to enter and exit the neuronal membrane to generate the voltage for resting and action potentials.
16
Q
Depolarization
A
The reversal of the electrical charge (more +) across the membrane of the neuron. The first phase of the action potential.
Less of a difference in the charges of the extracellular and intracellular liquids.
17
Q
Voltage threshold
A
Critical level to which a neuron’s membrane potential must be depolarized to initiate action potential (~55 mV). Once threshold is passed, voltage-gated ion channels open allowing positively charged sodium (Na+) ions to flood in. The interior of the cell is now more + charged than the outside. All or nothing response. There is no such thing as a strong/weak action potential.
18
Q
Repolarization
A
The portion of the action potential during which the cell returns to its resting potential. As depolarization occurs, channels that were letting sodium (Na+) pass through close, but potassium (K+) channels remain open and those ions flow out of the cell.
19
Q
Refractory period
A
Temporary dip below resting potential. During this period it is very hard to get the neuron to fire again. This period also ensure that action potential is propagated forward.
20
Q
Synaptic cleft
A
Gap separating neurons. To traverse synapse, electrical signal has to be converted to a chemical one. To do do, presynaptic neurons send neurotranmitters.
21
Q
Neurotransmitters
A
Chemical messengers released upon arrival of the action potential. Sent by presynaptic neurons to convert the electrical signal to a chemical one, and allow it to traverse synapse. Cross the synaptic cleft to bind to receptors on the postsynaptic neuron.
22
Q
Receptor
A
Channel in membrane of a neuron that binds neurotransmitters in a “lock-and-key” manner.
23
Q
Tidying up the synapse : Diffusion
A
Neurotransmitters drift out of synapse.
ESSENTIAL TO TIDY UP THE SYNAPSE TO TERMINATE THE CHEMICAL MESSAGE.
24
Q
Tidying up the synapse : Degradation
A
Neurotransmitters are broken down in the synapse.
ESSENTIAL TO TIDY UP THE SYNAPSE TO TERMINATE THE CHEMICAL MESSAGE.
25
Tidying up the synapse : Reuptake
Neurotransmitters are reabsorbed into the presynaptic terminal branches.
## Footnote
ESSENTIAL TO TIDY UP THE SYNAPSE TO TERMINATE THE CHEMICAL MESSAGE.
26
Excitation
Receiving neuron slightly depolarized. Moves it closer towards voltage threshold and increases likelihood of initiation of action potential.
27
Inhibition
Receiving neuron slightly hyperpolarized. Moves it further from threshold & reduces likelihood of action potential.
## Footnote
Ex: Coordination between muscle contraction (excitatory inputs) and muscle relaxation (inhibitory inputs) required for coordination.
Ex 2: Tetanus lockjaw (bacteria destroys inhibitory inputs).
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Neurotransmitter (amino acid): GABA (Gamma-aminobutyric acid)
Most common inhibitory neurotransmitter; downregulation of stress, anxiety, fear.
- Many sedative drugs act by targeting GABA receptors.
- Alcohol also promotes activity at GABA receptors.
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Neurotransmitter (amino acid): Glutamate
Binds to exitatory receptors; helps form long-term memories.
30
Amino acids
The brain's most abundant class of neurotransmitters, including glutamate (important for neuronal exitation), and gamma-aminobutyric acid (GABA, important for neuronal inhibition and the regulation of muscle tone).
31
Neurotransmitter: Acetylcholine
- Can trigger both excitatory and inhibitory signals.
- Commonly found in neuromuscular junction (drugs that interfere with ACh, like curare, used as a bioweapon, result in paralysis and death).
- Plays key role in autonomic nervous system, which carries commands from brain to glands & organs, regulates cardiac activitiy.
- Brain circuits involved in learning and memory (low levels associated with dementia of Alzheimer’s disease).
32
Monoamines
A neurochemical class that inlcudes norepinephrine, dopamine and seratonin (important for fight-or-flight and reward responses).
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Neurotransmitter (monoamine): Norepinephrine/noradrenaline
Important for “fight or flight response”; contributes to arousal & vigilance.
- In excess, can contribute to high blood pressure, anxiety.
34
Neurotransmitter (monoamine): Serotonin
Contributes to regulation of sleep, appetite, mood, and aggression.
- Thought to play in depression, although precise mechanism still debated.
35
Neurotransmitter (monoamine): Dopamine
Involved in movement, planning, and aspects of reward.
- Most addictive drugs (ex: meth) stimulate increased activity in dopaminergic circuits.
- Excess levels associated with schizophrenia, low levels with Parkinson’s disease.
36
Neurotransmitters (neuropeptides): Endorphins
- “Endogenous morphine”.
- Promote feelings of pleasure and
reduce pain.
- The OPRM1 gene codes for the opioid receptor where endorphins bind.
## Footnote
Ex: Rat mom + affection study (high vs low LG).
37
Psychoactive drugs
Chemical substances that alter a person’s thoughts, feelings, or behaviors by influencing the activity of neurotransmitters in the nervous system.
- Includes prescription medications like anti-depressants and drugs like cocaine, heroin, LSD, etc.
- Other commonplace examples: caffeine, nicotine and alcohol.
38
Agonist
Enhances action of a neurotransmitter by increasing release, blocking its reuptake, or mimicking neurotransmitter & activating its postsynaptic receptor.
## Footnote
Ex: Heroin.
39
Antagonist
Inhibits actions of a neurotransmitter by blocking release, destroying neurotransmitter in synapse, or mimicking neurotransmitter & binding to a postsynaptic receptor to block neurotransmitter.
## Footnote
Ex: Naloxone = opioid receptor antagonist used upon overdose.
40
Opioid addiction model
- Opioid drugs (e.g., heroin) hijack & eventually overpower reward function of endogenous opioids.
- Repeated use causes changes to receptor structure (decreased # or sensitivity).
- Tolerance to drug, loss of sensitivity for naturally occuring rewards. Taking larger doses of the drug for the same effect.
- Locus of control for drug-seeking behaviour shifts from positive reinforcement (taking drug to feel good) to negative reinforcement (taking drug to alleviate negative feelings/withdrawal).
41
Nervous system
Complex network of nerves (bundles of neurons) that controls & regulates all bodily functions. Subdivisions include:
- Central nervous system (brain, spinal cord). Sensory and motor nerves that travel throughout the body.
- Peripheral nervous system (nerves connecting brain to the rest of your body).
42
Peripheral nervous system subdivisions
**Somatic nervous system:**
- Carries commands for voluntary movement from CNS to muscles.
- Brings sensory input to CNS; allows you to feel external sensations.
**Autonomic nervous system:**
- Carries involuntary commands to organs, blood vessels, & glands.
- Operates outside your conscious control.
- Allows you to feel internal sensations.
- Further subdivided into sympathetic and parasympathetic branches.
43
Sympathetic nervous system
Prepares body for situations requiring
expenditure of energy (fight-or-flight
response). Acts on blood vessels, organs and glands.
- Pupil dilation, increased breathing, heart rate, & blood flow to muscles.
- Redirects energy from non-essential
processes (e.g., digestion).
## Footnote
"Has sympathy for you."
44
Parasympathetic nervous system
Controls blood vessels, glands & organs during calm periods; returns body to resting state (rest-and-digest).
- Nutrient storage, repair, growth.
45
Endocrine system
Network of glands (hormone-secreting organs) that work together with CNS and PNS.
46
Hormone
Blood-borne chemical messengers that enable the brain to regulate the body's activities.
- Slower than CNS neurotransmitters
- Travel over greater distances
- Involved in regulating arousal, metabolism, growth, & sex.
47
Adrenal glands
Located on top of kidneys.
- SNS activates adrenal glands during
stressful/threatening events → release of adrenaline and cortisol.
- Boost energy, increased heart rate, blood pressure, blood sugar levels.
- Cortisol has slower onset but longer lasting efects (not the first rush of stress!).
48
Pituitary gland
The ‘master endocrine gland’ located at the base of the brain.
- Directs other glands
- Regulates hunger, sexual arousal,
growth, sleep (via pineal gland), navigation of social world.
49
Oxytocin
Hormone released into bloodstream by
pituitary gland.
- Involved in parturition (stimulates uterine contractions during birth).
- Artificial forms of oxytocin used to
induce labour.
- Promotes lactation.
- Thought to play role in social bonding.
## Footnote
Ex: A tale of two voles study = Prairie voles (high density of oxytocin receptors in reward related areas of the brain, pair bonds after mating) VS montane voles (low density of oxytocin recpetors in said regions, no pair bonds, more solitare).
Ex: Humans and economic trust game.
50
Spinal cord
Major bundle of nerves connecting brain to rest of the body.
51
Spinal reflexes
Initiated by spinal cord without involvement of the brain.
52
Example of a spinal reflex (response to painful stimulus)
1) Pain receptors in skin detect potentially harmful stimulus.
2) Electrical signals from pain receptors carried by sensory neurons to spinal cord.
3) Interneurons within spinal cord process signal and relay it to motor neuron.
4) Motor neurons send command to muscles to react.
53
Brainstem
Lowest region of the brain, sits on top
of spinal cord:
- Where spinal nerves & most cranial
nerves connect.
- Regulates vital functions; **damage to
this area is often lethal.**
- Contains the midbrain, pons, and
medulla.
54
Medulla oblongata
- Heart rate, blood pressure, reflexes like coughing and swallowing.
- Autonomic, involuntary, vital survival functions.
## Footnote
Remember as "medal goes over your heart and lungs, thus medulla controls those things".
55
Pons
- Breathing.
- Balance & coordination
- Relays sensations (hearing, taste) to higher levels of the brain (i.e. cortex and subcortex).
## Footnote
Remember as "bridge = need balance and coordination to cross a bridge".
56
Reticular formation
- Arousal (not the sexy kind), attention, sleep and wakefulness.
- Filters which stimuli we focus on.
- Degrades with age, linked to Alzheimer’s.
57
Midbrain
- Orientation towards salient stimuli
(tegmentum).
- Movement (substantia nigra).
- Motivation & reward (ventral tegmental area).
- Downregulation of pain (periaqueductal grey). Uses endorphins so we are able to get away from predators, not focus on pain.
58
Cerebellum
- Coordination, balance,
precise movements &
accurate timing.
- Looks like "mini" brain.
- Helps us integrate sensory feedback.
- Overall cognition.
- First place booze affects.
- Divided into left and right hemisphere.
- **If damaged, you may imitate a movement, but lack the necessary coordination and precision.**
59
Limbic system
Known as the ‘emotional brain’, but plays a number of other important roles as well. Bridges the newer, higher brain structures related to more complex mental functions to older, lower regions that regulate your body and its movements. Includes:
- Hypothalamus.
- Thalamus.
- Amygdala.
- Hippocampus.
- Basal ganglia (though not always considered as part of this system).
60
Executive functions
Cognitive processes that allow you to plan, focus attention, and organize multiple tasks to complete your goals; associated with the function of the prefrontal cortex.
61
Hypothalamus
- ‘Interface’ between brain &
body. 4 Fs: Feeding, Fleeing, Fighting, Fornication.
- Important for homeostatic regulation:
temperature, thirst, hunger,
biological rhythms.
- Motivation, reward seeking.
- Fight-or-flight response.
- Directs the autonomic nervous system & endocrine system.
## Footnote
Remember as "under the thalamus".
62
Thalamus
- ‘Relay station’ for all sensory signals (except smell).
- Alertness & consciousness. Helps you tune out sounds as you sleep.
- **Damage can lead to blindness, loss of touch.**
- Synesthesia linked to it (seeing music as colours).
63
Amygdala
- Processing emotional significance of sensory information.
- Responds both to positive and negative stimuli.
- Works with hippocampus to create vivid memories.
- **Damage can lead to
psychic blindness = normal vision, but visual stimuli lose their emotional significance. Ex: Capgras syndrome.**
64
Hippocampus
- Memory (especially long term).
- Spatial navigation.
- Mental time-travel (picture the past or the future).
## Footnote
Remember as figure that looks like a seahorse.
65
Basal ganglia
- Interconnected structures.
- Planning , executing, & controlling voluntary movement.
- Suppression of unwanted
movement (substantia nigra). *Parkison disease affects the basal ganglia.*
- Reward and pleasure (nucleus accumbens).
66
Cerebral cortex
- Outermost and largest part of the human brain.
- Divided into left and right hemispheres connected by large bundle of nerve fibers (corpus callosum).
- Further divided into five lobes
1) Frontal
2) Parietal
3) Occipital
4) Temporal
5) ( + insular lobe).
## Footnote
Remember as FPOiT going around from front of head to back.
67
Frontal lobe
Movement and planning. Contains the primary motor cortex (a “map” of the body’s muscles). The rest consists of the prefrontal cortex:
- Responsible for executive function (self-regulation & control of behaviour): planning, judgment, decision-making.
- Conscious experience of emotions.
## Footnote
Ex: Phineas Gage's imapled prefrontal cortex changed his personality (ability to feel emotions).
Ex 2: Frontal lobotomies used to treat mental disorders in 1940-50s lead to apathy, antisocial behaviours, impulsiveness...
68
Parietal lobe
- Contains the primary somatosensory cortex (a ”map” of the body’s skin surface) enabling us to process touch.
- Helps pay attention to and locate objects, navigate our surroundings.
- **If damaged, you may be more prone to run into things.**
69
Occipital lobe
Vision:
- Contains the primary visual cortex which is necessary for sight.
- Interprets input from eyes by responding to basic information about image (e.g., shading, edges, colour).
- Links to temporal and parietal lobes allow you to recognize objects and process their movement.
70
Temporal lobe
- Contains the primary auditory cortex which allows you to hear and understand language, and recognize objects and people.
- Contains primary olfactory cortex.
**- Damage may cause you not to know what an object is or the meaning of a word, even though you can still see and hear.**
71
Insular lobe
Allows us to perceive our inner world.
- Perceives state of internal organs (racing heart, pain...). What gives pain its "flavour". 🤤YUMMY🤤😋🥚🪴
- Includes the primary taste cortex. Stimulation produces sensation of taste. **Damage = loss of conscious experience of taste.**
## Footnote
Remember as "INsular, INner world, INternal".
72
Primary sensory areas
First cortical areas to receive signals
from their associated sensory nerves:
▪ Parietal lobe = somatosensory area
▪ Occipital lobe = visual area
▪ Temporal lobe =auditory & olfactory areas
▪ Insular lobe = primary taste area.
73
Association cortex
- Integrates incoming information from sensory areas with existing
knowledge to produce meaningful experience of the world. Ex: Recognizing complex visual objects or sounds.
- Association = connection (bridge between sensation & action, language, abstract thought). Allows you to recognize something as what it is and tie it into prexistsing knowledge.
74
How are the primary somatosensory and motor areas organized?
Organized togographically:
- Brain areas “map” onto specific
parts of the body.
- Body parts that are physically close are represented in adjacent areas of cortex.
- Amount of cortex space corresponds to amount of fine control or sensory discrimination required.
**IS SPECIES SPECIFIC.
75
Corpus callosum
- Bridge of fibres that connecting the
two cerebral hemispheres.
- Helps the two hemispheres “talk” to
each other (interhemispheric
transfer).
76
Brain hemispheres
- Both hemispheres involved in
receiving sensory information from
your body, and sending motor
commands to your muscles.
- Each hemisphere does this for the opposite side of the body (**contralateral**).
77
Left hemisphere distinctions (Lateralization, specialization of said side)
Specialized for language.
- **Damage = Deficits using and understanding language.**
- Makes sense of everything we do, the “interpreter”.
## Footnote
Ex: Chicken claw + snowy scene experiment.
78
Brain networks
The collection of brain regions that are connected together to support brain functions.
79
Right hemisphere distinctions (Lateralization, specialization of said side)
Specialized for nonverbal, visuospatial processing of information. **Damage = Deficits recognizing faces, reading maps, drawing geometric
shapes.**
80
Split brain procedure
Severing of the corpus callosum.
- Performed in cases of severe epilepsy to limit extent of seizures.
- Disrupts interhemispheric transfer.
- Revealed that in special conditions, when information is provided to only one
hemisphere, split-brain patients behave as if they have two separate minds.
- Possible to send visual or tactile information to just one hemisphere, and test the knowledge of this information.
## Footnote
Ex: If we present a picture of an object to the right visual field of a patient, they will be able to describe it (because language is controlled by the left hemisphere). If we present the picture to the left visual field, the patient will no longer be identify it verbally, but they will be able to reach for it with their left hand (although they won’t know why they did that).
81
Broca's area
- Left frontal lobe (very close toregions controlling motor abilities of the tongue.)
**- Damage = telegraphic speech. Ex: “I hungry.”**
- Can understand speech.
82
Wernicke's area
- Temporal lobe.
- **Damage: fluent but nonsensical speech, difficulty understanding language. Ex:“Nothing the keesereez the, these are davereez and these and this one and these are living. This one’s right in and these are . . . uh . . . and that’s nothing, that’s nothing”**
83
Phrenology
19th century pseudoscientific belief that all mental faculties and characteristics are localized in specific brain regions and can be inferred from pattern of indentations on the skull.
84
Neurophsychology brain stimulation methods
- DBS (Deep brain simulation)
- TMS (Transcranial magnetic stimulation)
- TDCS (Transcranial direct current stimulation)
85
Neurophsychology methods with good spatial resolution, but poor temporal resolution
- PET (Positron emission tomography)
- fMRI (Functional magnetic resonance imaging)
86
Neurophsychology methods with good temporal resolution, but poor spatial resolution
- EEG (Electroencephalogram)
87
Neurophyscology
Study of brain function by examining functional alterations following brain damage.
88
Lesion
Abnormal tissue resulting from disease, trauma, or surgical intervention.
## Footnote
Ex:
- Role of Broca’s area and Wernicke’s area in speech.
- Phineas Gage.
- Split brain patients & the contralateral organization of the brain.
89
Single dissociation
Lesion to brain structure A disrupts function X but not function Y.
90
Dissociation
The neuropsychological evidence, following brain damage or a lesion, that a specific brain area is involved in particular function but not in others.
91
Double dissociation
Lesion to brain structure A disrupts function X but not function Y, and lesion to brain structure B disrupts function Y but not function X (“gold standard” in neuropsychology).
## Footnote
Ex: Broca's area and Wernicke's area.
92
Limitations to double dissociation
- Naturally occurring brain damage is not specifically localized & may spread over time.
- Difficulty generalizing from one person’s brain and behaviour to another.
- Confounding factors: did the person suffer brain damage beforehand from previous incidents/conditions?
93
Deep brain stimulation
Stimulating specific parts of the brain with implanted electrodes (very invasive). Used for treatment of disorders like depression.
94
Transcranial magnetic stimulation (TMS)
Exposure to magnetic field to create temporary disruption or enhancement of cortical brain function.
95
Transcranial direct current stimulation (TDCS)
Low levels of direct current delivered via electrodes on the head to stimulate brain function, such as enhancing hand-eye coordination.
96
Advantages to brain simulation studies
- Causal insights into brain function.
- Some techniques may have therapeutic potential.
97
Limitations to brain simulation studies
- Limited spatial precision (particularly TMS & TDCS).
- Limited depth penetration.
- More invasive (reluctant patients).
98
Position emission tomograpgy (PET)
- Injection of radioactive tracer (glucose, but possible for other substances).
- The radiotracer is taken up by brain tissues involved during particular task.
- PET detects radiation emitted by the trace.
- Areas with higher concentration of the tracer emit more radiation.
## Footnote
Ex: Revealed that expectation of pain relief can cause reductions in pain (placebo effect).
99
Functional magnetic resonance imaging (fMRI)
Used to measure brain activity by detecting changes in blood oxygenation.
- When a part of you brain is active, it needs more oxygen.
- Blood carries oxygen to active areas, which then becomes consumed.
- Because oxygenated and deoxygenated blood has different magnetic properties, fMRI can use strong magnets to detect changes in blood flow and oxygenation.
## Footnote
Ex: Study where participants viewed images of loved ones vs strangers.
100
Magnetic resonance imaging (MRI)
A structural imaging technique that uses magnetic fields and radio waves to create images of the brain.
101
fMRI vs PET
- fMRI has better spatial and temporal resolution than PET, although temporal resolution (“when” brain activity happens) is still limited.
- Less invasive (does not require injection of radioactive substance).
- Unlike PET, fMRI cannot reveal changes in neurochemical activities (i.e., which neurotransmitters may be actively involved in a process).
- But can combine with other methods-–e.g., drug administration.
102
Interpreting imaging data
Determine which brain areas are “active” by subtracting amount of activity in each brain region in the control condition from the activity seen those in those brain regions in the experimental condition.
- Need to think carefully about the control condition: are all variables but one kept constant?
- Neuroimaging data is correlational.
103
Single-cell recording
Measurement of the electrical activity of a single neuron (where & when it is firing). VERY INVASIVE.
104
Electroencephalography (EEG)
- Recording of electrical waves from many thousands of neurons in the brain, gathered using electrodes placed on the scalp.
- Can be used to diagnose brain states such as sleep or wakefulness.
- Synchronized electrical response to a sensory, cognitive, or motor event.
- Extracted from EEG data; "signature".
- Allows researchers to see how brain responds to specific stimuli or tasks.
105
Magnetoencephalography (EMG)
The recording of the magnetic fields produced by the brain’s electrical currents.
Allows greater temporal resolution than EEG.
106
Limitations of EEG & EMG
- Good temporal but not spatial resolution.
- Can tell us “when” but not “where” something happens.
107
Neural plasticity
Brain’s ability to change and adapt throughout individual’s life. Includes reorganization of neural networks in response to learning, experience, or injury.
- How learning is possible!
## Footnote
Ex: "If you use it it will grow" studies with London cab drivers and rats housed in enriched/deprived enviroments.
108
Neurogenesis
The process by which new neurons are formed in the brain.
109
Critical periods
Specific timeframe during development when brain is particularly receptive to environmental stimuli, allowing for larger changes in neural connections.
## Footnote
Ex: Visual stimulation in early life required for visual abilities like depth perception & recognizing faces = blindfolded baby animals.
110
Damage plasticity
Neural modification/reorganization following injury.
111
Adult plasticity
The shaping and reshaping of neural circuits throughout adulthood, which occur everyday as you experience the world.
112
Phantom limb syndrome
Continuing sensation in limb that has been amputated.
- Cortical reorganization following amputation: “freed up” space in somatosensory cortex gets taken over by adjacent brain regions.
- Similar reorganization happens following other sensory deprivation (blind, deaf, etc. individuals).
113
Stem cells
Cells that have not yet undergone gene expression to differenciate into specialized cell types. Can be found in human embryos.
114
Cerebral cortex
The outermost layer of the brain; supports cognitive skills, complex emotions, and complex mental activity, including your sense of mind and self.
115
Neurons
The cellular building blocks of the brain.
116
Nervous system
A network of neurons running throughout your brain and body.
117
Motor neurons
These neurons in your brain send messages to the whole body, enabling you to interact with your environment.
118
Sensory neurons
Other nerves send a status report back to your brain. These sensory neurons carry information from within your body and the outside world to your brain. The term sensory refers to sensors for detecting change. Thus, the brain does not just send orders down to the body. It also senses changes in the body and the environment to make sure it follows the orders that you give it. You have "only" about six million sensory and motor neurons combined.
119
Neurogenesis
The process by which new brain cells are born in adult brains.
120
Interneurons
The rest are interneurons that are in between, connecting other neurons. They interpret, store, and retrieve information about the world, allowing you to make informed decisions before you act. This means that most of your brain's resources are devoted to processing the immense amount of sensory data it receives and using that data to plan and excecute future actions.
121
Spinal cord
The major bundle of nerves, encased in your spine, that connects your body and your brain.
122
Neocortex
The evolutionarily newest cerebral cortex that is the largest part of the human brain; supports complex functons including language, thought, problem solving, and imagination.
123
Primary motor cortex
Responsible for voluntary movements. Connects with motor neurons that make the body move.
124
Nerve
A whitish fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.
