Chapter 4: Neuroscience Flashcards
What is neuroimaging?
techniques that allow for the stuyding of brain activity by obtaining visual images in awake humans
What are the two most useful neruoimaging methods?
PET scan: enable the detection of the uptake of certain molecules so that brain areas with increased activity can be identified
fMRI scan: allows for the detection of changes in blood flow, a presumed indicator of changes in the acidity of nerouns
What is a neruon?
a nerve cell
What do neurones have?
A cell body; filled with cytoplasm with a nucleus; dendrites; extend like brahcnes from the cell body to collect INPUTS from other nerusons, can have many dendrites; axons; also extend from cell body, function to carry information AWAY from the cell body toward other neurones, with a specialized region at the end called the axon terminal
What are the different types of neurones?
Sensory; in the skin, musles that respond to pressure, temp, or pain; Motor, that stimulate our muscle cells into action, and Interneurons that contact these two types; all neurones are covered by a membrane, all nerouns are capable of communication with other cells by producing and sending electrical signals
What are glia?
Non-neuronal cells
What do they do?
buffer the neurones from the rest of the body, control the nutrient supply to neurones, and destroy and removed diseased and dead neurones
How do nerouns work?
they send messages to one another bia electrochemical actions/ cause an electrical signal to be generated/ sudden electoral change of a neurones axon causes it to a release a neurotransmitter
What are the nerve cells surrounded by
The nerve cells are surrounded by an extracelluar fluid that has ions/ there are also ions inside the neruon which gives it an electrical charge even when it is resting
What is the resting charge called?
Resting potential and it is negative b.c fluid INSIDE the nueron is more negative then the fluid OUTSIDE the ncell
What are ion channels?
neruons membrane is selectively permeable/ ion channels only allow passage of certain ions into and out of the cell/ they open and close depiing on the info received from other nerusons
What are the key ions in determining the resting potential?
positively charged sodium ions NA+, and potassium K+ and negatively charged chloride CL- ion
When the neurone is at rest, which ions are in higher concentration and where are they?
postive sodium ions, and they are in higher concentration outside the cell
What is this unequal distribution of ions on each side of the cell membrane called?
The concentration gradient
How is the resting charge maintained
By the sodium potassium pump
How does the sodium potassium pump work?
it uses energy to hold the reading potential at a negative charge by continuously pumping Na+ out of the axon, enhancing Na+ for K+; pumps push out 3 sodiums and only put in 2 potassium ions
When does the concentration gradient change?
when an electrical charge increases the permeability of the membrane to Na+, which allows Na+ ions to go out of cell
What is the Action Potential?
A sudden postitive change in the electrical charge of a neurones axon, when the AP has been generated the neruon “fires”; the AP occurs when EXCITATROY signals outweigh the number of INHIBITORY sign as and each a certain threshold
What is the definition of a threshold?
the point at which the relative excitiarty influence of other neurons succeeds in causing a neruon to initiate an action potential
What happens during an Action Poential?
Ion channels that allow the passage of Na+ open, this lets Na+ (high concentrationoutside the axon) to rush through the Na+ channels and into the axon; influx of postiv ions shifts electrical charge of axon from positive to negative, when the peak of the action potential reachers a membrane charge of 50 mV, the sodium channels close
What has this caused?
Neighbouring sodium chanels to open and the action potential action potential sweeps down the axon to the neruon
What happens when the sodium channels close in an axon section?
Potassum channels open, and potassium ions exit the cell, restoring the negative charge within that area of the cell
What are the neurones insulted by and what does it do?
Myelin sheath which is made from spepcialed glial cells, that facilitate he movement of an AP down the axon
What are Nodes of Ranvier?
Exposed regions on the axon that are exposed to extracellular fluid
What is saltatory conduction?
It is when the action potential jumps from node to node
What is the refractory period?
After the neurone fires it cannot fire again for a short time
What is the Absoulte refractory period?
Immediately following an AP, the axon is completely unable to fire no matter how stron gthe stimulus to the nueron
What is the Reletive refractory period?
Happens a bit later on, the cel can fire if it is given a stung enough stimulus, threshold for spiking is high
What are neurones separated by?
Synapeses; spaces between the axon terminal of one cell and the dendrite of another cell which neurones communicate
What is needed to facilitate communication across the synapees?
Neruttransmitters
What are the contained within?
smal synaptic vessesl, in the axon terminal (pre synaptic terminal) of the neruson sending the information
What happens when the AP reaches the presynaptic axon terminal?
It causes the realse of a NT molecule into the synapse, it diffuses across, and binds to the NT receptor on the dedicate of the receiving (post synaptic neruon)
What are NT receports?
proteins in the cell membrane that recognize specific molecules and operate in a lock and key fashion
What does the NT Glutamate do?
involved in learning and movement, associated drug is ketamine
What does the NT GABA do?
involved in learning, and anxiety regulation, associated drug is vellum, ambien
What does the NT ACh do?
learining and attention; associated drug is nicotine
What does the NT Dopamine do?
inolved in movement and reward learning; cocanie, herion and meth
What does the NT Serotonin do?
mood regulation, ectasty, lsd, anitdepresents
What does the NT Nrepinephrine do?
attention and arsousal, adderall
What happens when a NT binds to a receptor?
The combo stimulates an electrical event in post synaptic membrane, which are called POSTSYNTAPTIC POTENTIALS ( can be excitatory of inhibitatroy)
What happens if the receptory has an excitatory action?
the postsynatpic cell will be depolarized; membrane potential will become less negative; may not be big enough to trigger an ap in the postysnaptic neruon but can be summed together wit other depolaritions; threshold will be reached an neruon will fire again
What happens in the report has an inhibitory action?
The postsynaptic cell will be hyperpoloarized; its membrane potential will becomme more negative, less likely the post synaptic neruon will fire an action potential
What is plasticity?
Chane in the nervous system, it refers to the brains ability to fix itself or to repurpose neurones
What is the PNS?
consists of the somatic and the autonomic nervous system
What is the somatic nervous system?
all the nerves that gather sensory info from the body and deliver it to the spinal chord and brain; and vice versa
What is the autonomic nervous system?
doesn’t use a lot of help from the CNS, broken into the sypatheic and the parasympathetic nervous system
What is the Sympathetic?
activaed under stress, responsible for “fight or flight”
What is the Parasympathetic?
inhibited during stress, and active under restful times, controls basic functions that occur wh not at immediate risk, e.g. digestion
What does the CNS consists of?
The spinal chord and the brain
What does the spinal chord do?
gathers info from the body and sends it into the brain, and bales the brain to control movement of the body
What is the brain divided into?
3 regions, serve varying functions; the hindbrain (or brainstem), the midbrain and the forebrain
What is the Hindbrain?
closet part to the spinal chord, consists of the medulla, reticular formation, pons and the cerebellum
What is the Medulla?
attached to the spinal chord, important for basic bodily functions, respiration, heart rate
What is the Reticular formation?
Groups of neurones, nuclei, which is important for sleep and wakefulness
What is the NT that is found in nerusons in the Reticular formation
Serotonin, RF brain major source of this
What is the Pons?
above medulla, pons acts a bridge sending signals between to the forebrain and the cerebellum, involved in sleep, breathing, swallloing, eye movement, expression, also contains cell groups called the locus coeruleus that belong to the RF
Which NT do the neurones of the locus coeruleus use?
Norepinephrine/ under functioning in this area could cause ADD
What is the Cerebellum?
back of brain, important for motor coordination, and learning involving movement
What is the Midbrain?
above the pons, it is a collection of brain regions, contains many nuclei, one of the nuclei is called the substantia nigra,/ damage in this region is caused by Parkinsons disease
What does the substantia nigra do?
important for movement produce the NT dopamine
What is the Thalamus?
large collection of nuecli, relay stations for incoming sensory information; two major components; LGN (visual stimuli) and MGN (autidoty stimuli)
What is the Hypothalamus?
collection of nuecli underneath the thalamus, important for motivational process, eating, drinking, sex drive, maternal behaviour, also critical for the control of the endocrine hormonal system
What is the Pituitary gland?
Attacthed the to hypothalamus, works together to control hormones that are important for growth, repodruction, metabolism and stress; proceeds relating factors that control exocrine glands such as ovaries, tests, thyroid and the adrenal glands
What is the Amygdala?
involved in regaining, learning and responding to stimuli that induce fear
What is the Hippocampus?
communicates with amygdala, people with damage here cannot form new memories about events, important for learning about sptial environment, and memory
What is the Striatum?
midline of the brain, works with the substantia nigra, to produce fluid movement, learning and memory
What is the Nucleus Accumbens?
important for motivation and reward learning
What is the Neocortex?
is highly developed in humans, responsible for our most complex behaviours, language and thought; divided into 4 different parts or lobes, Occipital, temporal, parietal and frontal
What are the 2 major classifications?
Primary sensory and motor areas, responsible for processing basic info about senses, and Association cortex, responsible for higher order sensory pocessing, thinking, planning etc
What is the Occipital Cortex?
back of skull, processing basic info about visual stimuli, arrives via partially crossed connections. association areas integrate info about colour, complex patterns and motion
What is the Temporal Cortex?
sides of head, important for processing info about auditory stimuli or sounds, language comprehension,
What two areas work together?
Wernikes area which helps understand language and Broccas area which is language rules and production of speech, Brocca located in the frontal lobe
What is the Parietal Cotrex?
top middle part of the brain, info about touch or somatosensory stimuli, touch pressure, vibration and pain, also contains a region known as the somatosesnory strip which is a band of cotex that processes tackle info about dif body parts, higher order bisial stimuli
What is the Frontal Cortex?
front of brain, planning and movement, primary motor stir is invalid i control of voluntary movement, broccas area, has the prefrontal cortex which is from of head and is important for short-term memory and working memory and moral reashoning
What is the Corpus callosum?
communication of one side of the neocortex to the other occurs via a dense bundle of mural fibbers and connects the two sides of the brain
