chapter 3: biology and neuroscience Flashcards
main interpreter of both the event in your body and those in the outer world, overall purpose is to create behaviour and make sense of the surroundings
human nervous system
makes up the central nervous system, the ultimate problem solvers that send and receive information to and from all areas of your body
brain and spinal cord
cells that transmit electrical impulses
neurons
brain’s communicators that provide structural support
glial cells
anything related to nervous system structure or function
neural
interconnected group of dendrites and axons of many neurons dedicated to a set of functions
neural networks
extensions for the membrane of the cell body and they receive chemical messages from other neurons
dendrites
can tell the neuron to activate (excitation) or quiet down (inhibition)
neurotransmitter
proteins that are embedded in the membranes that binds with neurotransmitters that help communication in the nervous system
receptors
cell body of a neuron, the location of metabolic processing and contains the cell’s organelles
soma
a long, narrow projection from the cell body that transmits the signal from the soma to the end of the axon
axon
the beginning of the axon, intersection between soma and axon
axon hillock
the part of axon that releases the neurotransmitter, once action potential gets to the axon terminal, it triggers the release of the neurotransmitter
axon terminal
“synaptic knobs”, they very end of the axon terminal where neurotransmitters exit into the synapse
terminal buttons
little bubbles at the terminal button that store neurotransmitter molecules, which are then released in the synaptic cleft
vesicles
space between the end of the neuron that releases a neurotransmitter and the end of the receiving neuron
synaptic cleft
small fluid-filled gap between neurons into which neurotransmitters are released
synapse
the portion of the neuron that releases the neurotransmitter into the synapse
presynaptic neuron
the other side of the synapse, contains receptors ready to bind with neurotransmitters released from the presynaptic neuron
postsynaptic receptor
a protein and fatty substance that wraps around the axon to protect and increase the speed of action potential
myelin
breaks in the myelin that helps the signal travel down the axon by allowing ions to enter and change the charge inside the cell for a more efficient transmission
nodes of ranvier
caused by the natural imbalance of electrical charge that exists between the inside and outside of the axon, rests at -70mV (more sodium on the outside and potassium on the inside maintained by unequal permeability of the membrane and the sodium-potassium pump)
resting potential
charge is far from 0
polarized
refers to when we are moving away from being polarized, the more depolarized = more likely to get action potential
small influx of sodium ions trigger a cascade of voltage sensitive sodium ion channels, allowing more sodiums to move to the inside of the membrane down the concentration gradient, causing the membrane potential to raise to +40mV, if enough sodium gates open to reach threshold, action potential occurs
depolarization
potassium channels open and they move to the outside of the axon down the concentration gradient, causing the membrane to drop back to -65mV, leaving the membrane with more sodium on the inside and potassium on the outside
repolarization
another action potential can’t happen until proper concentration is established so ATP attaches to sodium-potassium pump, allowing 3 sodiums out and 2 potassiums in to re-establish the balance
recovery
causes a neuron to move closer to activation (more positive)
excitatory
causes the charge inside a neuron to move away from the activation (more negative)
inhibitory
mimic the action of an endogenous neurotransmitter
agonists
neurotransmitter naturally produced by the body
endogenous
prevent the action of the endogenous neurotransmitter
antagonists
a chemical that either partially enhances, mimics, or blocks a neurotransmitter action, meaning that they activate the receptor with less power than endogenous neurotransmitter
partial agonists/antagonists
excitatory, helps with learning and movement
glutamate
inhibitory, helps with learning, anxiety regulation through inhibition of neurons, binds to its receptor to open chloride channel
GABA
excitatory, helps with learning and muscle action, binds to its receptor to open sodium channel
Acetylcholine
excitatory/inhibitory, helps with learning and reward/pleasure
dopamine
excitatory/inhibitory, helps with elevation/depression of mood
serotonin and norepinephrine
excitatory/inhibitory, helps with regulation of pain responses
endorphins
“caretaker”, provide structural support for neurons, bring nutrients, remove waste and dead neurons, and speed up electrical impulses
glial cells
glial cells that wrap the myelin insulation in the central nervous system
oligodendrocytes
glial cells that wrap the myelin insulation in the peripheral nervous system
Schwann cells
glial cells that help get nutrition to neurons and maintain the balance of charged particles inside and outside of the neuron
astrocytes
glial cells that clean debris and get rid of germs
microglia
disorders which neuron die over time and cause progressive loss of a particular ability (dysfunctional astrocytes have been implicated in this disorder)
neurodegenerative diseases
a large bundle of axons from many neurons together in a tube that extends a large distance, extend from cell bodies that are in the CNS
nerve
axons that carry signals away from CNS to trigger neurotransmitter or hormone release in organs or muscles
efferents
axons that carry signals back to CNS from organs and muscles
afferents
the ability of neurons and their networks to change and adapt
neuroplasticity
all the cells and support inside the skull vertebral column (brain and spinal cord), contains gray matter (neurons and glia) and white matter (bundled of myelinated axons
central nervous system
local processing of information
gray matter
helps different areas of the brain to share information by connecting neurons via axons and dendrites
white matter
the nerves outside the skull vertebral column, as well as the specialized sensory endings (retinal cells, touch receptors, hair cells in the ear)
peripheral nervous system
“information highway of the body” conducts simple reflex-level processing and communication with PNS
spinal cord
“voluntary” controls the movement of the torso, head, and limbs, nerves that control and communicate with skeletal muscles
somatic nervous system
“automatic” controls the more automatic functions of the body, anything below the level of consciousness
autonomic nervous system
individual joints that make up the vertebral column, allowing the ability to flex, extend, and twist the spine, also allows space for peripheral nerves to exit the spinal cord for connection and communication with the body
vertebrae
“fight or flight”, activated in a life or death situation, or when feeling nervous or frightened
when activated, heart rate and respiration increases, inhibition of digestive activity, more sweat as body temperature rises, narrow vision for focusing, blood flow routed to systems that aid in fighting
sympathetic nervous system
“resting”, responsible for resting, digestion, and repairing the body, originate in the lower brain and sacral spinal cord,
when activated, heart rate and respiration slow down, blood routed to digestive system, organs recover, digest, and become sexually aroused
parasympathetic
activates both sympathetic and parasympathetic nervous system
increases heart rate and respiration, increased neural activation of our muscles, and increased blood flow to the genitals
excitement of attraction
both regulate basic life functions and connect the PNS and CNS to regulate what we do and pay attention to
medulla and pons
the part of the brain closest to the spinal cord that helps regulate life functions such as breathing and heart rate, swallowing (basic life functions)
medulla oblongata
large amount of this ingredient will depress activity in the medulla so much that it will no longer sustain heart rate and respiration needed to be alive
ethanol
regulate arousal, coordinate the sense with the cerebellum, controls facial expressions and eye movements, and serves as the connection point between the upper brain to the lower brain and spinal cord
pons
originating in inner ear that helps the brain sense body’s orientation and regulates left-right coordination, enters the brain through pons
vestibulocochlear nerve
network of neuron in the centre of medulla and pons, regulate our level of arousal, focus of our attention, and filters out irrelevant stimuli on a daily basis (dysfunctional RAS may lead to ADHD)
reticular activating system (RAS)
regulate our endocrine systems, emotions, and emotional memory, contains the prefrontal cortex, olfactory cortex, amygdala, hippocampus, cingulate gyrus, and hypothalamus
the limbic system
involved in aggression responses to threats (fear), disgust, appetitive responses to food, and romantic love, increases secretion of norepinephrine in fight or flight response, active in forming memories associated with events tied to strong emotions
amygdala
experimental destruction of the amygdala in animals, making them docile, damaged amygdala in humans make them lose awareness of their emotions and often respond inappropriately in situations that trigger emotional responses
amygdalectomy
circular structure in the temporal lobes as a loop of neurons that are activated when we are forming memories, helps us remember what we want to return to or avoid
hippocampus
located underneath the neocortex, increased activity when there’s physical pain or excluded socially, helps us focus our attention and thoughts on unpleasant things
cingulate gyrus
modulate movement commands in the brain, increased activity when initiating or terminating a movement, helps us learn to make complex movements more automatic
basal ganglia
where the inputs to the basal ganglia come in
striatum
consisting of globus pallidus, substantia nigra, and subthalamic nucleus, closer to the lower part of the striatum, more associated with reward processing, motivation, and emotional aspects of behavior
ventral striatum
consisting of clustered groups of neurons called caudate and putamen, the upper part of the striatum, more involved in motor functions, habit formation, and procedural learning
dorsal striatum
send inhibitory outputs to thalamus to integrate sensory and motor plans
globus pallidus
(black substance) send inhibitory outputs to thalamus to integrate sensory and motor plans, secrete dopamine, loss of these cells results in loss of the circuit that initiates and terminates movements (Parkinson’s disease)
substantia nigra
excitatory effect on the thalamus and drives motor behaviour
direct pathway
net inhibitory effect on its target, helps the basal ganglia shut down motor patterns
indirect pathway
patients with Parkinson’s disease have a hard time initiating and terminating movements
cogwheel rigidity
“little brain”, rhythm and timing machine, simultaneously receive and organize input from many CNS networks
cerebellum
helps match sensory input with motor plans in order to fine-tune movement patterns
spinocerebellar
processes information from the inner ear to help adjust posture and balance
vestibulocerebellar / vestibular sacs
manages connections with the pons and thalamus to adjust the timing and planning of movements
cerebrocerebellar
the 6-layered portion of the thalamus that processes and organized visual information, send projections to the visual cortex
lateral geniculate nucleus
the portion of thalamus that evaluates and organizes auditory information, send projection to the auditory cortex
medial geniculate nucleus
“the relay station”, all senses except smell (straight to temporal lobes) must pass through the thalamus before they are relayed to neocortex for organization
thalamus
“higher-level processing” the outer layer of the brain, consists of four lobes, looks this way because of the gyri, sulci, and fissures allowing us to fit more brain in a small space
neocortex
parts of the neocortex that merge information from primary areas like the visual and auditory cortex (making sense of the things)
association cortex
“executive decisions”, decision making, movement, and personality, outputs tends to be inhibitory
frontal lobes
most posterior structure in the frontal lobes, initiate voluntary movement
motor cortex
axons that control movement of the muscles in the body (spinal) and head/face (cobulbar)
motor axons of the corticospinal and corticobulbar tracts
a graphical representation of how we would look like in proportion to the number of neurons dedicated to a specific body part/function in our brain
sensory homunculus
“coordinator” the front portion of frontal lobes, a network of neurons and glia heavily involved in decision making (when, why , and how we do things), last region to undergo the process of myelination, has both excitatory and inhibitory connections (if, then decision), dysfunction in the area correlate with negative symptoms in schizophrenic patients (social withdrawal)
prefrontal cortex (PFC)
bottom inside part of the cortex, helps modulate behaviour based on fear and been implicated in moral decision-making
ventromedial prefrontal cortex
top and side of the head, helps maintain information in our working memory and change how we do things depending on different tasks
dorsolateral prefrontal cortex
“space, time, and numbers”, processing of numbers and performing calculations
parietal lobes
if right side of our parietal lobes are injured, we will not navigate the space around us well or misinterpret sensation from our left side
spatial relations
anterior portion of the parietal lobes, receives input from the contralateral (opposite) side of the body, allowing information carried from sensory receptors to integrate with other areas of the brain, helps us coordinate both sides of the body
sensory cortex
“listen to memories”, right above the ear, assist us in forming memories and processing sound input from the auditory nerves, lesions in this area result in memory loss, and loss of ability to form new memories (anterograde amnesia), houses the cortical site of small and taste synpases
temporal lobes
neurons dies
lesions
neurons in the temporal lobe dedicated to receiving and processing messages sent from the ears through axons of the vestibulocochlear nerve
primary auditory cortex
important area for the processing and understanding of language
Wernicke’s area
“vision of the present”, processing light stimuli
occipital lobes
the x-shaped pathway that allows for the crossing of fibres from the nasal retina to the optic tract on the other side. This enables vision from one side of both the eyes to be appreciated by the occipital cortex of the opposite side
optic chaism
left visual field contact the medial portion of your left eye and the lateral part of the right eye’s retina, the neurons are then depolarized and activate in the right thalamus and the right occipital cortex
right visual field ends on in left occipital cortex
right visual field and left visual field
each hemisphere performs different functions
brain laterality
more artistic and creative, sees things globally, necessary to maintain a complete sense of what we are hearing and saying
right brain
analytic, logic, responds to detail and specificity, language
left brain
“tough body”, thick bundle of fibres to connect the two hemisphere and allow transfer of information, helps sensory information (except olfaction) to cross to other side, cutting this area is a treatment for severe epilepsy, which calms seizures
corpus callosum
have trouble seeing and naming an object in their left visual field because visual information from the left is process in the right visual cortex, and the information is stuck on one side of the brain
split-brain patients
consists of series of glands throughout the body that release hormones, and serves as a secondary control system that assist and gives valuable feedback to the nervous system
endocrine system
secretes hormones and controls the pituitary gland via direct nerve stimulation, regulates homeostasis, controls several functions in the autonomic and endocrine systems
damage to this area results in deficits in regulating hunger responses, sexual behaviour, body temperature, and aggression
hypothalamus
secretes melatonin to regulate sleep cycles
pineal gland
secretes hormones that affect sexual behaviour, reproduction, circulatory function, hunger, and responses to aggression
pituitary gland
“love hormone” secreted by hypothalamus, released during orgasms, when we look at pictures of loved one, or being near them
oxytocin
chronic stress involves a triangle connecting the brain and endocrine system
hypothalamus secretes hormones that control the pituitary gland, which controls the adrenal glands, chronic stress leads to hypothalamus being more active, driving the pituitary to tell the adrenal glands to produce more cortisol (stress hormone), leaving us feeling fatigued, storing more fat, and becoming less alert over time
hypothalamus-pituitary-adrenal axis (HPA axis)
how the nervous system modulates immune function
psychoneuroimmunology
how we know what we know
epistemology
techniques we use to look at structures in the nervous system in great detail
structural imaging
take tissue our of the system and tease it apart to see how things are connected
dissection
visualize and measure changes in nervous system activity simultaneously
functional imaging
published by ancient Egyptians about the brain around 1600BCE
oldest surviving texts
separated neurons by hand with the microscopes in the late 1800s
Otta Friedrich Karl Deiter
invented by Camillo Glogi, dyeing neurons, axons, and dendrites to make them more visible on microscopes
staining method
believed some forms of energy is needed to make muscles move, found out frog leg could move with electrical stimulation (animal electricity)
Luigi Galvanni
in the 1990s, he made it possible to stain neurons in living tissue
Martin Chalfie
developed by Erwin Neher and Bert Sakmann, to record electrical activity from individual neurons
patch-clamp
a method that allows us to record directly from clusters of electrical activity in the brain (Hans Berger in 1924), doesn’t show us activity changes in deeper brain structures like basal ganglia
electroencephalogram (EEG)
done by creating computer programs and equipment that filter noise (energy or magnetic field that interferes with the detection)
signal-to-noise ratio
projects an image onto a film of the brain
autorodiography
has access to deeper brain structures, measures the oxygen level changes as related to blood flow around neurons, non-invasive and no radiation though cardiovascular disease or compromised function can make results unreliable
fMRI
inserted into the brain during surgery to measure individual clusters of neurons
indwelling electrodes
helps us figure out which neurotransmitters were being released, injects a radioactively tagged molecule that competes with target neurotransmitter for its receptor binding site, has radiation exposure
PET scan
threes ways to shut down a circuit
injecting inhibitory drug that keeps the neuron from firing action potential (reversible), injecting a drug that overexcites neurons and kills them, and cutting them out of the nervous system physically through ablation (both are irreversible)
the surgical removal of a body tissue
ablation
a method used with MRI scans that allows white matter (axons with myelin) to be seen on scans, the interpretation can be difficult in tracts that have different kinds of fibres
diffusion tensor imaging (DTI)
uses x-rays that pass through the body and can generate images of slices of the body, fast and cheap but has radiation exposure
CT scan
uses magnetic fields to image alignments of hydrogen ions, its non-invasive with great precision and no radiation but really expensive
MRI
