Bio Psych Exam #1 Flashcards
Biological psychology definition
the relationship between the brain and behavior
Molecular neuroscience
what is happening in the brain at individual chemical levels (pharmaceuticals, understanding basis of neurological and psychological disorders)
Systems neuroscience
how do we see, hear and move → how do these systems come into play
Affective and social neuroscience
what is happening in the brain when you are feeling emotions or in social settings
Basic functions of the brain
1) Create a sensory reality
2) Integrate information
3) Produce behavior
In → integrate → out
10 principles of the nervous system
- The nervous system produces movement in a perceptual world that the brain constructs (different brains have different perceptions – color blindedness)
- Neuroplasticity is the hallmark of nervous system functioning (learning)
- Many brain circuits are crossed (interaction of activation)
- The brain is symmetrical and asymmetrical (language and spatial)
- Brain systems are organized hierarchically and in parallel
- The brain divides sensory input for object recognition and movement
- Brain functions are localized and distributed
- The nervous system works by juxtaposing excitation and inhibition
Parts of the Central Nervous system
- Brain
- Spinal cord
**function: controls and mediates behavior
Parts of the Peripheral Nervous system
- somatic nervous system
- autonomic nervous system
- enteric nervous system
Somatic nervous system
Cranial and spinal nerves
Autonomic nervous system
Regulates organs and glands → parasympathetic and sympathetic nervous system
Enteric Nervous system
control the gut → highly related to stress
Who is the father of modern neuroscience
Santiago Ramon y Cajal:
- pathologist from Spain → first one to look at neurons under a microscope
- When two different brain cells come together, they don’t actually touch → very important
Parts of a neuron
- dendrites
- cell body (soma)
- axon
- end/terminal buttons
Dendrites
look like tree branches
- where we receive information
- Includes dendritic spines: the bumpy part → take in information from other cells and funnels it to the cell body – spines give more surface area so we can have more connections
Cell body of a neuron
- Contains nucleus + other typical cell structures
- Computation happens here: decides what will happen and sends the signal down the axon to the ends
Axon of a neuron
- Goes from the cell body to the ends
- Myelinated: coated in myelin (a fat) → insulation
- Ends are called “terminal buttons”
Synapses
the space/gap between neurons
- Includes terminal buttons on one side (end of the axon) and the surface of the dendrite of the adjacent cell on the other side
- Contiguous not continuous
Myelin
acts as insulation for the electrical AP
- without myelin, electrical activity would bleed out and not get very far
- in breast/whole milk = helps build this in the brain for babies
- when myelin is degraded it causes multiple sclerosis (MS)
Types of neurons
- all have the same structure but look different
1) sensory neurons
2) interneurons
3) motor neurons
Histology definition
Study of tissues under a microscope
Use of histology
- Different ways to stain cells which can show us different things
1) Nissl staining: shows cell bodies (violet)
2) Golgi staining: cell bodies and dendrites
3) Individual neurons with electron microscope → allows us to see synapse
4) Multi-photon microscope
What do glial cells do (broadly)?
The glue: holding everything together and doing the “boring” functions – support, connect, protect
Types of glial cells
1) astrocyte: form a barrier that prevents toxic substances from entering the brain (“blood-brain barrier”)
2) Oligodendroglial cell and Schwann cell: form the myelin sheath over the axon
2a) Oligodendroglial / oligodendrocytes: in the central nervous system (CNS)
2b) Schwann cells: in the peripheral nervous system (PNS)
How do neurons talk to each other?
electrochemical transmission
oscilloscope
tool that looks at the inside of a cell’s electrical potential (intracellular recording)
- measures in millivolts
- put a micro-electrode into the axon and it records changes in membrane potential
What generates the resting membrane potential?
Movement of charges ions
What is the resting membrane potential (and why)?
-70mV
1) Potassium: on the inside of the cell BUT can leave the cell easily through its many leaky channels → why it is more negative as the anions can not move (always on the inside)
2) Outside: we do have chloride (-) but we have much more sodium (+) (there are sodium leaky channels but not as many as potassium so most Na +remain on the outside)
3) Sodium potassium pump: pumps out three Na+ for two K+ in → net result is -1
**no free diffusion - have a seperation of charge
What is inside of the cell at resting potential
1) potassium ions (K+)
2) anions (A-)
What is outside of the cell at resting potential
1) sodium ions (Na+)
2) Chloride ions (Cl-)
Methods for ion movement
1) membrane channels: specific to certain ions - always open
2) gates: open and close
3) pumps: sodium and potassium pump
What are graded potentials?
small voltage fluctuation (1-5 mv change)
Hyperpolarization
Even more extreme voltage: inside even more negative, outside becomes even more positive → moves away from 0)
Depolarization
Getting closer to equilibrium (0) → (-70 goes to -65 etc.)
Threshold potential for an AP
-50mV
Graded potentials and their product
Hyperpolarizations and depolarizations fight it out → if the resting membrane potential reaches -50mV, it triggers voltage-activated channels: open and close based on voltage – configuration of the gates change to allow Na+ in and K+ out
What happens when membrane potential reaches the threshold?
1) voltage gated channels open: sodium floods the cell (fast) and potassium leaves (slowly) – makes inside of the cell more positive
2) keeps happening until we get to +40mV
3) once we hit a peak (+40mV) sodium channels close and potassium continues to leave the cell until we get back to baseline (-70mV) – this is overshot a bit so it dips below baseline and then comes back
Absolute refractory period
no way to trigger another AP → both for depolarization and repolarization
- During the rising (depolarization) and falling phase (repolarizing)
Relative refractory period
Can make an AP work (but hard, generally doesn’t happen) → only during hyperpolarization
- during the overshoot phase
How does an action potential move?
Saltatory conduction:
-The action potential does not take us from cell A to cell B → takes us down the axon of the same cell
- The Na+ from 1 AP causes some local depolarization of adjacent areas of that membrane → continues to the end
- Node of ranvier: gaps in between the myelin → where the action potentials take place
Can you have half an action potential?
all or none → a neuron is either firing or it is not
Can action potentials flow in two ways?
NO - always going to go from the cell body, down the axon to the terminal
It’s how we get information down the cell so it can synapse with the next cell and talk to it – based on saltatory conduction
Postsynaptic potentials definition
how the action potential starts
Types of Postsynaptic potentials
1) Excitatory postsynaptic potentials (EPSPs) → positively charged; causes depolarization
2) Inhibitory postsynaptic potentials (IPSPs) → negatively charged; cause hyperpolarization
Temporal summation
Temporal = time
Ex: if 5 EPSP come in at the same time: you get a bonus (amplified)
Spatial Summation
Spatial = space
Ex: if 5 EPSP come in all right next to each other, you get another bonus (amplified)
Excitatory neurons
More Na+ channels open
Influx of Na+ is depolarization (inside of the cell becomes more positive than it once was) → get an increase in the likelihood of reaching the threshold potential
**EPSP
Inhibitory neurons
More K+ channels open (leave inside) or Cl- channels open (go inside)
Causes hyperpolarization: inside of the cell becomes even more negative than it once was
Can neurons be excitatory AND inhibitory?
no - usually one or the other
Why do we need the chemical part of electrochemical transmission?
If electricity entered the synaptic gap it would diffuse away and not enter the other cell
Presynaptic membrane:
encloses molecules that transmits chemical message
Postsynaptic membrane
contains receptor molecules that receive chemical messages