Biopsychology Exam 1

disembodied mind

cultural / religious perspective
- body = biological machine, robot to the spirit
- spirit = seat of personality memory, choice, mood, emotion
- brain = interface between body and spirit that exchanges info (contains no memory and not responsible for choice)

embodied mind

mind 'arises' from the brain, more scientifically accurate
- for every brain state, there is a corresponding mental state at that moment

biopsychology

physical processes fully cause and underlie all behaviors
- everything we do, think, feel, perceive, sense, etc. is the SOLE result of brain / body processes (embodied)

is a conscious mind necessary for adaptive behavior?

no
- ex: blindsight - cortical blindness; will state that they cannot see a dot on a screen (even though eyes work fine), but can accurately say which direction the dot moved
- schizophrenia
- alcohol disinhibits dopamine release, which is involved in desire, reinforcement, pleasure, etc.

parts of a neuron

dendrites, cell body (soma), nucleus, axon hillock, axon, axon terminal, synaptic cleft

cell body (soma)

contains the nucleus and other parts of the cell needed to sustain its life
- info filters into here

axon terminal

the endpoint of a neuron where neurotransmitters are stored

synaptic cleft

a gap into which neurotransmitters are released from the axon terminal
- physical distance that separates neurons

oligodendrocytes

type of glial cell that wraps axons in a myelin sheath (CNS)

radial glia

structural support

microglia

cell repair

peripheral nervous system

the sensory and motor neurons that connect the central nervous system (brain+spinal cord) to the rest of the body

3 important cranial nerves

olfactory nerve, optic nerve (or chiasm), and vagus nerve

olfactory bulb

first site of input for odor information from nose
- NOT a nerve

optic nerve / chiasm

carries visual information from the retina to the thalamus; allows left visual field to cross over to right hemisphere

autonomic nervous system

- the part of the PNS that controls the glands and the muscles of the internal organs (such as the heart)

ventral side of brain

bottom (aka inferior)

caudal side of brain

back (aka posterior)

horizontal plane

ipsilateral

on the same hemisphere of the brain / side of body

afferent

sensory, where a projection comes from

vertebra of spinal column

spinal cord runs through dorsally to ventrally, anatomically organized

motor neurons

neurons that carry outgoing info from the CNS to the muscles and glands

meninges of the brain

tightly-regulated membranous sacs that protect and minimize brain damage

sub-arachnoid lymphatic-like membrane

new, glymphatic system

sub-arachnoid space

contains cerebrospinal fluid

pia mater (meninge)

thin membrane next to brain; contains nerves and blood vessels to nourish cells of brain and spinal cord beneath

spinal cord meninges

dura mater, arachnoid mater, pia mater (same ones as brain)

central canal

filled with cerebrospinal fluid (made by the choroid plexus in the ventricles), which is released to immerse the brain, and is then absorbed by the bloodstream

medulla

spinal thalamic fibers of passage; respiration, salivation, etc.

midbrain

on top of pons, broken into subsets of tissues: tectum and tegmentum

inferior colliculus

auditory localization (pitch, etc)

cerebral cortex

aka cerebrum; higher processing, includes all the lobes

4 cortical lobes of the brain

frontal, temporal, parietal, occipital

sulcus (sulci)

depression or groove in the surface of the cerebral cortex; fissure

lateral fissure separates what lobes?

frontal and temporal

central sulcus separates what lobes?

frontal and parietal

longitudinal fissure separates what?

left and right hemispheres

occipital lobe

visual processing

parietal lobe

somatosensory processing (touch, body position), attention, body space awareness

Phineas Gage

railroad worker, pole went through his head, became an ill-tempered man (was originally good / friendly)
- personality change due to lesion in frontal lobe

what parts does the brainstem consist of?

medulla, pons, midbrain, thalamus, and hypothalamus

limbic system

neural system located below the cerebral hemispheres; associated with emotions, motivations / drives, and memory

what does the basal ganglia consist of?

Striatum (composed of caudate and putamen) and Globus Pallidus

the brain is not just cell bodies, but dendrite and axon connecting areas called...

coronal radiations and association fibers

embryonic divisions

forebrain, midbrain, hindbrain

hindbrain divisons

myelencephalon and metencephalon

metencephalon

pons, cerebellum, and 4th ventricle

midbrain divisions

mesencephalon

hypothalamus

motivated behavior (4 F's):
fighting, fleeing, feeding, and fornication (sex)

Nissl-Stained rat brain

stains cell bodies, saw different shades (layers) in the cortex

lamina

cell layers (usually of the cortex)

projection neuron

primary axons leave structure or layer

nucleus

1. collection of cell bodies in the CNS
2. part of neuron holding DNA

pituitary gland

"master" gland - in endocrine system, releases hormones that influence other glands

pineal gland

sleep wake cycle, not repeated in both hemispheres (just 1)

what would a stroke in the left hemisphere parietal lobe impair?

speech, motor, and memory

presynpatic neuron

neuron that sends the signal

what does an action potential represent?

information being carried / transported

basic flow of information in a neuron: step 5/10

electric potential summates in space / time, producing 'graded' potential

basic flow of information in a neuron: step 6/10

if voltage that reaches axon hillock is sufficient, neuron initiates an action potential to transmit a message to other neurons

basic flow of information in a neuron: step 9/10

when AP reaches axon terminal, it causes neurotransmitter to be released to the next neuron

ion channels

protein "tunnels" in the cell membrane that are typically selective for a particular ion (ex: Na+)

leak channels

open all the time, permeable to potassium (K+)

if we measure ion flow when the neuron is "at rest", we will find that...

- Na+ ions continuously ENTER the cell through leak channels
- K+ ions continuously LEAVE the cell through leak channels

why do ions flow in the direction they do?

they have different concentration gradients
- the inside and outside of the neuron contain billions of ions
- the internal and external concentrations of each ion differ, providing a gradient which the ions move DOWN

potassium (K+) ion concentration is greater....

INSIDE the cell (than outside)

what is the result of the electrical potential in the cell?

negatively drawing K+ back into the cell
- the 'reversal'
- 2 forces of moving ions in/out of the cell until the concentration force pushing out is exactly balanced by the electrical force pulling in

equilibrium potential (aka reversal potential)

the voltage at which an ion stops flowing down its concentration gradient

what is the typical voltage for K+ concentrations in neurons?

-80 mV

in normal conditions, do cells ever get more negative than -80 mV?

no, so K+ always flows out (>-80) or net flow will be equivalent (at -80mV)

do action potentials affect the concentration gradient of a cell?

BARELY
- approx 2,000,000 K+ ions leave during an action potential, but there are 47,000,000,000 K+ ions inside the cell
- so, each action potential decreases K+ concentration by .004%,
- thus, the concentration gradient remains effectively unchanged

what is the equilibrium potential voltage for sodium?

+55 mV

describe natural flow of Na+ down its concentration gradient

- 15x more Na+ outside than inside
- flows INTO neuron until the cell is more positive than +55 mV, thus preventing influx

describe natural flow of chloride (Cl-) down its concentration gradient

- there is ~7x more Cl- outside than in
- will flow INTO the cell until the cell is more negative than -60mV

what is the equilibrium potential voltage for calcium?

+150 mV

describe natural flow of calcium (Ca++) down its concentration gradient

there is >10,000x more outside than in
- it will ALWAYS flow INTO the cell

EPSP

excitatory post synaptic potential

what causes a EPSP?

action potential and neurotransmitter release from a excitatory presynaptic neuron

what causes a IPSP?

action potential and neurotransmitter release from an inhibitory neuron

receptor potential: Na+

enters cell, results in EPSP, depolarizing

- results from excitatory neurotransmitter binding (e.g., glutamate)

- also involved in positive phase of action potential

receptor potential: Cl-

enters cell, results in IPSP, hyperpolarizing

- results from inhibitory neurotransmitter (e.g., GABA)

- influx keeps cell from reaching threshold for AP

when do action potentials occur?

when the cell depolarized enough (to threshold level of -50mV at axon hillock)

do action potentials diminish?

no, regenerates at each point along the axon

voltage-gated ion channels

channel in axon hillock / axon that open and close based on voltage, NOT neurotransmitter binding

when do voltage-gated ion channels open?

when the membrane potential at the axon hillock reaches approximately -50 mV
- K+ and Na+ channels are activated at the same time and voltage (-50mV)

mechanisms of voltage-gated Na+ ion channels VS voltage-gated K+ ion channels

- Na+: open rapidly and stay open for ~1ms before inactivating; they then de-inactivate after cell is more negative than -50mV

- K+: open more slowly and close more slowly; they do not inactivate, but slowly close when cell is more negative than -50mV

Nodes of Ranvier

the unmyelinated distance between the sets of voltage gated ion channels in myelinated axons

Synaptosomal associated protein

sodium-potassium pump

maintains concentration gradient at resting potential

- slow process and is used for long-term balancing of ions (it is NOT used to bring the potential back to rest after an action potential)

how do K+ and Na+ move in a potassium pump?

- K+ will be pumped IN

- Na+ will be pumped OUT

- used to keep ions’ concentration at appropriate levels, by moving 3 Na+ out for 2 K+ in

steps in neurotransmitter utilization

1. synthesis
2. storage
3. release
4. binding
5. deactivation

step 1: synthesis

neurotransmitter synthesized at axon terminal or in cell body and then transported to terminal

step 3: release

vesicles fuse to axon terminal membrane and contents (~500-1000 NT molecules) diffuse into synaptic cleft (exocytosis)

which of the five steps can drugs disrupt / alter?

all of them!

vesicle availability

- ready and releasable pool, recycling pool, reserved pool

- only ready and releasable pool are actually released

- generation of AP doesn’t necessarily mean neurotransmitter will be released

- function: docking and priming

vesicle docking / exocytosis

- 2 vesicle snares (v-snare) and 2 proteins target snares (t-snare)
- t-snares tangle with v-snares, so vesicle can be docked

which is the most prevalent inhibitory neurotransmitter (ionotropic)?

GABA
- opens Cl- channels (IPSP)

g-protein coupled receptors (metabotropic)

induce intracellular cascades that change the state or "tone" of the neuron and/or produce long-term changes in connectivity or functioning

different g-protein coupled receptors & their different effects

- Gαs and Gαi/o excite and inhibit Adenylate Cyclase respectively
- Gαq/11 pathway excite phospholipase C