Exam 2 Flashcards by Emily Licata

(neurochemical)
- released at directed synapses
- act on neurons in immediate vicinity

neurotransmitters

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(neurochemical) (two)
- non-directed synapses (volume-transmission)
- act on more distant neurons

neuromodulators and neurohormones

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(neurochemical)

diffuse away from point of release

neuromodulators

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(neurochemical) travel in blood supply

neurohormones

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Acetylcholine synthesis

Choline + Acetate via enzyme ChAT

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Acetylcholine receptors

nicotinic (ionotropic)

muscarinic (metabotropic)

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Acetylcholine degradation

reuptake or broken down by enzyme AChE

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Acetylcholine role in peripheral nervous system (autonomic)

both pre-ganglionic, parasympathetic post-ganglionic

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Acetylcholine role in peripheral nervous system (somatic)

neuromuscular junction (think botox)

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Acetylcholine role in central nervous system

projections from basal forebrain to hippocampus and amygdala; septal area (part of limbic system); brainstem

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Acetylcholine behaviors

autonomic functions, movement, learning and memory

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Acetylcholine clinical conditions

Alzheimer’s, myasthenia gravis (effects neuromuscular junction), schizophrenia (lots of chemicals involved in schizo)?

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lose cells in these area

cholinergic areas

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cholinergic projections of the human brain

basal forebrain

pons and midbrain

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binds nicotine
blocked by curare
ionotropic
response is fast and brief
located at NMJ, ANS, CNS
excites target cells
postsynaptic

Nicotinic ACh Receptors

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plant based poison

curare

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binds muscarine
blocked by atropine
metabotropic./GPCR
response is slow and prolonged, amplified
found on Myocardial and smooth muscle, CNS
mediates inhibition and excitation in target cells
both pre- and postsynaptic

Muscarinic ACh Receptiors

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Small molecule neurotransmitters: monoamine neurotransmitters

catecholamines
indoleamines
histamine

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include: dopamine, norepinephrine, epinephrine

- synthesized from tyrosine

catecholamines

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include: serotonin, melatonin

- serotonin is synthesized from tryptophan

indoleamines

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catecholamine synthesis rate limiting step

Tyrosine Hydroxylase

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Dopamine (DA) role in PNS

neuromodulator for other neurotransmitters

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Dopamine role in CNS

substantia nigra (SN) -> basal ganglia

- ventral tegmental area (VTA) -> hippocampus, amygdala, nucleus accumbens, and frontal lobe

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Dopamine behavior(s)

movement control, reinforcement, planning

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Dopamine clinical conditions

Parkinson's disease, schizophrenia, drug abuse

Dopamine synthesis

- tyrosine hydroxylase is rate-limiting step | - dopa decarboxylase converts L-Dopa into dopamine

Dopamine receptors

- D1 D5 = stimulatory G-protein coupled receptors | - D2 D3 D4 = inhibitory G-protein coupled receptors

Dopamine degradation

enzymes Monomine oxidase (MAO), catechol-O-methyl transferase (COMT), and aldehyde dehydrogenase, acting in sequence to break down dopamine

finite resource. determines how much of these diff compounds you can produce

rate limiting step

area involved in decision making/reward

Ventral Tegmental Area (VTA)

precursor to Dopamine

L-Dopa

D1 family (D1 and D5)

beginning and end

D2 family (D2 D3 and D4)

all metabotropic

D2 is important in ______

Schizophrenia

what breaks down catecholamines?

COMT

Norepinephrine: role in PNS

autonomic: sympathetic post-ganglionic synapses

Norepinephrine: role in CNS

widespread projections from locus coeruleus (Pons) {blue spot. widespread projections to rest of brain}; medulla, hypothalamus

Norepinephrine: behavior(s)

arousal and vigilance, mood

Norepinephrine: clinical conditions

Depression, mania, PTSD

Norepinephrine: synthesis

dopamine beta hydroxolase converts DA into NE

Dopamine

Norepinephrine

Norepinephrine: receptors

Alpha and Beta

Norepinephrine: degradation

enzymes MAO, COMT, and aldehyde dehydrogenase, acting in sequence to break down norepinephrine

- slow heart down - off label use - alter physical effects of sympathetic nervous system

Betablockers

Locus Coeruleus

arousal, stress, anxiety, mania

- relatively minor role in brain, strong neurohumoral effect - adrenergic neurons - regulation of blood pressure, eating

Epinephrine/Adrenaline

Serotonin(5HT): role in PNS

enteric: digestive motility

Serotonin(5HT): role in CNS

widespread projection from Raphe nucleus (pons) to brain and spinal cord

Serotonin(5HT): behaviors

sleep-wake cycles, appetite, mood, aggression, social rank

Serotonin(5HT): clinical conditions

depression, OCD, alcoholism

Serotonin(5HT): synthesis

made from tryptophan

Serotonin(5HT): receptors

at least 15 types and sub-types | most are metabotropic, can be excitatory or inhibitory

Serotonin(5HT): degradation

- reuptake (why SSRIs are so effective) | - monamine oxidase

Raphe Nuclei

sleep/wake cycles, depression

in the brain neurotransmitter: regulates sleep, hormonal secretion, memory formation, and brain arousal

Histamine

Benadryl

anti-histamine helps w/ allergic reactions. makes you feel tired and drowsy most of the time

Amino Acid Neurotransmitters

GABA and Glutamate

principle inhibitory NT | mood. seizure threshold

GABA

principle excitatory NT | long term mem. may be associated w/ neurotrauma

Glutamate

- off switch - main inhibitory NT - always votes no - tied to anxiety

GABA

- on switch - yes vote - main excitatory NT

Glutamate

- product of Kreb's Cycle | - terminated by high affinity uptake systems in neurons and astrocytes

Glutamate synthesis and removal

Glia: Glutamine synthesis -->

glutamine --> neuron: Glutamate

Glutamate receptors: ionotropic

AMPA Kainate NMDA

Glutamate receptors: metabotropic

mGluRs

Glutamate receptors(ionotropic) most common. opens sodium channel.

AMPA

Glutamate receptors(ionotropic) opens sodium channel. rare.

Kainate

Glutamate receptors(ionotropic) opens channel for sodium and calcium. special.

NMDA

GABA is synthesized from ________ in reaction catalyzed by ___

- glutamate | - GAD

____ converts glutamate into GABA. inhibitory.

GAD

GABA is terminated by

high affinity uptake systems in neurons and glia

GABA receptors: synthesized from __________

glutamate

- GABA receptor - ionotopic - made up of 5 subunits - Cl ion channel - has multiple binding sites including benzodiazepines, barbiturates, and ethanol - more common

GABA A

- GABA receptor - metrabotropic - gates K+ channel

GABA B

Glycine: role in CNS

- major inhibitory NT in spinal cord interneurons - lesser role in brain - excitatory co-activator at NMDA Glutamate receptor

Glycine: behavior(s)

sleep/wake cycles

Glycine: toxins

strychnine

act in the CNS and in connections between autonomic neurons and the vas deferens, bladder, heart, and gut

ATP and Adenosine

is associated w/ pain perception and sleep-waking cycles

ATP

inhibits the release of namy neurochemicals, correlated with drowsiness blocked by caffeine

adenosine

more __________ that builds up the more sleepy you feel

adenosine

small molecule NTs are synthesized here

axon terminal

do small molecule NTs recycle vesicles?

yes

small molecule NTs activation`

moderate action potential frequency

small molecule NTs deactivation

reuptake or enzymatic degradation

Neuropeptide synthesis takes place

in cell body; require transport

Neuropeptides recycle vesicles?

Neuropeptide activation

high action potential frequency

Neuropeptide deactivation

diffusion away from the synapse or enzymatic degradation

Neuropeptides

- Endorphins - Substance P - Insulin and Cholecystokinin - Oxytocin and Vasopression

- Neuropeptide - neuromodulators that reduce pain and enhance reinforcement - "opium within" - feelings of well-being

endorphins

- Neuropeptide | - transmitter in spinal cord neurons sensitive to pain

Substance P

- Neuropeptides | - digestive functions

Insulin and cholecystokinin

- Neuropeptides - neuromodulators and neurohormones - relationships; levels influence whether species is monogamous or not

Oxytocin and vasopression

the cuddle hormone

oxytocin

learning and memory; Alzheimer's disease; muscle movement in the peripheral nervous system

ACh (Acetylcholine)

reward circuits; motor circuits involved in Parkinson's disease; schizophrenia

DA (Dopamine)

arousal; depression

NE (Norepinephrine)

depression; aggression; schizophrenia

5HT (serotonin)

learning; major excitatory neurotransmitter in the brain

GLU (glutamate)

anxiety disorders; epilepsy; major inhibitory neurotransmitter in the brain

GABA

pain; analgesia; reward

endorphins

diffuse through membranes and interact with intracellular receptors. can transmit info from the postsynaptic to the presynaptic neurons (retroactive)

gaseous neurotransmitters

Two gaseous NTs

- nitric oxide | - carbon monoxide

- found in CNS and PNS, smooth muscle - relaxes smooth muscle cells in blood vessels - erection

nitric oxide

colorless, odorless. undetectable by humans - low doses: hallucinations and paranoia - high doses: can kill you

carbon monoxide

any substance that alters the body or its functions

drug

relationship between concentrations of drug and biologic effects. (what drugs do to the body)

pharmacodynamics

what the body does to drugs - absorption - distribution - metabolism - excretion

pharmacokinetics

effective dose @ 50% of the population

plateau. more drug is not going to have more difference at _________

saturation

characteristics of drugs

- affinity - potency - efficacy

tenacity w/ which (how well) a drug binds to its receptor

affinity

fits perfectly to receptor

high affinity

fits but not as perfect of a match

medium affinity

doesn't bind very well

low affinity

affinity is a property/characteristic of the ______ not the _________

drug; receptor

amount of drug required to produce a certain response

potency

want higher ______ so can have a lower dose to get desired effect (lower dose leads to less likelihood for side effects)

potency

property of a drug that determines its ability to produce its biological effect

efficacy

more _______ leads to more response

efficacy

types of drugs

- agonist | - antagonist

- mimics or enhances the effect of a neurotransmitter - activate receptor - partial, full, or inverse - block reuptake or degradation

agonist

- blocks or decreases the effect of a neurotransmitter - block receptors without activating - competitive vs non-competitive - decrease availability of neurotransmitter by reducing production or release

antagonist

presynaptic drug actions

- neurotransmitter production - neurotransmitter storage - neurotransmitter release

manipulating the synthesis of a neurotransmitter will affect the amount available for release

neurotransmitter production

interfering with the storage of a neurotransmitters in vesicles within a neuron

neurotransmitter storage

drugs can modify the release of a neurotransmitter in response to the arrival of an action potential

neurotransmitter release

post synaptic drug actions

postsynaptic receptor effects

- can mimic the action of a neurotransmitter at the site (agonist) - can block the synaptic activity by occupying a binding site (antagonist) - can influence the activity of the receptor

postsynaptic receptor effects

drug actions: removal effects

- reuptake effects | - enzymatic degradation -deactivation of neurotransmitters

cocaine, amphetamine, and Ritalin inhibit ________ _______

dopamine reuptake

SSRIs (Prozac) inhibit _________ _______

serotonin reuptake

organophosphates interfere with _______

AChE | enzymatic degradation

drug effects are influenced by

- body weight - sex - genetics

- user expectations influence drug effects - can result in real biochemical and physiological effects in the brain - needs double-blind experiments

placebo effects

decreased response to drug with repeated use

tolerance

reduction in amount of drug that reaches site of action

metabolic tolerance

reduction in reactivity of sites of drug action - receptor down regulation (less) - receptor up regulation (more)

functional tolerance

learned tolerance

context specific

occurs when substance use is discontinued; opposite of the effects caused by the discontinued drug

withdrawal

- characterized by a compulsive need to re-administer a drug despite harm to user - the dopamine reward system, including nucleus accumbens - result of complex physical and environmental variables = extremely hard to treat

addiction

increase alertness and mobility

stimulants

list of stimulants

- caffeine - nicotine - cocaine - amphetamine

adenosine antagonist

caffeine (stim)

acetylcholine nicotinic receptor antagonist

nicotine (stim)

dopamine floods synapse, dopamine reuptake inhibitor so dopamine in synapse longer

cocaine (stim)

stimulates release and inhibits reuptake of dopamine and norepinephrine

amphetamine (stim)

decrease activity of CNS

depressants

list of depressants

- opioids | - alcohol

reduced release of GABA, less inhibition on DA neurons so more DA into synapse

opioids

GABA A agonist, increases chloride influx. | Glutamate antagonist, reduces excitation

alcohol

cause perceptional distortions

hallucinogens

list of hallucinogens

- marijuana - LSD - ecstasy - ketamine - PCP

active ingredient THC is an endogenous cannabinoid receptor agonist

marijuana

serotonin agonist

LSD

stimulates massive release of serotonin (and some oxytocin). taken up by serotonin transporters, reverse flow of serotonin, toxic to serotonin neurons

ecstasy (molly)

NMDA glutamate antagonist

ketamine

NMDA glutamate antagonist, nicotinic Ach antagonist

PCP (angel dust)

DNA --> RNA -->

proteins

candidate gene

look for specific gene associated with specific trait. spotlight search

genome-wide

large scale. zoomed out.

approx. ____________ genes in the human genome

20,000

__ autosomes pus X and Y

22 (46 diploid)

genes have ____ and _____

exons and introns

exons

coding sequence

introns

noncoding sequence found between exons

recessive genes on one X chromosome that are not duplicated on the Y chromosome will be expressed in male offspring

sex-linked characteristics

X-chromosome inactivation

one X is randomly silenced in females to equalize protein production in males and females

Genetic modification approaches

- knock in - knock out - CRISPR - retroviral gene therapy

take a gene from another species and insert it

knock in

delete a gene and see how it effects receptors and how that effects behavior

knock out

use viruses. put DNA in target cells

retroviral gene therapy

errors in DNA replication

mutations

single nucleotide polymorphisms (SNPs)

- DNA sequence change at one nucleotide | - SNPs in the APOE gene can predict risk for Alzheimer's disease

copy-number variations (CNVs)

- variable numbers of genes in gene series | - associated w autism and schizophrenia

A goes w

C goes w

can occur spontaneously or in response to radiation, chemicals, or other mutagens

genetic mutations

average human baby born w __________ mutations

~130 (most have little to no effect)

a dominant mutant allele or two copies of a recessive mutant allele will affect organism's ___________

phenotype

neg effects: poor oxygen capacity | pos effects: some protection against malaria

sickle cell anemia

genetic variant near olfactory receptor genes influences cilantro preference

Genetics of cilantro

_____ markedly exacerbates tau-mediated neurodegeneration in a mouse model of tauopathy

ApoE4

three copies of 21st chromosome. developmental delays. physical disabilities

down syndrome

the contribution of genetics to the variation of a trait observed in a population

heritability

heritability always refers to a __________, not to individuals

population

o = genes play no role in __________

phenotypical differences

X = X% of the __________ ____________ we see in a trait can be accounted for by genetic differences

population variation

100 = genetics are ___________ responsible for phenotypical differences

completely

changes in gene expression or phenotype that don't involve changes to the DNA sequence

epigenetics

DNA may unwrap or be stopped from unwrapping from the histone a methyl group or other molecule bind to the tails of histones, either blocking them from opening or allowing them to open for transcription

histone modification

``` transcription of DNA into mRNA may be enabled or blocked methyl groups (m) bind to CG base pairs to block transcription ```

DNA modification

mRNA translation may be enabled or blocked | ncRNA binds to mRNA preventing translation

mRNA modification

first week: human zygote has divided into three germ layers

ectoderm mesoderm endoderm

second week: zygote is referred to as an ________

embryo

third week: inducing factors differentiate the ectoderm layer into skin and ________ _________

neural plate

the developing neural plate forms the _________ _________

neural tube

outer layer; becomes skin and neural tissue

ectoderm

middle layer; becomes connective tissue such as ligaments, muscles, blood vessels, and urogenital system

mesoderm

inner layer; becomes many internal organs

endoderm

thickened region of the ectodermal layer that gives rise to the neural tube

1. neural plate

formed when the plate invaginates

2. neural groove

structure in the early stage of brain development from which the brain and spinal cord develop

3. neural tube

______ ______ forms ventricles and central canal of spinal cord surrounding tissue becomes brain and spinal cord

neural tube

stages of neural development

1. cell proliferation 2. migration 3. differentiation 4. circuit formation 5. neuron death (apoptosis) 6. refinement of connections

cell proliferation

make cells

generation of new neurons

neurogenesis

generation of new glia

gliogenesis

migration

put them where need to be

differentiation

specialized roles

circuit growth

(connections) axon growth synaptogenesis

neuron death

apoptosis

refinement of connections

synaptic pruning | synaptic rearrangement

embryonic stem cell

totipotent | unlimited capacity for self-renewal

ability to develop into any type of cell in the body

totipotent

neural stem cell

pluripotent | on neural or glial track

ability to develop into many types of mature nervous system cells

pluripotent

neural progenitor cell (blast cells)

unipotent or oligopotent | limited capacity for self-renewal

ability to develop into one or a few types of mature nervous system cells

unipotent or oligopotent

new neural cells are produced from the mitosis of neural or glial progenitor cells in the _______ _______ lining the neural tube

ventricular zone

up to 250,000 new neural cells

per minute

migration via _____ ____ ____

radial glial cells

provide structural support | rope to climb up

radial glial cells

neurons move from _____ ______ outward to final location

ventricular zone

"inside out" _____ | subcortical (towards skull)

migration

differentiation of neural tube (dorsal-ventral axis) | dorsal half -->

``` sensory neurons (BMP Protein) dorsal root in spinal cord ```

differentiation of neural tube (dorsal-ventral axis) | ventral half -->

``` motor neurons (Sonic Hedgehog; linked w very fast motor output) ventral root in spinal cord ```

differentiation of neural tube (rostral-caudal axis)

rostral-caudal (anterior-posterior) Hox genes

- spinal cord - myelencephalon - mesencephalon - diencephalon - telencephalon

neuronal maturation and circuit formation

chemical and molecular signposts attract or repel advancing neurites

________ grow to provide surface area for synapses w other cells

dendrites

______ grow toward target cells and form functional connections

axons

dendrites

listen

axons

have something to say

reading the environment with growth cones: flopodia

long, fingerlike extensions from growth cones of neurites

reading the environment with growth cones: lamellipodia

flat, sheet like extensions from core of growth cones

axons growing in same direction stick together

fasciculation

once axons reach their destination they must establish new synapses

synaptogenesis

significant numbers of new neurons die during a process called

apoptosis

destroyer. begins apoptosis. inhibiting the destroyer keeps you cell alive

caspase

brain produces extra neurons. | excess neurons and synapses must be eliminated

synaptic pruning

use it or lose it =

activity dependence

occipital peak

4 mos

prefrontal cortex peak

1-4 years

occurs in rostral direction starting w the spinal cord, then hindbrain, midbrain, and forebrain burst in myelination around the time of birth

myelinogenesis

___________ _________ not completely myelinated until early adulthood (age 21-25)

prefrontal cortex

the nervous system's ability to change

plasticity

time when particular experience is influential and after which experience has little or no effect

critical period

adult neurogenesis fist discovered in _________ and _________ _______

hippocampus and olfactory bulbs

the brain in adolescence : puberty

- surge of gray matter development and pruning - thickening of cortex; frontal lobe - amygdala matures first (explains teen risky behavior?)

brain is fully mature at age

weight of brain starts to decrease at age

stimulus for vision is

light

light =

moving waves of photons

wavelength =

color or shades of gray

amplitude =

brightness

light can be

- reflected - absorbed - refracted

our eyes _________ light

refract

protecting the eyes

- located in orbit of the skull - cushioned by fat - eyelids/eyelashes/blinking - tears produced from lacrimal gland

optical functions:

capture light and form detailed spatial images

neural functions: | of the eye

transduce light into neural signals, then relay and process those signals

outer surface of the eye. curved, transparent dome that initially bends incoming light (lot of pain receptors here)

cornea

neural tube defects associated with folic acid

spinal bifida | anencephaly

strong immune response to phenylaniline, found in food.

PKU

transparent, gelatinous mass that fills space from cornea to pupil (first point where light can be refracted)

aqueous humor of anterior chamber

colored area; contains muscles that control the pupil

iris

black opening that lets light in

pupil

transparent disk that uses accommodation to focus light rays for near or far distances (bends the light)

lens

transparent, gelatinous mass that fills space from pupil to retina (large fluid filled area. jello like texture)

vitreous humor

innermost layer in back of the eye where light is converted to neural impulses. contains visual interneurons and photoreceptors.

retina

part of the retina where light rays are most sharply focused (focal point. where we have most clear vision)

fovea

transmits impulses from retina to brain

optic nerve

6 muscles rotates eye in all directions

eye muscles

the eye is like a camera | accommodation:

changing the shape of the lens to focus on objects of varying distances

convex

( ) near object

concave

) ( far object

features of retina

-visual interneurons and photoreceptors -optic disk -macula (fovea) -tapetum lucidum

very center of macula is where we have our ...

fovea

cows and most mammals have this in their eyes. shiny. reflective. helps w night vision.

tapetum lucidum

filled w light-sensitive chemicals called photopigments

photoreceptor cells

- scotopic vision (dim light) - useful at night - no color, low acuity - high density in the peripheral retina

rods

- photopic vision (bright light) - color, high acuity - high density near fovea

cones

contains rhodopsin photopigment | sensitive to dim light in the blue to green range of electromagnetic spectrum

rods

contain lodopsin requires more light than rds in order to respond 3 diff types

cones

3 diff types of cones

- blue/short - green/middle - red/long wavelength

the resting potential of rod outer segment in complete darkness is about

-30 mV

_____ have more activity in the dark than they do in the light

rods

dark =

depolarized

light =

hyperpolarized (more negative)

light releases enzyme that breaks cGMP. less cGMP means fewer _______ channels remain open, and receptor hyperpolarizes

sodium

In the dark photoreceptors are

depolarized

in the light photoreceptors are

hyperpolarized

photoreceptors produce __________ __________ not action potentials

graded potentials

graded potentials: the more photons, the less ___________

neurotransmitter

optic disk

blind spot

where blood vessels and optic nerve leaves the retina there are no photoreceptors = no vision

the blind spot

located between photoreceptors and bipolar cells. perform lateral inhibition. responsible for center-surround receptive fields.

horizontal cells

bridge between photoreceptors and ganglion cells

bipolar cells

connection between eye and brain. receives info from bipolar cells and sends info via the optic nerve. uses action potentials.

ganglion cells

order of cells (for eye)

photoreceptor cells bipolar cells ganglion cells

receives input from photoreceptors and horizontal cells

bipolar cells

input from one cone --> ganglion cells | in bipolar cells

midget

input from several photoreceptors --> ganglion cells

diffuse

bipolar cell depolarized

on-center cell

bipolar cell hyperpolarized

off-center

direct input from singe set of photoreceptors

center

indirect input from horizontal cells connected to photoreceptors

surround

on-center is always

off-surround

- receives input from amacrine and bipolar cells - generates action potentials - provides sole output of visual info to brain, axons form optic nerve - have receptive fields w antagonistic center-surround organization

ganglion cells

- horizontal cells inhibit activity of neighboring bipolar cells - contrast enhancement helps us see edges, boraders

lateral inhibition

ganglion cells are _______ detectors, not light detectors

contrast

types of ganglion cells

P-type M-type K-type

-90% of ganglion cells, small receptive fields -receive input from midget bipolar cells -involved in fine visual acuity, color, and shape processing slow but detailed

P-type

-5% of ganglion cells, larger receptive field -receive input from diffuse bipolar cells -involved in motion processing fast but fuzzy

M-type

similar to P cells, color sensitive but less well understood

K-type

part of environment registered on retina

visual field (VF)

processed in left hemisphere (not just right eye)

Right VF

processed in right hemisphere (not just left eye)

left VF

looks like an X. where cross over of right and left VFs goes to brain

optic chiasm

ganglion cell axons bundle together and exit each eye through the optic disk, forming an _______ ______ leaving each eye

optic nerve

- located in hypothalamus - regulates sleep/wake cycle - small number of retinal axons

suprachiasmatic nucleus

- located in midbrain - guides head and eye movements - about 10% of retinal axons

superior colliculus

- located in thalamus - projects to primary visual cortex (V1), visual perception - about 90% of retinal axons

Lateral geniculate nucleus (LGN)

main destination of fibers | main sensory pathway

lateral geniculate nucleus

optic nerve to optic chiasm to

optic tract

- 6 distinct sacked layers (1 and 2 magnocellular, 3-6 parvocellular) - keeps input from each eye separate - antagonistic center-surround receptive fields

Lateral geniculate nucleus (LGN)

about 80% of input to LGN comes from

primary visual cortex

layers 1 and 2 of LGN

where we get input from M ganglion cells

layers 3-6 of LGN

where we get input from P ganglion cells

- large cells. layers 1 and 2. - receive input from M ganglion cells - respond best to large, fast moving objects

Magnocellular

- smaller cells. top 4 layers (3-6) - receive input from P ganglion cells - respond best to fine spatial details of stationary objects

Parvocellular

a major transformation of visual info takes place in

striate cortex (aka primary visual cortex, or V1)

with V1 we look at

lines of light and how they're moving

locations of retina and LGN correspond to location in

areas 4, 5, and 6. most of V1 is in very close proximity to fovea. where we have most processing for vision

foveal magnification

- receptive fields maintain antagonistic center surround, produced by combining outputs of LGN cells - shape of receptive field elongated - respond to stimuli shaped like bars or edges that have a particular slat or orientation - reinotropic mapping

simple cortical cells

- longer receptive fields - no off region - shows preferred stimulus size and orientation but not location within visual field - sensitive to unidirectional movement - retinotopic mapping

complex cortical cells

preferred stimulus = vertical but off to side. moving light. less vertical. less firing. sensitive to direction of movement

complex cortical cells

responds to lines of a single angle for single eye | made of simple cortical cells

orientation column

responds to input from either the left or right eye, but not both. preferred orientation changes.

ocular dominance column

complex cells

movement

cytochrome oxidase blobs

color

"what" and "where" pathways | "what"

ventral stream

"what" and "where" pathways | "where/how"

dorsal stream

- magnocellular - specialized for movement, locating objects, and visual control of skilled actions - "how"; provides info on how to interact w object

the dorsal pathway

- rare disorder of motion blindness caused by damage at the occipito-parietal junction - vision without movement - can't perceive motion

akinetopsia

- parvocellular - responds to shapes (different forms) and colors - associated w storage of long-term memory

the ventral pathway

rare disorder of face blindness caused by damage at the fusiform face area within temporal lobe

prosopagnosia

responds preferentially to places, such as pictures of houses

PPA: Parahippocampal place area

responds to faces more than other objects (damage --> prosopangnosia)

FFA: fusiform face area

specifically involved in the perception of body parts

EBA: extrastriate body area

striate cortex responds to patterns of lines

gratings

color visiton based on combo of activity in short (B), medium (G), and long sensitive (R) cones

trichromatic theory of color

color vision based on exciting one color and inhibiting its opposites supported by complementary colors, afterimage effects

opponent process theory of color vision

3 types of color receptors

red blue green

myopia

nearsighted

hyperopia

farsighted

process of converting an external energy or substance into neural activity

transduction

activation is greatest when we first detect a stimulus

sensory adaptation

sound results from

a collision of molecules

intensity (loudness) of sound wave

amplitude

wavelength of a sound wave

frequency

above range of human hearing | used in imaging

ultrasound

below range of human hearing used by many animals dizziness, nausea, bowel movements

infrared sound

- collects, focuses, and localizes sound | - signals emotion in some animals

pinna

- tube-shaped opening to middle ear | - the length and shape enhances certain sound frequencies

the auditory canal

boundaries of middle ear are formed by two membranes

- tympanic membrane | - oval window

eardrum

tympanic membrane

leads to cochlea

oval window

bones that amplify and transfer vibrations from air to fluid

ossicles

ossicle bones

- malleus - incus - stapes

malleus

hammer

incus

anvil

stapes

stirrup

muscles that decrease ossicle vibrations when tensed

tensor tympani and stapedius

responds to vibrations from middle ear

cochlea

fluid filled. 3 different chambers.

cochlea

cochlea's 3 chambers are

``` vestibular canal (perilymph) middle canal (endolymph) tympanic canal (perilymph) ```

perilymph

like CSF

endolymph

high K+, low Na+

type of fluid in vestibular and tympanic canals

perilymph

type of fluid in middle canal

endolymph

two membranes of inner ear

reissner's and basilar

extends from oval window at base of cochlea to helicotrema at the apex. contains perilymph

vestibular canal

thin sheath of tissue separating the vestibular and middle canals

reissner's membrane

sandwiched between the tympanic and vestibular canals and contains the cochlear partition. contains endolymph

middle canal

plate of fibers that forms the base of the cochlear partition and separates the middle and tympanic canals in the cochlea

basilar membrane

extends from round window at base of cochlea to helicotrema at the apex. contains perilymph

tympanic canal

on the basilar membrane, composed of hair cells and dendrites of auditory nerve fibers. transduces movements of cochlear partition

organ of corti

a gelatinous structure, attached on one end, tat extends into the middle canal of the ear, floating above inner hair cells and touching outer hair cells

tectorial membrane

convey almost all info about sound waves to brain. 3,500 total. (important for sensory processes)

inner hair cells

convey info from brain (use of efferent fibers). they are involved in elaborate feedback system/. 10,500 total.

outer hair cells

"tip links"

stereocilia movement opens and closes mechanically-gated K+ channels

carries signals from cochlea to brain stem. projects to both hemispheres.

the auditory nerve

in medulla. first brain stem nucleus at which afferent auditory nerve fibers synapse

cochlear nucleus

an early brain stem region (mostly pons) in the auditory pathway where inputs from both ears converge. useful for timing

superior olive

a midbrain nucleus in the auditory pathway

inferior colliculus

in thalamus. relays auditory signals to the primary auditory cortex (part of temporal cortex) and receives input from the inferior colliculus

medial geniculate nucleus

in temporal lobe

auditory cortex (A1)

most of hearing is processed

contralaterally

sounds in left ear processed mostly in right side of brain

descussation (crossing over) in

brainstem

- columns respond to frequencies - some neurons respond maximally to input from one ear, others respond maximally to input from both ears - some neurons respond to intensity of sounds

primary auditory cortex

- activated by more complex sounds including speech - responds to vibration - dorsal where and ventral what pathways

secondary / association auditory cortices

firing of a single neuron at one distinct point in the period (cycle) of a sound wave at a given frequency

phase locking

multiple neurons can provide a temporal code for frequency if each neuron fires at a distinct point in the period of a sound wave but does not fire on every period

the volley principle

pitch at proximal end of cochlea (near oval window)

high pitch

pitch at distal end of cochlea (near center of coil)

low pitch

frequency follows individual neuronal firing up to 4 kHz

frequency theory

higher frequencies better represented by the patterns of neuronal firing

place theory

- comparison of arrival times of sounds at each ear and differences in intensities; important in horizontal plane - pinna important for this in vertical plane

localization of sound

arrival time and intensity of sound at each ear analyzed by

superior olive

smooth muscles :

digestive tract arteries reproductive system

striated muscles :

skeletal muscles | cardiac muscles of the heart