neurotransmission

what are neurons?

nerve cellls that are the building blocks of behavior

what do neurons do?

they send electrochemical messages to the brain so that people can respond to stimuli via neurotranismission

how does neurotranmission work?

the process by which messages are sent.

1. the electrical impulse that travels along the body of the neuron is called an action potential.

2. when it travels down the axon of the neuron, it releases neurotranssmitors stored in the neuron’s terminal buttons.

3. the neurotransmitters are then released into the gap between neurons called the synapse.

4. then they fit into the receptor sites on the post-synaptic membrane like a key and lock.

5. once the message is passed, the neurotransmitters are either broken down by an enzyme or reabsorbed by the terminal buttons in something called reuptake

what is reuptake?

neurotranismitters reabsorbed by terminal buttons after message is transmitted

what type of behavior does neurotransmission usually affect?

mood, sleep, learning, memory, sexual arousal, and mental illness

Acetycholine

plays a role in memory consolidation in the hippocampus

Dopamine

controls the brain’s reward and pleasure center, plays a key role in motivation (low levels are linked to addictive behavior)

Norepinephrine

arousal and altertness

Serotonin

sleep, arousal levels, and emotion

how are neurotransmitters categorized?

by how they affect a neuron; either excitatory or inhbitory

excitatory neurotransmitters

increase the likelihood of neuron firing by depolarizing the neuron. includes AcH

inhbitatory neurotransmitters

decrease the likelihood of neuron firing by hyperpolarizing the neuron. includes GABA

how did drugs develop to mimic neurotransmitters?

because neurotransmitters fit tightly into receptor sites, drugs have been developed to stimulate the neurotransmitter if not enough of it or to block the site if it is excessive; depression medication

what criticism is there of reducing the explaination of behavior to workings of neurotransmitters alone?

said to be reductionist because a complex human behavior like falling in love be attributed to just dompaine and norepinephrine. you cannot rely soley on neurotransmitters to explain behavior even though they play a role

explain roger and kessner (2003)

• aim: to determine role of acetycholine in memory formation/hippocampus

• procedure: first group of rats injected with scopolamine and second a placebo (to make sure getting an injection alone did not change memory); put back into a maze to see how long it would take them to find food they had found previously

• results: scopolamine group took longer and made more mistakes; AcH plays a big role in memory consolidation

what are the strengths and limits of roger and kessner

• strengths: procedure is simple, replicatable, reliability can be tested, highly controlled (only difference was level of AcH), saline as a control to rule out placebo effect

• limits: cannot be clearly generalized to humans even though Alzheimer’s patients have less AcH

explain antonova et al (2011)

• aim: wanted to see the effects of scopolamine on spatial memory of humans through new tech like fmri

• procedure: 20 males split into two groups with one getting a placebo and the other scopolamine. while in an fmri, they were tasked with finding their way to a pole in a virtual reality game, the screen being reset, and finding it again.

• results: less activity seen in the hippocampus with those who took scopolamine. their spatial memory was worse and led to more mistake; showed AcH is key in encoding spatial memory in humans and rats

most important inhibitory neurotransmitter is GABA because…

it inhibits neural activity both in hippocampus and in frontal lobe, which allows us to increase our cognitive load (how we are able to use our working memory)

what happens when GABA levels are too low?

intrusive thoughts may make it difficult for us to concentrate and lay down new memories

explain proges et el (2017)

• aim: to see if there was a correlation between GABA and cognitive performance

• procedure: GABA concentrations in frontal lobe in a sample of 94 older adults without a history of dementia; asked to take Montreal Cognitive Assessment to test cognitive functioning

• results: correlation between higher concentrations of GABA in frontal lobe and superior cognitive performance; significant b/c GABA decreases with age and this could help with dementia treatments

what are neurotransmitter chemicals referred to as?

antagonists or agonists depending on the effect they have on the post-synaptic receptor sites

all neurotransmitters are…

agonists for receptor sites. they are endogenous agonists (natrual) since they are biologically already part of the nervous system (ACh is a agonist for ACh receptor sites)

• It binds to its receptor

• It activates it

• It produces the receptor’s natural effect (excitatory or inhibitory)

So:

• Glutamate is an agonist at glutamate receptors

• GABA is an agonist at GABA receptors

• Dopamine is an agonist at dopamine receptors

• Serotonin is an agonist at serotonin receptors

what are drugs?

exogenous agonists (artifical); nicotine is an agonist for ACh receptors and has benefical short term effects and negative long term effects on memory

antagonists are…

drugs that block the receptor sites and do not allow the neurotransmitter to do its job, preventing an action potential; scopolamine is an antagonist for ACh

what is excitatory vs inhibitaory?

• Excitatory = turns the volume up → makes the neuron more likely to fire.

• Inhibitory = turns the volume down → makes the neuron less likely to fire.

• just the result; has nothing to do with the actual molecule 

what is an antagonist vs agonist?

• Agonist = presses the button (activates the receptor).

• Antagonist = covers or jams the button (blocks the receptor).

what is an antagonist and agonist in roger and kessner?

• agonist: ach

• antagonist: scopolamine

what neurotransmitters are involved in falling in love?

seratonin, dopamine, noradrenaline (norephinephrine)

research by rogers and kesner supported the theory ACh played a role in

the transfer of memory from short term memory to long term memory

define biopsychology

the study of the interaction of biology, behavior, and the environment

define neuroscience

focus on brain and its role in psychological processes

define neuron

a nerve cell; a basic building block of nervous system

define each of the parts of a neuron:

• dendrites

• soma

• myelin sheath

• terminal branches

• dendrites: branch fibers that listen to neurotransmitters and send them towards body

• soma: central part of a neuron containing nucleus, energy, and organelles

• myelin sheath: fatty tissue that encloses some axons speeding neural impulses

• terminal branches: where messages are passes towards the synaptic gap and other neurons; speaks

what are the two types of neurons located in the brain? where are they located in the brain?

1. motor is the outgoing instruction from brain and spinal cord to muscles and glands (efferent). this is in the frontal lobe and brainstem

2. interneurons connect sensory and motor neurons and processors. this is in the cerebral cortex, hippocampus, and cerebellum

what is action potential? how is it different from resting potential?

• action potential: when positive sodium ions displace the negative P ions insidem meaning the neuron’s been triggered. the electrical charge travels down axon

• resting potential: the outside is positive and inside is negative

define depolarization

positive sodium ions flood the soma after neurotransmitters trigger the dendrites and depolarize the negative potassium ions to open the next channel

define all or nothing response

once a certain threshold is reached with neurotransmitters, it will fire with the same intensity and speed

what are the gaps between neurons called?

synaptic gaps, —-, —-

what are the chemical messangers between neurons called?

neurotransmitters

what are the electrical messengers in neurons called?

neural firing

what is an agonist? with an example

an excitatory neurotransmitter that mimics. morphine mimics endorphins with high and pain relief

what is an antagonist? with an example

an inhibitatory neurotransmitter that mimics. botulin blocks ACh release, paralyzes

what is the body’s electrochemical network called?

nervous system

diagram the central nervous system (c ns)

the decision maker: brain and spinal cord

diagram the peripheral nervous system (p ns)

relays info between body and cns: somatic (skeletal muscles, voluntary) nervous system and automatic (sympathetic for fight or flight and energy use, parasympathetic for calming and rest, non voluntary)