Show Menu
Cheatography

1.4 Neurotransmitters + their effect on behaviour Cheat Sheet by

- Synapse (how these relate to excitatory and inhibitory neurotransmitters) - Definition of agonist and antagonist - Explanation of the role of acetylcholine in memory - Antagonist/agonist: Antonova et al (2011) Acetylcholine in memory formation - Use of smart drugs - Role of culture in the formation of memories

Antonova (2011)

 
Aim:
wanted to see if scopol­amine affected hippoc­ampal activity in the creation of spatial memory.
Procedure
-
20 healthy male adults (mean age 28). were injected with either Scopol­amine or a placebo
-
Pts were put into an fMRI and scanned whilst playing the "­Arena task." A virtual reality game where the goal was to navigate around an "­are­na" to reach a pole.
-
After learning where the pole was located, the pts were told to actively rehearse how to get to the pole in the arena.
-
Repeated measures design - pts returned 3/4 weeks later and redid the test - receiving the opposite treatment
Research method
Experiment
IVs
Scopol­ami­ne/­Placebo
DV
fMRI - Brain activity
Antagonist
Scopol­amine
Agonist
Acetyl­choline
Findings
1) When pts were injected with scopol­amine, they demons­trated a signif­icant reduction in the activation of the hippoc­ampus compared to when they received a placebo.
2) They were also more accurate in the placebo group.
Counte­r-a­rgu­ment: Kulkofsky

Neuron

Neurons are cells within the nervous system that transmit inform­­ation to other nerve cells, muscle, or gland cells. Most neurons have a cell body, an axon, and dendrites.

Explain synaptic transm­ission

Synaptic transm­ission is the biological process by which a neuron commun­icates with a target cell across a synapse. Chemical synaptic transm­ission involves the release of a neurot­ran­smitter from the pre-sy­naptic neuron, and neurot­ran­smitter binding to specific post-s­ynaptic receptors.

Excitatory + Inhibitory

Neurot­ran­smi­tters have either an excitatory or Inhibitory effect of the neighb­oring neuron.
= Excitatory neurot­ran­smi­tters are released into an excitatory synapse causing a neuron to fire, leading to an action potential, this produces stimul­ating effects on the brain.
E.g E.g. Acetyl­choline when in excitation it makes the receiving neuron positively charged and more likely to fire and is thought to be involved in the process of memory consol­ida­tion.
 

Neurot­ran­smitter

Neurot­ran­smi­tters are electr­och­emical messages that result in a vast array of behavi­ours. The effects of Neurot­ran­smi­tters can be amplified or reduced.

*Human behaviour is highly complex, thus trying to determine cause and effect is difficult to prove.

Neurot­ran­smi­ssion

Describe Neurot­ran­smi­ssion

Neurot­ran­smi­ssion is the process of nerve cell commun­ica­tion. The neurons that are interc­onn­ected commun­icate with each other by releasing chemicals called neurot­ran­smi­tters into small gaps between the two nerve cells call the synapse gap (see above).

The process of electr­och­emical transm­ission starts in the dendrites that branch out from the cell body and these receive incoming impulses from neighb­oring neurons.

The impulse passes down the axon as action potential, down to the terminal buttons, containing synaptic vesicles (tiny sacs) filled with neurot­ran­smi­tters which are released into the synapse.

A released neurot­ran­smitter is available for the synapse gap for a short amount of time during which it may be destroyed, pulled back into the presyn­aptic axon terminal through reuptake (reabs­orp­tion), or reach the postsy­naptic membrane and bind to one of the receptors on its surface.

If the neurot­ran­smitter bind onto the receptor on the postsy­naptic neuron, this process changes the membrane potential and so contri­butes to activating an electrical pulse in the postsy­naptic neuron. Here the chemical mechanism becomes electrical again.
 

Conclu­sions (Antonova (2011)

It appears that acetyl­choline may play an important role in memory consol­idation - why do you think this?
Becausethe hippoc­ampus was activated - so what??
It was demons­trated that neurot­ran­smi­tters themselves can be affected by other chemicals - why?
Because drugs interfere with the way neurons send, receive, and process signals via neurot­ran­smi­tters.
= Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurot­ran­smitter in the body. This allows the drugs to attach onto and activate the neurons.

Antagonist

Is a substance that fits into a receptor site on the postsy­naptic neuron, preventing the neuron from firing by blocking access to it.

Agonist

Looks like the neurot­ran­smitter and fits in the receptor site but it amplifies the behaviour. The reaction can be excitatory or inhibitory.

= Drugs are exogenous agonists.

= Neurot­ran­smi­tters are endogenous agonists.
 

Comments

No comments yet. Add yours below!

Add a Comment

Your Comment

Please enter your name.

    Please enter your email address

      Please enter your Comment.

          Related Cheat Sheets

          More Cheat Sheets by Sruby

          1.1 Techniques used to study the brain Cheat Sheet
          The Outsider (Stranger) - Albert Camus Cheat Sheet