BLA: All About Neurotransmitters

Neurotrasmitters

• The Biological Level of Analysis in IB psychology suggests that there are physiological origins of many behaviors
• The Biological Level of Analysis suggests that human beings should be studied as biological organisms
• This view is controversial, so IB psychology attempts to approach human behavior with a holistic view -- considering the cognitive, biological and socio-cultural factors that a person experiences daily -- to determine origins for human behavior
• The relationship between cognition and biology are bidirectional -- cognition can affect biology, while biology can affect cognition
• Many physiological factors play a role in human behavior, such as:
• Brain processes
• Neurotransmitters
• Hormones
• Genes

Let us first review the three principles of the BLA before proceeding...

1. Behavior can be innate

2. Studying animal behaviors can help us understand human behavior

3. There are biological components to behavior -- such as a neurotransmitter for a certain trait

The BLA is often criticized for trying to break down complex and complicated human behavior down into its smallest component parts -- such as into a specific molecule, hormone, neurotransmitter. This is too simplistic an approach to take when we are trying to analyze complex organisms. "There are no easy answers to complex questions"

-N E U R O T R A N S M I T T E R S-

A. Neurons (nerve cells) are one of the building blocks of behavior. Neurons can make up to 13 trillion connections with each other.

B. Neurons relay electrochemical messages to the brain, so the organism can respond to internal and external stimuli

i) When electrochemical messages are sent to the brain, this is called neurotransmission

ii) When an electrochemical impulse travels down the body of the neuron, neurotransmitters are released and cross the synapses (gaps) between the neurons. 

iii) Neurotrasmitters can be considered as the body's natural chemical messengers which transmits information transmits information from one neuron to another neuron

C. Neurotransmitters have a range of different effects on human behavior, such as:

1) Mood 

2) Memory

3) Sexual arousal

4) Mental illness

- E X A M P L E -

Martinez and Kesner 1991 - The Role of the Neurotrasmitter Acetylcholine on Memory Formation -

•  Aim: To see the role that acetylcholine (a neurotransmitter) has in memory formation 
• Acetylcholine: believed to play a role in memory formation, thus the experiment was testing this assumption / hypothesis
• Procedure: The rats learned how to complete a maze that had food at the destination. The rats were then separated into three different groups and:

• Group 1: A group of rats injected with scopolamine, which blocks acetylcholine receptors on the neurons, thus decreasing the available acetylcholine.
• Group 2: A group of rats injected with physostigmine, which blocks the clean up process of cholinesterase, which is responsible for the clean up of acetylcholine from the receptors.
• Group 3: A group of control rats, not treated with anything
• Results: The rats in Group 2 were able to complete the maze quicker than any other rats of the other groups. Group 1 was slowest at completing the race. The control group (Group 3) was able to complete the race at an average pace.
• Interpretation: Acetylcholine is responsible for the formation of memory, as the rats that had blocked acetylcholine receptors were unable to complete the race as efficiently as the other rats. On the other hand, we can also confirm that acetylcholine is responsible for the formation of memory because Group 2 (that had been injected with physostigmine, a compound that prevents cholinesterase from cleaning up the receptor sites and ridding the sites of acetylcholine) was quickest at finding its way through the mazes.

Evaluation of this experiment: