Outline one example of an excitatory neurotransmitter.

Introduction to the approach

The biological approach argues that there are physiological origins of many behaviors and that human beings should be studied as biological systems. Biologists have found that the relationship between biological factors and behaviour is bidirectional.

Introduction to the topic

Neurotransmission is the process by which nerve cells send electrochemical messages to the brain so that people can respond to stimuli. The messages reach the nerve ends as an electrical message and then are transmitted through the synapse, via neurotransmitters as chemical messengers. Every neuron has a certain threshold of excitation and if this excitation exceeds the threshold, the neurotransmitter is fired. After the release of neurotransmitters back into the synapse, three things can occur - they could be metabolised, pulled back through re-uptake or reach the postsynaptic membrane and bind to one of its receptors. All neurotransmitters are broadly divided into two groups - excitatory and inhibitory. 

Introduction to the subtopic

Excitatory neurotransmitters allow the impulse to cross the synapse. They produce stimulating effects on the brain. Inhibitory neurotransmitters stop the impulse, preventing it from crossing the synapse. They produce calming effects on the brain. These neurotransmitters are always in a state of dynamic balance.

Thesis

This response will show the effect of an excitatory neurotransmitter; acetylcholine on human behaviour; memory. Acetylcholine is an excitatory neurotransmitter as it causes the neuron to fire and cross the synapse. It plays an important role in the normal function of the brain and body. Disruptions in the release and function of this neurotransmitter can result in significant problems in areas such as memory and movement. Evidence by Antonova will be used to show the effect of acetylcholine on memory.

Antonova et al (2011) - Aim and Participants

To demonstrate that blocking acetylcholine receptors by administering scopolamine in the brain can affect spatial memory tasks in humans using a repeated measures design. A sample of 20 healthy male adults, with a mean age of 28 years old were recruited and randomly allocated to one of two conditions.

Antonova et al (2011) - Method

• Participants were injected with either Scopolamine or a placebo 70–90 minutes before the experimental task.

• They were then placed in an fMRI scanner while performing a virtual reality “Arena task.”

• Participants navigated a virtual arena with the goal of finding a pole.

• Once they learned the location of the pole, the screen went blank for 30 seconds.

• During this blank period, participants were instructed to mentally rehearse the route to the pole.

• When the arena reappeared, participants were placed at a new starting point.

• They then had to use spatial memory to find the pole’s location from the new position.

Antonova et al (2011) - Results

When participants were injected with scopolamine, they demonstrated a significant reduction in the activation of the hippocampus compared to when they received a placebo. Therefore participants injected with scopolamine made more errors as compared to the placebo condition.

Link

This study clearly demonstrated that when the action of an excitatory neurotransmitter is prevented it affects the subsequent function in this case memory. It showed how scopolamine prevented the natural action of acetylcholine thus affected the spatial memory.

Conclusion

In conclusion, it can be said that human behaviour is affected largely by biological factors like neurotransmitters as seen in the response, which further asserts the assumption that we are biological units and must be studied as one for insight into the behavioural outcomes.