The following case concerns a commuter who has taken a new medication that crosses the blood-brain barrier. He reports reduced anxiety but also feels drowsy...
Question 1 Report
The following case concerns a commuter who has taken a new medication that crosses the blood-brain barrier. He reports reduced anxiety but also feels drowsy when driving home. A researcher wants to investigate the drug's action on GABA.
(a) Outline how GABA normally affects neural activity. [2]
(b) Explain why increasing GABA activity may reduce anxiety. [2]
(c) Describe a suitable double-blind study of the medication. [3]
(d) Explain one reason why the researcher should not use the commuter's report as the only evidence. [1]
(e) Use knowledge of synapses to explain why the drug may also cause drowsiness. [4]
Answer Details
(a) GABA is an inhibitory neurotransmitter [1]. It reduces the likelihood that the next neurone will fire / transmit an impulse [1]. (b) Increased inhibition reduces excessive neural activity [1]. This can reduce physiological arousal / anxious responses [1]. (c) Recruit an appropriate sample and randomly allocate participants to medication or placebo [1]. Neither participants nor researchers assessing anxiety know the condition [1]. Compare a standardised anxiety measure before and after treatment / between groups [1]. (d) His report may be subjective / affected by expectations / is only one person [1]. (e) The drug increases GABA action at synapses [1]. This produces greater inhibition in neurones [1]. Reduced activity in brain systems involved in alertness can occur [1]. Therefore reaction speed / wakefulness may decrease, causing drowsiness [1].
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