After an injury, a patient can see faces clearly but can no longer recognise people they know. A CT scan shows damage in two brain regions, R and S.
Researchers inject healthy volunteers with a radioactive glucose tracer. They use PET scans while the volunteers view photographs of familiar and unfamiliar faces.
| brain region | mean detector count rate when viewing familiar faces (counts per second) | mean detector count rate when viewing unfamiliar faces (counts per second) |
|---|---|---|
| R | 340 | 190 |
| S | 275 | 270 |
Explain why the evidence supports the conclusion that region R is involved in recognising familiar faces, but does not prove this conclusion.
111 exam-style questions on Edexcel GCSE Biology 2.3 The nervous system and brain, covering 2.3.1 Structures and functions of the brain, 2.3.2 Imaging brain function with scanning, 2.3.3 Limitations in treating nervous system damage, 2.3.4 Neurones and impulse transmission, and 2.3.5 Structure and function of a reflex arc. Each one has a worked solution and a mark scheme showing where the marks go.