Dyspnoea is the uncomfortable shortness of breath that debilitates millions of patients with lung disease, heart failure and cancer. It is often very difficult to treat. The sensations of dyspnoea are processed in the brain, and we believe that psychological factors modify and amplify these sensations, frequently exacerbating symptoms.

This study aims to identify the importance of learning in the brain mechanisms of dyspnoea by investigating a cohort of patients with chronic breathlessness undergoing pulmonary rehabilitation . Pulmonary rehabilitation is a six-week course of exercise, education and group therapy that improves dyspnoea but does not improve lung function. This leads us to hypothesise that some of the beneficial effects of PR maybe due to changes in brain processing, potentially relating to a learning effect.

Therefore to probe whether learning is important in the beneficial effects of pulmonary rehabilitation, we intend to modify learning with the drug d-cycloserine. D-cycloserine is an antibiotic that enhances learning due to its effects at N-methyl D-aspartate (NMDA) receptors in the hippocampus. Our previous study in a similar group of patients demonstrated the importance of the hippocampus in breathlessness perception, and we now wish to investigate this in more depth.

The study involves collecting physiological, psychological and clinical measures on in conjunction with brain scanning, before, during and once after pulmonary rehabilitation. Subjects will either receive d-cyloserine or placebo before the first four pulmonary rehabilitation sessions.

Inclusion Criteria:

• Males and females with chronic lung disease, aged between 45 and 85 years old who have been referred for pulmonary rehabilitation.
• The subject is able and willing to give fully informed consent.

Exclusion Criteria:

Any of the commonly accepted contraindications to MRI scanning, for example, severe claustrophobia, presence of metallic implants, a pacemaker etc.

• Pregnancy. The risk to foetus of radiofrequency energy of the MRI scan is unknown.
• Inadequate understanding of verbal and written information in English, sufficient to complete an MRI safety screening.
• Unable to lie flat and still for 1/2 hour
• Requirements for oxygen therapy
• Significant cardiac, neurological, psychiatric or metabolic disease
• Contra-indications to d-cycloserine: Alcoholism, known hypersensitivity, severe renal failure
• Regular therapy with prescribed opioid analgesics
• Antidepressant therapy (this may alter hippocampal plasticity)
• Previous pulmonary rehabilitation (because the learning may be different on repeat pulmonary rehabilitation treatments)