The effects of volitional breathing and carbon dioxide inhalation on human local field potentials

Thesis

Breathing is an automatic process that we hardly pay any attention to in our daily life. As a social species, we interact using body movement, speech and emotion and these actions require modification of the respiratory pattern.

While we understood how the respiratory rhythm is generated, we do not have clear evidence on how higher cortical signals modulate the respiratory pattern. The deep cortical structures in the human brain are inaccessible under normal circumstances, and deep brain stimulation electrode recordings offer an opportunity to understand the neurophysiological interactions ofdeeper brain structures.

In this thesis, I investigated deep brain stimulation recordings from implanted electrodes in chronic neuropathic pain subjects in the right and left anterior cingulate cortices, the ventral posterior lateral nucleus of the thalamus and periventricular gray region.

The objectives of this research were to elucidate the feed-forward mechanisms of volitional breathing, cortical autonomic regulation, and to investigate whether any of the investigated nuclei haveany carbon dioxide-sensitive neurons which may encode respiratory sensation.

The results show lateralisation of the cortical autonomic control whereby the left anterior cingulate exhibits increases in beta band activity (30 to 90 Hz) with cognition and vocalisation tasks. Meanwhile, right anterior cingulate activity increases with hyperoxia. Respiration using various carbon dioxide concentrations shows a constant rise in the alpha band (8 to 14 Hz) activity in the PVG which suggests a sensitive, nonspecific neuronal activity related to systemic carbon dioxide levels.

Authors: Ahmad Bahuri, N

• Publication date: 2014
• DOI: 10.5287/ora-exr59bvao
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: deep brain stimulation; autonomic nervous system; mental task; neurophysiology; carbon dioxide inhalation; voluntary respiration
• Subjects: Neuroscience; Neurology; Surgery; Physiology