Quantification of blood fraction (fblood), blood oxygenation (S<img src="http://onlinelibrary.wiley.com/store/10.1002/jbio.201200055/asset/equation/tex2gif-inf-2.gif?v=1&amp;t=h70man4a&amp;s=4a6d004ec608a2a6ec8e8597f73bdb6be30286e8" />), melanin, lipofuscin and oxidised and reduced Cytochrome aa 3 and c was done from diffuse reflectance spectra captured in cortex, white matter, globus pallidus internus (GPi) and subthalamus during stereotactic implantations of 29 deep brain stimulation (DBS) electrodes with the aim of investigating whether the chromophores can give physiological information about the targets for DBS. Double-sided Mann-Whitney U -tests showed more lipofuscin in GPi compared to white matter and subthalamus (p &lt; 0.05). Compared to the other structures, fbloodwas significantly higher in cortex (p &lt; 0.05) and S<img src="http://onlinelibrary.wiley.com/store/10.1002/jbio.201200055/asset/equation/tex2gif-inf-4.gif?v=1&amp;t=h70man4c&amp;s=855c70105e88a292de25618487573dfc7d30e08a" /> lower in GPi (p &lt; 0.05). Median values and range for fblood were 1.0 [0.2–6.0]% in the cortex, 0.3 [0.1–8.2]% in white matter, 0.2 [0.1–0.8]% in the GPi and 0.2 [0.1–11.7]% in the subthalamus. Corresponding values for S<img src="http://onlinelibrary.wiley.com/store/10.1002/jbio.201200055/asset/equation/tex2gif-inf-6.gif?v=1&amp;t=h70man4e&amp;s=151ec25bee7270bcfc2292e70d6f4aea18348dbc" /> was 20 [0–81]% in the cortex, 29 [0–78]% in white matter, 0 [0–0]% in the GPi and 0 [0–92]% in the subthalamus. In conclusion, the measurements indicate very low oxygenation and blood volume for DBS patients, especially in the GPi. It would be of great interest to investigate whether this is due to the disease, the normal situation or an artefact of doing invasive measurements.

La stimulation cérébrale profonde (SCP) est actuellement un traitement efficace pour la maladie de parkinson. Cette approche est maintenant fortement envisagée pour le traitement des addictions. Elle consiste à délivrer des impulsions électriques au sein d’une structure cérébrale : le noyau subthalamique. Nous avons montré dans le noyau subthalamique l’existence de signatures associée à la transition vers l’addiction et la prise compulsive de drogue, ainsi que le potentiel thérapeutique de la SCP pour réduire la consommation pathologique et compulsive de cocaïne chez des rats. Nous avons également montré le contrôle spécifique du noyau subthalamique sur la motivation pour la nourriture sucrée et les drogues d’abus. Dans l’ensemble, cette thèse devrait permettre une meilleure compréhension des mécanismes de la SCP, de son potentiel thérapeutique pour les addictions et de ses éventuels effets secondaires. / Deep brain stimulation (DBS) is currently one form of effective treatment for Parkinson’s disease. This approach is currently considered for the treatment of addiction. It consists in the delivery of small electric impulses inside a brain structure: the subthalamic nucleus. We have shown in the subthalamic nucleus the existence of signature associated with the transition to addiction and compulsive drug abuse, as well as the therapeutic potential of DBS to reduce pathological intake and compulsive cocaine abuse in rats. We also established the specific control exerted by the subthalamic nucleus on the motivation for sweet food and drug of abuse. Overall this thesis could allow a better understanding of the mechanisms of DBS, its therapeutic potential in addiction and possible side effects.

Dopamine agonist therapy and deep brain stimulation (DBS) are both linked to increased impulsivity in Parkinson’s disease (PD), but the underlying mechanisms remain unclear. We trained intact and PD-like rats on a rat gambling task (rGT) measuring impulsive choice and premature responding. Animals were then retested with/without treatment, pramipexole (PPX) or DBS, administered chronically prior to rGT testing. Early PD-like rats did not exhibit major differences in rGT performance or treatment response. Our work suggests that DBS and PPX are not intrinsically linked with increases in impulsivity. Neither DBS nor PPX disrupted gambling-like behaviour in our paradigm, while differential effects on premature and perseverant responding in the task were observed with treatment. Based on our findings, the previously reported ability of PPX to increase impulsive choice might not be mediated by the dopamine D3 receptor. Interestingly, our work suggests that the effects of STN-DBS on impulse control might be amplitude-dependent.

Dopamine agonist therapy and deep brain stimulation (DBS) are both linked to increased impulsivity in Parkinson’s disease (PD), but the underlying mechanisms remain unclear. We trained intact and PD-like rats on a rat gambling task (rGT) measuring impulsive choice and premature responding. Animals were then retested with/without treatment, pramipexole (PPX) or DBS, administered chronically prior to rGT testing. Early PD-like rats did not exhibit major differences in rGT performance or treatment response. Our work suggests that DBS and PPX are not intrinsically linked with increases in impulsivity. Neither DBS nor PPX disrupted gambling-like behaviour in our paradigm, while differential effects on premature and perseverant responding in the task were observed with treatment. Based on our findings, the previously reported ability of PPX to increase impulsive choice might not be mediated by the dopamine D3 receptor. Interestingly, our work suggests that the effects of STN-DBS on impulse control might be amplitude-dependent.