Behavioral disturbances have been reported with subthalamic (STN) deep brain stimulation (DBS) treatment in Parkinson's disease (PD). We report correlative functional imaging (fMRI) of mood and motor responses induced by successive right and left DBS. A 36-year-old woman with medically refractory PD and a history of clinically remitted depression underwent uncomplicated implantation of bilateral STN DBS. High-frequency stimulation of the left electrode improved motor symptoms. Unexpectedly, right DBS alone elicited several reproducible episodes of acute depressive dysphoria. Structural and functional magnetic resonance imaging (fMRI) imaging was carried out with sequential individual electrode stimulation. The electrode on the left was within the inferior STN, whereas the right electrode was marginally superior and lateral to the intended STN target within the Fields of Forel/zona incerta. fMRI image analysis (Analysis of Functional NeuroImages, AFNI) contrasting OFF versus ON stimulation identified significant lateralized blood oxygen level-dependent (BOLD) signal changes with DBS (P < 0.001). Left DBS primarily showed changes in motor regions: increases in premotor and motor cortex, ventrolateral thalamus, putamen, and cerebellum as well as decreases in sensorimotor/supplementary motor cortex. Right DBS showed similar but less extensive change in motor regions. More prominent were the unique increases in superior prefrontal cortex, anterior cingulate (Brodmann's area [BA] 24), anterior thalamus, caudate, and brainstem, and marked widespread decreases in medial prefrontal cortex (BA 9/10). The mood disturbance resolved spontaneously in 4 weeks despite identical stimulation parameters. Transient depressive mood induced by subcortical DBS stimulation was correlated with changes in mesolimbic cortical structures. This case provides new evidence supporting cortical segregation of motor and nonmotor cortico-basal ganglionic systems that may converge in close proximity at the level of the STN and the adjacent white matter tracts (Fields of Forel/zona incerta).

RÉSUMÉ: Marqueurs cognitifs de la progression de la maladie d'Alzheimer. Cette revue constitue un sommaire de la littérature sur l'utilisation de batteries de tests cognitifs pour suivre la progression de la maladie d'Alzheimer (MA). Les études publiées en anglais ont été identifiées par une recherche PubMed (1983PubMed ( -2004. Elles étaient incluses s'il s'agissait d'études longitudinales sur des patients atteints de MA probable, diagnostiquée selon les critères du National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association ou du Manuel diagnostique et statistique des maladies mentales III/IV; et si la validité et la fiabilité des techniques utilisées pour les évaluations successives étaient bien établies. Les études longitudinales sur la progression de la MA rapportent des taux annuels de progression très variables. Il n'est pas clair si cette observation est attribuable à l'évolution de la maladie chez des sous-groupes de patients ou à des taux de déclin en relation avec les stades de la maladie. Conclusions: Nous suggérons qu'une combinaison de tests cognitifs appropriés à différents stades de la maladie tels le Mattis Dementia Rating Scale et le Severe Impairment Battery, ainsi que des méthodes statistiques appropriées tenant compte de la variabilité individuelle du taux de déclin puissent évaluer la progression de la MA et pourraient être utiles dans les études futures.

Seventeen patients diagnosed with Parkinson's disease completed a complex computer-based task that involved planning and management while also performing an attention-demanding secondary task. The tasks were performed concurrently, but it was necessary to switch from one to the other. Performance was compared to a group of healthy age-matched control participants and a group of young participants. Parkinson's patients performed better than the age-matched controls on almost all measures and as well as the young controls in many cases. However, the Parkinson's patients achieved this by paying relatively less attention to the secondary task and focusing attention more on the primary task. Thus, Parkinson's patients can apparently improve their performance on some aspects of a multidimensional task by simplifying task demands. This benefit may occur as a consequence of their inflexible exaggerated attention to some aspects of a complex task to the relative neglect of other aspects. (JINS, 2008, 14, 257-265.)

Unconditioned reward and conditioned reinforcing effects may reflect an isomorphic motivational process because increased conditioned reinforcing effects were seen with increased amounts of saccharin consumed in taste and place conditioning. Reinforcing effects in place conditioning leveled off as saccharin unconditioned consumption reached maximum amounts of approximately 140 mg/rat. Posttrial consumption, but not intraperitoneal injection, of saccharin significantly enhanced conditioned place and taste preferences as well as conditioned taste aversions. Saccharin's memory-improving effects in both aversive and appetitive conditioning suggest a process separate from the reward-reinforcement process. Independent of effects on blood glucose, the motivational property of saccharin's sweet taste undergoes differential central processing to mediate reward-reinforcement versus memory improvement processes.