“The primate prefrontal (PFC) and posterior parietal cortices (PPC) have been
shown to be cardinal structures in processing abstract absolute magnitudes, such as numerosity or length. The neuronal click here representation of quantity relations, however, remained largely elusive. Recent functional imaging studies in humans showed that blood flow changes systematically both in the PFC and the PPC as a function of relational distance between proportions. We investigated the response properties of single neurons in the lateral PFC and the inferior parietal lobule (IPL, area 7) in rhesus monkeys performing a lengths-proportion-discrimination task. Neurons in both areas shared many characteristics and showed peaked tuning functions with preferred
proportions. However, a significantly higher percentage of neurons coding proportions was found in the PFC compared with the IPL. In agreement with human studies, our study shows that proportions are represented in the fronto-parietal network that has already been implicated for absolute magnitude processing. “
“There is widespread evidence that dopamine is implicated in the regulation of reward and salience. However, it is less known how these processes interact with attention and recognition memory. To explore this question, we used the attentional boost test in patients with Parkinson’s disease (PD) before and after the administration PIK-5 of dopaminergic medications. mTOR inhibitor Participants performed a visual letter detection task (remembering rewarded target letters and ignoring distractor letters) while also viewing a series of photos of natural and urban scenes in the background of the letters. The aim of the game was to retrieve the target letter after each trial and to win as much virtual money as possible. The recognition of background scenes was not rewarded. We enrolled
26 drug-naïve, newly diagnosed patients with PD and 25 healthy controls who were evaluated at baseline and follow-up. Patients with PD received dopamine agonists (pramipexole, ropinirole, rotigotine) during the 12-week follow-up period. At baseline, we found intact attentional boost in patients with PD: they were able to recognize target-associated scenes similarly to controls. At follow-up, patients with PD outperformed controls for both target- and distractor-associated scenes, but not when scenes were presented without letters. The alerting, orienting and executive components of attention were intact in PD. Enhanced attentional boost was replicated in a smaller group of patients with PD (n = 15) receiving l-3,4-dihydroxyphenylalanine (L-DOPA). These results suggest that dopaminergic medications facilitate attentional boost for background information regardless of whether the central task (letter detection) is rewarded or not.