2022-03-12 08:11:00 CAFIAC FIX 2022-01-17 08:11:00 CAFIAC FIX 2022-01-11 08:11:00 CAFIAC FIX 2021-12-27 08:20:00 CAFIAC FIX 2021-11-06 23:20:00 CAFIAC FIX 2021-11-06 23:20:00 CAFIAC FIX 2021-11-06 19:50:00 CAFIAC FIX 2021-11-06 18:59:00 CAFIAC FIX 2021-11-01 19:20:00 CAFIAC FIX 2021-11-01 17:30:00 CAFIAC FIX 2021-02-11 10:42:37 Have you ever had to take a decision in an unfamiliar situation? How did your brain do it? Is the human brain special? I have written a post for the @UniofOxford science blog, talking in lay terms about our recent @Nature paper on novel choices in monkeys https://t.co/eWwzCNcEhL 2021-02-11 10:42:37 Have you ever had to take a decision in an unfamiliar situation? How did your brain do it? Is the human brain special? I have written a post for the @UniofOxford science blog, talking in lay terms about our recent @Nature paper on novel choices in monkeys https://t.co/eWwzCNcEhL 2021-01-20 12:03:23 @RyanPaulBadman1 @nature @MKFlugge @davidefolloni @LennartVerhagen @jerome_sallet Thanks, and good point. Our model comparison suggests that instead of non-linear basis functions, the choices are better explained by non-multiplicative integration, which does not affect the map axes (Extended Data Fig.6) 2021-01-08 11:04:49 @Niloy_Maity_ It does not mean "ablated" because in separate tests we observed no tissue damage. Activity may be inhibited or just altered, causing a transient functional disconnection of the area. 2021-01-08 09:08:05 Together, these results suggest the existence of a medial frontal circuit in the primate brain causally involved in making novel choices – choices based on attribute integration rather than previous direct reinforcement – and grid-like encoding of such multi-attribute spaces. 8/8 2021-01-08 09:07:09 Finally, we transiently disrupted MFC with a new focused ultrasound method. This caused choice behaviour to rely more on the two attributes considered separately, and less on their interaction, proving MFC’s key role in the value integration process underlying novel choice. 7/8 https://t.co/QlDdxz1aom 2021-01-08 09:04:53 How does MFC represent novel 2-dimensional value (magnitude and probability)? We presented options one at a time, so that the monkeys could “navigate” this space, and we observed a hexagonal symmetry in the MFC fMRI activity, analogous to the grid encoding of physical space. 6/8 https://t.co/pFTU5dBkVE 2021-01-08 09:02:45 We searched for a value comparison effect in the BOLD signal (chosen minus unchosen option value). As expected, such a signal was present in OFC and equally for all trials, but it was strikingly different in MFC when choosing among unfamiliar compared to familiar options. 5/8 https://t.co/DvLfqwcgva 2021-01-08 09:00:38 The macaques chose between pairs of stimuli, each characterised by two attributes: magnitude and probability of reward. Crucially, some attribute combinations were pre-trained for months (in grey in the right panel), others were novel at the time of fMRI testing (in white). 4/8 https://t.co/pQ6PECRA98 2021-01-08 08:57:54 Lab animals routinely make thousands of choices among a small set of options. But in real life people often face new items they have never tried before, requiring value to be computed on the fly. Here we designed a task to get monkeys to make new choices, just like humans. 3/8 2021-01-08 08:56:18 Have you always wondered why electrophysiological studies of value-guided decisions in primates find consistent effects in orbitofrontal cortex (OFC), while human fMRI studies typically identify value effects in medial frontal cortex (MFC)? We may have found an explanation... 2/8 2021-01-08 08:55:32 Excited to announce that my PhD research is now out in @Nature. We characterise a medial-frontal network for novel choice in primates involving a grid representation of value https://t.co/6hxFp4xhMw W/ Matthew Rushworth @MKFlugge @davidefolloni @LennartVerhagen @jerome_sallet 1/8 2001-01-01 01:01:01