Associative learning
In a project with Dr Leila Reddy and in collaboration with Amsterdam University and medical centre, we looked at neural plasticity in the medial temporal lobe (MTL) using single-unit recordings in patients. We asked participants to remember a sequence of pictures and while they were learning, we observed that the neurons that preferentially respond to a specific image started to respond before the image was presented, in anticipation of the images (Reddy et al., 2015). This study showed, for the first time, real-time modification of neural responses in the human brain during learning. This demonstrates the flexibility of representations at the single-neuron level which could help explain the formation of new associations between stimuli.
Using the same paradigm, we also showed that neuronal spikes are phase-locked to the theta oscillation and fire at an earlier phase of the theta oscillation as the sequence of stimuli progresses (Reddy et al., 2021). This study is the first evidence of phase-precession in humans. |
Short and long-term visual memory
To test incidental memory for briefly flashed natural scenes, we asked participants to perform a familiar/non-familiar task on a stimulus set that comprised images that the participants had seen 22 times for 20 ms each during the previous weeks (familiar images) and images that were new to them (unfamiliar images). Participants could recognise the set of familiar images (Delorme et al., 2018). Brain responses were different for the familiar and the new set of images. Interestingly, they also contained information about the category of the images suggesting that image category was automatically processed. This study highlights the impressive capacity of human memory by showing that flashed stimuli are retrieved in detail in long-term memory without explicit instruction.
I worked with Dr Margaret Jackson on her ESRC project "Remembering who was where". Using eye-tracking and behavioural approaches we investigated visuospatial working memory for competing emotional faces. This study shows that visuospatial memory for faces (who was where?) is affected by facial expression, even if it is irrelevant for the task (Poncet et al., 2024).
I worked with Dr Margaret Jackson on her ESRC project "Remembering who was where". Using eye-tracking and behavioural approaches we investigated visuospatial working memory for competing emotional faces. This study shows that visuospatial memory for faces (who was where?) is affected by facial expression, even if it is irrelevant for the task (Poncet et al., 2024).