The brain regions supporting schema-related processing of people’s identities

Schematic knowledge about people helps us to understand their behaviour in novel situations. The ventromedial prefrontal cortex (vmPFC) and hippocampus play important, yet poorly understood, roles in schema-based processing. Here, we manipulated schematic knowledge by familiarizing participants over the course of a week to the two lead characters of one of two TV shows. Then during MRI scanning, they viewed pictures of all four characters and performed a recognition memory test afterwards. Memory was also tested for short videos. Schematic knowledge boosted performance on both memory tests. Whole-brain analyses revealed knowledge related activation increases in the vmPFC and retrosplenial cortex while a similar effect was identified in a hippocampal region-of-interest. Representational similarity analyses identified person-specific patterns of activity in the vmPFC but not hippocampus, but no effect of familiarization. Our findings suggest complementary roles for the vmPFC and hippocampus in processing schematic knowledge that was acquired in a naturalistic manner

The neural representation of events Is dominated by elements that are most reliably present

An episodic memory is specific to an event that occurred at a particular time and place. However, the elements that constitute the event—the location, the people present, and their actions and goals—might be shared with numerous other similar events. Does the brain preferentially represent certain elements of a remembered event? If so, which elements dominate its neural representation: those that are shared across similar events, or the novel elements that define a specific event? We addressed these questions by using a novel experimental paradigm combined with fMRI. Multiple events were created involving conversations between two individuals using the format of a television chat show. Chat show “hosts” occurred repeatedly across multiple events, whereas the “guests” were unique to only one event. Before learning the conversations, participants were scanned while viewing images or names of the (famous) individuals to be used in the study to obtain person-specific activity patterns. After learning all the conversations over a week, participants were scanned for a second time while they recalled each event multiple times. We found that during recall, person-specific activity patterns within the posterior midline network were reinstated for the hosts of the shows but not the guests, and that reinstatement of the hosts was significantly stronger than the reinstatement of the guests. These findings demonstrate that it is the more generic, familiar, and predictable elements of an event that dominate its neural representation compared with the more idiosyncratic, event-defining, elements

Activation of Person Knowledge in Medial Prefrontal Cortex during the Encoding of New Lifelike Events

data for figures for publication with doi: 10.1093/cercor/bhab02

Neurobiology of specific and general prior knowledge

To understand the world around us we largely rely on our prior knowledge, which can help us structure newly incoming information. My research implemented naturalistic fMRI studies to investigate how previously acquired information affects the encoding and retrieval of new, but related, events. It is important to note that our stored knowledge can be either more general (schematic) knowledge – such as what typically happens at restaurants – or can be referring to a specific event – such as when we start listening to a lecture to which we have missed the beginning. In my first experiment I focused on examining effects of more specific prior knowledge. I presented participants with the first and second halves of clips. The speech in some of the first half videos was made unintelligible. The second half clips were identical for everyone. This design allowed me to investigate how we integrate prior (topic specific) information with newly incoming information. I observed better memory for the clips for which prior information was provided. Interestingly I also observed higher brain activity synchronization across participants sharing the same prior knowledge in a subset of brain regions. This result suggested that these brain regions play a role in the integration of new and prior information. In a separate experiment I examined the effects of more generic prior knowledge. I familiarised participants over the course of a week with one of two shows. Inside the scanner participants performed a picture and a video clip task. In the picture task participants watched pictures of characters that were either from the trained or the untrained show. I found higher activations in ventromedial prefrontal cortex, hippocampus and retrosplenial cortex when participants were viewing pictures from the trained show versus the untrained show. In the video task I asked participants to watch and recall previously unseen clips from both the trained and untrained shows. I observed higher pattern similarity between trained clips when compared to the untrained clips, in frontal regions suggesting that they are involved in maintaining schema knowledge during encoding of new information. Apart from schema knowledge effects, I ran a project where I examined which brain regions might be particularly important for representing knowledge about social categories. I have also examined event cognition in individuals with mild cognitive impairmen

Is effect of mid-life activities on late-life cognition mediated by functional segregation of resting-state networks in late-life

see https://psyarxiv.com/dqr79