Despite recent criticism from Quiroga to our claim that Concept Neurons emerge from Conjunctive Coding Neurons we claim: “And yet, the hippocampus codes conjunctively!”. We hope it sparks a smile (and maybe a few debates). Read here:

Read Quirogas Letter here: Read our original Opinion piece here:

RT @Gedankient: 🧠 New preprint!. We used human intracranial EEG + pharmacology to test a core question in memory research: is hippocampal t….

RT @SuthanaLab: 🚨 New lab paper!🚨 . Dream study of mine for 20 yrs not possible until now thanks to NIH 🧠 funding & 1st-author lead @m_seeb….

I now moved over to Blue Sky and am working on rebuilding my network there. I’d love to stay connected—please reach out so I can find you!.

Thank you to my fantastic co-authors on this project: @sjo09 and @SimonHanslmayr who have been an absolute joy to work with! 15/15.

Check out our opinion paper for more on engrams, and the role of hippocampal subfields, inherent connectivity, inhibitory neurons, and schemas in the hippocampus: 14/15.

We believe that focusing on computational principles allows a more fruitful discourse between researchers studying different species. 13/15.

This process shows how index neurons, initially coding for specific episodes, may semanticize over repeated experiences into concept neurons linked to the shared element across all episodes: the friend. 12/15.

Meeting the same friend at the movies repeats this process, a subset of neurons now codes for all three episodes. 11/15.

Meeting a friend in a cafe is allocated to more excitable green neurons. Later seeing the same friend in the park reactivates the cafe memory, increasing the excitability of the initially allocated neurons. A subset of these neurons are also allocated to the park episode. 10/15

Overlapping memories transform a subset of index neurons into concept neurons. Keep in mind according engram research, more excitable neurons are more likely to be allocated to an episodic memory and recently active neurons become more excitable. 9/15.

Center: Over time, excitability normalizes (smaller green circles). Right: Reactivation (e.g., seeing the café again) boosts excitability allowing linking of memories. 8/15.

Left: When an episodic memory (e.g., meeting a friend at a café) is formed, certain neurons in a heightened excitability state form an engram (larger green circles). 7/15

Right panel: Under the concept neuron framework, each neuron codes a distinct element, and their concurrent activity represents the entire event. 6/15.

Left panel: According to the Indexing Theory, index neurons in the hippocampus conjunctively link various elements of an episode (e.g., loungy jazz music, your friend, the waiter). 5/15

Engram literature supports this process: neurons are allocated to a memory trace based on excitability, and reactivation boosts excitability—linking and updating memories. 4/15.

We integrate new findings of index neurons in humans and animals with the concept-specific memory framework, proposing that index neurons transform into concept neurons through overlapping memories. 3/15.

The hippocampus is essential for episodic memory. There are two main theories: one proposes that concept neurons represent specific elements of an episode, while another posits a conjunctive code where index neurons code the entire episode (Kolibius et al., Nat Hum Behav). 2/15.

New manuscript published! ✍️👀. Concept neurons evolve from index neurons through overlapping memories. Check it out here: 1/15