Ben Kanter @beneuroscience@qoto.org

Today's history focus is on Menno Witter, widely recognized as the premier neuroanatomist of the hippocampal formation of this generation. His accomplishments are massive, including his role in getting the journal Hippocampus started. I had the honor of presenting at a 'retirement' party for Menno in Trondheim a few months ago, where I learned even more about him. A person who is always available to students and colleagues for advice, ideas, and more. And a superb chef to boot. Menno and I have engaged in scientific conversations for decades, and I always came out better for it. His thoughts on the questions I raised about his career emphasize that the field of hippocampal research has always been a multi-continental enterprise, and highlights the unique importance of Norwegian science. More on this tomorrow perhaps.

But for now, here are Menno's thoughts (along with a photo of him and me at the Nobel Proze ceremony in 2014) - he started his career in Amsterdam, which is the referent in these early answers:

1.
What got you interested in the hippocampus?
Essentially nothing aside from serendipity. My background is in histology and embryology and I was recruited to teach an introduction in Biology to medical students as a junior faculty at the department of Anatomy. The department just had recruited a new chair (Anthony Lohman) who had a strong background and interest in comparative neuroanatomy (note my reason of being in Japan above, to teach my old love) and had a good friend and colleague who worked on epilepsy, including MTL epilepsy (Fernando Lopes da Silva). They were intrigued by the publications of Van Hoesen and Pandya about the entorhinal cortex as a node mediating hippocampal cortical interactions, so important to mediate memory consolidation, but also the potential spread of hippocampally generated seizures, and wanted to study this in more detail. As a junior faculty, I was supposed to get my PhD and since I was trained in histology, what was more logical than to study the connectivity of EC with the, at that time, most modern tracing techniques, anterograde tracing with radioactive aminoacids and retrograde HRP tracing, soon after to be followed by the fluorescent retrograde tracers developed and promoted by another influential Dutch neuroanatomist Hans Kuypers.
Aside from being intrigued by the challenge of studying complex tissue from a histological point of view, I happened to be educated about hippocampal anatomy by Theodor Blackstad, who was a close friend of Anthony. In several courses and exchanges, Theodor radiated his immense enthusiasm for the hippocampus, and that was contagious. I got hooked to the entorhinal-hippocampal connections since I was surprised that so little was done on the perforant pathway after the original description of Cajal, followed by the work of Steward cs. The addition of a return connection mediated by deep layers of EC to the neocortex provided my challenge. How was this organized and why was EC so special, or alternatively, why would an evolutionary old structure like the hippocampus end up being at the top of cortical hierarchy. And now that I am getting close to end of my active career, I believe/hope I have found the light at the end of that tunnel.

2. Aside from your own work, what findings about hippocampus (and related brain parts) in the past 50 years most excited you, and why?
The easy answer would be the discovery of the grid cell, since that emerged from anatomically derived predictions; always nice to see anatomy being able to make functional predictions, but arguably that is too close to my own work. Likewise the discovery of a functional difference along the long hippocampal axis has been a satisfying endeavor, but credit to who described it first, you were ahead of me.
The real influential discovery that influenced my work and my thinking was the description of the possible output of the hippocampus through deep layers of EC, in addition to the traditional fornix output. That was the start of my neuroscience career, and surprisingly, that seems to potentially be a major challenge at the end of my career. Of course that is probably still too close to my own work for your taste, so if I move beyond that, and put the hippocampus and parahippocampus where they belong, as integrated parts of this complex structure that we refer to as the brain. What I have considered the most intriguing finding is the complexity of how these structures are functionally connected and the fact that there is more and more evidence that functional connections can be ‘actively’ selected, and that these different functional relationships seem to prefer certain structures in the hippocampus/parahippocampus. Not surprising maybe, if you think about it, but something that is still largely overlooked in much of ongoing ‘hippocampal research. Several examples can be given, such as the work on the interactions between hippocampus and mPFC to name one or the amazing selectivity of the perirhinal to entorhinal connections. This automatically brings me to your third question

3. Can you relate one personal story about interactions with colleagues that most exemplifies the world of hippocampal research? the discovery/description of the place cell, and the work on classical conditioning did excite me most.
One of the things I will always remember is the striking debates among neuroscientists where a kind of schools, or maybe even better beliefs, seemed to guide research sometimes towards what led to a dead-end. The endless debate between some of the major monkey groups in the US about whether the hippocampus or amygdala were critically involved in episodic learning and memory, finally to be settled more or less by serendipity when two students independently gave almost identical talks. The alternative more productive approach can be illustrated by my encounter with Phil Best and Dick Thompson, when I was a young PhD student on my first educational trip to the US. I wanted to learn more about hippocampal place cells and classical conditioning and those were two leaders in the field at that time who responded positively on my request to be allowed to visit them. When Phil showed me a rat running on a radial arm maze and I heard a place cell, that was impressive, but I, likely naively asked him how we could be sure that the neuron was coding for space. There were many alternative correlations in my view that might explain the firing of the cell. He agreed, and said that it might be a cell responding to the fact that the animal was thinking something like ‘there was food here on an earlier trial’ or even the rat praying to a deity ‘let there be food here, like yesterday, but that we would not be able to know that for sure; place was for now the most parsimonious correlate. After that I visited Dick and he showed me his then quite recent data that the classical nictitating membrane reflex in conditioning in rabbits did not depend on the hippocampus, but was likely more associated with the cerebellum. He almost seemed to enjoy the fact that he had recorded in the hippocampus, reporting these beautifully correlated signals, that now turned to be irrelevant. This of course led to the subsequent discovery of trace conditioning.

4. What would tell a young researcher interested in the hippocampus to focus on now?

Difficult one to answer and challenging. Probably first advise them to take time to read and find something that they find interesting themselves. If pressured, I would urge them to focus on ways to assess the functions of the hippocampus in a the multidimensional context for which it seems to be made. If we accept that the hippocampus is critically involved in allowing the brain to store episodic memories, not for the sake of memory but to be used to guide future behaviors and make predictions about the value of the outcomes, than a focus on space and navigation is too limited. We need to move out of that limitation and try to develop new ways to understand how space is part of how we define/describe/code for memories. This holds true in my view for many studies into the molecular/genetic underpinnings of cellular mechanisms and those cellular mechanisms as well to explain hippocampal functions. All those have provided a lot of information about how neurons do what they do, but not how networks of neurons do their job. Same holds for studies on the role of interneurons or glia, very interesting for neuroscience in general, but we need something more specific if we want to understand the hippocampus. So the study of networks on which the hippocampus uniquely depends, and use any technology one can, to get to an increased understanding. So build a multidisciplinary network of colleagues to achieve that.

Hi all 😃​
Our latest #Review on #SplitterCells is now published in @eLife !!
I will probably write a real thread on it when I get a chance... for now:

link: https://elifesciences.org/articles/82357

why: some neurons in the #Hippocampus (and other brain regions) of #Rats (and other mammals) have the fascinating ability to discriminate not just different presents, but different past or future states or trajectories in the same current situation. They could be related to #EpisodicMemory or #DecisionMaking 🤔​They are called 'trajectory-dependent cells' or Splitter Cells. 🔀​ We tried to make sense of them!

what: Hippocampal Splitter cells do a lot of puzzling stuff. For example there's a lot of them even in tasks that do not require the Hippocampus to be solved. They spread asymmetrically on a linear track leading to a choice point - 'past' splitters around the start and 'future' splitters towards the choice point. #TimeCells cells can be splitter cells (but they're usually #PlaceCells). Splitter cells evolve with experience, or maybe it is performance, nobody really knows. ​⁉️​ ... and a lot more weird stuff

conclusion: Two different computational models, the temporal context model and the latent state model, each explain a subset of the properties of splitter cells... so perhaps the Hippocampus implements both! But more experiments are needed to disentangle them 😄​

now what: questions or comments? Please let us know!! ✍️​

#Neuroscience #Cognition #NeuroPaper

@dlevenstein @tyrell_turing @NicoleCRust @cogneurophys @charanranganath @PessoaBrain
@dbarack

This is a little different, but Paul Glimcher's book (https://mitpress.mit.edu/9780262572279/decisions-uncertainty-and-the-brain/) spends a lot of time going through the history of the Sherringtonian view and how it has led us astray. In a nutshell, the Sherringtonian (which is basically a Cartesian or Pavolovian view) is that action is a reflex in response to sensory input. Paul draws on game theory (in particular the work of John Maynard-Smith) to argue that competing animals cannot be "reflexive" because we need to be unpredictable. I don't recall if he directly connects this unpredictability with attractor dynamics

#neuroscience

Slowly figuring out how predictive coding happens in the brain ...

A beautiful piece by @ViolaPriesemann and her team.

Out now in TINS

https://www.cell.com/trends/neurosciences/fulltext/S0166-2236(22)00186-2

Geometric constraints on human brain function
https://www.biorxiv.org/content/10.1101/2022.10.04.510897v1
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RT @DrBreaky
@AFornito presenting great work with @jchrispang & @Kevin_M_Aquino on brain eigenmodes at #brainmodes2022

https://www.biorxiv.org/content/10.1101/2022.10.04.510897v1
https://twitter.com/DrBreaky/status/1594695990908702720

Honestly pretty fascinated by the gloomy person with two mouths. Is this what science is?

"What is behavior? No seriously, what is it?"

https://www.biorxiv.org/content/10.1101/2021.07.04.451053v1.full.pdf

Something deeply unsettling is growing in the top left picture

"One-to-one mapping between deep network units and real neurons uncovers a visual population code for social behavior"

https://www.biorxiv.org/content/10.1101/2022.07.18.500505.full.pdf

#Introduction
I'm a professional editor with @NatureEcoEvo. I spend my days reading a huge variety of ecology manuscripts and helping papers through the review process.

I lurk on sites like this one (and Twitter for now) to stay aware of what ecologists are excited about. I also share exciting recent papers and editorial rants/wisdom from time to time.

Before becoming an editor, my research background was in disease ecology and animal behavior.

I don’t see them here, so check out this amazing project! h/t @Neurograce

New paper: preclinical proof of concept of retinal functional ultrasound for assessing neurovascular coupling alterations non-invasively.
Such alterations could be early markers of neurodegenerative diseases.
Ultrasound does not go through the skull so easily so we use the retina as a functional window to the brain.

We demonstrate this on rat models of Alzheimer's disease.

https://psyarxiv.com/2uxwk/
This paper is so awesome it is prompting me to write my first toot.
The science, the writing, the conclusion about scientific writing. I laughed out loud multiple times reading it. Hats off!

Hmm. I am usually the last to join a new technology/trend (refused cell phones for years, didn't want to upgrade from windows 3.11 to 95 😃 and kept Keynote9 for way too long). So moving to mastodon so early makes me nervous.

Consider this my @introduction. I am tentatively here :).

Computational neuroscientist by training (RL FTW), now comp psychiatry & psychotherapy (human behavior & individual diff FTW), and on sabbatical learning & practicing CBT! Lab @ Princeton full of wonderful people.

🚨 BIG DATA RELEASE 🚨 We are beyond excited to announce the release of our Brain Wide Map of neural activity during decision making! It consists of 547 Neuropixel recordings of 32784 neurons across 194 regions of the mouse brain 🐭🧠

All these recordings were performed in a distributed fashion in 12 different labs, spanning Europe and the US 🌎 Rigorous standardization of methods and materials allowed us to pool the data from these labs together into a single gigantic dataset 🐙

Mice are performing our standardized perceptual decision-making task in which they have to position a stimulus in the center of a screen to receive reward. The dataset contains the stimuli and decisions, but also videos from three angles and DeepLabCut pose information. We're even releasing all the raw ephys data!

We know, it's a lot. At your own pace you can read all the details about the experimental setup, the task, processing of the data, and much more in the technical paper which accompanies this data release: https://figshare.com/articles/preprint/Data_release_-_Brainwide_map_-_Q4_2022/21400815

To explore the data at your leisure, visit our visualization website where you can scroll through different recording sessions, look at neural activity during example trials, and see trial-based activity of single neurons: https://viz.internationalbrainlab.org

Do you have itchy fingers to run your models on this humongous dataset? We totally get it! Here you can find how to download the data using our API so you can fire up those computing clusters: https://int-brain-lab.github.io/iblenv/notebooks_external/data_release_brainwidemap.html

This was a collective effort of our stellar team, who all put in so much work to make this monumental achievement possible. Our collaboration consists of 22 PIs, 37 researchers, and 11 staff members who all worked tirelessly to bring these data to you, the community 👏🍾

Greetings fediverse!

Time for my official #introduction.

I'm a #PhD researcher in Cognitive #Neuroscience based in Leipzig (Germany) where I work with @martin_hebart and many more wonderful scientists.

I'm primarily interested in how the brain builds representations of every-day objects in a way that supports our experience and behavior. And I get to use some seriously cool large-scale #fMRI data to do so! (check out the preprint here: https://tinyurl.com/4c28uny6).

Great to meet all of you!

There's a bit of a storm happening around the criteria for joining http://fediscience.org - the Mastodon instance for scientists, on which I'm hosted.

It's been noted that the requirement to be a publishing scientist (who has published in the past 5 years) will exclude many junior scientists, retired sciences, and those who have maybe switched to teaching.

I agree with these concerns and wonder if the criteria can be changed to be more inclusive?

Cc https://fediscience.org/@FrankSonntag

The most detailed map ever made of the communication links between the hippocampus and the rest of the brain has been created by Australian scientists. And it may change how we think about human memory. https://www.technologynetworks.com/neuroscience/news/most-in-depth-map-of-the-hippcampus-raises-connection-questions-367546

#neuro #neuroscience #brain #science #memory #learning #research #health #medicine #mentalhealth #psychiatry #psychology #cogpsych

Time for an #introduction! I'm a research scientist at MIT and I run http://lookit.mit.edu, a platform for remote infant & child development studies.

I'm generally interested in open science, big collaborations, and building tools for reproducible science & data management. I love being curious about how & why we work the way we do!

My research background is in language acquisition and cognitive development (event semantics! transitive verbs!)

Some projects: