Category Archives: resources

#Hubbian: the toy that makes navigating 20,000 abstracts fun.


Over 30,000 people attend the annual Society for Neuroscience meeting and for this reason alone people either love it or hate it. On one hand, you can learn about any type of neuroscience research imaginable. On the other hand, it can be extremely difficult to find the meaningful stuff. The online itinerary planner. It works. Kind of. Did you search the right keywords? What about that new technique you’re interested in* – it’s mentioned in 100s of abstracts – which ones are worth checking out? What are other neuroscientists looking at? And in case you’ve missed something interesting you now find yourself at the meeting, aimlessly scanning titles, just a brainstem….being pulled towards the larger crowds…failing to penetrate the bobbling masses… Continue reading #Hubbian: the toy that makes navigating 20,000 abstracts fun.

Studies of adult hippocampal neurogenesis in primates

For obvious reasons, studying neurogenesis in primates is useful. Primates are phylogenetically more related to us than rodents, and so understanding their nervous system can better help us to understand our own. For over a decade we have known that neurogenesis continues in adulthood in primates and in many ways, the process is similar to what has been observed in rodents. For example, neurogenesis is reduced with age in primates, is decreased by stress, increased in pathological conditions such as epilepsy, and increased by antidepressant treatment.

My goal in compiling this list was to assess the magnitude of adult neurogenesis in primates. It’s definitely more challenging than assessing the magnitude of neurogenesis in rodents, which we know much more about, and so I had put it off. At this point I haven’t reached a clear conclusion but, in quickly skimming these papers, the number of proliferating cells and/or new neurons averages thousand(s) of cells in the young adult primate hippocampus. The range is much much larger, and many studies cannot be easily compared due to variability in the methods, which is partly understandable since primates are scarce and are often used in multiple studies, thereby limiting the analyses that can be performed.

Download the list

Dorsoventral vs. Septotemporal hippocampus

Everybody knows what the hippocampus is for: memory. And…maybe something about anxiety or depression? Yes – over the last 10 years or so many studies have been published showing that the hippocampus has these two roles and that the mnemonic and emotional functions of the hippocampus are associated with its septal (dorsal) and temporal (ventral) ends, respectively. This new knowledge means that we’ve had to reorient our perspective. What we see when we consider the septal hippocampus may not be the same if we only consider its temporal end. My goal here is not to provide a review of the memory vs. emotional functions of the hippocampus (btw this dichotomy is a vast oversimplification). Instead, I’d like to talk about how people have differentiated these two ends of the hippocampus in their analyses. I’m also happy to showcase a bunch of pretty anatomical images that will probably never be published in a traditional journal article. Continue reading Dorsoventral vs. Septotemporal hippocampus

Studies of adult hippocampal neurogenesis in humans

As we accumulate more and more data on adult neurogenesis in rodents I keep asking myself what kind of impact these new cells could have. The dearth of literature on primate and human adult neurogenesis seems to make these questions all the more relevant. As a starting point, I created a Pubmed collection of all the studies of adult hippocampal neurogenesis in humans. They’re also listed below in a Google spreadsheet. Note that human studies often do not directly measure neurogenesis but instead measure 1) cell proliferation (which usually correlates with neurogenesis in rodents, but assumes that proliferation results in surviving neurons in humans), 2) stem cell markers (such as nestin, which correlates with neurogenesis only if they indeed divide and produce new neurons), 3) immature neurons (which, technically speaking, is neurogenesis, but whether these neurons mature and become functional remains to be determined), or 4) other factors that correlate with neurogenesis, such as blood flow or stem cell biomarkers. So, while the conclusions of these studies may be exciting (or depressing), they have to be taken with a grain of salt at this point.

Download the list

SFN2010 Neuroblogging List

So today the list of “official” SFN neurobloggers was released at the SFN website. And it immediately created a bit of an uproar. My initial beef was that I couldn’t ever seem to find the SFN blogging info without using Google. And also, I would like to know which other bloggers will be writing about SFN but I can’t seem to find this info.

For my part, Functional Neurogenesis is slated to post on the Theme A topic, development. But I will also post on more general topics in the neurobiology of behavior (mainly in animals – e.g. place cells, plasticity, structural or functional correlates of behavior). Posts are to be at least daily, following SFN’s guidelines. Which (if you know my frequency) means I will be taking full advantage of the big brown vats of lukewarm Starbuck’s coffee. No, seriously, I will probably take the streetcar to a cafe in old town to avoid the lines. And still make it to the poster session faster. Oh, also, there will be tweets.

This year’s SFN meeting marks the 1-year anniversary of the decision to startup Functional Neurogenesis. And it feels like things are only getting started – from within the scientific community FN has gotten some great feedback for which I’m thankful. The blogosphere is a whole different story. .

And now, because I haven’t made a list in weeks, and because there will be much coverage by non-official bloggers…

These bloggers will all be at the meeting. No guarantee that they’ll actually be blogging the meeting though. Let me know in the comments or email jasonscottsnyder (gmail) if you should be on here (or not).

Functional Neurogenesis / @jsnsndr
Genetic Expressions / @geneticexpns
Blogging on the Brain (@hillaryjoy
Fresh Eyes
House of Mind / @houseofmind
Pascal’s Pensees / @Pascallisch
Neuromusings / @neurodilettante
David Deriso / @davederiso
Dormivigilia / @Beastlyvaulter
Blogging Behavior / @aechase
Stanford Neuroblog / @stanfordneuro
SFN2010 / @thekhawaja

Fumbling Towards Tenure Track / @doc_becca
Some Lies / @Tideliar
Drugmonkey / @drugmonkeyblog
Neurocritic / @sarcastic_f
Bjorn Brembs / @brembs
Neurokuz / @kuzyx
Juniorprof / @juniorprofblog
Oscillatory Thoughts / @bradleyvoytek
Ferris Jabr / @ferrisjabr
Neuron Culture / David Dobbs
Danio Reri

Twitter lists of SFN attendees:
@stanfordneuro’s list
@mocost’s list
@noahWG’s list

Everything you always wanted to know about neurogenesis timecourses (but were afraid to ask)

Most studies of adult neurogenesis are concerned with neuronal age. Or at least they should be. This is because new neurons develop from a stage where they have no excitatory synapses to one where they have many. If we assume the traditional view that information is stored at excitatory synaptic connections, then young neurons are initially useless and only become physiologically and behaviorally meaningful when they have matured to a point where they can relay and process information. It is therefore critical that the developmental timecourse of new neurons be mapped out, so we know when new neurons become functionally relevant, or whether they might even have different functions at different ages.

Below are what I hope to be comprehensive visual collages of all published timecourse experiments, where a certain property of new neurons is examined at multiple (≥ 3) different ages. They are grouped by studies of: 1) cell survival, 2) marker expression, 3) functionality, and 4) miscellaneous studies that do not quite fit into the first 3 categories. I’ve ordered the data roughly chronologically and have included the first author’s name and publication year so you can read deeper, if needed. Indeed, if you know these studies already, a brief look at the graphs will bring back the take home message. However, since the data is stripped of text, if the studies are unfamiliar, you’ll have to go to the original source to figure out what the heck they mean (use Pubmed to at least obtain abstracts for the original studies if I didn’t provide a direct link).

Personally, I like timecourse studies for the same reason I like to have all my music albums or books visible at the same time: at a single glance they provide a lot of information – each individual stage of maturation can be interpreted within a bigger picture. The result of these many hours of work will either be a) that the purpose of adult neurogenesis will become immediately clear, or b) that we’ll all have some fancy collages to pin on our bulletin boards and look intelligent.

The survival timecourse

addition of new neurons

New neurons are born and then many die. The survival timecourse answers the questions: How many new neurons are born? Where are they born and where do they end up, anatomically? How many of them survive and can their survival be altered? Survival timecourses are typically performed by injecting animals with a mitotic marker that will label new neurons as they’re being born, e.g. ³H-thymidine (old school), BrdU (tried and true – example), or a GFP-expressing retrovirus (new school). At a later date one can then detect these birthdated new neurons and count them, see where they’re located etc.

Continue reading Everything you always wanted to know about neurogenesis timecourses (but were afraid to ask)

A list of experiments that relate adult hippocampal neurogenesis to behavior

The list as a Google spreadsheet (also excel | HTML | RSS feed of updates)
List last updated 3/9/2011.

I’ve always enjoyed making lists. As a kid I can remember writing lists of rhyming words, lists of all the Ocean Pacific clothes I owned, lists of all the people I knew. Many years later, I hope I’ve now made a list that is actually useful.

Adult neurogenesis is now undisputed. Pretty much on a weekly basis there is a new paper that examines both levels of adult hippocampal neurogenesis and behavior, attempting to draw a functional connection. The good news is that the argument for a behavioral function for adult neurogenesis continues to get stronger. The bad news is that there’s a massive pileup of data, and it’s becoming hard to filter through the relevant studies – first you have to find them amongst the 1000+ studies of adult neurogenesis. Then you have to read them. What behaviors are examined? Is there an effect of reducing or enhancing neurogenesis? What method is used to manipulate neurogenesis? What do other studies find that performed a similar analysis? Continue reading A list of experiments that relate adult hippocampal neurogenesis to behavior