Learning, Gamma Rhythm, and Speed

Rhythms in the brain that are associated with learning become stronger as the body moves faster, UCLA neurophysicists report in a new study. The research team, led by professor Mayank Mehta, used specialized microelectrodes to monitor an electrical signal known as the gamma rhythm in the brains of mice. This signal is typically produced in a brain region called the hippocampus, which is critical for learning and memory, during periods of concentration and learning.

The researchers found that the strength of the gamma rhythm grew substantially as running speed increased, bringing scientists a step closer to understanding the brain functions essential for learning and navigation. (via.)

Brain-Derived Neurotrophic Factor & Serotonin Effects on Aging, Plasticity & More

BDNF and 5-HT: a dynamic duo in
age-related neuronal plasticity and
neurodegenerative disorders

Brain-derived neurotrophic factor (BDNF) and serotonin (5-hydroxytryptamine, 5-HT) are known to regulate synaptic plasticity, neurogenesis and neuronal survival in the adult brain. These two signals co-regulate one another such that 5-HT stimulates the expression of BDNF, and BDNF enhances the growth and survival of 5-HT neurons. Impaired 5-HT and BDNF signaling is central to depression and anxiety disorders, but could
also play important roles in the pathogenesis of several age-related disorders, including insulin resistance syndrome, Alzheimer’s disease and Huntington’s disease.
Enhancement of BDNF signaling may be a key mechanism whereby cognitive stimulation, exercise, dietary restriction and antidepressant drugs preserve brain function during aging. Behavioral and pharmacological manipulations that enhance 5-HT and BDNF signaling
could help promote healthy brain aging. [...]

By promoting neurogenesis,
synaptic plasticity and cell survival, BDNF plays a pivotal
role in the development and plasticity of the brain. During
development of the cerebral cortex and hippocampus,
BDNF induces the differentiation of neural stem cells into
neurons and promotes the survival of newly generated
neurons [1–3]. BDNF signaling at synapses enhances
long-term potentiation (LTP), a process of synaptic
strengthening associated with learning and memory;
the effect of BDNF on LTP is apparently mediated by
cAMP-response-element-binding protein (CREB), which
regulates the expression of genes involved in LTP and
memory formation [4]. Levels of BDNF are increased in
the hippocampus of rats during and after performance
of a spatial learning task (a radial-arm maze), and both
acquisition and maintenance of spatial memory are
impaired when BDNF levels are decreased using antisense
methods [5]. In rats that had previously acquired
spatial memory by extensive training, suppression of
BDNF expression impaired both reference and working
memory [5]. Another study showed that mice lacking one
copy of the BDNF gene exhibit impaired spatial learning
in the Morris water maze [6]. BDNF also plays an important
role in preventing death of neurons during development,
and promotes cell survival during stressful conditions
such as ischemia and trauma in the adult brain [7]. [...]

[A]ctivation of 5-HT1A receptors can impair learning and
memory whereas 5-HT2A and 5-HT2C receptors facilitate
memory formation [10]. [...]

5-HT can
also promote the survival of neurons in the adult brain, as
demonstrated by the abilities of a 5-HT receptor agonist
and SSRI to protect neurons against excitotoxic and
ischemic injury in animal models [12,13]. There are therefore
several commonalities of function in the CNS for
BDNF and 5-HT in terms of their effects on synaptic
plasticity, neurogenesis and cell survival. [...]

Conversely, BDNF
can stimulate the growth and sprouting of 5-HT neuron
axons innervating the cerebral cortex, thereby presumably
increasing the number of 5-HT synapses in this brain
region [14]. (via: pdf.)

Novel Reading for Language Learning

We’ll classify this as barely-neuro, but I enjoyed a few of these interesting tidbits from “Language Fixation” blog:

A lot of people have this idea that learning comes out of a textbook. The textbooks or classrooms have all the knowledge inside of them, and you are the empty vessel. You pour the knowledge out of the textbook until it fills up your brain and then you know it! Simple, right?

In reality, learning anything, particularly a new language, is more about the habits that you form and the things that you do. You need to continually make contact with the language and try to understand it, and to enjoy it. When your only contact is a boring textbook, it’s hard to keep going back. It usually starts to feel like “work”.

So, what I’ve been recommending to these people is to make a personal habit of trying to read a book in that language, and to listen to real audio content. This usually takes a bit of explaining, because people will start saying “but that’s the end result I want, not the first step!”. Actually, you get good at books by reading books. They have the best content, and they will keep you coming back for more, which is exactly what you need to do over and over again. [...]

For Extensive Reading, you might want to have a goal of the number of words. I had read about some Japanese students who were reading English books, and they had a goal of 1 million (1,000,000) words read (without using the dictionary while reading). They said that if you read 1 million words, there’s no way that you can suck at that language.

They were right! By the time I hit the 1M word mark in German, I could enjoy any novel I picked up. I rarely had to use a dictionary any more, and there were very few words per page that were unfamiliar….I actually had to actively search to find words that I didn’t know. It varies a bit from book to book, so I started to seek out harder novels, but they soon became easy.

Extensive reading, our language spelunking friend defines, as reading without the dictionary. He’s saying, if you drag your eyes across 1 million words, then you will have achieved your goal. (Obviously this means you’ll probably be looking up words as soon as you’re done with a reading session!).

Go check out the original post at LanguageFixation.

Software for Learning Languages: ming-a-ling, languagebob, antconc & more

You may be interested in these websites/programs/information intended for language acquisition:

  • ming-a-ling (firefox addon) – Helps you learn the vocabulary of a foreign language. You add words and phrases in your language, and when they appear on the pages you visit, they’re replaced by Google’s translation into the foreign language. Hover your cursor over a translated phrase and a tooltip will popup that tells you the original.
  • LanguageBob (firefox addon) – Very similar to ming-aling. Maybe identical? “Browse the Internet as normal and LanguageBob will drip-feed you the language. Let your Internet-time double as language-learning time.”
  • The Polyglot Project – A library of foreign language content for you to work with, starting with classic literature from all over the world.“We’ve made it easier for you to immerse yourself by building a translation tool that will help you learn new vocabulary without interrupting your reading flow. Just double click on a word and the English translation will briefly appear and then get out of your way so you can keep reading (and you won’t need a dictionary in your hand or another browser window slowing you down).”
  • speech accent archive
  • Learn Any Language Wiki – Unofficial offshoot of the learnanylanguage forum. Also has an IRC channel #learnanylanguage on irc.freenode.net.
  • Amhrán is Fiche“On Amhrán is Fiche (“Twenty-one Songs”), three well-known singers from three different Gaeltachts sing twenty-one favourite songs. Follow the bouncing ball in this karaoke-style program. Listen to the singers, and then play the songs without voice so that you can sing them yourself. Printable versions of the lyrics, on-screen English translations and sample lesson plans based on the songs are also available. The CD can also be played as music CD in a normal CD player.”
  • Wiktionary’s Frequency Lists
  • AntConc – AntConc is software for creating a concordance from a body of text. Basically, make your own frequency lists from text you want to learn.
  • This javascript applet also appears to do something similar to what antconc does.