Brain Blog

I’m still working on improving my understanding of how reading works in the brain. A new book by Stanislas Dehaene called “Reading in the Brain” seems to be a great primer on what we know and what it seems to be telling us about the process of reading. It’s a fairly dense read, but I recommend it if you are hungry for details.

The premise of the book is that our “primate brain” was not designed for reading. We are, after all, the only primates that do read and we haven’t been reading for all that long, from an evolutionary perspective.  Dehaene hypothesizes that though our brain was not “designed” for reading, some circuts are recycled or refocused to let us do so. An interesting question is…what is lost then when we recycle or refocus neural circuitry for reading? But that’s another topic for another day…

What I want to write about today is the parallel processes that are going on in reading. This week at my school we had a staff development meeting on fluency with a focus on phonemic skills.  We measure and track the progression of grapheme recognition (letter sound correspondence), phonemic awareness and oral fluency — accurage “sounding out” of words. That is a complex progression in and of itself. Dehaene presents a nice graphic of the steps in this route to reading. There is visual normalization (or recognition) — which is a pretty complex piece in isolation. The human eye is a poor scanner since only the fovea or very central part of the eye is useful for reading. Text needs to be in just the right place in our visual field in order to recognize it. There’s a lot more — but just keep in mind that simply getting the visual input from reading is very complex from a neurological point of view. Anyway, once text is visualized there is a spelling-to-sound conversion and recognition of phonological units (phonemes, syllables). Then speech production needs to occur. Think about this as a nested route in the reading process. As I understand it, this is the route that we focus on with phonics=based interventions such as Wilson.

The second route is the lexigraphic access /semantic interpretation. The orthographic units, while converted to sounds per the last paragraph, are also being run through your mental lexicon.  Actually, Dehaene points out, it should be lexicons (plural) since our brains track many kinds of information about words.  We have phonological lexicons that reflect sound relationships as well as grammatical lexicons that track parts of speech, and other sematic lexicons based on elements of meaning (carrot is a type of food — is orange — is edible, etc.) So orthographic units are run through orthographic lexicons, semantic lexicons, phonological lexicons. I picture our brains accessing a series of mental dictionaries, “flipping through” options until corresponding information is found. This information, combined with the phonological units from the first route, come together to lead to speech production that includes understanding. By isolating the first “route to reading” — previous paragraph — we get speech production but not necessarily with semantic understanding.

So…how might this help us work with struggling readers at the intermediate level? Dehaene doesn’t have a lot of specific things to say about this. He is outspoken in his criticism of “whole language” instruction for young readers. Research,  he says, clearly supports the need for focused, well-sequenced phonics instruction. This instruction actually changes the brain, which must be changed in order to refocus those neural circuits for reading. In kindergarten students must play with words and component sounds and recognize and trace letter shapes. Then — primary students must be taught how each letter or group of letters corresponds to phonemes, specifically being told that each speech sound can be represented in different “clothes” and each letter may be pronounced in different ways. Instruction must start with simplest and most frequent sounds that are consistently pronounced (t, k and a). The more complex graphemes b, m, f, i, o, un, ch, and ough, for example, need to be introduced later and gradually and in thoughtful ways. He strongly advises against calling any attention to ascending and descending letter patterns since children who pay attention to the global contour of words often think they can guess at words without studying component letters. (Consider how useless this would be with the words “eight” and “sight,” for example.)

At the intermediate level, though making up for gaps in this grapheme knowledge and phonemic awareness is important, I am equally concerned about the differences in the students’ mental lexicons — both that students may have smaller or fewer lexicons because they’ve been exposed to less knowledge, and that there may be errors or inefficiencies in these lexicons because of poor sequencing of word study or misconceptions. It seems to me we know less about how mental lexicons are constructed and what they look like and how differences in the structure of mental lexicons effect reading success.

Many teachers have started focusing on the importance of background knowledge in reading comprehension, observing that building background knowledge is as important as understanding comprehension strategies…in fact background knowledge is the fuel upon which comprehension strategies must feed. I wonder if the same is true in terms of word knowledge?  Do we need to be thinking more explicitly about a better organized sequence of word study to ensure that students have enough semantic knowledge available to help them access new words?  That would seem to make sense.

Sound and meaning…it’s incredible that these two routes to reading work as seamlessly as they do for most readers. But for readers who struggle… the journey toward effective interventions continues.

Neurogenesis, or the production of new neurons, is an important area of research with many interesting threads. In earlier days — when I was in college! — we were taught that adult animals didn’t make new neurons. (Only developing animals did.) However, newer research has shown that neurogenesis does continue into adult life in vertebrates (as well as invertebrates.) In humans, it’s been confirmed in the hippocampus. Located in the central part of the brain, the hippocampus is part of the “limbic system” and is involved in memory formation.

Research over recent years has suggested that memories — declarative memories specifically – are encoded in the hippocampus but stored elsewhere. I’ve written in earlier posts about the suggested importance of sleep and exercise, for example, in making sure memories are stored for the long term. As this process occurs the memories are apparently, for a while, stored in both places.

New research from Japan published in Cell last week sheds new light on the relationship between forming new memories (neurogenesis) and clearing old memories from the hippocampus.  Experimenting with mice, they found that neurogenesis is important not only to form new memories, but to clear the old ones from the hippocampus. (Remember, the memories that have been “transferred” or “copied” to long-term memory aren’t lost — just the copies in the hippocampus.) The researchers suggest that neurogenesis — new learning — may be important in order to prevent the hippocampus from just “filling up” with old memories.

Clearing old memories makes way for new learning. Hmmm…that’s fine it seems, as long as the memories are available elsewhere.  I want to know more about the transfer of memories to long-term memory. What else helps or hinders the transfer and is there any selective mechanism that chooses which memories are encoded long-term. Expect emotions are an important piece of that… Also, does this suggest anything about the pace of new learning? Can the hippocampus really “fill”? Seems to me I’ve heard that yes, it does. If so and you just keep adding…are you losing what was learned first? Or just not adding anything new? Or maybe both?

What does this suggest for the pace of instruction?

I’ve been thinking a lot about the term dyslexia lately and trying to get a better handle on exactly what it is. Standard definitions say that it’s a learning disability in which a person has difficulties reading or writing.  Stated differently, it’s having serious difficulties in decoding the written words and spelling them correctly. So are all those who struggle with reading — or with reading and spelling — by definition dyslexic (literally meaning dys –”bad” lexia — “words and letters.”)

Some say yes and their critics imply the term is poor because it means “everything and nothing.” Others focus more on a specific range of symptoms that include poor reading, writing, poor memory, perhaps lack of physical coordination.  Digging deeper, you can find references to different subtypes — Visual dyslexia, Auditory dyslexia, and Orthographic dyslexia. However, from what I have been able to find, there is not general agreement on use of these subtypes or an understanding of whether they even reflect any physical or neurological differences. Some intriguing research based on brain scans suggests that dyslexia may in fact represent a range of wide neurocognitive differences, but that research doesn’t seem to address the three subtypes mentioned above. So the jury’s still out. Regardless of how you slice it up, however, dyslexia reportedly affects 4-10 percent (some estimates go as high as 15%) of the population.

What’s actually going on the brain? Research has taken many directions, looking at inability to filter visual signals, for example. But consensus seems to be building around the idea that it is about sound processing as much as (or maybe even more than?) visual processing. Some newer research reported by multiple sources is shedding new light on the neuro-anatomy. It’s long been recognized that the struggle is in breaking down words into the sounds that make them up. People with dyslexia have to work harder to integrate (or mentally connect or correspond) written letter symbols to the sounds they represent.  This idea is not new, but what is new is brain imaging studies that seem to confirm it. The new functional imaging studies compared adult dyslexics with “normal” readers, and found that the dyslexic readers had less activity in a portion of the brain called the superior temporal cortex:  the physical (brain-based) system does not seem to be in place to associate the visual and sound.  The neuro-anatomy seems to be different.

The same researchers are now trying to untangle the sequence of issues. Do problems processing the sounds of language come before the problems making a connection between letters and sounds? Or vice versa? How are they connected?  The problem may become obvious when children first see printed letters and try to read, but has the sound processing issue been a problem all along?

One study found that sound training (no reading at all) led to improved reading by children with dyslexia. The exercises (an eight-week intervention) involved having children “click” when a chirp’s pitch went up or down. This study did not include long-term follow up so it’s not clear whether the reading improvement was sustained. A lot more research is needed. But…the question this leaves with me as a classroom teacher is….is dyslexia more about sound than visual struggles or even the sound-visual connections? The current intervention of multisensory reading instruction does incorporate sound, which seems to be on the right track. But is even more emphasis needed on phonological skills?

Researchers and clinicians have long realized the important link between receptive and expressive language — the ability to perceive tone, rhythm, and pitch of speech and the ability to initiate fluent, grammatically correct speech. A paper published in Science a few weeks ago (and widely reported) found a somewhat surprising closer physical link between the two.

It was long believed that expressive language was controlled by a part of the brain called Broca’s area and receptive language was controlled in a separate area called Wernicke’s area. This new research was based on real-time analysis of speech (electrodes in the brain!) of volunteers who were going to have portions of brain tissue removed for treatment of epilepsy. What the researchers found was that three separate steps — recognition of words, formation of a decision about grammar, and preparation of a verbal response — all took place within a very small portion of  Broca’s area. Also, the process was extremely fast…from first seeing words to recognizing them and then cuing up a response took only 450 milliseconds.

Most surprising and interesting to researchers is that all three processes take place within a very small area — possibly adjacent cells or even the same cells are involved in all three processes!   I wonder if it will change the way we think about receptive – expressive language: connected expressions of the same neurobiology rather than separate…steps.

I found myself having a number of conversations this week — with parents and colleagues — about…conversation. This year our faculty has added a new lens to our analysis of readers, looking at oral language among our intermediate-age struggling readers.  What we found is that among many of our struggling readers, receptive oral language — the ability to repeat sentences that they hear — was much less accurate than we would have expected. As a result, we are focusing on engaging these students in more small-group conversations in the classroom

That’s part of the reason that a recently published article in Pediatrics, the journal of the American Academy of Pediatrics, makes a lot of sense to me. Involving young children (ages 0-4) in two-way dialogue (back and forth conversation) is up to 6 times more important in fostering good language development than simply exposing children to adult narration (read-alouds, etc.) According to the researchers, more conversations allow more opportunities for errors and corrections, as well as more opportunities to practice vocabulary.  Another source interviewed in a report about this research suggests that the “give and take” is not only important for cognitive development, but also for social and emotional development.

It seems to make sense that for student who continue to struggle wtih language, back and forth conversation would have similar benefits — allowing more opportunities for having errors corrected and practicing vocabulary.  That’s what we’re doing in the classroom and what I will suggest to parents. However, I wish we knew more about the neurochemical differences between simply listening to ideas and exchanging ideas via dialogue. It would also be nice to have some research on the effects of dialogue vs. listening on language development in older children.

According to this report from the FASEB journal as reported by Science Daily a nasal spray has been shown to enhance the retention of memory during REM sleep. Excuse me if I’m skeptical.

Previously I’ve written about the importance of sleep. Research has suggested that sleep is needed in order to encode long term memories. This new report described a study in which healthy volunteers were given a story to read and then given a nasal spray containing interleukin-6 prior to a good night’s sleep. (IL-6 is an immune system regulator of inflammation.)

After waking, those receiving the nasal spray with interleukin-6 could write down more words from the story than those receiving a placebo.  The authors say that, “Here, we provide the first evidence that the immunoregulatory signal interleukin-6 plays a beneficial role in sleep-dependent formation of long-term memory in humans.”

It would be great to have a nasal spray that would help students remember learning from the day.  All participants in the study had a good night’s sleep, though, so the spray doesn’t seem to replace sleep… but still, sounds too good to be true. Sample size of 17.

Willpower isn’t something you can activate as though turning on a spigot and letting it flow, according to this intriguing report  in Science Daily (about research published in Psychology and Health.) This work suggests that willpower is a limited resource that can be used up. And in some people, it’s more limited than in others.

Immediately I am picturing students in my classroom who have to work so hard to focus for just five minutes to write two sentences. Or those who have to pull together all they’ve got to actually read a math problem and figure out what they’re being asked to do — and not because they have trouble reading, but because they have trouble making themselves read. I redirect, I encourage…alright, I even nag. “Just focus, you need to step up,” I can hear myself say.  Often they do, but then I find myself, just 10 minutes later, asking again.  If I infer the implications of this article correctly, I need to adjust my thinking about this.

This research specifically looked at exercise and found that cognitive and emotional tasks deplete a person’s capacity to exercise.  Researchers asked volunteers to do the exercise where they read names of colors printed in other colors  (read “red” printed in blue ink) which challenges an inclination to simply report the color they see. After doing so, the volunteers were more likely to reduce effort or even skip exercise. They summarize by saying, “You only have so much willpower.”  They likened it to a muscle, saying you can build it up, but only if you exercise it. So constantly forcing yourself to resist temptation or do something (like homework) that you don’t really want to do can build your capacity to self-regulate.

OK — this is one research study. But it makes sense.  (Maybe it’s even too obvious.) But for those nearly- impossible-to-motivate students, my work to get them to build more intrinsic motivation is probably mostly about building self-regulatory capacity.  Those words are helpful. Setting small goals, building will-power like building muscles…that’s something that students may understand better.  It also gives me a new metaphor.

“You don’t see something until you have the right metaphor to help you perceive it.” (Robert Stetson Shaw, supposedly echoing Thomas Kuhn.)

The first few weeks of school, as always, have been mostly about setting up routines and getting students ready for new learning. That’s why I’ve been thinking a lot about reactivation. It’s a term teachers use often — we talk about activating (reactivating) knowledge at the beginning of a year/unit/lesson so students can build on what they already know. I use KWL charts a lot, having students write what they know and want to learn at the beginning, and come back later to fill in what they’ve learned. The research continues to support how critical this is.

Putting aside for the moment students saying they can’t recall ever having been exposed to learning…(frustrating when you know they have) if students did indeed learn something specific at an earlier time, scientists are learning some interesting things about the process of reactivation.  What happens from a neurochemical perspective when you relearn something?

A 2008 report suggests that synapses are only disabled when something is “forgotten” — not physically abolished.  (There are some exceptions — trivia, for example, that we don’t seem to keep, but that’s another topic.)  For most learning, some connections remain so reactivation is faster than initial activation.  (Reminds me of the immune system…) Researchers studying brain reorganization and healing following an eye injury described the brain needing to save connections “for a rainy day” in case the injury reoccurred.  As a classroom teacher, this reassures me that if something was learned, students should be able to reactivate it.

More good news — scientists are also finding that by reactivating memory (at least one specific instance of spacial memory) it is being strengthened and updated.  French researchers observed that mice who had learned a skill (finding a slightly submerged platform to escape a tank of water) used/updated the same labeled neurons formed when they first learned the skill. They observed updating/invovlement of these same neurons when the same mice were put back into the same situation a month later.  They did not observe this in mice who had not learned the skill initially. That’s exciting, too, as a teacher. By reactivating memories we truly can strengthen them.

I do wonder if we need to more carefully consider how we reactivate, so that students are updating rather than creating new neurons/connections in the classroom.  How important is it that the learning be reactivated in specific ways that mimic the initial experience? To me, that may suggest that  things like common language among teachers and deep understanding of not only what but HOW students were exposed to ideas across the grade levels would help us make sure students are accessing those initial memories and strengthening those, rather than simply making new memories from scratch.

Oh ..by the way, we still don’ t know how the brain holds so many memories in the first place, but that’s a question for another day.

This report caught my attention  not only because of my students, but my husband and kids. Multi-tasking is something they all do. They also take pride in their ability to struggle many tasks at once. It must mean they are better at things — balancing, juggling, focusing…yes?

Uh…no, according to a new research report. A new report in the most recent Proceedings of the National Academy of Sciences (PNAS) found that people who “bombard” themselves with multiple streams of electronic information under-perform those who don’t in terms of memory, attention, and ability to switch gears.   Their findings suggest that multi-taskers just can’t keep separate streams of information separate in their minds — they’re not filtering, researchers say. Does  chronic multii-tasking damage cognitive control? That has yet to be studied.

Reading this report, I realize  how much I, too, have come to value multi-tasking. I watch those who do so many things at once and think “they must be so productive!”  It never occurred to me they were losing something in the process. Since our “e-kids” are increasingly multitasking — listening to music, video-streaming, homework, live chats — this research poses some important questions for educators who expect students to be effectively learning while doing homework or other at-home activities.  Are we expecting too much from those homework assignments if they are being done as one of many simultaneous tasks?

If this research is confirmed and developed, this is an example of neuroscience research we really need to tell our students about.  As for my family — I’ve already emailed the article to them. But…since I expect they’re reading it while listening to music, emailing, and watching videos, I think I’ll bring it up over dinner, too.

This weekend a new friend told me about a school in our school district where students only have recess once a week. I was skeptical. “Are you sure?” I asked, unable to believe that with all the research about how important exercise is for learning — on top of the issues related to childhood inactivity and obesity — that any school could make that decision.

“Kids need at least an hour a day of physical activity to ensure good health, according to the findings of a CDC-backed expert panel.” This is from a government-sponsored group back in 2005. “The panel presented evidence that physical activity actually helps children perform better academically.”

Consensus is building, as is the research base, as I discussed in my 8-05-09 post.  What I glean from all the research is that absent exercise and physical activity (as well as sleep and some other important factors) more class time doesn’t boost learning. It would seem to be about as productive as pouring water into an already full glass.