Friday, October 27, 2006

Brain fitness program benefits elderly?

Thanks to the Mouse Trap for the FYI about a study that demonstrated a brain plasticity-based program let to significant specific cognitive improvements in elderly

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Working memory for familiar and novel information

Developing Intelligence beat me to the blogsphere with a post regarding a new article in Trends in Cognitive Scienes that explores possible neural mechanisms involved in working memory processing of familiar and novel information. Thanks DI. I really did have this article set aside for some comments.

My contribution will be to post a figure from the article (above) as well as provide a direct link to the article.

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Thursday, October 26, 2006

Looking for comments, ideas, and feedback: Suggestion box is open

To date I, as the IQ Brain Clock blog dictator, have been posting information that I think is exciting, informative, etc. I'd like to make this blog useful to a wide variety of professionals and scholars who have an interest in mental time keeping and the application of neuroscience research to cognition and learning.

If anyone has ideas for material I should be paying attention to (articles, researchers, web pages, other blogs, etc.), ideas for posts, self-nominations for guest posts by yourself, etc., please drop me a note in the blog "comment" feature or, email me at

I'm particularly interested (at this time) in finding neurotechnology-based programs that focus on improving human performance (in any domain) via attempts to increase the efficiency of the master mental interval timing clock.
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Mental time keeping and human speech

Earlier today I made an FYI post (with link to article) dealing with the role of the timing function of the auditory brainstem in speech. This reminded me of an article in a recent special issue of Cognitive Brain Research that reviewed recent neuroscience research (lesion and neuroimaging) that investigated the role of timing in human speech.
  • Schirmer, A (2004). Timing speech: a review of lesion and neuroimaging findings. Cognitive Brain Research, 21, 269–287 (click to view)
What I find particularly interesting is the spotlight (in this review article) on the basal ganglia, cerebullum and the left frontal cortex in speech-related timing behavior. Why?

Because the preponderance of mental interval time-keeping research consistently is pointing to the "master internal brain clock" being localized in the same general areas; particularly the basal ganglia, cerebullum, dorsolateral prefrontal cortex, and the frontial-striatal loop (Buhusi & Meck; 2005; Janata & Grafton, 2003; Nobre & O’Reilly, 2004; Peretz & Zatorre, 2005). Schimer concludes that the "BG [basal ganglia] and the cerebellum might perform more general timing operations that feed into other cognitive processes such as the processes specific to speech." In other words, Shimer is arguing for a domain-general, brain-based, mental time-keeper that functions in synchrony with possible domain-specific cognitive mechanisms specific to speech behavior.

  • Time is a fundamental dimension of behavior and as such underlies the perception and production of speech. This paper reviews patient and neuroimaging studies that investigated brain structures that support temporal aspects of speech. The left-frontal cortex, the basal ganglia, and the cerebellum represent structures that have been implicated repeatedly. A comparison with the structures involved in the timing of nonspeech events (e.g., tones, lights, finger movements) suggests both commonalities and differences: while the basal ganglia and the cerebellum contribute to the timing of speech and non-speech events, the contribution of left-frontal cortex seems to be specific to speech or rapidly changing acoustic information. Motivated by these commonalities and differences, this paper presents assumptions about the function of basal ganglia, cerebellum, and cortex in the timing of speech.
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Role of auditory brainstem timing in speech

Thanks to SCLin's neuroscience blog for the tip about an article in the Journal of Neuroscience that implicates the role of auditory brainstem timing and speech. (Click here to view article)

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Wednesday, October 25, 2006

Automatic vs cognitively controlled cognitive timing: Plus working memory link

[Double click on image to enlarge]

Contemporary research (Buhusi & Meck, 2005; Lewis & Miall, 2006) supports the idea that there are two mental timing circuits that can be dissociated: (1) an automatic timing system that works in the millisecond range, which is used in discrete-event (discontinuous) timing, and involves the cerebellum; and (2) a continuous-event, cognitively controlled timing system that requires attention and involves the basal ganglia and related cortical structures.

The above figure, which is based on a meta-analysis of studies (see Lewis & Miall, 2006), provides neurological evidence for two such systems via the localization of each system in different parts of the brain. What I (as a cognitive psychologist with a primary interest in psychological testing and theories of intelligence-see IQs Corner) find particularly intriguing is the conclusion (as reported in the Lewis & Miall, 2006 article as well as many other articles I've read) that the primary brain region associated with the cognitively controlled timing system is that also primarily associated with working memory--the dorsolateral prefrontal cortex (DLPFC).

More on this potentially important relationship in future posts.
  • Buhusi, W. & Meck, C. (Oct, 2005). What makes us tick: Functional and neural mechanism of interval timing. Nature Reviews: Neuroscience, 6, 755-765
  • Lewis, P. & Miall, C (2006). Remembering the time: a continuous clock. Trends in Cognitive Sciences, 10(9), 401-406.

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Introduction to pacemaker-accumulator mental time-keeping model

I previously made a couple of tease posts re: the predominant theoretical model of mental interval time-keeping (viz., the pacemaker-accumulator model). It is now time to "buck up" and provide my brief overview. Above is the best figure I've found to date (click here to see the original source article).

Human behavior based on the perception and timing in the range of seconds-to-minutes has traditionally been explained bythe pacemaker–accumulator model. The pacemaker-accumulator model (PAM), which is based on scalar expectancy or timing theory (Church, 1984; Gibbon et al., 1984; Meck, 1983), “is relatively straightforward, and provides powerful explanations of both behavioural and physiological data” (Buhusi & Meck, 2005; p. 755).

Briefly, the PAM model implicates the processing of temporal information via three synchronized modular information processing systems (see Buhusi & Mech, 2005.) The “clock” system consists of a dopaminergic pacemaker that regularly generates or emits neural ticks or pulses that are transferred (via a “gaiting” switch) to the accumulator, which accumulates ticks/pulses (neural counting) that correspond to a specific time interval. The raw representation of the stimulus duration in the accumulator is then transferred to working memory, a component of the PAM “memory” system. The contents of working memory are then compared against a “reference standard” in the long-term (reference) memory, the second component of the PAM memory system. Finally, the “decision” level of the PAM is conceptualized to consist of a comparator that determines an appropriate response based on a decision rule which involves a comparison between the interval duration value present in working memory and the corresponding duration value in reference memory. In other words, a comparison is made between the contents of reference memory (the standard) and working memory (viz., are they “close?”).

Considerable research evidence suggests that the PAM could be conceptualized as domain-general master internal clock central to many complex human behaviors (see Buhusi & Meck, 2005 and Lewis & Miall, 2006). Mental interval time-keeping and temporal processing research has suggested that a higher mental clock rate enables individuals to perform specific sequences of mental operations faster and reduces the probability of occurrence of interfering incidents (i.e., less disinhibition), two conditions that produce superior performance on cognitive tasks as well as more efficient basic information processing skills (Rammsayer & Brandler, in press).

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Tuesday, October 24, 2006

Neuroimaging of interval timing: Special issue of Cognitve Brain Research

I just ran across a special issue of Cognitive Brain Research devoted to "neuroimaging of interval timing.". The editorial introduction reference is listed below, along with a link to the editorial. A copy of the table of contents can also be found by clicking here.

If any readers of The IQ Brain Clock blog would like to examine any of the particular articles, I would willing to provide a copy, in exchange for a guest blog post (i.e., I'll send the article in exchange for a brief blog post about the contents of the article. Contact me via email if this is of interest --
  • Meck, W. & Malapan, C. (2004). Editorial Neuroimaging of interval timing. Cognitive Brain Research, 21,133– 137. (click here to view)
  • Exactly how the brain is able to measure the durations of events lasting from seconds to minutes while maintaining time-scale invariance remains largely a mystery. Neuroimaging studies are only now beginning to unravel the nature of interval timing and reveal whether different timing mechanisms are required for the perception and production of sub- and supra-second intervals that can be defined by different stimulus modalities. We here review the impact that neuroimaging studies have had on the field of timing and time perception and outline the major challenges that remain to be addressed before a physiologically realistic theory of interval timing can be established involving cortico-striatalcircuits.

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Sunday, October 22, 2006

Off task - Free hugs

This is WAY off task for this blog.

I ran across one of the more popular videos being viewed on YouTube and it hit a personal chord (Free Hugs Campaign). Don't ask me why.  I think the music (by Sick Puppies) resonated to something inside me.  Also, given all the partisian political bickering (here in the US) as we approach the mid-term elections and the stuff going on in the world (Iraq, N. Korea, school violence, etc.), sometimes one person can make a difference.

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Friday, October 20, 2006

Application of cognitive neuroscience research to education: Good overview/intro article

Following up on yesterday's small burst of posts regarding the fact/fiction surrounding the implications of brain-based (i.e., based on neuroscience) for education, I found the following very good overview article. Although not exhaustive or a definitive statement of the state-of-the-art of the neuroscience of education, I think this is a very good introductory overview article. I found the overview of neuroscience methods particulary good. I had not appreciated the differential sensitivity of different brain study methodologies as a function of temporal and spatial sensitivity (see above figure). Readers interested in the application of neuroscience research to the study of severe reading (dyslexia) and math (dyscalculia) disabilities will find the later half of the article interesting, although I believe these disability-related reviews are more illustrative than definitive (does not integrate all relevant neuroscience research findings regarding these forms of learning disabilites)

  • Katzir, T & ParĂ©-Blagoev, J. (2006) Applying Cognitive Neuroscience Research to Education: The Case of Literacy. Educational Psychologist, 41(1`), 53,74 (click here to view)
  • Neuroscience has provided fascinating glimpses into the brain’s development and function. Despite remarkable progress, brain research has not yet been successfully brought to bear in many fields of educational psychology. In this article, work on literacy serves as a test case for an examination of potential future bridges linking mind, brain, and educational psychology. This article proposes a model for integrating research in the cognitive neurosciences with educational psychology and reviews how neuroscience is providing new data relevant to 3 major controversies in the field of dyslexia. This article also discusses the relevance of these findings for psychoeducational assessment and instruction and suggests innovative venues for interdisciplinary research.
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Neuroscience of learning (brain-based learning): Posts moving to The IQ Brain Clock

FYI. The following post was just made to IQs Corner blog. Long story short....posts related to the neuroscience of learning (esp. in education) will now be made to The IQ Brain Clock blog (what you are now reading)

  • Yesterday's posts (click here, here) dealing with facts and fictions regarding brain-based learning in education, plus the response of SharpBrains, set me off digging through my electronic library of professional search of articles on the use of neuroscience in learning in education. I found a number of good overview articles that I will comment and post shortly.
  • However, it dawned on me that this line of research is probably more consistent with the focus of my new blog (Tick Tock Talk: The IQ Brain Clock). Thus, this note is to inform regular IQs Corner readers that I'm going to start shifting posts focused on the neuroscience of learning over to The IQ Brain Clock Blog. I will likely also broaden the definition and purpose of that blog.

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Wednesday, October 18, 2006

Mental time-keeping model "tease" # 2

Another blog tease :)...sorry. (click here to see tease post #1)

The above figure is another variation of the most prominent model of mental time keeping, namely....the pacemaker-accumulator model of timing based on scalar expectancy/timing theory. As in my prior tease post, I hope to describe the basics of this model in a series of blog posts...I just need to find the "time."

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Book review of Jensen's "Clocking the Mind"

Since posting information about Aruthur Jensen's new book (Clocking the Mind: Mental Chronometery of Individual Differences) yesterday, I did some sleuthing via the intelligence grapeview. I'm pleased to report, that a credible source (I've always wanted to say that....I love politics) indicates that a book review (by a top notch scholar in the field of intelligence) is in the works for the journal Intelligence. When I shall know. I will post information as soon as I see it.

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Tuesday, October 17, 2006

Arthur Jensen's "Clocking the mind" book

Thanks to an annonymous commenter for reminding me of the publication of Arthur Jensen's new book: Clocking the Mind: Mental Chronometry and Individual Differences.

As mentioned in a prior post (click here), Jensen is "the" name associated with the use of reaction time measures in the search for the essence of g (general intelligence). Although my prior post was in reference to an "in press" article that suggested that measures of temporal processing (vs. reaction time) may represent a temporal g ability that may be equal to or better than Jensen's reaction time paradigm, there is little doubt that Jensen's treatise will be relevant to understanding mental or interval time keeping. I'm anxious to see if Jensen draws any links to temporal processing and elementary timing tasks.

I placed my order for the book this evening. I also conducted a search for any professional reviews of the book, but could find none. If any readers become aware of any professional reviews of this book, please notify me.

Below is the description for the book provided by the publisher (I lifted this from

Mental Chronometry (MC) comprises a variety of techniques for measuring the speed with which the brain processes information.

First developed in mid-1800, MC was subsequently eclipsed by more complex and practically useful types of psychometric tests stemming from Alfred Binet. This class of mental tests, however, has no true metric relating the test scores to any specific properties of the brain per se. The scores merely represent an ordinal scale, only ranking individuals according to their overall performance on a variety of complex mental tasks. The resulting scores represent no more than ranks rather than being a true metrical scale of any specific dimension of brain function. Such an ordinal scale, which merely ranks individuals in some defined population, possesses no true scale properties, possessing neither a true zero or equal intervals throughout the scale. This deficiency obstructs the development of a true natural science of mental ability. The present burgeoning interest in understanding individual differences in mental abilities in terms of the natural sciences, biology and the brain sciences in particular, demands direct measures that functionally link brain and behavior. One such natural ratio scale is time itself - the time it takes the brain to perform some elementary cognitive task, measured in milliseconds.

After more than 25 years researching MC, Jensen here presents results on an absolute scale showing times for intake of visual and auditory information, for accessing short-term and long-term memory, and other cognitive skills, as a function of age, at yearly intervals from 3 to 80 years. The possible uses of MC in neurological diagnosis and the monitoring of drug effects on cognition, the chronometric study of special time-sensitive talents such as musical performance, and presents a theory of general intelligence, or g, as a function of the rate of oscillation of neural action potentials as measured by chronometric methods. Finally, Jensen urges the world-wide standardization of chronometric methods as necessary for advancing MC as a crucial branch of biopsychological science.

*Provides a different scale to report Mental Chronometry (MC) findings
*Argues for the global adoption of an absolute scale as opposed to the traditional ordinal scale
*An important contribution to MC researchers and psychologists and neuroscientists

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Is ADHD related to a poor internal mental clock?

I just ran across a 2004 study that examined prospective (reproducing a 30 second time interval) and retrospective (how long did a task take?) time judgements in children with reading disorders and ADHD (RD and ADHD groups).

Although prior research with ADHD subjects has implicated deficient mental/interval time-keeping (at the milisecond level--see introduction/review of lit in actual article--see below) as a potentail causal mechanism for ADHD, the current study attempted to determine if ADHD subjects, consistent with Barkley's ADHD impaired behavioral inhibition conceptualization (which articulates four primary self-regulation subsystems--working memory and sense of time, internalization of speech, affect regulation, and "reconstitution" or the formation of novel, complex behavioral sequences), differed from RD subjects in more "everday" time perception/judgments.

With regard to the focus of Tick Tock Talk: The IQ Brain Clock blog, the most interesting finding was a difference between RD and ADHD subjects in retrospective time estimation. As stated by the authors:
  • The most unusual and interesting finding of the study was discovering the retrospective exaggeration of ADHD children when judging how long the CCPT had taken. When asked “how long did that take?” of the CCPT, ADHD children gave more extreme estimates (“Oh! That took 3 hours!”). This finding underscores the temporal distortion problems found in ADHD (West et al., 2000). Childrens’ time estimations become less accurate with increasing duration of the time interval to be perceived, and distortion decreases with age (Zakay, 1992). Barkley’s theory emphasizes that ADHD childrens’ time judgements will be developmentally delayed relative to agemates.
  • McGee et al. (2004). Time Perception: Does it Distinguish ADHD and RD Children in a Clinical Sample? Journal of Abnormal Child Psychology, Vol. 32, No. 5, October 2004, pp. 481–490 (click here to view)

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Types of elementary timing or temporal processing experiences

According the Rammsayer and Brandler (2006, in press), a major controversy in the field of human timing is whether psychological time is governed by a unitary (domain-general) timing mechanism, separate (domain-specific) mechanisms, and/or whether a domain-general internal mental clock can explain the subset of distinct elementary temporal/timing experiences.

What are the major classes of elementary timing experiences that a master internal mental clock theory/model would need to explain? According the Rammsay and Brandler, they are:
  • Interval timing: Is often explained by the general assumption of a hypothetical internal clock based on neural counting. The neural pacemaker generates pulses or ticks with the number of pulses corresponding to a physical time interval that is recorded by an accumulator. The number of pulses counted during a given time interval is the internal representation of this interval.
  • Rhythm perception: The subjective grouping of objectively separate events or discrimination processes in serial temporal patterns.
  • Temporal-order judgment (TOJ): Refers to the question of how much time must intervene between the onsets of two different stimuli for their order to be perceived correctly.
  • Simultaneity and successiveness: Concerned with the size of the temporal interval between two sensory events that is required for them to be perceived as two separate events (successiveness) rather than fused as one event (simultaneity)

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Monday, October 16, 2006

Mental time keeping model: A sneak preview of "comming attractions"

This is a preview post.

The figure on the left is a simple visual representation (from Buhusi and Mecck, 2005 article in Nature Reviews: Neuroscience) of the most prominent model of mental time keeping..namely....the pacemaker-accumulator model of timing based on scalar expectancy/timing theory ( that a mouthful). Shortly, in a series of forthcomming posts, I will explain the basics of the pacemaker-accumulator model for an underlying internal (brain-based) mental/interval time clock. This will then be followed by posts devoted to some recent alternative models.

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Synchronized metronome tapping (SMT): WD-40 for the brain clock?

Can a person's internal master mental clock be improved? Can the temporal resolution, as reflected by a higher "clock rate," be improved vis-a-vis some form of intervention? possibility...namely...synchronized metronome tapping (SMT). I won't repeat my prior original post re: the possible efficacy of SMT here (as operationalized by Interactive Metronome-IM), which also includes a necessary potential conflict of interest (click here to visit this post @ IQs Corner).

The purpose of this post is to make readers of this neophyte blog aware of where my interest in internal mental or interval time keeping an external consultant to an SMT intervention study. More importantly, I want readers to know that this blog (Tick Tock Talk: The IQ Brain Clock) is NOT a blog for IM. My consultant statistical work for the IM studies simply started me down my current interest path in this area of cognitive functioning. Also, the current post should alert readers to the fact that the scope of the IQ Brain Clock blog will be to deal not only with mental/interval time-keeping theory and research, but also interventions that may improve cognitive performance via this brain-based mechanism.

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Internal brain/mental clock as domain-general mechanism

It is an assumption of the IQ Brain Clock blog, based on my reading of the extant psychological and neuroscience literature, that a master internal master clock can be conceptualized as a domain-general cognitive mechanism. A few comments by what I mean by domain-general:
  • There is a long-standing tradition within psychological research to search for general principles or cognitive mechanisms that can be used to address all aspects of behavior and cognition (e.g., g or general intelligence)
  • Such mechanisms are not tied to any specific content or domain and can be applied to a wide range of novel problems and domains of performance
  • “Jack-of-all-trades” mechanisms (Chiappe & McDonald,2005)

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Time is fundamental dimension of life: Interval and milisecond mental timing

I'm now convinced, after considerable reading of psychological and neuroscience research the past few years, that Buhusi and Meck (2005) are correct (and they are not the first to make this obvious statement) that "time is a fundamental dimension" of life. I must confess that, as an applied psychometrican, I've failed to appreciate the importance of timing and temporal cognitive processes in my measurement/assessment work to date. I hope, via this blog, to make up some ground.

In their October 2005 article in Nature Reviews: Neuroscience (What makes us tick? Functional and nural mechanisms of interval timing), the authors present a very interesting figure (that represents a compilation of animal and human studies) that suggests that, in order "to deal with time, organisms have developed multiple systems that are active over more than 10 orders of magnitude with varying degrees of precision." A larger version of this excellent figure can be viewed by clicking here.

As can be seen in the figure, three general classes of timing systems, that are associated with different behaviors, brain structures, and brain mechanisms, have been identified. The three systems are labled circadian, interval, and milisecond timing. The later two (interval and milisecond) are the two systems of particular interest to the IQ Brain Clock blog, as they appear most involved in empirical and theoretical explanations related to cognitive/intellectual functioning, my primary area of interest (see IQs Corner). Brief defintions (from Buhusi and Meck, 2005) follow below
  • Interval timing: Perception, estimation and discrimination of durations in the range of seconds-to-minutes- to-hours.
  • Milisecond timing: Perception, estimation and discrimination of durations in the sub-second range.
More to come.

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Mental time keeping research at Duke: Good stuff

This post is a "blast from the past" (over on IQs Corner) . During the past year the Science Blog had a nice post (What makes the brain tick, tick, tick) about research on mental time keeping by two neuroscientists at Duke (Buhusi and Meck). Since then, I've read a number of their publications. I believe that Meck and Buhusi are doing some of the best empirical and theoretical research regarding the brain's internal master clock. I will be making a series of posts regarding the essence of their findings.

Stay "tunned."

Tick Tock Talk: The IQ Brain Clock blog starts ticking

I may be nuts. Here I am starting a new sister blog to IQs Corner devoted to the narrow topic of the psychology of time, particularly brain-based research and theory regarding internal mental/interval time keeping and the idea of a master internal master brain-based clock.

Why? Because, as I've mentioned on IQs Corner on-and-off the past few years, I've become very interested with the growing research that suggests that the brain may have a master internal clock that governs interval timing and, more importantly, this internal master clock may be one of the major "essences" of complex human cognition (e.g., g or general intelligence).

So, at the urging of a few folks, I've set out to attempt to maintain a blog where contemporary research and theory in this field is provided to interested readers. I have no shortage of material that I've accumulated over the past three years....the big problem will be to carve out the necessary "time" to feed this new blog....Tick, Tock, Talk: The IQ Brain Clock.

Be patient as I get the mechanics of the blog (hit counter; technorati pings etc.) up-and-running and attempt to provide some degree of consistent material.

Let the games begin! Start your clocks.

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Temporal g: General intelligence (g) = internal mental time keeper?

Check out a rather lenghty post I made at IQs Corner re: a recent study suggesting that temporal processing (a master internal interval timing clock) may be a major explanatory basis for the concept of g (general intelligence). It was this post that got me started on the idea of a separate blog devoted to brain-based mental time-keeping.

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