The brain's "stop and go" mechanisms: The basal ganglia weighs in

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More evidence for brain network involved in controlled attention

A broken theme at the IQ Brain Clock is the hypothesis that the prefrontal cortex(especially the dorsolateral prefrontal), left parietal cortex , cerebellum, and basal ganglia network is key to mental timing, working memory and executive attention. Here is another study providing addition support for the first two cortical areas, with an extension to spatial working memory/attention and motor intention.

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Working memory and IQ brain clock training and mechanisms linked?

It is no secret that I believe that there is a significant link between contemporary working memory (and training related studies) and mental timing mechanisms (and training to improve) that can not be ignored.  I keep running across the common neurological mechanisms of the frontal (esp. the dorsolateral PFC) and parietal cortex's, the frontal-parietal loop, the basal ganglia and dopamine.  I have hypothesized about this in a variety of posts (esp. the possibility of a temporal g domain-general mechanism) and have made this link in a couple on-line PPT slide shows.  Klingberg's article below is entirely consistent with these hypotheses (click here for more info on Klingberg's strong program of working memory research).

Klingberg, T. (2010).  Training and plasticity of working memory.  Trends in Cognitive Sciences, 14 (7), 317-324. (click here to view)

Working memory (WM) capacity predicts performance in a wide range of cognitive tasks. Although WM capacity has been viewed as a constant trait, recent studies suggest that it can be improved by adaptive and extended training. This training is associated with changes in brain activity in frontal and parietal cortex and basal ganglia, as well as changes in dopamine receptor density. Transfer of the training effects to non-trained WM tasks is consistent with the notion of training-induced plasticity in a common neural network for WM. The observed training effects suggest that WM training could be used as a remediating intervention for individuals for whom low WM capacity is a limiting factor for academic performance or in everyday life.

Technorati Tags: Psychology, school psychology, educational psychology, cognitive psychology, neuropsychology, neurosciences, neurotechnology, neurology, brain, brain function, cognitive abilities, intelligence, IQ brain clock, brain timing, mental timekeeping, brain rhythms, rhythm perception, brain synchrony, brain synchronization, neural synchrony, neural synchronization, brain clock, dyslexia, temporal processing, temporal g, working memory, brain fitness, brain training

Follow-up to brain "time stamp" reseach

I previously made a brief post about interesting research done in primates that suggested that the brain uses a "time stamp" method to keep track of the time of events.  I've now located a copy of the research article published in PNAS (National Academy of Sciences) and now provide a link to those who really want to read the actual (but very technical) research report.

Technorati Tags: psychology, educational psychology, school psychology, neuropsychology, neuroscience, mental timing, IQ brain clock, brain clock, brain time stamp, temporal processing

IQ Brain Clock brain localization overview

I previously blogged about a special issue of Acta Neurobiologiae devoted to the minds brain clock. I provided a TOC and links to the papers. I just now skimmed one of the papers by Rubia & Smith (2004):

RUBIA K. and SMITH A. The neural correlates of cognitive time management: a review 

My conclusion is that this is an excellent overview of the basic empirical research and theoretical literature regarding mental time-keeping (i.e., the IQ Brain Clock). It also provides a nice summary of the general consensus re: the major areas of the brain believed to be involved in motor and cognitive timing, areas featured in prior posts here. Below is a copy of the first concluding paragraph...where I've added tag links to all prior IQ Brain Clock posts that refer to these brain areas or concepts. I will shortly add Rubia to the mental timing scholars blogroll and this article to the key research articles section of this blog.

• In conclusion, this review on the neural correlates of cognitive time management shows that predominantly right hemispheric dorsolateral and inferior prefrontal cortices, anterior cingulate, the SMA, the basal ganglia and the lateral cerebellar hemispheres appear to be involved in both functions of motor timing and time estimation. Furthermore, the review shows that the dichotomy between motor and perceptive timing functions may be artificial. Both functions appear to be mediated by identical neural networks and may be inseparable.

The IQ brain clock: Role of basal ganglia and cerebellum

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Dr. Ivry, a "mental timing scholar" (aka., IQ Brain Clock doc) has done it again!

In a prior post I drooled over the means by which he explained possible different neural models of temporal processing (the IQ Brain Clock) via visual-graphic diagrams. As a result of his most recent article (see prior post link above), I went and found an earlier 2004 publication (with Spencer) that again presents an excellent visual-graphic explanation of hypothesized different neural timing models (see figure above), but more importantly, presents a very nice visual-graphic explanation of the hypothesized role of the basal ganglia (and dopamaine), which have been repeatedly implicated in mental timing and such clinical disorders as Parkinson's (see figure below). I've always known that the basal ganglia play a prominent role in mental timing, but have never been able to grasp (probably reflecting my limitations) the possible "why" or underlying mechanism. They offer an interesting and understandable hypothesis.

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In the Ivry and Spencer (2004) article in Current Opinion in Neurobiology, the authors suggest that the basal ganglia works like a gating mechanism....which I have compared to the switch operator function in a railway system (see PPT slide show). According to the authors, who also prominently feature the cerebellum in brain clock timing system models:

• The current evidence does not preclude distributed models or hypotheses that assign a central role for timing to another specialized system, such as the basal ganglia. As reviewed here, the results of imaging and lesion studies are ambiguous with respect to the role of the basal ganglia in timing short intervals. A clear dissociation between the cerebellar and the basal ganglia contributions on temporal processing tasks remains elusive, primarily because similar deficits have been observed in patients with lesions of either structure ..... The cerebellar hypothesis offers a parsimonious account over a broad set of tasks, and neurobiologically feasible models have been developed. Nonetheless, a specialized system hypothesis must be able to account for similar patterns of performance following damage to distinct systems.

• As a starting point, we propose that the basal ganglia are an integral part of decision processes, operating as a threshold mechanism (Figure 2). Activations into the basal ganglia are gated such that only those reaching threshold are implemented [69]. The activation functions for different decisions can reflect multiple factors, such as goals, sensory inputs, and contextual information. These representations engage in a competitive process for control. According to this view, the basal ganglia ensure that response implementation or working memory updating does not occur until a criterion level of activation is reached. Dopamine inputs to the striatum modulate threshold settings, providing one mechanism by which the competition can be biased. Thresholds for reinforced actions are lowered, increasing the likelihood of implementation, even if the input patterns are unchanged.

An excellent and brief article. I will be adding it to the "key timing articles" link section of the IQ Brain Clock.

Technorati Tags: psychology, educational psychology, school psychology, biological psychology, neuropsychology, neuroscience, brain clock, IQ Brain Clock, mental timing, cerebellum, basal ganglia, dopamine, Parkinsons, temporal processing

Brain Clock Research Bytes # 1: Parkinsons, schizophrenia, and temporal pattern recognition

I found time to quickly skim a number of interesting journal articles this afternoon. Check out the following research bytes:

• Wong et al. (2008), in the Canadian Journal of Experimental Psychology, present an interesting sequential model of human temporal pattern recognition.

• Yet another study (Jones et al., in press, Brain and Cognition) linking the brain clock to Parkinson's with the usual cast of neuroscience characters implicated (basal ganglia; dopamine). A snipet from the authors conclusions "the data suggest that the integrity of the basal ganglia is necessary for ‘typical’ time production in the seconds range as well as for time reproduction at shorter intervals"

• In a prior post I reviewed one of the key brain clock research articles (see right side of this blog) by Buhusi and Meck 2006), where they implicated the brain clock in a variety of mental disorders, including schizophrenia. I just skimmed another article "in press" in Brain and Cognition (see link above in prior bulleted byte), this type by Carroll et al., that suggests a deficit in auditory temporal processing precision in schizophrenics.

Technorati Tags: psychology, educational psychology, school psychology, clinicial psychology, neuropsychology, neuroscience, brain clock, IQ Brain Clock, Parkinsons, schizophrenia, dopamine, basal ganglia, temporal processing

Scientific American Mind IQ Brain Clock article

Another popular press article addressing the importance of the brain and the perception/temporal processing of time...this time in the Feb/March 2008 issue of Scientific American Mind.

The cover of the issue teases the reader with the title "The time machine inside your head." The actual title of the article is "An odd sense of timing" by Pascal Wallisch (currently located as a Postdoctoral Fellow at NYU/CNS).

In general, given the page-length constraints of these popular press type of articles, this is a well-written article. As is the case with most articles that attempt to cut a wide swath in the coverage of a wide and deep field of research and theorization, it has a number of strengths and limitations. The author correctly points out the fact that many questions still remain unanswered regarding the neuro-cognitive mechanisms involved in human temporal processing.

The regular reader of the IQ Brain Clock understands that human time perception covers a broad array of timing behaviors that have been ordered on the order of 10-12 scales of magnitude (click here for prior post). Although not made explicit to the reader, the authors discussion of the precision of timing involved in the brains coordination of motor control/timing is referencing the mental timing system operating at the second and millsecond levels. A quick transition (in the article) is then made to the top end of the end of human timing systems, namely the circadian system that regulates sleep and wake cycles. Potentially lost in this transition is the important understanding that human beings have a wide range of behaviors that are governed by multiple systems of timing, each operating on a different range of time.

On the positive side, the author does touch on some of the key brain areas involved in the processing of time at the second and millisecond levels (the key focus of this blog), temporal processing important to intellectual performance (see prior posts regarding temporal g). Correct mention is made of the importance of the the basal ganglia, striatum, cerebullum, and frontal lobes (the prefrontal cortex/lobes should have received more mention..but I'm probably being a bit picky). The author makes use of two common metaphors used to explain the IQ brain clock, namely, the synchrony involved in the performance of a symphony orchestra (see "Brain Clock IM 2007 Keynote" PPT slides, located on the right side of the home blog page, for the use of this analogy in some of my attempts to explain mental timing) and the "beat of a metronome" to represent the "salvo of nerve cell impulses in the brain" that are "counted" by the brain to represent time.

A significant portion of the article, and probably the material of most popular interest, is the coverage of the subjective perception of time. That is, why, under different circumstances, does time seem to "fly" while in other circumstances time seems to "stand still." Readers who want more information should check check out a prior post re: temporal awareness.

Bottom line - I'm pleased to see the increased recognition of the internal brain clock in more mainstream media. Understanding human temporal processing, IMHO, has the potential to help us better understand a range of important intellectual behaviors and, more importantly, has the potential to produce neuro-cognitive based IQ Brain Clock "fine tunning" interventions that may improve intellectual and academic performance.




Technorati Tags: psychology, educational psychology, school psychology, neuropsychology, neuroscience, IQ Brain Clock, brain clock, mental clock, mental timing, interval timing, circadian, basal ganglia, striatum, frontal lobes, prefrontal cortex, metronome, temporal awareness, Scientific American Mind

Time Doc Byte # 3 - Brain clock importance and clinical groups

Here is my third Time Doc Byte. Categories - "importance" of the human brain clock and mental time-keeping; relevance to clinical groups/populations

This time the quotes come from a chapter from Meck (2003); Introduction to edited book - Functional and Neural Mechanisms of Interval Timing - yep, I've got the book and am hoping I can get through the technical and deep material - the book is listed as a "recommended book" on the right side of this blog).

Underline or italic emphasis added by blogmaster.

• The term interval timing is used to describe the temporal discrimination processes involved in the estimation and reproduction of relatively short during the seconds-to-minutes range that form the fabric of our everyday existence and unite our mental representations of actions and rhythmical structures.

• Human learning and memory is highly sensitive to temporal factors, and oscillator-based models have been proposed for the coding of serial order in memory...In addition, deficits in learning, memory, set shifting, and interval timing have been observed in a variety of patient populations with damage to the basal ganglia, including Parkinson's disease and Huntington's disease patients, as well as other cortical and subcortical brain structures affected by Alzheimer's disease, injury, and stroke.

• ...understanding temporal integration by the brain will be among the premier topics to unite systems, cellular, computational, and cognitive neuroscience over the next decade.

• It is interesting to note that some researchers have argued that a primary function of the internal clock is to allow for the efficient transfer of information from one stage of information processing to another at regularly spaced intervals.
  

Technorati Tags: psychology, educational psychology, neuropsychology, neuroscience, interval timing, brain clock, mental time keeping, Parkinsons, Huntingtons, Alzheimers, stroke, brain injury, temporal processing, Time Doc Byte

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Brain clock temporal processing review article

I just finished reading Mauk and Buonomano's 2004 review (Annual Review of Neuroscience) of "The Neural Basis of Temporal Processing." This is a bit of a hard read, but it is a good general overview summary article on contemporary mental time-keeping or temporal processing research and theory. All major mental time-keeping models are discussed, although the authors have a clear preference for the state-dependent distributed "emergent" neural models (vs. the internal clock model). I've posted a link to the article (that includes some yellow highlighting I did while reading the article) in the "key research articles" section of this blog. This is a good article for getting a handle on some of the key terms and theoretical concepts/models. I hope to take the notes I extracted and make some specific posts in the near future. I'm doing this reading largely to try get a handle on this entire domain of research....my learning curve is a bit slow right now.

A key comment in the review is that this field of research is very much in it's formative stage (stage of infancy).

Technorati Tags: psychology, educational psychology, school psychology, neuropsychology, neuroscience, brain clock, interval timing, mental time-keeping, internal clock models, pacemaker-accumulator, time, time perception, temporal processing, temporal awareness

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Random tidbits from the mind blogsphere - 2-23-07

• Thanks to Boing Boing for the "small world in your head" neuroscience related post

• Brain Injury has an interesting post about a partnership between the Brain Injury Association and Bob Woodruff (notable reporter who sustained brain injury in Iraq)
• Very interesting visual-graphic of the "whimsical image of the blogosphere from the edge to the core" over at the Data Mining blog.
• The always rich Developing Intelligence blog continues its series of excellent posts re: the development of prospective memory (remembering to remember)
• Thought provoking post (based on recent research article, as per usual) over at the Eide Neurolearning blog on the positive impact on cognitive due to heavily visual-based (Gv) video games...with the question asked--"what about auditory" (Ga)
• More on the whole brain fitness revolution...this time Consumer Reports making suggestions. Thanks to Happy Neuron for the tip
• Thanks to Mind Hacks for the tip re: some cutting edge Parkinson's disease research. This should be of interest to regular readers of the IQ Brain Clock blog, as Parkinson's has been linked to the brain structures closely linked to mental/interval time-keeping.
• Positive Technology Journal has an interesting neurotechnology post re: a recent study (n=5 clinical cases) of the use of some virtual reality neurotechnology in stroke rehab.

Technorati Tags: psychology, education, educational psychology, neuropsychology, school psychology, neuroscience, neurotechnology, brain fitness, stroke rehabilitation, virtual reality, brain injury, memory, video games, Ga, Gv

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What makes us tick? Nice research summary

Previously in this blog I've drawn attention to one of the key contemporary articles dealing with the neural mechanisms of mental/interval time keeping (by Buhusi and Meck). A copy of the complete article is listed under the "Key Research articles" portion of this blog ("What Makes Us Tick?).

Today I ran across a nice bulleted Neuroscience ummary of the article. It can be found by clicking here.

Technorati Tags: psychology, educational psychology, neuroscience, neuropsychology, mental timing, brain clock, interval timing, cognition, intelligence, temporal processing, internal clock model


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Mental time clock - fewer brain areas involved?

In prior posts re: mental/interval time-keeping, I have drawn on key neuroscience research articles regarding the potential brain areas/functions involved in the brain's master clock (this information was summarized in the "Interactive Metronome: Whats happening under the hood" on-line PPT slide show available on the right side of this blog) . This week I ran across a new fMRI study that questions the number and breadth of involvement of some of these key areas of the brain (viz., cerebullum, basal ganglia, frontal-striatal loop, dorsolateral prefrontal cortex, parietal lobe) in mental time-keeping. Below is the article reference and abstract. I believe the article speaks for itself.

As with all science, this is one more bit of information that needs to be added to the extant research knowledge base. The preponderance of research to date suggests the involvement of the areas summarized above, but this new study needs to examined (and hopefully replicated) so that possible adjustments to current thinking can be modified as needed.

I've also placed this article in the the "key research articles" section of this blog.

Livesey, A., Wall, M. Smith, A. (2007). Time perception: Manipulation of task difficulty dissociates clock functions from other cognitive demands Neuropsychologia,45,321–331. (click here to view)

Abstract (italics added by blogmaster)

• Previous studies suggest the involvement in timing functions of a surprisingly extensive network of human brain regions. But it is likely that while some of these regions play a fundamental role in timing, others are activated by associated task demands such as memory and decisionmaking. In two experiments, time perception (duration discrimination) was studied under two conditions of task difficulty and neural activation was compared using fMRI. Brain activation during duration discrimination was contrasted with activation evoked in a control condition (colour discrimination) that used identical stimuli. In the first experiment, the control task was slightly easier than the time task. Multiple brain areas were activated, in line with previous studies. These included the prefrontal cortex, cerebellum, inferior parietal lobule and striatum. In the second experiment, the control task was made more difficult than the time task. Much of the differential time-related activity seen in the first experiment disappeared and in some regions (inferior parietal cortex, pre-SMA and parts of prefrontal cortex) it reversed in polarity. This suggests that such activity is not specifically concerned with timing functions, but reflects the relative cognitive demands of the two tasks. However, three areas of time-related activation survived the task-difficulty manipulation: (i) a small region at the confluence of the inferior frontal gyrus and the anterior insula, bilaterally, (ii) a small portion of the left supramarginal gyrus and (iii) the putamen. We argue that the extent of the timing “network” has been significantly over-estimated in the past and that only these three relatively small regions can safely be regarded as being directly concerned with duration judgements.

Technorati Tags: psychology, educational psychology, school psychology, neuropsychology, neuroscience, mental time keeping, interval timing, mental timing, time perception, brain clock, fMRI, brain localization

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Teach your brain to stretch time

In my late night web searching I ran across an excellent summary news article that does a decent job of summarizing the broad strokes of contemporary mental time-keeping research. The article "Teach your brain to stretch time" was published at New Scientist.com.

The article highlights the pacemaker-accumulator model of timing and also indicates that another alternative model (coincidence detection model) is gaining status among mental time-keeping researchers. I hope to provide a brief summary of the coincidence detection model sometime soon.

This news type summary article does a good job of summarizing the gist of the major mental time-keeping research. It is worth the read and is a good non-technical article to share with others.

Technorati Tags: psychology, educational psychology, cognition, school psychology, neuropsychology, neuroscience, neurology, intelligence, IQ, interval timing, mental timing, brain timing, master clock, brain clock, IQ Brain Clock.temporal tracking, temporal processing,Interactive Metronome,scalar timing

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.

Abstract

• 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.

Technorati Tags: psychology, educational psychology, neuropsychology, neuroscience, neurology, speech, language, timing, mental time clock, master brain clock, metronome, interval timing, mental time keeping, pacemaker accumulator model, scalar timing theory, basal ganglia, cerebullum, frontal cortex, dorsolaterial prefrontal cortex, auditory brain stem

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Automatic vs cognitively controlled cognitive timing: Plus working memory link

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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.

Technorati Tags: psychology, educational psychology, cognition, school psychology, neuropsychology, neuroscience, neurology, intelligence, IQ, interval timing, mental timing, brain timing, master clock, brain clock,temporal processing,Interactive Metronome,scalar timing,working memory,prefrontal cortex,Gsm