Friday, October 31, 2008

Mental time keeping scholar - Dr. Richard Ivry

Another researcher has been added to the mental time keeping scholar blog roll. Below is information taken directly from Dr. Richard Ivry's web page.

Institute of Cognitive and Brain Sciences
Member, Executive Committee Helen Wills Neuroscience Institute

My research explores the neural basis of sensorimotor control and learning. Our experiments involve neurologically healthy and impaired individuals, use behavioral and neuroimaging methods to characterize the functional role of different parts of the motor pathways. For example, we have hypothesized that a primary role for the cerebellum is to regulate the temporal aspects of movement. Moreover, the cerebellum also appears to be involved in perceptual tasks that require precise timing. We are currently exploring how the brain may represent temporal information at a mechanistic level. We hypothesize that the cerebellum may be conceptualized as a network of interval-based timing elements, with these elements tuned to specific intervals that are task-specific.

This decade has seen a great deal of interest in higher-level functions of the cerebellum, inspired by various results in the neuroimaging literature as well as intriguing findings that this structure is abnormal in autistic individuals. Functional hypotheses include the idea that this structure is essential for attention shifting, internal speech, and/or preparation of response alternatives. We are testing these hypotheses in our patient population.

Another primary area of research involves the study of motor learning. We have conducted behavioral and neuroimaging studies comparing explicit and implicit motor sequence learning. This work suggests separable psychological and neural systems associated with these two forms of motor learning. Our current work is designed to clarify differences between the systems in terms of how they represent learned association.

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Understanding the IQ brain clock: Excellent overview article

[double click on image to enlarge]

Damn I love the journal Trends in Cognitive Science. It routinely publishes concise articles that circumscribe the state of the knowledge in important areas of human cognition/intelligence. I just finished reading yet another outstanding article ("Dedicated and intrinsic models of time perception") by Ivry and Schlerf (2008) (click to review)

Throughout the past year I've posted material regarding different neural models that have been advanced to explain the IQ brain clock (temporal processing). I've never felt I've done a good job in pulling all of this together. These authors do an exceptional job in describing the four primary hypothesized models that have been advanced to explain the neural mechanisms underlying the human brain clock. More importantly they do so which the aid of great visual-graphics (see the one above). I liked the article so much that I've added it to the "key research articles" section of this blog and have also added Dr. Ivry to the "mental timing scholars" link section.
  • Abstract: Two general frameworks have been articulated to describe how the passage of time is perceived. One emphasizes that the judgment of the duration of a stimulus depends on the operation of dedicated neural mechanisms specialized for representing the temporal relationships between events. Alternatively, the representation of duration could be ubiquitous, arising from the intrinsic dynamics of nondedicated neural mechanisms. In such models, duration might be encoded directly through the amount of activation of sensory processes or as spatial patterns of activity in a network of neurons. Although intrinsic models are neurally plausible, we highlight several issues that must be addressed before we dispense with models of duration perception that are based on dedicated processes.
A few tidbits extracted (directly) from the article, some that reinforce information posted at the IQ Brain Clock over the past few years---and some that is new. italics added by blogmaster:
  • we focus on a fundamental question that has defined much of the recent discussion: is our perception of the passage of time the consequence of dedicated, clock-like neural mechanisms? Or is duration coded in an accessible manner as an intrinsic and ubiquitous property of neural activity?
  • The facile manner with which we compare time across different modalities suggests some sort of internal clock.
  • Dedicated models of time perception are, at their core, modular. As vision scientists speak of dedicated mechanisms for color or motion perception, modular models of time perception entail some sort of specialized mechanism that represents the temporal relationship between events. The pacemaker-counter model is one example of a modular system .
  • Intrinsic models offer a radically different perspective on the perception of time. These models assume that there is no specialized brain system for representing temporal information, asserting that time is inherent in neural dynamics.
  • the cerebellar timing hypothesis is based on the assumption that the cerebellum has a unique representational capability and is accessed whenever a particular task requires precise timing.
  • Similar arguments have been developed for other neural regions that might serve as dedicated timing systems [25]. These include the basal ganglia [26,27], supplementary motor area [28,29] and prefrontal cortex, especially in the right hemisphere [30,31]. For the most part, converging evidence has been offered in support of all of these candidate regions.
  • considerable debate continues on the question of whether temporal-processing deficits are uniquely associated with damage to a particular neural structure.
  • Other dedicated models avoid localization issues by postulating that the representation of time results from activity across a network of regions
  • The role of nontemporal factors on perceived duration Performance on time-perception tasks entails several component processes, many of which are not specific to time. These include attention, working memory and long-term or reference memor

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Happy Halloween

Reynolds Unwrapped by Dan Reynolds

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Thursday, October 30, 2008

Timing and the cerebellum

From the CognAc Lab.

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Multitasking may not be good for you

Interesting post from PSYCH CENTRAL on the price paid in poor learning
when we multitasking.

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Global brain fitness consortium

As usual another great post from SHARP BRAINS.

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Cognitive and Action Lab & Richard Ivry: Mental timing scholar

Only time for a quick note. I just discovered a great new research lab that conducts research related to topics covered by the IQ Brain Clock. It is the Cognitive and Action Lab run by Dr. Richard Ivry. I'm in the middle of reading a great overview article by Dr. Ivry....and will be making a post in the next few days. I've already added Dr. Ivry to the "mental timing scholars" list at this blog. I'll make a separate mental timing scholars post regarding Dr. Ivry soon.

More later. Some exciting and great work.

Levels of human timing systems

[double click on image to enlarge]

The human timing machine has been described as possessing at least 10 different timing systems that vary according to the length of time perception processed (click here for prior post). Of the 10 different systems, the focus of this blog has been on the fastest (lowest in the timing hierarchy) timing systems...mental timing at the level of milliseconds to seconds.

I just found another table in an article that puts this in perspective (see above). The neural rhythm, in this table, is the focus of this blog. As you can see, this is just one level of the complex timing systems that govern human behavior. Click here if you want to see the source article.

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The brain clock and IQ: Another supporting article

I've blogged extensively on the intriguing relation between the hypothesized internal brain clock and intelligence. I've found the research supporting the notion of a temporal g (temporal general intelligence mechanism) particularly intriguing.

There is a new article "in press" in the journal Intelligence that adds support to the hypothesis that temporal processing may be more related to general intelligence than the "holy grail" research that attempts to explain g via reaction time (RT). The focus of the article is an attempt to identify the underlying mechanisms that explain the relation between general intelligence and temporal processing (in this case, the authors used a isochronous serial interval production task as the measure of temporal processing). The article is rather technical, so I'll cut to the bottom line take-away messages.

The authors argue that their findings support a bottom-up (BU) explanation of temporal processing, in contrast to the alternative top-down (TD) explanation. The supported BU explanation suggests that the aspect of temporal processing related to general intelligence is grounded in certain basic neural properties that influence temporal variability in neural activity. The alternative TD hypothesis suggests that some form of higher-order component of the neural system (e.g., the construct of attention) is responsible for the link. The authors suggest that the support for the BU hypothesis, and not the TD hypothesis, supports a biological underpinning for intelligence and, more importantly, the hypothesis that temporal accuracy of neural activity has a causal effect on the neural processes that are involved in cognition (intelligence).

Also of interest was the authors suggestion that this basic underlying mechanism (of the brain clock?) is the result of a network of brain regions (sensorimotor cortx, supplementary and pre-supplementary motor areas, later premotor areas of the frontal lobe, auditory regions in the superious temporal gyrus, the basal ganglia and cerebellum). The efficient networked interaction of many of these brain regions have been implicated in other research discussed at this blog.

Of course, the small sample (n=36) and the reliance on a single psychometric measure (Raven's matrix test) of fluid intelligence (Gf) to define intelligence are significant limitations that argue for caution and the need for replication in larger samples and a broader array of indicators of the construct of intelligence. Click here for a prior discussion of my concerns for the reliance on the Raven's Gf test.

Madison, G., Forsman, L., Blom, O., Karabanov, A & UllĂ©n, F. (2009) Correlations between intelligence and components of serial timing variability. Intelligence,37, 68–75 (click to view)

  • Abstract: Psychometric intelligence correlates with reaction time in elementary cognitive tasks, as well as with performance in time discrimination and judgment tasks. It has remained unclear, however, to what extent these correlations are due to top–down mechanisms, such as attention, and bottom–up mechanisms, i.e. basic neural properties that in?uence both temporal accuracy and cognitive processes. Here, we assessed correlations between intelligence (Raven SPM Plus) and performance in isochronous serial interval production, a simple, automatic timing task where participants ?rst make movements in synchrony with an isochronous sequence of sounds and then continue with self-paced production to produce a sequence of intervals with the same inter-onset interval (IOI). The target IOI varied across trials. A number of different measures of timing variability were considered, all negatively correlated with intelligence. Across all stimulus IOIs, local interval-to-interval variability correlated more strongly with intelligence than drift, i.e. gradual changes in response IOI. The strongest correlations with intelligence were found for IOIs between 400 and 900 ms, rather than above 1 s, which is typically considered a lower limit for cognitive timing. Furthermore, poor trials, i.e. trials arguably most affected by lapses in attention, did not predict intelligence better than the most accurate trials. We discuss these results in relation to the human timing literature, and argue that they support a bottom–up model of the relation between temporal variability of neural activity and intelligence.

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Tuesday, October 14, 2008

Sharp Brains news

I have an FYI feed on my two major blogs that provides constant
updates from their blog. Occassionally I like to feature a post or
two. The link below should take you to an important post regarding a
new research sponsorship program they have just announced.

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Friday, October 10, 2008

IQ Brain Clock "followers" gadget option

I just added the Blogger "followers" gadget to this blog. It can be found in the right column of the blog. Please join.

Sunday, October 05, 2008

Neurotech Reports News Updates


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October 5, 2008

Welcome to Neurotech Reports News Updates. Here's the latest headlines and summaries from Neurotech Business Report.

Neurotech Startup Firms to Present at 2008 Neurotech Leaders Forum
Several new and emerging neurotechnology firms will make presentations at the 2008 event.
Read the article, free

New Polymers Promise to Enhance Neural Interfaces
Two commercial firms are offering new polymer materials for neurostimulation devices.
Read the article, free

New Textbooks Focus on Neuroengineering and Neuromodulation Topics
The books are aimed at the growing number of research and academic labs.
Read the article, free

Neurotech Vendors Advance Therapies for Migraine
Two new treatments were described at the American Headache Society meeting.
Read the article free

Commentary: Electrodes Go Live
Editor James Cavuoto comments on implications of new electrode technology based on conducting biopolymers.
Read the article free

Patterned TMS Manipulates Brain Excitability
The temporal pattern of rTMS can have a profound effect on cortical excitability.
To read the rest of this article, click here to subscribe to Neurotech Business Report

Other Articles in Recent Issues of Neurotech Business Report
Research Institution Profile:
Cold Spring Harbor Laboratory Pursues Fundamental Neuroscience Research
Conference Report: Neural Engineers Convene in Cleveland for Neural Interfaces Conference
Vendor Profile: Texcel Medical Delivers Stimulation Components for Neurotech Firms
VC Firm Profile: The Innovation Factory Offers New Approach to Incubator Strategy
News Briefs: Updates on new FDA device approvals, neurotechnology events, corporate activity
Financial News: Financial results and projections from key players in the industry
Research Briefs: Summaries of the most relevant journal articles and conference proceedings that stand to impact commercial development

Friday, October 03, 2008

Writing can make you feel good

The BRAIN BLOGGER has a nice post on the therapeutic impact of keeping
a diary or journal. This is not new news to folks who have been doing
this for years-but it is nice to have some research comfirmarion. I
often wonder if my blogging provides a similar benefit. Hmmmm.

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IM Gait Mate brain clock based technology

Previous research reported at this blog has established a link between rhythm training (a topic under temporal processing) and improving gait in subjects with cerebral palsy. I've now learned that Interactive Metronome (IM) has a new product in this field (the Gait Mate - click here for more info), based on IM's mental timing synchronization technology. Check out link above for more information.

[Conflict of Interest disclosure - I'm on the Scientific Advisory Board for IM]

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