Month: October 2010

November 3, 2010

What: Brain Imaging Series Lecture
When: November 3, 2010 3:15-4:15pm
Who: Free, Open to the public
Where: Center for Advanced Brain Imaging, Conference Room

Tim Martin, Assistant Professor
Department of Psychology
Kennesaw State University

Lecture Title:A gentle introduction to magnetoencephalography (MEG)

Magnetoencephalography (MEG) is the recording of fluctuations in the magnetic field surrounding the head. It is a sibling of electroencephalography (EEG) and cousin of fMRI. Like EEG, MEG provides theoretically unlimited temporal resolution. Because the magnetic fields caused by neuronal currents do not interact appreciably with biological tissue, MEG also provides spatial resolution that is empirically equivalent to 1.5 T fMRI, with one important caveat: the biomagnetic inverse problem. This presentation will introduce the key concepts of MEG and discuss pros and cons relative to other methods of measuring brain activity.

Posted in Uncategorized

October 27, 2010

What: Brain Imaging Series Lecture
When: October 27 2010 3-4pm
Who: Free, Open to the public
Where: Georgia Tech, Coon bldg, Rm 250
Mick Rugg, PhD
Department of Neurobiology and Behavior
Department of Cognitive Sciences , University of California, Irvine

Title: What is the functional significance of age-related cortical over-recruitment during memory encoding and retrieval?

Abstract: Several studies have reported that encoding- and retrieval-related cortical activity is greater in magnitude and more widespread in
older than in young adults. The functional significance of these age-related cortical ‘over-recruitment’ effects is uncertain. Whereas
some researchers have argued that they reflect an adaptive compensatory mechanism that supports memory function in the face of
age-related decline in neural efficiency, others have argued that over-recruitment is indicative of age-related pathology that
contributes to cognitive decline. The presentation will describe data from several fMRI studies of episodic encoding and retrieval relevant
to this debate. Over-recruitment of encoding-related neural activity is most apparent in subjects with relatively poor memory function. To
date, there is no clear evidence of an association between over-recruitment and performance at the time of retrieval. The
significance of these findings for the compensation hypothesis of over-recruitment will be discussed.

Posted in Uncategorized

October 20, 2010

What: tDCS mini-workshop
When: Wednesday, October 20, 2010 12-1pm
Who: Free, Open to the public
Where: CABI Conference Rm

Reply to ncanty@gatech.edu RSVP

Lucas C. Parra, Ph.D.

Title: Weak non-invasive currents can modulate ongoing brain activity

Davide Reato, Abhishek Data, Thomas Radman, Yuzhuo Su, Xiang Zhou,
Jacek Dmochowski, Marom Bikson, *Lucas C. Parra*

Over the last decade several experiments have shown that very weak
electric currents of approximately 1mA can entrain the activity of
neuronal networks and indeed have a causal effect on human brain
function — including enhancement of cognitive function. Computational
modeling and slice experiments indicate that 1mA applied
non-invasively will polarize neurons by at most 1mV (more typically
around 0.1mV). How such small currents can have an observable effect
remains a mystery — a mystery worth answering given the tremendous
implications for therapeutic electrical stimulation. Our team at CCNY
has developed a theory on how small fields can significantly affect
the timing of neural activity and how they modulate firing rate and
frequency of ongoing oscillatory activity. The work tightly couples
theory, computational modeling and experimental exploration and
validation with small electric fields applied to hippocampal slices.

Posted in Uncategorized

October 20, 2010

What: Brain Imaging Series Lecture
When: October 20, 2010 3:15-4:15pm
Who: Free, Open to the public
Where: Coon Building, room 250

Gregory Samanez-Larkin, PhD
Department of Psychological Sciences, Vanderbilt University

Title: Value-Based Learning and Decision Making in the Aging Brain

Abstract: As the proportion of older adults continues to grow rapidly here in the U.S. and across the globe, aging adults may be required to make more independent health-related and financial decisions. Thus, it is increasingly imperative to better understand the impact of age-related psychological changes on decision making. Although a growing body of research has linked age-related deficits in attention, memory, and cognitive control to changes in medial temporal and lateral prefrontal cortical function, remarkably little research has investigated the influence of aging on valuation and associated mesolimbic function in the striatum and medial prefrontal cortex. In this talk I will present a set of experiments focused on age differences in value-based learning and decision making. Overall, neuroimaging results suggest that age-related changes in mesolimbic function (e.g., changes in signal variability and the representation of prediction errors) are associated with changes in learning and decision making. Importantly, follow-up behavioral experiments also reveal that age-related impairments are reduced or eliminated under supportive task conditions. I will also briefly discuss some of the methodological issues with comparing younger and older adults using neuroimaging, and how these issues can be addressed.

Posted in Talks

October 11, 2010

What: Brain Imaging Series Lecture
When: October 11, 2010 3:00-4:00pm
Who: Free, Open to the public
Where: Coon Building, room 250

Facundo Manes
Director, Institute of Neurosciences – Favaloro University
Professor of Neurology and Cognitive Neuroscience.
Favaloro University. Buenos Aires. Argentina
Director, Institute of Cognitive Neurology (INECO)
President. Federation of Neurology Research Group on Aphasia and Cognitive Disorders (RGACD)
Title: Neuropsychological Approach to Early Behavioral Variant Frontotemporal Dementia 

Abstract: From a clinician’s perspective, it can very frustrating to evaluate a patient with a convincing history of executive and social cognition deficits, particularly as described by family members, and yet, observe minimally impaired or within normal performance on formal neuropsychological testing using the standard measures. The family shares this frustration, as they are keenly aware that something is wrong, yet no ‘objective’ evidence of impairment can be found on comprehensive assessments. Especially in cases of very early behavioral variant frontotemporal dementia (bvFTD), patients may be misleadingly diagnosed as having primary psychiatric disorder, or malingering, or the family would be suspected of distorting the facts for some other gain. For this reason, being able to enhance traditional cognitive assessment batteries with the addition of more ‘comprehensive’ tests of complex executive-social functioning is important. In this presentation, we will discuss the way in which these more ‘ecological’ tests can mimic real life demands more reliably, and thus, increase sensitivity for the detection of executive and social cognitive impairment in patients with early bvFTD. We will also delve into how these tests can prove useful in determining patients’ competency, since early bvFTD patients present unique legal and ethical problems and current regulation does not necessarily apply to this patient population, since legal aspects of dementia are based primarily on Alzheimer disease. 

Posted in Uncategorized

October 5, 2010

What: Brain Imaging Series Lecture
When: October 5 2010 3-4pm
Who: Free, Open to the public
Where: Center for Advanced Brain Imaging, Conference Room

David Pitcher, PhD
Department of Brain and Cognitive Sciences , MIT

Lecture Title: TMS reveals two critical and functionally distinct time periods for early face and body perception

Abstract: The human visual system perceives faces and bodies in a series of stages in which stimulus features of increasing complexity are extracted and analyzed. In this talk I will demonstrate how transcranial magnetic stimulation (TMS) can be exploited to reveal two early and functionally distinct time periods for visual face and body perception. Across a series of experiments TMS was delivered over the right occipital face area (OFA) and the right extrastriate body area (EBA) at different times after stimulus onset while subjects performed a range of face and body discrimination tasks. Results demonstrated that TMS disrupted task performance during two temporally distinct time periods, the first at 40-50ms and the second at 100-110ms. A follow up experiment revealed that these two time periods exhibit functionally distinct patterns of discrimination impairments. Specifically that TMS delivered during the first time period (at 40-50ms) disrupted both preferred (faces at OFA and bodies at EBA) and non-preferred (bodies at OFA and faces at EBA) task performance. By contrast TMS delivered in the second time period (at 100-110ms) disrupted the preferred task performance only. This pattern of results suggests how and when faces and bodies are categorized and discriminated in extrastriate cortex.

Posted in Uncategorized