MRIcro free viewing software

http://www.sph.sc.edu/comd/rorden/mricro.html
This software could be used for localizing and comparing lesions across patients and in a patient across the course of disease or treatment. It supports MRI along with other imaging modalities (?).

Action-Related Properties Shape Object Representations in the Ventral Stream

Bradford Z. Mahon, Shawn C. Milleville, Gioia A.L. Negri, Raffaella I. Rumiati, Alfonso Caramazza, Alex Martin
Neuron, Vol 55, 507-520, 02 August 2007

The principles driving the organization of the ventral object-processing stream remain unknown. Here, we show that stimulus-specific repetition suppression (RS) in one region of the ventral stream is biased according to motor-relevant properties of objects. Quantitative analysis confirmed that this result was not confounded with similarity in visual shape. A similar pattern of biases in RS according to motor-relevant properties of objects was observed in dorsal stream regions in the left hemisphere. These findings suggest that neural specificity for “tools” in the ventral stream is driven by similarity metrics computed over motor-relevant information represented in dorsal structures. Support for this view is provided by converging results from functional connectivity analyses of the fMRI data and a separate neuropsychological study. More generally, these data suggest that a basic organizing principle giving rise to “category specificity” in the ventral stream may involve similarity metrics computed over information represented elsewhere in the brain.

Fulltext: http://download.neuron.org/pdfs/0896-6273/PIIS0896627307005387.pdf

Vision and the Brain: Unseen Complexities – Part 2

Why do we need vision? As it turns out, there are two answers to this question. On the one hand, we need vision to give us detailed knowledge of the world beyond ourselves, knowledge that allows us to recognize things from minute to minute and day to day. On the other hand, we also need vision to guide our actions in that world at the very moment they occur. These are two quite different job descriptions, and nature seems to have given us two different visual systems to carry them out. Dr. Goodale discusses how separate but interacting visual systems have evolved for the perception of objects on the one hand and the control of actions directed at those objects on the other, examining how both systems process information but each using the information in different ways.
By: Melvyn Goodale, Ph.D., C.Psych., F.R.S.C., research professor in visual neuroscience, University of Western Ontario
http://www.researchchannel.org/prog/displayevent.aspx?rID=16250&fID=345

Context familiarity enhances target processing by inferior temporal cortex neurons.

Mruczek RE, Sheinberg DL
J Neurosci. 2007 Aug 8;27(32):8533-45

Experience-dependent changes in the response properties of ventral visual stream neurons are thought to underlie our ability to rapidly and efficiently recognize visual objects. How these neural changes are related to efficient visual processing during natural vision remains unclear. Here, we demonstrate a neurophysiological correlate of efficient visual search through highly familiar object arrays. Humans and monkeys are faster at locating the same target when it is surrounded by familiar compared with unfamiliar distractors. We show that this behavioral enhancement is driven by an increased sensitivity of target-selective neurons in inferior temporal cortex. This results from an increased "signal" for target representations and decreased "noise" from neighboring familiar distractors. These data highlight the dynamic properties of the inferior temporal cortex neurons and add to a growing body of evidence demonstrating how experience shapes neural processing in the ventral visual stream.

PMID: 17687031

Fulltext: http://www.jneurosci.org/cgi/content/full/27/32/8533

The unsolved mystery of vision

Richard H. Masland, Paul R. Martin
Current Biology Vol 17 No 15

Vision looms large in neuroscience — it is the subject of a gigantic literature and four Nobel prizes — but there is a growing realization that there are problems with the textbook explanation of how mammalian vision works. Here we will summarize the evidence behind this disquiet. In effect, we shall present a portrait of a field that is ‘stuck’. Our initial focus, because it is our area of expertise, is on evidence that the early steps of mammalian vision are more diverse and more interesting than is usually imagined, so that our understanding of the later stages is in trouble right from the start. But we will also summarize problems, raised by others, with the later stages themselves.

Hardware/Software Hacking: Joining the Real and the Virtual

For the experimental neuroscientists who need to connect their computers to the external world!

Research Channel

http://www.researchchannel.org For Scientific lecture fans! Who download the entire Internet! ;-)
Specifically see Science section, with some lectures on Neurosciences.

Is That My Brother? Perceptual and Neurobiological Factors in Face Blindness

Face blindness (technically known as prosopagnosia) is a condition in which people with otherwise normal vision cannot discriminate one ... all » face from another. They may not be able to pick out their own husband or children in a crowded room or even themselves in a mirror. One woman reported she once had to crinkle her face in a crowded rest room to discriminate herself from others in the mirror. This problem can occur through injury to particular areas within the brain (either through head trauma, stoke or surgery), but it can also occur developmentally. In the latter case, the brain appears completely normal, yet developmental prosopagnosics (DP) have never learned to accurately discriminate faces.

There is a large scientific body of work on face perception published in the psychological, social and neurobiological literature, and I will highlight some of the more important findings. I will then discuss work from my own laboratory on perceptual processing of faces; emphasizing training methods we have developed to help individuals with DP identify faces, sometimes for the first time in their lives. This discussion will be complemented by inclusion of documented neurobiological and cognitive changes that accompany the emergence of face recognition abilities.

Technology Insight: future neuroprosthetic therapies for disorders of the nervous system

Richard A Normann
Nature Clinical Practice Neurology (2007) 3, 444-452 doi:10.1038/ncpneuro0556

Most disorders of the nervous system result from localized sensory or motor pathologies attributable to disease or trauma. The emerging field of neuroprosthetics is focused on the development of therapeutic interventions that will be able to restore some of this lost neural function by selective electrical stimulation of sensory or motor pathways, or by harnessing activity recorded from remnant neural pathways. A key element in this restoration of function has been the development of a new generation of penetrating microelectrode arrays that provide unprecedented selective access to the neurons of the CNS and PNS. The active tips of these microelectrode arrays penetrate the nervous tissues and abut against small populations of neurons or nerve fibers, thereby providing selective access to these cells. These electrode arrays are not only beginning to provide researchers with the ability to better study the spatiotemporal information processing performed by the nervous system, they can also form the basis for new therapies for disorders of the nervous system. In this Review, three examples of this new generation of microelectrode arrays are described, as are potential therapeutic applications in blindness and spinal cord injury, and for the control of prosthetic limbs.

Free full text: http://www.nature.com/ncpneuro/journal/v3/n8/pdf/ncpneuro0556.pdf

Behavioural improvements with thalamic stimulation

N. D. Schiff, J. T. Giacino, K. Kalmar, J. D. Victor, K. Baker, M. Gerber, B. Fritz, B. Eisenberg, J. O’Connor, E. J. Kobylarz, S. Farris, A. Machado, C. McCagg, F. Plum, J. J. Fins, A. R. Rezai
Nature 448, 600-603(2 August 2007) doi:10.1038/nature06041

Widespread loss of cerebral connectivity is assumed to underlie
the failure of brain mechanisms that support communication and
goal-directed behaviour following severe traumatic brain injury.
Disorders of consciousness that persist for longer than 12 months
after severe traumatic brain injury are generally considered to be
immutable; no treatment has been shown to accelerate recovery or
improve functional outcome in such cases1,2. Recent studies have
shown unexpected preservation of large-scale cerebral networks in
patients in the minimally conscious state (MCS)3,4, a condition
that is characterized by intermittent evidence of awareness of self
or the environment5. These findings indicate that there might be
residual functional capacity in some patients that could be supported
by therapeutic interventions. We hypothesize that further
recovery in some patients in the MCS is limited by chronic underactivation
of potentially recruitable large-scale networks. Here, in
a 6-month double-blind alternating crossover study, we show that
bilateral deep brain electrical stimulation (DBS) of the central
thalamus modulates behavioural responsiveness in a patient
who remained in MCS for 6 yr following traumatic brain injury
before the intervention. The frequency of specific cognitively
mediated behaviours (primary outcome measures) and functional
limb control and oral feeding (secondary outcome measures)
increased during periods in which DBS was on as compared with
periods in which it was off. Logistic regression modelling shows a
statistical linkage between the observed functional improvements
and recent stimulation history. We interpret the DBS effects as
compensating for a loss of arousal regulation that is normally
controlled by the frontal lobe in the intact brain. These findings
provide evidence that DBS can promote significant late functional
recovery from severe traumatic brain injury. Our observations,
years after the injury occurred, challenge the existing practice of
early treatment discontinuation for patients with only inconsistent
interactive behaviours and motivate further research to
develop therapeutic interventions.

PMID: 17671503
Fulltext: http://www.nature.com/nature/journal/v448/n7153/full/448539a.html