Scholars@Duke
Leonard Edward White

Leonard Edward White

Associate Professor in Neurology
Neurology, Comprehensive Neurology
len.white@duke.edu
Box 91003, Duke Institute for Brain Sciences, Durham, NC 27708
M056 Levine Science Research Center, 308 Research Drive, Durham, NC 27708

Featured Works

Initial neighborhood biases and the quality of motion stimulation jointly influence the rapid emergence of direction preference in visual cortex.

Journal article J Neurosci · May 23, 2012 Featured Publication Visual experience plays a critical role in the development of direction-selective responses in ferret visual cortex. In visually naive animals, presentation of a bidirectional "training" stimulus induces rapid increases in the direction-selective responses ... Full text Link to item Cite

Gaussian process methods for estimating cortical maps.

Journal article Neuroimage · May 15, 2011 Featured Publication A striking feature of cortical organization is that the encoding of many stimulus features, for example orientation or direction selectivity, is arranged into topographic maps. Functional imaging methods such as optical imaging of intrinsic signals, voltag ... Full text Link to item Cite

Incorporating gross anatomy education into radiation oncology residency: a 2-year curriculum with evaluation of resident satisfaction.

Journal article J Am Coll Radiol · May 2011 Featured Publication PURPOSE: Radiation oncologists require a thorough understanding of anatomy, but gross anatomy is not part of the standard residency curriculum. "Oncoanatomy" is an educational program for radiation oncology residents at Duke University that integrates cada ... Full text Link to item Cite

Universality in the evolution of orientation columns in the visual cortex.

Journal article Science · November 19, 2010 Featured Publication The brain's visual cortex processes information concerning form, pattern, and motion within functional maps that reflect the layout of neuronal circuits. We analyzed functional maps of orientation preference in the ferret, tree shrew, and galago--three spe ... Full text Link to item Cite

Clinical and imaging findings suggesting human herpesvirus 6 encephalitis.

Journal article Pediatr Neurol · January 2010 Featured Publication We sought to distinguish patients testing positive for human herpesvirus 6 from those testing negative, based on clinical features and magnetic resonance images. Sixteen immunosuppresed patients were tested by polymerase chain reaction for human herpes vir ... Full text Link to item Cite

Cerebral white matter integrity mediates adult age differences in cognitive performance.

Journal article J Cogn Neurosci · February 2009 Featured Publication Previous research has established that age-related decline occurs in measures of cerebral white matter integrity, but the role of this decline in age-related cognitive changes is not clear. To conclude that white matter integrity has a mediating (causal) c ... Full text Link to item Cite

Experience with moving visual stimuli drives the early development of cortical direction selectivity.

Journal article Nature · December 18, 2008 Featured Publication The onset of vision occurs when neural circuits in the visual cortex are immature, lacking both the full complement of connections and the response selectivity that defines functional maturity. Direction-selective responses are particularly vulnerable to t ... Full text Link to item Cite

Extrahippocampal involvement in human herpesvirus 6 encephalitis depicted at MR imaging.

Journal article Radiology · December 2008 Featured Publication PURPOSE: To test the hypothesis that patterns of signal intensity abnormality in human herpesvirus 6 (HHV6)-positive patients would allow distinction from patients who did not test positive for HHV6 encephalitis. MATERIALS AND METHODS: This retrospective s ... Full text Link to item Cite

Age-related slowing of memory retrieval: contributions of perceptual speed and cerebral white matter integrity.

Journal article Neurobiol Aging · July 2008 Featured Publication Previous research suggests that, in reaction time (RT) measures of episodic memory retrieval, the unique effects of adult age are relatively small compared to the effects aging shares with more elementary abilities such as perceptual speed. Little is known ... Full text Link to item Cite

Vision and cortical map development.

Journal article Neuron · October 25, 2007 Featured Publication Functional maps arise in developing visual cortex as response selectivities become organized into columnar patterns of population activity. Recent studies of developing orientation and direction maps indicate that both are sensitive to visual experience, b ... Full text Link to item Cite

Diffusion tensor imaging assessment of brain white matter maturation during the first postnatal year.

Journal article AJR Am J Roentgenol · August 2007 Featured Publication OBJECTIVE: The purpose of this study was to use diffusion-weighted and diffusion tensor imaging to investigate the status of cerebral white matter (WM) at term gestation and the rate of WM maturation throughout the first year of life in healthy infants. MA ... Full text Link to item Cite

Adult age differences in the functional neuroanatomy of visual attention: a combined fMRI and DTI study.

Journal article Neurobiol Aging · March 2007 Featured Publication We combined measures from event-related functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and cognitive performance (visual search response time) to test the hypotheses that differences between younger and older adults in top-do ... Full text Link to item Cite

Role of aerobic fitness and aging on cerebral white matter integrity.

Journal article Ann N Y Acad Sci · February 2007 Featured Publication Neuroimaging research suggests that cerebral white matter (WM) integrity, as reflected in fractional anisotropy (FA) via diffusion tensor imaging (DTI), is decreased in older adults, especially in the prefrontal regions of the brain. Behavioral investigati ... Full text Link to item Cite

The development of direction selectivity in ferret visual cortex requires early visual experience.

Journal article Nat Neurosci · May 2006 Featured Publication Development of the selective response properties that define columns in sensory cortex is thought to begin early in cortical maturation, without the need for experience. We investigated the development of direction selectivity in ferret visual cortex using ... Full text Link to item Cite

Cortical cartography revisited: A frequency perspective on the functional architecture of visual cortex.

Journal article Prog Brain Res · 2006 Featured Publication Viewed in the plane of the cortical surface, the visual cortex is composed of overlapping functional maps that represent stimulus features such as edge orientation, direction of motion, and spatial frequency. Spatial relationships between these maps are th ... Full text Link to item Cite

Functional organization of visual cortex in the prosimian bush baby revealed by optical imaging of intrinsic signals.

Journal article J Neurophysiol · October 2005 Featured Publication Cells in primary visual cortex (V1) of primates and carnivores respond most strongly to a visual stimulus presented to one eye, in a particular visual field location, and at a particular orientation. Each of these stimulus attributes is mapped across the c ... Full text Link to item Cite

Diffusion tensor imaging of adult age differences in cerebral white matter: relation to response time.

Journal article Neuroimage · March 2004 Featured Publication Diffusion tensor imaging (DTI) measures the displacement of water molecules across tissue components, thus providing information regarding the microstructure of cerebral white matter. Fractional anisotropy (FA), the degree to which diffusion is directional ... Full text Link to item Cite

Visual experience promotes the isotropic representation of orientation preference.

Journal article Vis Neurosci · 2004 Featured Publication Within the visual cortex of several mammalian species, more circuitry is devoted to the representation of vertical and horizontal orientations than oblique orientations. The sensitivity of this representation of orientation preference to visual experience ... Full text Link to item Cite

Mapping multiple features in the population response of visual cortex.

Journal article Nature · June 26, 2003 Featured Publication Stimulus features such as edge orientation, motion direction and spatial frequency are thought to be encoded in the primary visual cortex by overlapping feature maps arranged so that the location of neurons activated by a particular combination of stimulus ... Full text Link to item Cite

The contribution of sensory experience to the maturation of orientation selectivity in ferret visual cortex.

Journal article Nature · June 28, 2001 Featured Publication Sensory experience begins when neural circuits in the cerebral cortex are still immature; however, the contribution of experience to cortical maturation remains unclear. In the visual cortex, the selectivity of neurons for oriented stimuli at the time of e ... Full text Link to item Cite

Consistent mapping of orientation preference across irregular functional domains in ferret visual cortex.

Journal article Vis Neurosci · 2001 Featured Publication The mammalian visual cortex harbors a number of functional maps that represent distinct attributes of stimuli in the visual environment. How different functional maps are accommodated within the same cortical space, especially in species that show marked i ... Full text Link to item Cite

Maps of central visual space in ferret V1 and V2 lack matching inputs from the two eyes.

Journal article J Neurosci · August 15, 1999 Featured Publication In the visual cortex, the representation of central visual space is supplied by matching geniculate inputs that are driven exclusively by one eye or the other. In layer 4 of early visual areas (V1 in primates and V1 and V2 in cat), these inputs form a near ... Full text Link to item Cite

Unequal representation of cardinal and oblique contours in ferret visual cortex.

Journal article Proc Natl Acad Sci U S A · March 3, 1998 Featured Publication We have measured the amount of cortical space activated by differently oriented gratings in 25 adult ferrets by optical imaging of intrinsic signal. On average, 7% more area of the exposed visual cortex was preferentially activated by vertical and horizont ... Full text Link to item Cite

Structure of the human sensorimotor system. I: Morphology and cytoarchitecture of the central sulcus.

Journal article Cereb Cortex · 1997 Featured Publication We have studied the morphology of the central sulcus and the cytoarchitecture of the primary sensorimotor cortex in 20 human brains obtained at autopsy. Although the surface appearance of the central sulcus varies greatly from brain to brain (and between h ... Full text Link to item Cite

Structure of the human sensorimotor system. II: Lateral symmetry.

Journal article Cereb Cortex · 1997 Featured Publication We have evaluated the lateral symmetry of the human central sulcus, brainstem and spinal cord using quantitative histological and imaging techniques in specimens from 67 autopsy cases. Our purpose was to determine whether the preferred use of the right han ... Full text Link to item Cite

Is neural development Darwinian?

Journal article Trends Neurosci · November 1996 Featured Publication Gradually, and without much debate, the idea that the developing nervous system is in some sense darwinian has become one of the canons of neurobiology. In fact, there is little evidence to support this idea. ... Full text Link to item Cite

Temporal events in cyclopean vision.

Journal article Proc Natl Acad Sci U S A · April 16, 1996 Featured Publication The majority of neurons in the primary visual cortex of primates can be activated by stimulation of either eye; moreover, the monocular receptive fields of such neurons are located in about the same region of visual space. These well-known facts imply that ... Full text Link to item Cite

Monocular preferences in binocular viewing.

Journal article Proc Natl Acad Sci U S A · August 30, 1994 Featured Publication Faced with an unobstructed view, both foveas can be readily aligned with a distant visual target. The minor difference in the view of the two eyes (which arises from slightly different lines of sight) presents no special problem and is, indeed, the basis o ... Full text Link to item Cite

Manual asymmetry and handedness.

Journal article Proc Natl Acad Sci U S A · May 24, 1994 Featured Publication Volumetric measurements show that right-handed individuals have larger right hands than left hands. In contrast, the hands of left-handers are much more nearly symmetrical. Based on what is known about trophic interactions between neurons and targets, thes ... Full text Link to item Cite

Cerebral asymmetry and handedness.

Journal article Nature · March 17, 1994 Featured Publication Full text Link to item Cite

Neural activity and the development of the somatic sensory system.

Journal article Curr Opin Neurobiol · February 1994 Featured Publication Present thinking about the role of neural activity in the developing brain is based largely upon observations in the visual system. Attempts to generalize these findings in the somatic sensory system, however, have yielded perplexing results. Unlike the vi ... Full text Link to item Cite

Colocalization of excitatory and inhibitory neurotransmitter markers in striatal projection neurons in the rat.

Journal article J Comp Neurol · January 15, 1994 Featured Publication The principle neuronal output of the neostriatum comes from medium spiny neurons that project from the caudate/putamen to the globus pallidus and substantia nigra. Although current evidence generally indicates that gamma-aminobutyric acid (GABA) is the pri ... Full text Link to item Cite

Categories of cortical structure.

Journal article Prog Brain Res · 1994 Featured Publication Full text Link to item Cite

The functional anatomy of limbic status epilepticus in the rat. II. The effects of focal deactivation.

Journal article J Neurosci · November 1993 Featured Publication Limbic status epilepticus was induced in awake, unrestrained rats by electrically stimulating the anterior piriform cortex or the basal amygdaloid nucleus for about 40 min. As described in the preceding article (White and Price, 1993), one of four stable f ... Full text Link to item Cite

The functional anatomy of limbic status epilepticus in the rat. I. Patterns of 14C-2-deoxyglucose uptake and Fos immunocytochemistry.

Journal article J Neurosci · November 1993 Featured Publication Limbic status epilepticus was induced in awake, unrestrained rats by electrically stimulating the olfactory cortex or the basal amygdaloid nucleus for about 40 min. One of four stable forms of status was induced, which were distinguished on the basis of th ... Full text Link to item Cite

Differential metabolic and electrical activity in the somatic sensory cortex of juvenile and adult rats.

Journal article J Neurosci · October 1993 Featured Publication We have examined relative levels of metabolic and electrical activity across layer IV in the primary somatic sensory cortex (S1) of the rat in relation to regions of differential postnatal cortical growth. Each of several indices used--mitochondrial enzyme ... Full text Link to item Cite

Distributions of choline acetyltransferase and acetylcholinesterase activities in the retinal layers of the red-tailed hawk and road runner.

Journal article J Comp Neurol · January 1, 1991 Featured Publication The activities of choline acetyltransferase and acetylcholinesterase were assayed in submicrogram samples from layers of red-tailed hawk and road runner retina. Both enzyme activities were concentrated in and near the inner plexiform layer. Within the inne ... Full text Link to item Cite

Distributions of choline acetyltransferase and acetylcholinesterase activities in the retinal layers of pigeon red and yellow fields.

Journal article Vision Res · 1990 Featured Publication The activities of choline acetyltransferase and acetylcholinesterase were assayed in submicrogram samples from layers of pigeon retina. Red and yellow fields were sampled separately to investigate quantitatively the relationship between these enzymes of ac ... Full text Link to item Cite