Neuroscience and Neurobiology Commons^™

To See Or Not To See: Prestimulus Α Phase Predicts Visual Awareness, Kyle E. Mathewson, Gabriele Gratton, Monica Fabiani, Diane M. Beck, Tony Ro

Publications and Research

We often fail to see something that at other times is readily detectable. Because the visual stimulus itself is unchanged, this variability in conscious awareness is likely related to changes in the brain. Here we show that the phase of EEG α rhythm measured over posterior brain regions can reliably predict both subsequent visual detection and stimulus-elicited cortical activation levels in a metacontrast masking paradigm. When a visual target presentation coincides with the trough of an α wave, cortical activation is suppressed as early as 100 ms after stimulus onset, and observers are less likely to detect the target. Thus, …

Neural Substrates Of Sound–Touch Synesthesia After A Thalamic Lesion, Michael S. Beauchamp, Tony Ro

Publications and Research

Neural plasticity induced by stroke can mediate positive outcomes, such as recovery of function, but can also result in the formation of abnormal connections with negative consequences for perception and cognition. In three experiments using blood-oxygen level dependent (BOLD) functional magnetic resonance imaging, we examined the neural substrates of acquired auditory-tactile synesthesia, in which certain sounds can produce an intense somatosensory tingling sensation in a patient with a thalamic lesion. Compared with nine normal controls, the first experiment showed that the patient had a threefold greater BOLD response to sounds in the parietal operculum, the location of secondary somatosensory cortex. …

Maternal Cocaine Administration In Mice Alters Dna Methylation And Gene Expression In Hippocampal Neurons Of Neonatal And Prepubertal Offspring, Svetlana I. Novikova, Fang He, Jie Bai, Nicholas J. Cutrufello, Michael S. Lidow, Ashiwel S. Undieh

Publications and Research

Previous studies documented significant behavioral changes in the offspring of cocaine-exposed mothers. We now explore the hypothesis that maternal cocaine exposure could alter the fetal epigenetic machinery sufficiently to cause lasting neurochemical and functional changes in the offspring. Pregnant CD1 mice were administered either saline or 20 mg/kg cocaine twice daily on gestational days 8–19. Male pups from each of ten litters of the cocaine and control groups were analyzed at 3 (P3) or 30 (P30) days postnatum. Global DNA methylation, methylated DNA immunoprecipitation followed by CGI2 microarray profiling and bisulfite sequencing, as well as quantitative real-time RT-PCR gene expression …

Using A Paradigm Shift To Teach Neurobiology And The Nature Of Science—A C.R.E.A.T.E.-Based Approach, Sally G. Hoskins

Publications and Research

Decades ago, classic experiments established the phenomenon of “neural induction” (Spemann and Mangold, 1924; Holtfreter, 1933). It appeared clear that amphibian ectoderm was pre-programmed to form epidermis, and that the neural phenotype was induced by a chemical signal from mesoderm. The “ectoderm makes skin, unless induced to make nervous system” model appeared in many textbooks. This interpretation, however, was not simply incorrect but 180 degrees out of alignment with the actual situation. As subsequently demonstrated, the default state of amphibian ectoderm is neuronal, and the expression of the epidermal phenotype requires cell signaling (Hemmati-Brivanlou and Melton, 1992; 1994; 1997). In …

Diverse Antidepressants Increase Cdp-Diacylglycerol Production And Phosphatidylinositide Resynthesis In Depression-Relevant Regions Of The Rat Brain, Kimberly R. Tyeryar, Ashiwel S. Undieh, Habiba Ou Vongtau

Publications and Research

Background: Major depression is a serious mood disorder affecting millions of adults and children worldwide. While the etiopathology of depression remains obscure, antidepressant medications increase synaptic levels of monoamine neurotransmitters in brain regions associated with the disease. Monoamine transmitters activate multiple signaling cascades some of which have been investigated as potential mediators of depression or antidepressant drug action. However, the diacylglycerol arm of phosphoinositide signaling cascades has not been systematically investigated, even though downstream targets of this cascade have been implicated in depression. With the ultimate goal of uncovering the primary postsynaptic actions that may initiate cellular antidepressive signaling, we …

Human Mst But Not Mt Responds To Tactile Stimulation, Michael S. Beauchamp, Nafi E. Yasar, Neel Kishan, Tony Ro

Publications and Research

Previous reports of tactile responses in human visual area MT/V5 have used complex stimuli, such as a brush stroking the arm. These complex moving stimuli are likely to induce imagery of visual motion, which is known to be a powerful activator of MT. The area described as “MT” in previous reports consists of at least two distinct cortical areas, MT and MST. Using functional magnetic resonance imaging, we separately localized human MT and MST and measured their response to vibrotactile stimuli unlikely to induce imagery of visual motion. Strong vibrotactile responses were observed in MST but not in MT. Vibrotactile …

Sensory Deprivation Alters Aggrecan And Perineuronal Net Expression In The Mouse Barrel Cortex, Paulette A. Mccrae, Mary M. Rocco, Gail Kelly, Joshua C. Brumberg, Russell T. Matthews

Publications and Research

An important role for the neural extracellular matrix in modulating cortical activity-dependent synaptic plasticity has been established by a number of recent studies. However, identification of the critical molecular components of the neural matrix that mediate these processes is far from complete. Of particular interest is the perineuronal net (PN), an extracellular matrix component found surrounding the cell body and proximal neurites of a subset of neurons. Because of the apposition of thePNto synapses and expression of this structure coincident with the close of the critical period, it has been hypothesized that nets could play uniquely important roles in synapse …

Maintenance Of Visual Stability In The Human Posterior Parietal Cortex, Erik Chang, Tony Ro

Publications and Research

Visual stability refers to our stable visuospatial perceptions despite the unstable visual input caused by saccades. Functional neuroimaging results, studies on patients with posterior parietal cortex (PPC) lesions, and single-unit recordings in the lateral intraparietal sulcus of primates indirectly suggest that the PPC might be a potential locus of visual stability through its involvement with spatial remapping. Here we directly explored the role of the PPC in visual stability by applying transcranial magnetic stimulation (TMS) while participants performed a perisaccadic displacement detection task. We show that TMS over the PPC but not a frontal control site alters sensitivity to displacement …

Strokes Of Existence: The Connection Of All Things, Mari Gorman

Graduate Student Publications and Research

Acted or real—and all life is real whether one is acting or not—the common denominator and consistent, ubiquitous reality of life and all behavior is that it manifests in the form of relationships on all scales. But what is a relationship? Until now, the answer to this question has not been sufficiently known. As a result of many years of empirical research that began with the aim of discovering what is going on in a gifted actor when s/he is playing a character that can be observed and experienced as a living, intuitive being, and based on the knowledge that …

Daily Rhythm Of Cerebral Blood Flow Velocity, Deirdre A. Conroy, Arthur J. Spielman, Rebecca Q. Scott

Publications and Research

Background: CBFV (cerebral blood flow velocity) is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1) CBFV changes are due to sleep-associated processes or 2) time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day.

Methods: Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored …

Visual Enhancing Of Tactile Perception In The Posterior Parietal Cortex, Tony Ro, Ruth Wallace, Judith Hagedorn, Alessandro Farnè, Elizabeth Pienkos

Publications and Research

The visual modality typically dominates over our other senses. Here we show that after inducing an extreme conflict in the left hand between vision of touch (present) and the feeling of touch (absent), sensitivity to touch increases for several minutes after the conflict. Transcranial magnetic stimulation of the posterior parietal cortex after this conflict not only eliminated the enduring visual enhancement of touch, but also impaired normal tactile perception. This latter finding demonstrates a direct role of the parietal lobe in modulating tactile perception as a result of the conflict between these senses. These results provide evidence for visual-to-tactile perceptual …

D1 Dopamine Receptor Regulation Of Microtubule-Associated Protein-2 Phosphorylation In Developing Cerebral Cortical Neurons, Z.-M. Song, Ashiwel S. Undieh, Y.-Y. Fang, L. Zhang, S. Dracheva, S.C. Sealfon, M.S. Lidow

Publications and Research

This study addresses the hypothesis that the previously described capacity of D1 dopamine receptors (D1Rs) to regulate dendritic growth in developing cortical neurons may involve alterations in the phosphorylation state of microtubuleassociated protein-2 (MAP2). The changes in phosphorylation of this protein are known to affect its ability to stabilize the dendritic cytoskeleton. The study involved two systems: primary cultures of mouse cortical neurons grown in the presence of the D1R agonists, SKF82958 or A77636, and the cortex of neonatal transgenic mice overexpressing the D1A subtype of D1R. In both models, a decrease in dendritic extension corresponded with an elevation in …

Ipsilesional Biases In Saccades But Not Perception After Lesions Of The Human Inferior Parietal Lobule, Tony Ro, Chris Rorden, Jon Driver, Robert Rafal

Publications and Research

We examined the effects of chronic unilateral lesions to either the inferior parietal lobe, or to the dorsolateral prefrontal cortex including the frontal eye fields (FEFs), upon human visual perception and saccades in temporal-order-judgment (TOJ) tasks. Two visual events were presented on each trial, one in each hemifield at various stimulus onset asynchronies (SOAs). In the saccade task, patients moved their eyes to whichever stimulus attracted gaze first. In the perceptual-manual task, they pressed a button to indicate which stimulus was perceived first. Frontal patients showed appropriate TOJs for visual targets in both tasks. Parietal patients showed appropriate TOJs in …

Ionic Mechanisms Underlying Repetitive High-Frequency Burst Firing In Supragranular Cortical Neurons, Joshua C. Brumberg, Lionel G. Nowak, David A. Mccormick

Publications and Research

Neocortical neurons in awake, behaving animals can generate high-frequency (.300 Hz) bursts of action potentials, either in single bursts or in a repetitive manner. Intracellular recordings of layer II/III pyramidal neurons were obtained from adult ferret visual cortical slices maintained in vitro to investigate the ionic mechanisms by which a subgroup of these cells generates repetitive, high-frequency burst discharges, a pattern referred to as “chattering.” The generation of each but the first action potential in a burst was dependent on the critical interplay between the afterhyperpolarizations (AHPs) and afterdepolarizations (ADPs) that followed each action potential. The spike after depolarization and …

Mechanism Of Triazolo-Benzodiazepine And Benzodiazepine Action In Anxiety And Depression: Behavioral Studies With Concomitant In Vivo Ca1 Hippocampal Norepinephrine And Serotonin Release Detection In The Behaving Animal, Patricia A. Broderick, Omotola Hope, Pierrot Jeannot

Publications and Research

1. Real time, in vivo microvoltammetric studies were performed, using miniature carbon-based sensors, to concurrently detect norepinephrine (NE) release and serotonin (5-HT) release, in 2 separate electrochemical signals, within CA₁ region of hippocampus in the freely moving and behaving, male, Sprague Dawley laboratory rat.

2. Concurrently, four parameters of open-field Behavior I.E. Ambulations, Rearing, Fine Movements and Central Ambulatory behavior (a measure of anxiety reduction behavior), were assayed by infrared photobeam detection.

3. Time course studies showed that the mechanism of action of the triazolobenzodiazepine (TBZD), adinazolam, (Deracyn®) is dramatically different from that of the classical benzodiazepine (BZD), diazepam …

Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal

Publications and Research

The contributions of the superior prefrontal cortex (SPFC) and the superior parietal lobule (SPL) in generating voluntary endogenous and reflexive visually guided saccades were investigated using transcranial magnetic stimulation (TMS). Subjects made choice saccades to the left or right visual field in response to a central arrowhead (endogenous go signal) or a peripheral asterisk (exogenous go signal) that were presented along with a single TMS pulse at varying temporal intervals. TMS over the SPFC increased latencies for saccades made in response to an endogenous go signal toward the contralateral hemifield. No effects were observed when the go signal was exogenous …