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Neuroscience and Neurobiology

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Articles 241 - 258 of 258

Full-Text Articles in Neurosciences

Comparison Of Affective Analgesia And Conditioned Place Preference Following Cholinergic Activation Of, Elena Schifirnet Jan 2010

Comparison Of Affective Analgesia And Conditioned Place Preference Following Cholinergic Activation Of, Elena Schifirnet

Wayne State University Dissertations

Activation of the dopaminergic mesolimbic reward circuitry that originates in the ventral tegmental area (VTA) is postulated to preferentially suppress affective reactions to noxious stimuli (affective analgesia, AA). VTA dopamine neurons are activated via cholinergic inputs, and we have observed that microinjections of the acetylcholine agonist carbachol suppressed vocalizations of rats that occur following administration of brief (1 sec) tail-shocks (vocalization afterdischarges = VAD). VADs are a validated rodent model of pain affect. In addition, the capacity of carbachol to support reinforcement appears to be regionally dependent within VTA. Ikemoto and Wise (2002) reported that carbachol was self-administered in the …

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The Brain In Its Body: Motor Control And Sensing In A Biomechanical Context, Hillel J. Chiel Oct 2009

The Brain In Its Body: Motor Control And Sensing In A Biomechanical Context, Hillel J. Chiel

Faculty Scholarship

Although it is widely recognized that adaptive behavior emerges from the ongoing interactions among the nervous system, the body, and the environment, it has only become possible in recent years to experimentally study and to simulate these interacting systems. We briefly review work on molluscan feeding, maintenance of postural control in cats and humans, simulations of locomotion in lamprey, insect, cat and salamander, and active vibrissal sensing in rats to illustrate the insights that can be derived from studies of neural control and sensing within a biomechanical context. These studies illustrate that control may be shared between the nervous system …

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To See Or Not To See: Prestimulus Α Phase Predicts Visual Awareness, Kyle E. Mathewson, Gabriele Gratton, Monica Fabiani, Diane M. Beck, Tony Ro Mar 2009

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, …

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Neural Substrates Of Sound–Touch Synesthesia After A Thalamic Lesion, Michael S. Beauchamp, Tony Ro Dec 2008

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. …

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Blunted Cystine–Glutamate Antiporter Function In The Nucleus Accumbens Promotes Cocaine-Induced Drug Seeking, Kristen S. Kau, Aric Madayag, John R. Mantsch, Mark D. Grier, Omer Abdulhameed, David A. Baker Aug 2008

Blunted Cystine–Glutamate Antiporter Function In The Nucleus Accumbens Promotes Cocaine-Induced Drug Seeking, Kristen S. Kau, Aric Madayag, John R. Mantsch, Mark D. Grier, Omer Abdulhameed, David A. Baker

Biomedical Sciences Faculty Research and Publications

Repeated cocaine alters glutamate neurotransmission, in part, by reducing cystine–glutamate exchange via system xc−, which maintains glutamate levels and receptor stimulation in the extrasynaptic compartment. In the present study, we undertook two approaches to determine the significance of plasticity involving system xc−. First, we examined whether the cysteine prodrug N-acetylcysteine attenuates cocaine-primed reinstatement by targeting system xc−. Rats were trained to self-administer cocaine (1 mg/kg/200 μl, i.v.) under extended access conditions (6 h/day). After extinction training, cocaine (10 mg/kg, i.p.) primed reinstatement was assessed in rats pretreated with N-acetylcysteine (0–60 mg/kg, i.p.) in the …

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Human Mst But Not Mt Responds To Tactile Stimulation, Michael S. Beauchamp, Nafi E. Yasar, Neel Kishan, Tony Ro Aug 2007

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 …

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Neuromechanics Of Multifunctionality During Rejection In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel Oct 2006

Neuromechanics Of Multifunctionality During Rejection In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel

Faculty Scholarship

How are the same muscles and neurons used to generate qualitatively different behaviors? We studied this question by analyzing the biomechanical and neural mechanisms of rejection responses in the marine mollusk Aplysia californica and compared these mechanisms with those used to generate swallowing responses (Ye et al., 2006). During rejection, the central grasper of the feeding structure closes to push inedible food out of the buccal cavity. This contrasts with swallowing, during which the grasper is open as it moves toward the jaws (protracts). We examined how the shape change of the grasper during rejection mechanically reconfigured the surrounding musculature. …

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Neuromechanics Of Coordination During Swallowing In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel Feb 2006

Neuromechanics Of Coordination During Swallowing In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel

Faculty Scholarship

Bernstein (1967) hypothesized that preparation of the periphery was crucial for correct responses to motor output. To test this hypothesis in a behaving animal, we examined the roles of two identified motor neurons, B7 and B8, which contribute to feeding behavior in the marine mollusk Aplysia californica. Neuron B7 innervates a hinge muscle and has no overt behavioral effect during smaller-amplitude (type A) swallows, because the hinge muscle is too short to exert force. Neuron B8 activates a muscle (I4) that acts solely to grasp material during type A swallows. During larger-amplitude (type B) swallows, the behavioral actions of both …

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A New Interpretation Of The Drug Levodopa In The Treatment Of Parkinson's Disease, Joanne T. Vannah Jun 2005

A New Interpretation Of The Drug Levodopa In The Treatment Of Parkinson's Disease, Joanne T. Vannah

Graduate Masters Theses

An argument for levodopa induced dyskinesias (LID) as an expression of long term potentiation (LTP) in the striatum is presented. Normally, with an intact nigrostriatal dopamine (DA) input, long term depression (LTD) is expressed in the striatum, however, striatal LTD is lost following DA denervation and chronic levodopa treatment. It is possible that these changes in synaptic efficacy are due to two other chemical modulators, achetylcholine (ACh) and glutamate, which in turn leads to the induction of striatal LTP. ACh and glutamate may produce these changes in motor behavior by affecting the striosomal pathway in addition to their effect on …

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Visual Enhancing Of Tactile Perception In The Posterior Parietal Cortex, Tony Ro, Ruth Wallace, Judith Hagedorn, Alessandro Farnè, Elizabeth Pienkos Jan 2004

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 …

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Ipsilesional Biases In Saccades But Not Perception After Lesions Of The Human Inferior Parietal Lobule, Tony Ro, Chris Rorden, Jon Driver, Robert Rafal Oct 2001

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 …

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Neuromotor And Cognitive Development In Children With Cerebral Palsy In Relation To Neural Plasticity, Vaniecea Pollard May 2001

Neuromotor And Cognitive Development In Children With Cerebral Palsy In Relation To Neural Plasticity, Vaniecea Pollard

McCabe Thesis Collection

Infants with neurological disabilities, such as cerebral palsy (CP) and Down syndrome (DS), show severe delays in motor and cognitive development relative to chronological age. Involvement of neural plasticity as a treatment of such neurological disorders is increasingly being seen. Previous studies have found that interventions involving sensory linked motor performance have been critical in facilitating motor improvement. The purpose of this study was to compare self-initiated mobility in children with CP and DS. Three infants, ages 8, 9, and 22 months, with diagnoses of no CP, DS, and CP respectively, participated in the study. The infants were videotaped in …

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Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal Jul 1997

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 …

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An Identified Histaminergic Neuron Can Modulate The Outputs Of Buccal-Cerebral Interneurons In Aplysia Via Presynaptic Inhibition, Hillel J. Chiel Jan 1988

An Identified Histaminergic Neuron Can Modulate The Outputs Of Buccal-Cerebral Interneurons In Aplysia Via Presynaptic Inhibition, Hillel J. Chiel

Faculty Scholarship

We have identified 2 buccal-cerebral interneurons (BCIs), B17 and B18, that appear to be involved in the coordination of feeding behavior in Aplysia. The BCIs have their cell bodies in the buccal ganglion, but send axons to the cerebral ganglion via the cerebral-buccal connectives. The BCIs appear to make monosynaptic connections with neurons in the cerebral ganglion that modulate extrinsic muscles involved in feeding behavior. B17 and B18 are activated antiphasically during a motor program induced by stimulating the esophageal nerve and appear to 'read out' different phases of the buccal program to different cells in the cerebral ganglion. B17 …

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Activity Of An Identified Histaminergic Neuron, And Its Possible Role In Arousal Of Feeding Behavior In Semi-Intact Aplysia, Hillel J. Chiel Jan 1986

Activity Of An Identified Histaminergic Neuron, And Its Possible Role In Arousal Of Feeding Behavior In Semi-Intact Aplysia, Hillel J. Chiel

Faculty Scholarship

The possible functions of histaminergic neuron C2 were studied in an isolated head preparation from which it was possible to obtain intracellular recordings while the buccal mass exhibited feeding-like responses. Application of food to the lips of the isolated head preparation elicited rhythmic buccal movements that appeared to be ingestion responses, since they moved seaweed into the buccal cavity and towards the esophagus, and their frequency and regularity was similar to the ingestion responses studied in a group of intact animals. The ingestion responses of the buccal mass consisted of 2 main phases of movement of the radula from a …

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Sensory Function And Gating Of Histaminergic Neuron C2 In Aplysia, Hillel J. Chiel Jan 1986

Sensory Function And Gating Of Histaminergic Neuron C2 In Aplysia, Hillel J. Chiel

Faculty Scholarship

This paper explores the possible sensory function of the identified histaminergic neuron C2. Mechanical stimulation of a narrow region around the mouth of the animal (perioral zone) elicits brief depolarizing potentials in C2. Extracellular recordings from the peripheral axons of C2 indicate that the depolarizing potentials are due to action potentials that are conveyed from the periphery but do not invade the cell body, since they fail at a region with a low safety factor within the cerebral ganglion. These blocked axonal spikes (A- spikes) function as if they were excitatory synaptic inputs to C2, since the synaptic output of …

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An Identified Histaminergic Neuron Modulates Feeding Motor Circuitry In Aplysia, Hillel J. Chiel Jan 1986

An Identified Histaminergic Neuron Modulates Feeding Motor Circuitry In Aplysia, Hillel J. Chiel

Faculty Scholarship

An identified histaminergic neuron, C2, in the marine mollusk Aplysia is a complex mechanoafferent which appears to contribute to the maintenance of food arousal by means of its synaptic connections to the metacerebral cell (MCC). Because C2 also has extensive synaptic outputs to neurons other than the MCC, we studied its possible motor functions. We identified several synaptic followers of C2 and found that some were excitatory motor neurons for extrinsic muscles of the buccal mass, while others were modulatory motor neurons that inhibited contractions. In addition, we found that these neurons and other synaptic followers of C2 received powerful …

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Cerebral Anoxia And Its Residuals: Pt. Iii. The Structural Changes, Cyril B. Courville Oct 1947

Cerebral Anoxia And Its Residuals: Pt. Iii. The Structural Changes, Cyril B. Courville

Medical Arts and Sciences: A Scientific Journal of the College of Medical Evangelists

No abstract provided.

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