Oxford Eprints
(1.101 recursos)
Oxford E-prints is a cross-disciplinary digital archive for research articles written by Oxford University authors. The repository has been developed as part of the SHERPA (Securing a Hybrid Environment for Research Preservation and Access) project and is running on eprints.org open archives software.
Mostrando recursos 1 - 16 de 16
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Therapeutic Challenges in Work With Childhood Sexual Abuse Survivors: The Contribution of Cognitive Analytic Therapy - Llewelyn, Susan
Cognitive Analytic Therapy (CAT) provides a useful therapeutic structure for addressing the range of difficulties presented by survivors of childhood sexual abuse. The concept of reciprocal roles can be helpful when addressing dysfunctional relationship patterns, especially as shown in therapeutic ruptures. Two case histories are presented that demonstrate the importance of attending to repetitive patterns in relationships in order to avert therapeutic impasse. It is suggested that CAT as a collaborative and time-limited therapy is well placed to facilitate brief treatment from the point of view of both client and therapist.
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Aware or Unaware: Assessment of Cortical Blindness in Four Men and a Monkey - Stoerig, Petra; Zontanou, Aspasia; Cowey, Alan
In four patients and one monkey with unilateral visual field defects caused by retro-geniculate lesions we measured forced-choice localization of square-wave gratings as a function of contrast, and compared results from the patients' absolutely and relatively blind fields. In addition, the patients indicated verbally whether they were aware of the stimuli. We then switched to a signal detection task in which the subjects had to signal a stimulus as in the localization task, by touching it, no matter whether it appeared in the good or bad hemifield, and in addition to signal a blank trial by touching an outlined square...
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Unilateral Lesions of the Cholinergic Basal Forebrain and Fornix in One Hemisphere and Inferior Temporal Cortex in the Opposite Hemisphere Produce Severe Learning Impairments in Rhesus Monkeys - Easton, A.; Ridley, R.M.; Baker, H.F.; Gaffan, D.
It has been proposed that isolation of the inferior temporal cortex and medial temporal lobe from their cholinergic afferents results in a severe anterograde amnesia. To test this hypothesis directly, seven rhesus monkeys received a unilateral immunotoxic lesion of the cholinergic cells of the basal forebrain with an ipsilesional section of the fornix. In a second surgery, inferior temporal cortex was ablated in the opposite hemisphere. All animals were severely impaired at learning visual scenes and object-reward associations. The impairment in learning scenes was correlated with cholinergic cell loss in the basal forebrain, but not with generalized tissue damage. Two...
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Changes of Cortico-striatal Effective Connectivity during Visuomotor Learning - Toni, Ivan; Rowe, James; Stephan, Klaas E.; Passingham, Richard E.
It has been suggested that the cortico-striatal system might play a crucial role in learning behavioural plans of action. We have tested this hypothesis by studying the dynamics of functional coupling among the neural elements of cortico-striatal circuitry. Human cerebral activity was measured with functional magnetic resonance imaging (fMRI) during the learning of an associative visuomotor task. Structural equation modelling of regional fMRI time-series was used to characterize learning-related changes in effective connectivity. We report that learning to associate visual instructions with motor responses significantly altered cortico-striatal functional couplings. Specific learning-related increases of effective connectivity were found in temporo-striatal and...
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Asymmetry of the Uncinate Fasciculus: A Post-mortem Study of Normal Subjects and Patients with Schizophrenia - Highley, J. Robin; Walker, Mary A.; Esiri, Margaret M.; Crow, Timothy J.; Harrison, Paul J.
The uncinate fasciculus interconnects the anterior temporal and inferior frontal lobes. The temporal lobes show a number of anatomical asymmetries, some of which are altered in schizophrenia. This study was performed to assess the size and symmetry of the uncinate fasciculus in normal subjects and in patients with the disorder. The area, fibre density and total fibre number of left and right uncinate fasciculi were estimated using stereological methods in 21 control subjects and 17 schizophrenics. The uncinate fasciculus was found to be asymmetrical in both sexes, being 27% larger and containing 33% more fibres in the right than the...
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Instructed Delay Activity in the Human Prefrontal Cortex is Modulated by Monetary Reward Expectation - Ramnani, N.; Miall, R.C.
Goal-directed actions are executed with greater efficiency when the goals of the actions are rewarded and so the reward expectation must influence systems concerned with action-planning and motor control. However, little is known about how this influence is achieved in primates. Here, we demonstrate in human subjects that manual performance is enhanced when the goals of the visually cued actions are monetary rewards. We also used event-related fMRI in the same subjects to localize neural activity related to action preparation and selection that was influenced by the reward. We found three areas with significant interaction between reward and preparation: the...
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Choreography of Early Thalamocortical Development - Molnár, Zoltán; Higashi, Shuji; López-Bendito, Guillermina
Thalamic axons, which carry most of the information from the sensory environment, are amongst the first projections to reach the cerebral cortex during embryonic development. It has been proposed that the scaffold of early generated cells in the ventral thalamus, internal capsule and preplate play a pivotal role in their deployment through sharp gene expression boundaries. These ideas were recently evaluated in various strains of mutant mice. In Tbr1, Gbx2, Pax6 KO both thalamic and corticofugal projections fail to traverse the striatocortical junction. In both Emx2 and Pax6 KO brains, the misrouted thalamic afferents are accompanied by displacements of the...
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Blockade of GABAB Receptors Alters the Tangential Migration of Cortical Neurons - López-Bendito, Guillermina; Luján, Rafael; Shigemoto, Ryuichi; Ganter, Paul; Paulsen, Ole; Molnár, Zoltán
To better understand the role of neurotransmitter receptors in neuronal differentiation and maturation a detailed knowledge of their identity, location and function in the plasma membrane of specific neuronal populations during development is required. Combining pre-embedding immunocytochemistry with cell tracking in embryonic brain slice cultures we show that virtually all neurons (~98%) migrating through the lower intermediate zone (LIZ) on their way from the medial ganglionic eminence to the cerebral cortex, express GABABR1. Blockade of GABABRs with a specific antagonist, CGP52432, resulted in a concentration-dependent accumulation of these tangentially migrating neurons in the ventricular/sub-ventricular zones (VZ/SVZ) of the cortex and...
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Defining a Left-lateralized Response Specific to Intelligible Speech Using fMRI - Narain, C.; Scott, Sophie K.; Wise, Richard J.S.; Rosen, Stuart; Leff, Alexander; Iversen, S.D.; Matthews, P.M.
Functional imaging studies of language have shown bilateral superior temporal activations in response to 'passive' perception of speech when the baseline condition did not control for the acoustic complexity of speech. Controlling for this complexity demonstrates speech-specific processing lateralized to the left temporal lobe, and our recent positron emission tomography study has emphasized a role for left anterolateral temporal cortex in speech comprehension. This contrasts with the more usual view that relates speech comprehension to left temporal-parietal cortex, the ill-defined area of Wernicke. This study attempted to reconcile these differences, using a more sensitive 3 T functional magnetic resonance imaging...
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Signal-, set- and movement-related activity in the human brain: an event-related fMRI study - Toni, I; Schluter, ND; Josephs, O; Friston, K; Passingham, RE
Electrophysiological studies on monkeys have been able to distinguish sensory and motor signals close in time by pseudo-randomly delaying the cue that instructs the movement from the stimulus that triggers the movement. We have used a similar experimental design in functional magnetic resonance imaging (fMRI), scanning subjects while they performed a visuomotor conditional task with instructed delays. One of four shapes was presented briefly. Two shapes instructed the subjects to flex, the index finger; the other two shapes coded the flexion of the middle finger. The subjects were told to perform the movement after a tone. We have exploited a...
11.
Spatial view cells in the primate hippocampus: allocentric view not head direction or eye position or place - Georges-François, P; Rolls, ET; Robertson, RG
Hippocampal function was analysed by making recordings from hippocampal neurons in monkeys actively walking in the laboratory. 'Spatial view' cells, which respond when the monkey looks at a part of the environment, were analysed. It is shown that these cells code for the allocentric position in space being viewed and not for eye position, head direction or the place where the monkey is located. This representation of space 'out there' would be an appropriate part of a primate memory system involved in memories of where in an environment an object was seen, and more generally in the memory of particular...
12.
The connectional organization of the cortico-thalamic system of the cat - Scannell, JW; Burns, GAPC; Hilgetag, CC; O'Neil, MA; Young, MP
Data on connections between the areas of the cerebral cortex and nuclei of the thalamus are too complicated to analyse with naked intuition. Indeed, the complexity of connection data is one of the major challenges facing neuroanatomy. Recently, systematic methods have been developed and applied to the analysis of the connectivity in the cerebral cortex. These approaches have shed light on the gross organization of the cortical network, have made it possible to test systematically theories of cortical organization, and have guided new electrophysiological studies. This paper extends the approach to investigate the organization of the entire cortico-thalamic network. An...
13.
Dissociation of normal feature analysis and deficient processing of letter-strings in dyslexic adults - Helenius, P; Tarkiainen, A; Cornelissen, P; Hansen, PC; Salmelin, R
Neuroimaging studies have revealed that the functional organization of reading differs between developmentally dyslexic and non-impaired individuals. However, it is not clear how early in the reading process the differences between fluent and dyslexic readers start to emerge. We studied cortical activity of ten dyslexic adults using magnetoencephalography (MEG), as they silently read words or viewed symbol-strings which were clearly visible or degraded with Gaussian noise. This method has previously been used to dissociate between analysis of local features and pre-lexical word processing in fluent adult readers. Signals peaking around 100 ms after stimulus onset and originating in the postero-medial...
14.
The Orbitofrontal Cortex and Reward - Rolls, Edmund T.
The primate orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odors is represented. The orbitofrontal cortex also receives information about the sight of objects and faces from the temporal lobe cortical visual areas, and neurons in it learn and reverse the visual stimulus to which they respond when the association of the visual stimulus with a primary reinforcing stimulus (such as a taste reward) is reversed. However, the orbitofrontal...
15.
The Role of the Dorsolateral Prefrontal Cortex during Sequence Learning is Specific for Spatial Information - Robertson, E.M.; Tormos, J.M.; Maeda, F.; Pascual-Leone, A.
Many studies have implicated the dorsolateral prefrontal cortex in the acquisition of skill, including procedural sequence learning. However, the specific role it performs in sequence learning has remained uncertain. This type of skill has been intensively studied using the serial reaction time task. We used three versions of this task: a standard task where the position of the stimulus cued the response; a non-standard task where the color of the stimulus was related to the correct response; and a combined task where both the color and position simultaneously cued the response. We refer to each of these tasks based upon...
16.
Priming of Motion Direction and Area V5/MT: a Test of Perceptual Memory - Campana, Gianluca; Cowey, Alan; Walsh, Vincent
Presentation of supraliminal or subliminal visual stimuli that can (or cannot) be detected or identified can improve the probability of the same stimulus being detected over a subsequent period of seconds, hours or longer. The locus and nature of this perceptual priming effect was examined, using suprathreshold stimuli, in subjects who received repetitive pulse transcranial magnetic stimulation over the posterior occipital cortex, the extrastriate motion area V5/MT or the right posterior parietal cortex during the intertrial interval of a visual motion direction discrimination task. Perceptual priming observed in a control condition was abolished when area V5/MT was stimulated but was...
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