Search results for "Functional Laterality"
showing 10 items of 274 documents
Right-handers and left-handers have different representations of their own hand
1998
The visual control of our own hand when dealing with an object and the observation of interactions between other people's hand and objects can be involved in the construction of internal representations of our own hand, as well as in hand recognition processes. Therefore, a different effect on handedness recognition is expected when subjects are presented with hands holding objects with either a congruent or an incongruent type of grip. Such an experiment was carried out on right-handed and left-handed subjects. We expected that the different degree of lateralisation in motor activities observed in the two populations [J. Herron, Neuropsychology of left- handedness, Academic Press, New York…
How functional coupling between the auditory cortex and the amygdala induces musical emotion: a single case study.
2013
Music is a sound structure of remarkable acoustical and temporal complexity. Although it cannot denote specific meaning, it is one of the most potent and universal stimuli for inducing mood. How the auditory and limbic systems interact, and whether this interaction is lateralized when feeling emotions related to music, remains unclear. We studied the functional correlation between the auditory cortex (AC) and amygdala (AMY) through intracerebral recordings from both hemispheres in a single patient while she listened attentively to musical excerpts, which we compared to passive listening of a sequence of pure tones. While the left primary and secondary auditory cortices (PAC and SAC) showed …
The Prefrontal Cortex and Neurological Impairments of Active Thought
2018
This article reviews the effects of lesions to the frontal cortex on the ability to carry out active thought, namely, to reason, think flexibly, produce strategies, and formulate and realize plans. We discuss how and why relevant neuropsychological studies should be carried out. The relationships between active thought and both intelligence and language are considered. The following basic processes necessary for effective active thought are reviewed: concentration, set switching, inhibiting potentiated responses, and monitoring and checking. Different forms of active thought are then addressed: abstraction, deduction, reasoning in well-structured and ill-structured problem spaces, novel st…
Spatial-temporal interactions in the human brain
2009
The review summarises current evidence on the cognitive mechanisms for the integration of spatial and temporal representations and of common brain structures to process the where and when of stimuli. Psychophysical experiments document the presence of spatially localised distortions of sub-second time intervals and suggest that visual events are timed by neural mechanisms that are spatially selective. On the other hand, experiments with supra-second intervals suggest that time could be represented on a mental time-line ordered from left-to-right, similar to what is reported for other ordered quantities, such as numbers. Neuroimaging and neuropsychological findings point towards the posterio…
The neural basis of sublexical speech and corresponding nonspeech processing: a combined EEG-MEG study.
2014
Abstract We addressed the neural organization of speech versus nonspeech sound processing by investigating preattentive cortical auditory processing of changes in five features of a consonant–vowel syllable (consonant, vowel, sound duration, frequency, and intensity) and their acoustically matched nonspeech counterparts in a simultaneous EEG–MEG recording of mismatch negativity (MMN/MMNm). Overall, speech–sound processing was enhanced compared to nonspeech sound processing. This effect was strongest for changes which affect word meaning (consonant, vowel, and vowel duration) in the left and for the vowel identity change in the right hemisphere also. Furthermore, in the right hemisphere, spe…
Modulation of excitatory and inhibitory circuits for visual awareness in the human right parietal cortex.
2005
The balance of specific patterns of excitation and inhibition in critical regions of both hemispheres could be relevant in orienting attention over the extrapersonal space. In the present study a group of normal subjects had to detect small rectangular stimuli presented briefly on a computer screen in three different conditions: unilateral presentation either to left or right visual periphery or bilateral simultaneous presentation. Paired transcranial magnetic stimulation (TMS), was applied over the right parietal cortex 150 ms after the presentation of the visual stimuli with different inter-stimulus intervals (ISIs: 1, 3,5 and 10 ms). When paired TMS was applied 150 ms, but not 100 ms, af…
Effects of escitalopram on the regulation of brain-derived neurotrophic factor and nerve growth factor protein levels in a rat model of chronic stres…
2009
Escitalopram (ES-CIT) is a widely used, highly specific antidepressant. Until now there has been very little evidence on how this drug under pathological conditions affects an important feature within the pathophysiology of stress-related disorders such as depression: the endogenous neurotrophins. By using a well-characterized rat model in which chronic stress induces depressive-like behavior, the levels of neurotrophins brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were determined in representative brain regions and serum using a highly sensitive improved fluorometric two-site ELISA system. There was a significant increase of BDNF in the left and right cortices aft…
Effect of claustrum stimulation on neurons of the contralateral medial oculomotor area, in the cat
1990
In chloralose-anaesthetized cats, the extracellular spontaneous unitary activity was recorded from 157 neurons, located in the medial oculomotor area. 98 units were identified as projecting onto the superior colliculus. Electrical stimulations of the contralateral claustrum provoked, on 13 of these cells, an excitatory effect, lasting 10-35 ms and appearing with a latency of 20-50 ms. Full length section of the corpus callosum totally abolished the contralateral claustrum effect. The results suggest that in the cat, the claustrum may have a role in the bilateral control of the visuo-motor performance.
Recognising a hand by grasp.
2000
The present study aimed to demonstrate that motor representations are used to recognise biological stimuli. In three experiments subjects were required to judge laterality of hands and forearms presented by pictures. The postures of the hands were those assumed when holding a small, medium and large sphere. In experiment 1, the sphere held in hand was presented, whereas in experiment 2 it was absent. In experiment 3, the same images, showing holding-a-sphere hands, as in experiment 1 were presented, but without forearm. In all experiments one finger of each hand could be absent. In experiment 1 recognition time was longer for those hand postures for which the corresponding grasping motor ac…
Immunfluorescence study of neuropeptides in identified neurons of the rat auditory superior olivary complex.
1999
The present study was conducted to investigate the distribution and immunohistochemical characteristics of ascending and descending projection neurons of the rat superior olivary complex (SOC), a group of interrelated brainstem nuclei. Ascending neurons were identified by injection of cholera toxin B subunit (CTB) into the central nucleus of the inferior colliculus (IC), descending neurons were labeled by application of Fluoro-Gold (FG) into the scala tympani of the cochlea, ipsilaterally to the IC injection. In accordance with the literature, we observed neurons innervating the IC located in the lateral superior olivary nucleus (LSO) and dorsal periolivary groups (DPO) on both sides, in th…