Search results for "Sensory system"
showing 10 items of 1266 documents
Music and Emotions in the Brain: Familiarity Matters
2011
The importance of music in our daily life has given rise to an increased number of studies addressing the brain regions involved in its appreciation. Some of these studies controlled only for the familiarity of the stimuli, while others relied on pleasantness ratings, and others still on musical preferences. With a listening test and a functional magnetic resonance imaging (fMRI) experiment, we wished to clarify the role of familiarity in the brain correlates of music appreciation by controlling, in the same study, for both familiarity and musical preferences. First, we conducted a listening test, in which participants rated the familiarity and liking of song excerpts from the pop/rock repe…
Sparse Distributed Representation of Odors in a Large-scale Olfactory Bulb Circuit
2013
In the olfactory bulb, lateral inhibition mediated by granule cells has been suggested to modulate the timing of mitral cell firing, thereby shaping the representation of input odorants. Current experimental techniques, however, do not enable a clear study of how the mitral-granule cell network sculpts odor inputs to represent odor information spatially and temporally. To address this critical step in the neural basis of odor recognition, we built a biophysical network model of mitral and granule cells, corresponding to 1/100th of the real system in the rat, and used direct experimental imaging data of glomeruli activated by various odors. The model allows the systematic investigation and g…
Space counts! Brain correlates of spatial and numerical representations in synaesthesia
2018
Over-learned semantic representations, such as numbers, are strongly associated with space in normal cognition, and in the phenomenon called number-space synaesthesia. In number-space synaesthesia, numbers are linked to spatial locations in an idiosyncratic way. Synaesthetes report numbers as belonging to a specific location, or feelings that a specific location is the right location for that number. What does really differentiate synaesthetes from non-synaesthetes with respect to their number-space representation? Here we present a number-space synaesthete, MkM, whose number-space representation dramatically differs from that of controls. We examined the impact of spatial distance with res…
Cellular Mechanisms of Subplate-Driven and Cholinergic Input-Dependent Network Activity in the Neonatal Rat Somatosensory Cortex
2008
Early coordinated network activity promotes the development of cortical structures. Although these early activity patterns have been recently characterized with respect to their developmental, spatial and dynamic properties, the cellular mechanisms by which specific neuronal populations trigger coordinated activity in the neonatal cerebral cortex are still poorly understood. Here we characterize the cellular and molecular processes leading to generation of network activity during early postnatal development. We show that the somatosensory cortex of newborn rats expresses cholinergic-driven calcium transients which are synchronized within the deeply located subplate. Correspondingly, endogen…
Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders
2015
The visual mismatch negativity (vMMN) response is an event-related potential (ERP) component, which is automatically elicited by events that violate predictions based on prior events. VMMN experiments use visual stimulus repetition to induce predictions, and vMMN is obtained by subtracting the response to rare unpredicted stimuli from those to frequent stimuli. One increasingly popular interpretation of the mismatch response postulates that vMMN, similar to its auditory counterpart (aMMN), represents a prediction error response generated by cortical mechanisms forming probabilistic representations of sensory signals. Here we discuss the physiological and theoretical basis of vMMN and review…
Auditory cortical and hippocampal-system mismatch responses to duration deviants in urethane-anesthetized rats.
2013
Any change in the invariant aspects of the auditory environment is of potential importance. The human brain preattentively or automatically detects such changes. The mismatch negativity (MMN) of event-related potentials (ERPs) reflects this initial stage of auditory change detection. The origin of MMN is held to be cortical. The hippocampus is associated with a later generated P3a of ERPs reflecting involuntarily attention switches towards auditory changes that are high in magnitude. The evidence for this cortico-hippocampal dichotomy is scarce, however. To shed further light on this issue, auditory cortical and hippocampal-system (CA1, dentate gyrus, subiculum) local-field potentials were …
Trait impulsivity associated with altered resting-state functional connectivity within the somatomotor network
2020
Knowledge of brain mechanisms underlying self-regulation can provide valuable insights into how people regulate their thoughts, behaviors, and emotional states, and what happens when such regulation fails. Self-regulation is supported by coordinated interactions of brain systems. Hence, behavioral dysregulation, and its expression as impulsivity, can be usefully characterized using functional connectivity methodologies applied to resting brain networks. The current study tested whether individual differences in trait impulsivity are reflected in the functional architecture within and between resting-state brain networks. Thirty healthy individuals completed a self-report measure of trait im…
Do Grading Gray Stimuli Help to Encode Letter Position?
2021
Numerous experiments in the past decades recurrently showed that a transposed-letter pseudoword (e.g., JUGDE) is much more wordlike than a replacement-letter control (e.g., JUPTE). Critically, there is an ongoing debate as to whether this effect arises at a perceptual level (e.g., perceptual uncertainty at assigning letter position of an array of visual objects) or at an abstract language-specific level (e.g., via a level of “open bigrams” between the letter and word levels). Here, we designed an experiment to test the limits of perceptual accounts of letter position coding. The stimuli in a lexical decision task were presented either with a homogeneous letter intensity or with a graded gra…
Cortical plasticity associated with Braille learning
1998
Blind subjects who learn to read Braille must acquire the ability to extract spatial information from subtle tactile stimuli. In order to accomplish this, neuroplastic changes appear to take place. During Braille learning, the sensorimotor cortical area devoted to the representation of the reading finger enlarges. This enlargement follows a two-step process that can be demonstrated with transcranial magnetic stimulation mapping and suggests initial unmasking of existing connections and eventual establishment of more stable structural changes. In addition, Braille learning appears to be associated with the recruitment of parts of the occipital, formerly `visual', cortex (V1 and V2) for tacti…
A Note on the Horizontal-Vertical Illusion - A Reply to Wade (2014).
2016
Like many others before him, Nicholas Wade, in a recent publication in this journal, did not provide the correct title of Adolf Fick's dissertation, approved by the University at Marburg, Germany, in 1851, and Wade also wrongly attributed now famous illusion figures, meant to illustrate the so-called horizontal-vertical illusion (the +, the L, and the inverted T), to this author. After having corrected these errors, I briefly relate Fick’s work to modern work in the field and note that it has been widely neglected.