Neural Basis of the Sound-Symbolic Crossmodal Correspondence Between Auditory Pseudowords and Visual Shapes.

Sound symbolism refers to the association between the sounds of words and their meanings, often studied using the crossmodal correspondence between auditory pseudowords, e.g., 'takete' or 'maluma', and pointed or rounded visual shapes, respectively.

Mnemonic strategy training increases neocortical activation in healthy older adults and patients with mild cognitive impairment.

Learning and memory deficits characterize the diagnosis of amnestic mild cognitive impairment (aMCI), which is widely viewed as a clinical precursor to Alzheimer's type dementia. There is a growing interest in non-pharmacologic interventions, such as mnemonic strategies, for improving learning and memory in patients with aMCI as well as for maintaining functioning in healthy older adults. Using an ecologically relevant object-location association paradigm, we conducted a randomized, controlled, single-blind study in which healthy older adults and patients with aMCI were randomized to either mnemonic strategy training or a control group that was matched for stimulus exposure.

Neural basis of the crossmodal correspondence between auditory pitch and visuospatial elevation.

Crossmodal correspondences refer to associations between otherwise unrelated stimulus features in different sensory modalities. For example, high and low auditory pitches are associated with high and low visuospatial elevation, respectively. The neural mechanisms underlying crossmodal correspondences are currently unknown.

Alterations of resting-state fMRI measurements in individuals with cervical dystonia.

Cervical dystonia (CD) is a neurological disorder with typical symptoms of involuntary and abnormal movements and postures of the head. CD-associated alterations of functional brain networks have not been well characterized. Previous studies of CD using resting-state functional MRI (rfMRI) are limited in two aspects: (i) the analyses were not directly focused on the functional brain network related to head movement and (ii) rfMRI measurements other than functional connectivity (FC) were not investigated.

Engagement of the left extrastriate body area during body-part metaphor comprehension.

Grounded cognition explanations of metaphor comprehension predict activation of sensorimotor cortices relevant to the metaphor's source domain. We tested this prediction for body-part metaphors using functional magnetic resonance imaging while participants heard sentences containing metaphorical or literal references to body parts, and comparable control sentences. Localizer scans identified body-part-specific motor, somatosensory and visual cortical regions.

A Functional Magnetic Resonance Imaging Study of Head Movements in Cervical Dystonia.

Cervical dystonia (CD) is a neurological disorder characterized by abnormal movements and postures of the head. The brain regions responsible for these abnormal movements are not well understood, because most imaging techniques for assessing regional brain activity cannot be used when the head is moving. Recently, we mapped brain activation in healthy individuals using functional magnetic resonance imaging during isometric head rotation, when muscle contractions occur without actual head movements.

Neural Substrates for Head Movements in Humans: A Functional Magnetic Resonance Imaging Study.

The neural systems controlling head movements are not well delineated in humans. It is not clear whether the ipsilateral or contralateral primary motor cortex is involved in turning the head right or left. Furthermore, the exact location of the neck motor area in the somatotopic organization of the motor homunculus is still debated and evidence for contributions from other brain regions in humans is scarce.

Spatial imagery in haptic shape perception.

We have proposed that haptic activation of the shape-selective lateral occipital complex (LOC) reflects a model of multisensory object representation in which the role of visual imagery is modulated by object familiarity. Supporting this, a previous functional magnetic resonance imaging (fMRI) study from our laboratory used inter-task correlations of blood oxygenation level-dependent (BOLD) signal magnitude and effective connectivity (EC) patterns based on the BOLD signals to show that the neural processes underlying visual object imagery (objIMG) are more similar to those mediating haptic perception of familiar (fHS) than unfamiliar (uHS) shapes. Here we employed fMRI to test a further hypothesis derived from our model, that spatial imagery (spIMG) would evoke activation and effective connectivity patterns more related to uHS than fHS.

Neural changes with tactile learning reflect decision-level reweighting of perceptual readout.

Despite considerable work, the neural basis of perceptual learning remains uncertain. For visual learning, although some studies suggested that changes in early sensory representations are responsible, other studies point to decision-level reweighting of perceptual readout. These competing possibilities have not been examined in other sensory systems, investigating which could help resolve the issue.

Mnemonic strategy training partially restores hippocampal activity in patients with mild cognitive impairment.

Learning and memory deficits typify patients with mild cognitive impairment (MCI) and are generally attributed to medial temporal lobe dysfunction. Although the hippocampus is perhaps the most commonly studied neuroanatomical structure in these patients, there have been few attempts to identify rehabilitative interventions that facilitate its functioning. Here, we present results from a randomized, controlled, single-blind study in which patients with MCI and healthy elderly controls (HEC) were randomized to either three sessions of mnemonic strategy training (MS) or a matched-exposure control group (XP).

Metaphorically feeling: comprehending textural metaphors activates somatosensory cortex.

Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging (fMRI) we show that texture-selective somatosensory cortex in the parietal operculum is activated when processing sentences containing textural metaphors, compared to literal sentences matched for meaning.

Dual pathways for haptic and visual perception of spatial and texture information.

Segregation of information flow along a dorsally directed pathway for processing object location and a ventrally directed pathway for processing object identity is well established in the visual and auditory systems, but is less clear in the somatosensory system. We hypothesized that segregation of location vs. identity information in touch would be evident if texture is the relevant property for stimulus identity, given the salience of texture for touch.

Where did I put that? Patients with amnestic mild cognitive impairment demonstrate widespread reductions in activity during the encoding of ecologically relevant object-location associations.

Remembering the location of objects in the environment is both important in everyday life and difficult for patients with amnestic mild cognitive impairment (aMCI), a clinical precursor to Alzheimer's disease. To test the hypothesis that memory impairment for object location in aMCI reflects hippocampal dysfunction, we used an event-related functional magnetic resonance imaging paradigm to compare patients with aMCI and healthy elderly controls (HEC) as they encoded 90 ecologically relevant object-location associations (OLAs). Two additional OLAs, repeated a total of 45 times, served as control stimuli.

Art for reward's sake: visual art recruits the ventral striatum.

A recent study showed that people evaluate products more positively when they are physically associated with art images than similar non-art images. Neuroimaging studies of visual art have investigated artistic style and esthetic preference but not brain responses attributable specifically to the artistic status of images. Here we tested the hypothesis that the artistic status of images engages reward circuitry, using event-related functional magnetic resonance imaging (fMRI) during viewing of art and non-art images matched for content.

Activation and effective connectivity changes following explicit-memory training for face-name pairs in patients with mild cognitive impairment: a pilot study.

Background: Mild cognitive impairment (MCI) is often a precursor to Alzheimer disease. Little research has examined the efficacy of cognitive rehabilitation in patients with MCI, and the relevant neural mechanisms have not been explored. The authors previously showed the behavioral efficacy of cognitive rehabilitation using mnemonic strategies for face-name associations in patients with MCI.

Cross-modal plasticity of tactile perception in blindness.

This review focusses on cross-modal plasticity resulting from visual deprivation. This is viewed against the background of task-specific visual cortical recruitment that is routine during tactile tasks in the sighted and that may depend in part on visual imagery. Superior tactile perceptual performance in the blind may be practice-related, although there are unresolved questions regarding the effects of Braille-reading experience and the age of onset of blindness.

Object familiarity modulates the relationship between visual object imagery and haptic shape perception.

Although visual cortical engagement in haptic shape perception is well established, its relationship with visual imagery remains controversial. We addressed this using functional magnetic resonance imaging during separate visual object imagery and haptic shape perception tasks. Two experiments were conducted.

Object familiarity modulates effective connectivity during haptic shape perception.

In the preceding paper (Lacey, S., Flueckiger, P., Stilla, R.

Neural processing underlying tactile microspatial discrimination in the blind: a functional magnetic resonance imaging study.

Although blindness alters neocortical processing of non-visual tasks, previous studies do not allow clear conclusions about purely perceptual tasks. We used functional magnetic resonance imaging (fMRI) to examine the neural processing underlying tactile microspatial discrimination in the blind. Activity during the tactile microspatial task was contrasted against that during a tactile temporal discrimination task.

Effective connectivity during haptic perception: a study using Granger causality analysis of functional magnetic resonance imaging data.

Although it is accepted that visual cortical areas are recruited during touch, it remains uncertain whether this depends on top-down inputs mediating visual imagery or engagement of modality-independent representations by bottom-up somatosensory inputs. Here we addressed this by examining effective connectivity in humans during haptic perception of shape and texture with the right hand. Multivariate Granger causality analysis of functional magnetic resonance imaging (fMRI) data was conducted on a network of regions that were shape- or texture-selective.

Posteromedial parietal cortical activity and inputs predict tactile spatial acuity.

We used functional magnetic resonance imaging (fMRI) to investigate the neural circuitry underlying tactile spatial acuity at the human finger pad. Stimuli were linear, three-dot arrays, applied to the immobilized right index finger pad using a computer-controlled, MRI-compatible, pneumatic stimulator. Activity specific for spatial processing was isolated by contrasting discrimination of left-right offsets of the central dot in the array with discrimination of the duration of stimulation by an array without a spatial offset.

Selective visuo-haptic processing of shape and texture.

Previous functional neuroimaging studies have described shape-selectivity for haptic stimuli in many cerebral cortical regions, of which some are also visually shape-selective. However, the literature is equivocal on the existence of haptic or visuo-haptic texture-selectivity. We report here on a human functional magnetic resonance imaging (fMRI) study in which shape and texture perception were contrasted using haptic stimuli presented to the right hand, and visual stimuli presented centrally.

Activity and effective connectivity of parietal and occipital cortical regions during haptic shape perception.

It is now widely accepted that visual cortical areas are active during normal tactile perception, but the underlying mechanisms are still not clear. The goal of the present study was to use functional magnetic resonance imaging (fMRI) to investigate the activity and effective connectivity of parietal and occipital cortical areas during haptic shape perception, with a view to potentially clarifying the role of top-down and bottom-up inputs into visual areas. Subjects underwent fMRI scanning while engaging in discrimination of haptic shape or texture, and in separate runs, visual shape or texture.

Short-term visual deprivation alters neural processing of tactile form.

Blindness is known to alter the responsiveness of visual cortex. Recently, reversible visual deprivation by blindfolding has been shown to affect non-visual abilities as well as visual cortical function. Here we investigated the effect of 2 h of blindfolding on cerebral cortical activation patterns during tactile form perception, using functional magnetic resonance imaging.

Tactile discrimination of grating orientation: fMRI activation patterns.

Grating orientation discrimination is employed widely to test tactile spatial acuity. We used functional magnetic resonance imaging (fMRI) to investigate the neural circuitry underlying performance of this task. Two studies were carried out.