Classical conditioned responses to absent tones

BACKGROUND: Recent evidence for a tight coupling of sensorimotor processes in trained musicians led to the question of whether this coupling extends to preattentively mediated reflexes; particularly, whether a classically conditioned response in one of the domains (auditory) is generalized to another (tactile/motor) on the basis of a prior association in a second-order Pavlovian paradigm. An eyeblink conditioning procedure was performed in 17 pianists, serving as a model for overlearned audiomotor integration, and 14 non-musicians. Results: During the training session, subjects were conditioned to respond to auditory stimuli (piano tones). During a subsequent testing session, when subjects performed keystrokes on a silent piano, pianists showed significantly higher blink rates than non-musicians. CONCLUSION: These findings suggest a tight coupling of the auditory and motor domains in musicians, pointing towards training-dependent mechanisms of strong cross-modal sensorimotor associations even on sub-cognitive processing levels

Ontogeny of ATP hydrolysis and isoform expression of the Plasma Membrane Ca2+-ATPase in mouse brain

© 2009 Marcos et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Stimulus-dependent spatial patterns of response in SI cortex

BACKGROUND: Recently we reported that vibrotactile flutter stimulation of a skin locus at different amplitudes evokes an optical response confined to the same local region of the primary somatosensory cortex (SI), where its overall magnitude varies proportionally to the flutter amplitude. In this report, we characterize the impact of the flutter amplitude on the spatial patterns of activity evoked within the responding SI region. RESULTS: In order to characterize the spatial pattern of activity within the responding SI region, images of the flutter-evoked SI optical response were segmented and analyzed with spatial frequency analysis. The analysis revealed that: (1) dominant spatial frequencies in the optical intrinsic signal emerge within the responding SI region within 3–5 sec of stimulus onset; (2) the stimulus-evoked activity is spatially organized in a form of several roughly parallel, anterior-posteriorly extended waves, spaced 0.4–0.5 mm apart; (3) the waves themselves exhibit spatial periodicities along their long axis; and (4) depending on the flutter stimulus amplitude, these periodicities can range from fine 0.15 mm "ripples" at 50 μm amplitude to well-developed 0.5 mm fluctuations at the amplitude of 400 μm. CONCLUSION: The observed spatiointensive fractionation on a sub-macrocolumnar scale of the SI response to skin stimulation might be the product of local competitive interactions within the stimulus-activated SI region and may be a feature that could yield novel insights into the functional interactions that take place in SI cortex

Vestibular effects on cerebral blood flow

Humans demonstrate a number of unique adaptations that allow the maintenance of blood pressure and brain blood flow after transition to the upright position. While these adaptations maintain heart-level mean arterial pressure similar to supine values, the brain remains ~30 cm above the heart, resulting in a ~25% decrease in perfusion pressure. To maintain brain blood flow, the cerebral vessels must dilate in response to this change in position. While several physiological systems are involved in adaptation to the upright posture, including cerebral autoregulation, the unique role that the vestibular system plays in helping to maintain brain blood flow is just beginning to be elucidated. Since the vestibular system not only assists in balance control and locomotion but provides direct information about the body's position relative to gravity, it can, within milliseconds, detect a change in posture. Thus it is possible that a vestibular signal indicating upright could assist in this necessary cerebral vasodilation. In this work we demonstrate a direct effect of vestibular activation on cerebral blood flow regulation. By stimulating the otoliths, the organs that sense gravity, using sinusoidal translation or tilt in the dark at five frequencies, we found that cerebral blood flow was modulated according to the frequency of stimulation. In addition, changes in cerebral blood flow were in opposition to blood pressure changes, likely indicating a direct effect of otolith activation on cerebral blood flow regulation. We anticipate these findings may lead to new treatment modalities for cerebral hypoperfusion under a variety of circumstances. For example, with aging there is well documented vestibular loss that might contribute to a general age-associated reduction in global cerebral blood flow. Similarly, patients with orthostatic intolerance could have vestibular impairment that exacerbates cerebral hypoperfusion when upright

Select cognitive deficits in Vasoactive Intestinal Peptide deficient mice

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Fingersomatotopy in area 3b: an fMRI-study

BACKGROUND: The primary sensory cortex (S1) in the postcentral gyrus is comprised of four areas that each contain a body map, where the representation of the hand is located with the thumb most laterally, anteriorly and inferiorly and the little finger most medially, posteriorly and superiorly. Previous studies on somatotopy using functional MRI have either used low field strength, have included a small number of subjects or failed to attribute activations to any area within S1. In the present study we included twenty subjects, who were investigated at 3 Tesla (T). We focused specifically on Brodmann area 3b, which neurons have discrete receptive fields with a potentially more clearcut somatotopic organisation. The spatial distribution for all fingers' peak activation was determined and group as well as individual analysis was performed. RESULTS: Activation maps from 18 subjects were of adequate quality; in 17 subjects activations were present for all fingers and these data were further analysed. In the group analysis the thumb was located most laterally, anteriorly and inferiorly with the other fingers sequentially positioned more medially, posteriorly and superiorly. At the individual level this somatotopic relationship was present for the thumb and little finger, with a higher variability for the fingers in between. The Euclidian distance between the first and fifth finger was 17.2 mm, between the first and second finger 10.6 mm and between the remaining fingers on average 6.3 mm. CONCLUSION: Results from the group analysis, that is both the location of the fingers and the Euclidian distances, are well comparable to results from previous studies using a wide range of modalities. On the subject level the spatial localisation of the fingers showed a less stringent somatotopic order so that the location of a finger in a single subject cannot be predicted from the group result