Do blind people develop superior abilities in auditory perception to compensate for their lack of vision? They are known to be better than sighted people at orientating themselves by sound, but it is ...not clear whether this enhanced awareness extends to other auditory domains, such as listening to music or to voices. Here we show that blind people are better than sighted controls at judging the direction of pitch change between sounds, even when the speed of change is ten times faster than that perceived by the controls--but only if they became blind at an early age. The younger the onset of blindness, the better is the performance, which is in line with cerebral plasticity being optimal during the early years.
The next steps followed the classical TBM approach: nonlinear registration, computation of the Jacobian matrices J =down triangleuTdown triangleu from the deformation fields u and statistical ...analysis of the deformation tensors S =square rootJTJ. In 3, we presented a new fluid registration algorithm that allows large deformations and penalizes anisotropic changes (i.e., ones with a preferred direction locally) in a way that is consistent with the subsequent statistical analysis.
Odor Localization and Sniffing Frasnelli, Johannes; Charbonneau, Genevieve; Collignon, Olivier ...
Chemical senses,
02/2009, Letnik:
34, Številka:
2
Journal Article
Recenzirano
Odprti dostop
For humans, the localization of an odorant seems only possible if the odorant also stimulates the trigeminal nerve. There is, however, some evidence that active sniffing may affect this ability and ...facilitate the localization of pure odorants. Therefore, we tested the ability of 40 subjects to localize a pure odorant and a mixed olfactory/trigeminal stimulus under 2 stimulation conditions: either odors were blown into the subjects’ nostrils (passive) or subjects had to actively sniff the odors (active). Subjects could only reliably localize the mixed olfactory/trigeminal stimulus. However, we found a significant interaction between stimulation condition and nature of the odorant. So, the mixed olfactory/trigeminal stimulus was more localizable in the passive condition, whereas the pure odorant was better localized in the active condition. Interestingly, subjects had more correct answers after stimulation of the right nostril than of the left nostril (where subjects performed significantly below chance when stimulated with the pure odorant), suggesting possible laterality effects. These results suggest that active sniffing may affect our ability to localize odors. Other than mixed olfactory trigeminal stimuli, pure odorants are, however, not localizable even in active condition of sniffing.
Sixteen consecutive patients with a partially or completely preserved temporal crescent (PTC) in right or left eye were identified by Goldmann kinetic perimetry. PTC etiologies were stroke, birth ...injury, trauma, aneurysm, and migraine. PTC eludes detection by automated static perimetry of the central visual field, but its ascertainment with Goldmann perimetry usually implies contralateral occipital lobe ischemia sparing a small portion of anterior primary visual cortex.
Blind individuals manifest remarkable abilities in navigating through space despite their lack of vision. They have previously been shown to perform normally or even supra-normally in tasks involving ...spatial hearing in near space 1, 2, a region that, however, can be calibrated with sensory-motor feedback. Here we show that blind individuals not only properly map auditory space beyond their peri-personal environment but also demonstrate supra-normal performance when subtle acoustic cues for target location and distance must be used to carry out the task. Moreover, it is generally postulated that such abilities rest in part on cross-modal cortical reorganizations 3–6, particularly in the immature brain, where important synaptogenesis is still possible 7–9. Nonetheless, we show for the first time that even late-onset blind subjects develop above-normal spatial abilities, suggesting that significant compensation can occur in the adult.
The inferior colliculus (IC) is an obligatory relay for the ascending and descending auditory pathways. Cells in this brainstem structure not only analyze auditory stimuli but they also play a major ...role in multi-modal integration of auditory and visual information. The aim of the present study was to determine whether cells in the central nucleus of the inferior colliculus (CNIC) of normal rats respond selectively to complex auditory signals, such as species-specific vocalizations, and compare their responses to those obtained in neonatal bilateral enucleated (P2-P3) adult rats. Extra-cellular recordings were carried out in anesthetized normal and enucleated rats using auditory stimuli (pure tones, broadband noise and vocalizations) presented in free field in a semi-anechoic chamber. The results indicate that most cells in the CNIC of both groups respond selectively to species-specific vocalizations better than to the same but inverted sounds. No significant differences were found between the normal and enucleated rat groups in their responses to broadband noise and pure tones.
Pain is an unpleasant and intrusive sensation, warning of actual or potential tissue damage. Over the last fifteen years, functional cerebral imaging research has demonstrated the involvement of many ...cerebral structures in the experience of pain.
Intimately linked to the notion of suffering, the affective dimension of pain relies on neurophysiological systems partly distinct anatomically from those involved more specifically in its sensory dimension. Some pathways convey nociceptive information to the somatosensory cortex and the insula, contributing to the sensory aspects of pain (e.g.: sensory intensity), and secondarily, to its affective dimension. Other pathways project directly to the anterior cingulate cortex, the insula, the amygdala and to the prefrontal cortices, which are structures involved in the affective dimension of pain (unpleasantness of pain and regulation of autonomic and behavioral responses). Interestingly, these latter regions are an integral part of the cerebral emotional networks.
This close anatomical relationship between pain and emotions circuits could explain the powerful emotional impact of pain as well as the reciprocal modulatory effect of emotions on pain observed in clinical and experimental studies. More specifically, this modulatory effect might reflect interactions between emotional and nociceptive systems in the prefrontal and cingulate cortices, ventral striatum, amygdala and hippocampal regions. Taken together, these observations further attest to the emotional nature of pain experience.
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