***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The deep layers of the superior colliculus ( SC ) integrate multisensory inputs and initiate an orienting response toward the source of stimulation ( target ) . Multisensory enhancement , which occurs in the deep SC , is the augmentation of a neural response to sensory input of one modality by input of another modality . Multisensory enhancement appears to underlie the behavioral observation that an animal is more likely to orient toward weak stimuli if a stimulus of one modality is paired with a stimulus of another modality . Yet not all deep SC neurons are multisensory . Those that are exhibit the property of inverse effectiveness : combinations of weaker unimodal responses produce larger amounts of enhancement . We show that these neurophysiological findings support the hypothesis that deep SC neurons use their sensory inputs to compute the probability that a target is present . We model multimodal sensory inputs to the deep SC as r and om variables and cast the computation function in terms of Bayes ' rule . Our analysis suggests that multisensory deep SC neurons are those that combine unimodal inputs that would be more uncertain by themselves . It also suggests that inverse effectiveness results because the increase in target probability due to the integration of multisensory inputs is larger when the unimodal responses are weaker Background : Aging is characterized by a decline in the postural control performance , which is based on a coherent and stable coupling between sensory information and motor action . Therefore , changes in postural control in elderlies can be related to changes in this coupling . In addition , it has been observed that physical activity seems to improve postural control performance in elderlies . These improvements can be due to changes in the coupling between sensory information and motor action related to postural control . Objective : The purpose of this study was to verify the coupling between visual information and body sway in active and sedentary elderlies . Methods : Sixteen sedentary elderlies ( SE ) , 16 active elderlies ( AE ) and 16 young adults ( YA ) were asked to st and upright inside a moving room in two experimental conditions : ( 1 ) discrete movement and ( 2 ) continuous movement of the room . Results : In the continuous condition , the results showed that the coupling between the movement of the room and body sway was stronger and more stable for SE and AE compared to YA . In the discrete condition , SE showed larger body displacement compared to AE and YA . Conclusions : SE have more difficulty to discriminate and to integrate sensory information than AE and YA indicating that physical activity may improve sensory integration Age-related deficits in visual selective attention suggest that the efficiency of inhibitory processes is particularly affected by aging . To investigate whether processing inefficiencies observed in visual attention are similar in auditory attention and when shifting attention across modalities , we conducted an fMRI study with healthy young and older adults using a task that required sustained auditory and visual selective attention and cross-modal attention shifts . Older adults in this study performed as well as the younger adults , but showed age-related differences in BOLD responses . The most striking of these differences were bilateral frontal and parietal regions of significantly increased activation in older adults during both focused and shifting attention . Our data suggest that this increased activation did not reflect new recruitment , but reliance on brain regions typically used by younger adults when task dem and s are greater . Older adults ' activation patterns suggested that even during focused attention conditions they were " shifting " attention to stimuli in the unattended modality . Increased activation during processing of both task-relevant and task-irrelevant information implies age-related loss of processing selectivity . These patterns may reflect both task-specific compensatory neural recruitment and degradation of sensory inhibition Transitions between disability states  in older people occur frequently . This study investigated predictors of disability transitions in the oldest old and was performed in the Leiden 85-plus study , a population -based prospect i ve cohort study among 597 participants aged 85 years . At baseline ( age 85 years ) , data on sociodemographic characteristics and chronic diseases were obtained .  Disabilities in basic activities of daily living ( BADL ) and instrumental activities of daily living ( IADL ) were measured annually for 5 years with the Groningen Activities Restriction Scale ( GARS ) . Mortality data were obtained . A statistical multi-state model was used to assess the risks of transitions between no disabilities , IADL disability , BADL disability , and death .  At baseline , 299 participants ( 50.0 % ) were disabled in IADL only , and 155 participants ( 26.0 % ) were disabled in both BADL and IADL .  During 5-year follow-up , 374 participants ( 62.6 % ) made > 1 transition between disability states , mostly deterioration in disability . Males had a lower risk of deterioration [ hazard ratio ( HR ) , 0.75 ( 95 % CI , 0.58–0.96 ) ] compared to females . No gender differences were observed for improvement [ HR , 0.64 ( 95 % CI , 0.37–1.11 ) ] . Participants with depressive symptoms were less likely to improve [ HR , 0.50 ( 95 % CI , 0.28–0.87 ) ] . Participants with depressive symptoms [ HR , 1.46 ( 95 % CI , 1.12–1.91 ) ] , > 1 chronic disease [ HR , 1.60 ( 95 % CI , 1.27–2.01 ) ] , and with cognitive impairment [ HR , 1.60 ( 95 % CI , 1.20–2.13 ) ] had the highest risk of deteriorating . Disability is a dynamic process in the oldest old . Deterioration is more common than improvement . Older men are less likely to deteriorate than women . The presence of depressive symptoms , chronic disease , and cognitive impairment predicts deterioration Background The maintenance of upright equilibrium is essentially a sensorimotor integration task . The central nervous system ( CNS ) has to generate appropriate and complex motor responses based on the selective and rapid integration of sensory information from multiple sources . Since each sensory system has its own coordinate framework , specific time delay and reliability , sensory conflicts may arise and represent situations in which the CNS has to recalibrate the weight attributed to each particular sensory input . The resolution of sensory conflicts may represent a particular challenge for older adults given the age-related decline in the integrity of many postural regulating systems , including musculoskeletal and sensory systems , as well as neural processing and conduction of information . The effects of aging and adaptation ( by repeated exposures ) on the capability of the CNS to select pertinent sensory information and resolve sensory conflicts were thus investigated with virtual reality ( VR ) in the present study . Methods Healthy young and older adults maintained quiet stance while immersed in a virtual environment ( VE ) for 1 hour during which transient visual and /or surface perturbations were r and omly presented . Visual perturbations were induced by sudden pitch or roll plane tilts of the VE viewed through a helmet-mounted display , and combined with or without surface perturbations presented in a direction that was either identical or opposite to the visual perturbations . Results Results showed a profound influence of aging on postural adjustments measured by electromyographic ( EMG ) responses and displacements of the center of pressure ( COP ) and body 's center of mass ( COM ) in the recovery of upright stance , especially in the presence of sensory conflicts . Older adults relied more on vision as compared to young adults . Aging affects the interaction of the somatosensory and visual systems on the control of equilibrium during st and ing and the ability of CNS to resolve sensory conflicts . However , even with a one-hour immersion in VE and exposure to sensory conflicts , it is possible for the CNS to recalibrate and adapt to the changes , while improving balance capability in older adults . Conclusion Preventive and rehabilitation programs targeting postural control in older adults should take into account the possible impairment of sensory organization or sensorimotor integration and include VE training under conditions of sensory conflicts Stimuli are processed concurrently and across multiple sensory inputs . Here we directly compared the effect of multisensory integration ( MSI ) on reaction time across three paired sensory inputs in eighteen young ( M=19.17 years ) and eighteen old ( M=76.44 years ) individuals . Participants were determined to be non-demented and without any medical or psychiatric conditions that would affect their performance . Participants responded to r and omly presented unisensory ( auditory , visual , somatosensory ) stimuli and three paired sensory inputs consisting of auditory-somatosensory ( AS ) auditory-visual ( AV ) and visual-somatosensory ( VS ) stimuli . Results revealed that reaction time ( RT ) to all multisensory pairings was significantly faster than those elicited to the constituent unisensory conditions across age groups ; findings that could not be accounted for by simple probability summation . Both young and old participants responded the fastest to multisensory pairings containing somatosensory input . Compared to younger adults , older adults demonstrated a significantly greater RT benefit when processing concurrent VS information . In terms of co-activation , older adults demonstrated a significant increase in the magnitude of visual-somatosensory co-activation ( i.e. , multisensory integration ) , while younger adults demonstrated a significant increase in the magnitude of auditory-visual and auditory-somatosensory co-activation . This study provides first evidence in support of the facilitative effect of pairing somatosensory with visual stimuli in older adults Normal vision overrides perturbed vestibular information for the optimization of performance during goal directed locomotion , suggesting down-regulation of vestibular gain . However , it is not known if the responses to vestibular perturbation are accentuated when vision is impaired . Furthermore , both visual and vestibular systems deteriorate with age . It is not clear , however , how age-related decline in these sensory systems influences visual – vestibular interaction . Therefore , the dual purpose of the present study was to investigate the effects of aging and blurring vision , that simulated the consequences of cataracts , on visual – vestibular interaction . Young and healthy elderly walked to a target located straight ahead with either normal or blurring vision . On r and omly selected trials vestibular system perturbation was achieved by applying transmastoidal galvanic vestibular stimulation ( GVS ) . Two different galvanic stimulation intensities were used to provide insight into scaling effect of vestibular perturbation on locomotor performance and how age and vision influences this scaling effect . Maximum path deviation , frontal trunk tilt and postural coordination in the mediolateral direction were evaluated . The magnitude of the path deviation and the trunk tilt response were scaled to the magnitude of the vestibular perturbation in older adults independent of the visual condition . Older participants demonstrated increased coupling of the head and trunk segments irrespective of visual and vestibular perturbations . The results suggest that when visual information was available , the vestibular input reweighting was less effective in older individuals , as shown by the scaled responses to the GVS intensities and the inability to converge efficiently towards the target We investigated whether ageing affects crossmodal selective attention ( the ability to focus on a relevant sensory modality and ignore an irrelevant modality ) and the spatial constraints on such selective processing . Three groups of 24 participants were tested : Young ( 19 - 25 years ) , Young-Old ( 65 - 72 years ) and Old-Old ( 76 - 92 years ) . The participants had to judge the elevation of vibrotactile targets ( upper/index finger and lower/thumb ) , presented r and omly to either h and while ignoring concurrent visual distractors . In a second task , the role of the target and distractor modalities was reversed . Crossmodal selective attention was assessed by comparing performance in the presence versus absence of distractors . Spatial constraints on selective attention were also investigated by comparing the effect of distractors presented on the same versus opposite side as the target . When attending to touch , the addition of visual distractors had a significantly larger effect on error rates in both of the older groups as compared to the Young group . This indicates that ageing has a detrimental effect on crossmodal selective attention . In all three age groups , performance was impaired when the target and distractor were presented at incongruent as compared to congruent elevations in both tasks . This congruency effect was modulated by the relative spatial location of the target and distractor in certain conditions for the Young and the Young-Old group . That is , participants in the two younger age groups found it harder to attend selectively to targets in one modality , when distractor stimuli came from the same side rather than from the opposite side . However , no significant spatial modulation was found in the Old-Old group . This suggests that ageing may also compromise spatial aspects of crossmodal selective attention In this study we examined the effects of intermittent short- duration Galvanic Vestibular Stimulation ( GVS ) during a multisensory perturbation of posture in young and elderly adults . Twelve young ( 24.91±6.44 years ) and eleven elderly ( 74.8±6.42 years ) participants stood upright under two task conditions : ( a ) quiet st and ing and ( b ) st and ing while receiving pseudo-r and omly presented bipolar 2 s GVS pulses . In both conditions , sensory reweighting was evoked by visual surround oscillations ( 20 cm , 0.3 Hz ) and Achilles tendon vibration ( 3 mm , 80 Hz ) , concurrently delivered during the middle 60 s of st and ing . Intermittent GVS decreased the excessive postural sway induced by the concurrent visual and proprioceptive perturbation in young but not in elderly participants . It is suggested that GVS increases sensory reliance on the vestibular system while elderly adults are less able to exploit this stimulation in order to reduce the destabilizing effect of the multisensory perturbation on their posture Regular training programs are a concrete means to prevent and /or reduce functional decline due to aging . A multisensory training approach seems to obtain better results in the elderly with regard to both balance and quality of life .  Forty subjects ( age 65±10 years , height 165±4 cm , weight 73.0±4.6 kg ) were r and omized into two groups ( GrHu and GrCl ) . Participants in the GrHu group received 3 months of balance and postural training , 3 sessions per week , with the use of 
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OA failing to weigh sensory information properly , has not been described in previous review s. Anatomical changes ( i.e. , reduction of brain volume and differences of brain areas ’ recruitment ) and information processing changes ( i.e. , general cognitive slowing , inverse effectiveness , larger time window of integration , deficits in attentional control and increased noise at baseline ) can only partly explain the differences between OA and YA regarding MSI .