Static and dynamic postural control: Comparison between community old adults and people with Parkinson's disease.

AIMS: To compare the static and dynamic postural control of people with Parkinson's disease and community old adults. METHODS: Thirty-five people were in the Parkinson's disease group (PDG; 12 women, 62.4 ± 11.0 years, 77.9 ± 15.6 kg, 166.5 ± 11.0 cm, 27.9 ± 3.8 kg/m2 , 1.9 ± 0.5 Hoehn & Yahr) and 32 were in the old adults group (OAG; 13 women, 69.5 ± 6.0 years, 74.2 ± 12.3 kg, 165.0 ± 8.3 cm, 27.2 ± 4.0 kg/m2 ). The static balance was measured on a force platform, three 30-s trials in four conditions: feet side-by-side (FSBS) and semi-tandem stance (ST) positioning, eyes open (EO) and eyes closed (EC). The total sway path length (SPL), sway area (SA), anterior-posterior (APSR) and medial-lateral (MLSR) sway range of the centre of pressure were obtained. Dynamic balance was assessed using the timed-up-and-go test (TUG). For comparison between groups and repeated-measures, a mixed-design ANOVA was carried out and the Mann-Whitney U test to compare TUG between groups. The significance level was set at p ≤ .05. RESULTS: Between groups, PDG presented higher mean values for SPL, APSR and SA in feet side-by-side eyes open compared to the OAG, for SPL in feet side-by-side eyes closed, for SPL and SA in STEO. For repeated-measures, both groups had higher mean values in the EC condition compared to EO and MLSR compared to APSR. No significant difference was found between groups for TUG. CONCLUSION: Balance disorders are found early in people with Parkinson's disease compared to healthy older adults. Thus, Parkinson's disease seems to advance the process of alterations in the postural control system.

Interictal abnormal fMRI activation of visual areas during a motor task cued by visual stimuli in migraine.

OBJECTIVE: To assess changes in blood-oxygen-level-dependent activity after light deprivation compared to regular light exposure in subjects with migraine in the interictal state and in controls. METHODS: Ten subjects with migraine and ten controls participated in two sessions of functional magnetic resonance imaging. In each session, they performed a finger-tapping task with the right hand, cued by visual stimuli. They were scanned before and after 30 minutes of light deprivation or light exposure. In subjects with migraine, functional magnetic resonance imaging was performed interictally. Analysis of variance was made with the factors time (before or after), session (light deprivation or exposure), and group (migraine or control). RESULTS: There were significant "group" effects in a cluster in the bilateral cuneus encompassing the superior border of the calcarine sulcus and extrastriate cortex. There were no significant effects of "time", "session", or interactions between these factors. CONCLUSION: The main result of this study is consistent with aberrant interictal processing of visual information in migraine. Light deprivation did not modulate functional magnetic resonance imaging activity in subjects with or without migraine. OBJETIVO: Avaliar mudanças na atividade cerebral por meio de ressonância magnética funcional após privação luminosa comparada à exposição à luz, em indivíduos com enxaqueca no estado interictal e em controles. MÉTODOS: Dez indivíduos com enxaqueca e dez controles participaram de duas sessões de ressonância magnética funcional. Em cada sessão, realizaram uma tarefa motora com a mão direita guiada por estímulos visuais. Foram colhidas imagens antes e após 30 minutos de privação luminosa ou exposição à luz. Em indivíduos com enxaqueca, a ressonância funcional foi realizada no período interictal. Foi feita a análise de variância com fatores tempo (antes ou depois), sessão (privação ou exposição à luz) e grupo (enxaqueca ou controle). RESULTADOS: Houve efeitos significativos de "grupo" em uma área no cúneo bilateral, incluindo a borda superior do sulco calcarino e o córtex extraestriado. Não houve efeitos significativos de "tempo", "sessão" ou interações entre estes fatores. CONCLUSÃO: O principal resultado deste estudo sugere um processamento interictal anormal das informações visuais em indivíduos com enxaqueca. A privação luminosa não modulou a atividade na ressonância magnética funcional em indivíduos com ou sem enxaqueca.

Interictal abnormal fMRI activation of visual areas during a motor task cued by visual stimuli in migraine / Ativação interictal anormal de áreas visuais por ressonância magnética funcional durante uma tarefa visuo-motora em indivíduos com enxaqueca

ABSTRACT Objective To assess changes in blood-oxygen-level-dependent activity after light deprivation compared to regular light exposure in subjects with migraine in the interictal state and in controls. Methods Ten subjects with migraine and ten controls participated in two sessions of functional magnetic resonance imaging. In each session, they performed a finger-tapping task with the right hand, cued by visual stimuli. They were scanned before and after 30 minutes of light deprivation or light exposure. In subjects with migraine, functional magnetic resonance imaging was performed interictally. Analysis of variance was made with the factors time (before or after), session (light deprivation or exposure), and group (migraine or control). Results There were significant “group” effects in a cluster in the bilateral cuneus encompassing the superior border of the calcarine sulcus and extrastriate cortex. There were no significant effects of “time”, “session”, or interactions between these factors. Conclusion The main result of this study is consistent with aberrant interictal processing of visual information in migraine. Light deprivation did not modulate functional magnetic resonance imaging activity in subjects with or without migraine.

RESUMO Objetivo Avaliar mudanças na atividade cerebral por meio de ressonância magnética funcional após privação luminosa comparada à exposição à luz, em indivíduos com enxaqueca no estado interictal e em controles. Métodos Dez indivíduos com enxaqueca e dez controles participaram de duas sessões de ressonância magnética funcional. Em cada sessão, realizaram uma tarefa motora com a mão direita guiada por estímulos visuais. Foram colhidas imagens antes e após 30 minutos de privação luminosa ou exposição à luz. Em indivíduos com enxaqueca, a ressonância funcional foi realizada no período interictal. Foi feita a análise de variância com fatores tempo (antes ou depois), sessão (privação ou exposição à luz) e grupo (enxaqueca ou controle). Resultados Houve efeitos significativos de “grupo” em uma área no cúneo bilateral, incluindo a borda superior do sulco calcarino e o córtex extraestriado. Não houve efeitos significativos de “tempo”, “sessão” ou interações entre estes fatores. Conclusão O principal resultado deste estudo sugere um processamento interictal anormal das informações visuais em indivíduos com enxaqueca. A privação luminosa não modulou a atividade na ressonância magnética funcional em indivíduos com ou sem enxaqueca.

Conscious distance monitoring and perceived exertion in light-deprived cycling time trial.

UNLABELLED: The monitoring of distance is crucial to calculate the metabolic requirement and the ratings of perceived exertion (RPE) for a given exercise bout. Visual cues provide valuable information for distance estimation, navigation and orientation. The present study investigated if light deprivation may affect the conscious monitoring of distance, RPE and associative thoughts to exercise (ATE) during a 20-km cycling time trial (TT20km). Eleven male, endurance cyclists performed two TT20km in illuminated-control and light-deprived laboratory. They were asked to self-report RPE and ATE when they perceived they had completed each 2km. RESULTS: The light deprivation resulted in elongated perceived distance at each actual 2km, rather than in illuminated-control trial (P<0.05). Although there was no difference in RPE when it was plotted as a function of the perceived distance, RPE was lowered in light-deprived environment when it was plotted as a function of the actual distance (P<0.05). Additionally, ATE was lowered during TT20km in light deprivation (P<0.01); however, pacing and performance were unaffected in light-deprived environment. CONCLUSION: Results suggest that pacing and performance were regulated through a system which was unaffected in light-deprived environment, despite the altered conscious distance monitoring and perceptive responses.

Effects of light deprivation in physical performance and psychophysiological responses to a time-to-exhaustion exercise test.

Studies have shown that there is no effect of light deprivation in closed-loop exercise performance, however less is known about the open-loop exercise performance. Thus, we verified if light deprivation may affect performance and psychophysiological responses to a time-to-exhaustion (TE), constant intensity exercise test. Twelve men performed TE tests (at 80% WPEAK of maximal incremental test) in control and light-deprived condition. Gaseous exchange (VE and VO2), heart rate (HR) and vastus lateralis electromyography (EMG) were continuously assessed, ratings of perceived exertion (RPE) and associative thoughts to exercise (ATE) were obtained every 60s. Responses at absolute time of exercise matched by the shortest time to exhaustion, and responses at exhaustion were compared between conditions (P<0.05). Exhaustion was shortened (5.0 ± 1.6 min vs 6.4 ± 2.4 min) and RPE slope was elevated in light deprivation, when compared to control (P<0.05). Responses of VE, VO2 and RPE were greater at exhaustion in light deprivation TE test than at the equivalent, paired time in control test. However, responses were similar at exhaustion of both TE tests; the exception was the lower EMG when the light was deprived. The light deprivation shortened the exhaustion and increased RPE in TE test, until the attainment of similar maximal psychophysiological responses.

Extracellular signal-regulated kinase (ERK) activity during sleep consolidates cortical plasticity in vivo.

Ocular dominance plasticity (ODP) in the cat primary visual cortex (V1) is induced during waking by monocular deprivation (MD) and consolidated during subsequent sleep. The mechanisms underlying this process are incompletely understood. Extracellular signal-regulated kinase (ERK) is activated in V1 during sleep after MD, but it is unknown whether ERK activation during sleep is necessary for ODP consolidation. We investigated the role of ERK in sleep-dependent ODP consolidation by inhibiting the ERK-activating enzyme MEK in V1 (via U0126) during post-MD sleep. ODP consolidation was then measured with extracellular microelectrode recordings. Western blot analysis was used to confirm the efficacy of U0126 and to examine proteins downstream of ERK. U0126 abolished ODP consolidation and reduced both phosphorylation of eukaryotic initiation factor 4E (eIF4E) and levels of the synaptic marker PSD-95. Furthermore, interfering with ERK-mediated translation by inhibiting MAP kinase-interacting kinase 1 (Mnk1) with CGP57380 mimicked the effects of U0126. These results demonstrate that ODP consolidation requires sleep-dependent activation of the ERK-Mnk1 pathway.

Chronic light deprivation inhibits appetitive associative learning induced by ethanol and its respective c-Fos and pCREB expression.

To address the role of mixed anxiety/mood disorder on appetitive associative learning, we verify whether previous chronic light deprivation changes ethanol-induced conditioned place preference and its respective expression of c-Fos and pCREB, markers of neuronal activity and plasticity. The experimental group was maintained in light deprivation for 24 h for a period of 4 wk. Subsequently, it was adapted to a standard light-dark cycle for 1 wk. As a control, some mice were maintained in standard cycle for a period of 4 wk (Naïve group). Then, all animals were submitted to behavioral tests to assess emotionality: elevated plus maze; open field; and forced swim. After that, they were submitted to ethanol-induced conditioned place preference. Ninety minutes after the place preference test, they were perfused, and their brains processed for c-Fos and pCREB immunohistochemistry. Light deprivation induced anxiety-like trait (elevated plus maze), despair (forced swim), and hyperlocomotion (open field), common features seen in other animal models of depression. Ethanol-induced conditioned place preference was accompanied by increases on c-Fos and pCREB in the hippocampus, prefrontal cortex and striatum. Interestingly, mice previously submitted to light deprivation did not develop either acquisition and/or expression of ethanol-induced conditioned place preference or increases in c-Fos and pCREB. Therefore, chronic light deprivation mimics several behavioral aspects of other animal models of depression. Furthermore, it could be useful to study the neurochemical mechanisms involved in the dual diagnosis. However, given its likely deleterious effects on appetitive associative memory, it should be used with caution to investigate the cognitive aspects related to the dual diagnosis.

Lasting facilitatory effects of neonatal vibrissae removal on the propagation of cortical spreading depression: an electrophysiological study in well-nourished and early-malnourished adult rats.

Early malnutrition interferes with the formation of somatosensory pathways and reduced sensory input activity during brain development can induce morphological and physiological changes in the cerebral cortex, altering their response properties in the long-term. Here, we investigated cortical spreading depression (CSD) propagation in male adult rats submitted to unilateral vibrissae removal, at postnatal days 2-3, and malnourished during lactation followed by nutritional recovery until adulthood (90-120 days), when CSD was recorded. Compared to nutrition-matched non-lesioned controls, CSD-propagation was increased in the hemisphere contralateral to the vibrissae removal. The findings indicate that vibrissae removal during brain development enhances CSD-propagation, and early malnutrition did not modify this effect. Considering that CSD-facilitation persisted until adulthood, we suggest that this effect is permanent. The data might contribute to the understanding of the mechanisms by which sensory input deprivation-induced plasticity modifies cerebral electrophysiological responses in the developing brain.

Early vibrissae removal facilitates cortical spreading depression propagation in the brain of well-nourished and malnourished developing rats.

Reduced sensory input activity during brain development can induce morphological and physiological changes in the cerebral cortex, altering their response properties. Malnutrition delays the formation of somatosensory pathways. Here we used cortical spreading depression as a neurophysiological parameter to investigate electrophysiological changes after vibrissae removal in well-nourished and malnourished rats. Male Wistar rat pups had the right mystacial vibrissae-removed at postnatal days 2-3, and were submitted to spreading depression recording at 30-40 days of life. In both nutritional conditions, spreading depression velocities were increased in the hemisphere contralateral to the vibrissae removal, as compared to age- and nutrition-matched non-lesioned controls, in which no inter-hemispheric differences were found. In contrast to the well-nourished rats, in the vibrissae-removed malnourished animals the spreading depression propagation in the ipsilateral hemisphere decreased as compared to the corresponding hemisphere of the non-lesioned malnourished rats. It is concluded that deprivation of sensory input from whiskers during brain development facilitates spreading depression propagation, and early malnutrition seems to influence this effect. Since the effect persisted until 40 days, it is tempting to suggest that it is permanent, or at least long-lasting. Data might contribute to the understanding of sensory input deprivation-induced plasticity mechanisms underlying cerebral electrophysiological changes in the developing brain.

Additional sensory information reduces body sway of individuals with anterior cruciate ligament injury.

The purpose of this study was to investigate whether the additional sensory information could improve postural control in individuals with unilateral anterior cruciate ligament (ACL) injury. Twenty-eight individuals with unilateral ACL injury (mean age 23.6, 26 males, 2 females) and 28 healthy young control subjects (mean age 22.1 years, 26 males, 2 females) participated in this study. Postural control was evaluated with subjects single-leg standing on a force platform with eyes closed under two sensory conditions: normal sensory information and light touch to a stationary bar (applied force below 1N). Three trials of 30s were performed in each single-leg stance and in each sensory condition. Mean sway amplitude and predominant frequency of center of pressure were calculated for both anterior-posterior and medial-lateral directions. Individuals with ACL injury showed greater mean sway amplitude than healthy control individuals even though the predominant frequency was similar for both groups. Additional sensory information improved postural control performance in individuals with ACL injury and healthy control, with a greater effect observed for the ACL group. Based on these results, we suggest that reduction in postural control performance in individuals with ACL injury would be due to the reduction of sensory information provided by the ACL, but when sensory information is enhanced, postural control performance improves. These results have implications for novel approaches to improve stability in individuals with ACL injury.

Abnormal tactile discrimination and somatosensory plasticity in familial primary hyperhidrosis.

Abnormal sensory processing seems to be involved in hyperhidrosis. To test this hypothesis, we investigated tactile acuity and cortical plastic changes in patients with primary hyperhidrosis (PH) and their asymptomatic relatives. We studied thirteen subjects belonging to two families with PH and thirteen age-matched healthy controls using Johnson-Van Boven-Phillips domes before and after 45min of transient visual deafferentation. Spatial discrimination thresholds (SDTs) were lower in controls than in the familial group (1.08+/-0.25 vs 1.59+/-0.71; p=0.0032). After 45min of light deprivation and blindfolding, SDTs decreased significantly in controls (0.83+/-0.3; p=0.003), but not in patients (1.4+/-0.62; p=0.108). Interestingly, two subjects without clinical complaints of hyperhidrosis had abnormal SDTs behavior after short term visual deprivation. This study demonstrates that sensory processing is abnormal in PH, with a lack of plastic cortical somatosensory changes regardless of clinical condition. These modulatory abnormalities would affect gating processes in the somatosensory cortex which may play a role in maintaining hyperhidrosis.

[Oral language of children with five years of experience using [corrected] cochlear implant]. / Linguagem oral de crianças com cinco anos de uso do implante coclear.

BACKGROUND: Cochlear implant (CI) in children. AIM: 1) to delineate a profile of receptive and expressive verbal language of children who have been using cochlear implant for five years and five years and eleven months; 2) to verify the influence of time of auditory sensorial privation in the receptive and expressive verbal language of these children. METHOD: 19 children users of CI with auditory deficiency acquired before language development, who have been using CI for 5y - 5y11m and who have an average time of sensorial privation of 3y (standard deviation of 1 year). These children were assessed using the Reynell Developmental Scales (RDLS) (Reynell e Gruber, 1990) which is composed of: Comprehension Scale (C), Expression Scale (E) and its Structure Sub-Scales (Es), Vocabulary (Ev) and Content (Ec). RESULTS: The median values and the values found for quartile 75 and quartile 25 were: .44, 57 and 54 for C; 48, 60 and 55 for E; 20, 21 and 20 for Es; 15, 19 and 17 for Ev; 15, 22 and 18 for Ec; 96, 116 and 108 for the total score. A statistical correlation between the time of sensorial privation and the score obtained for C (p=- 0.62; R=0.0044) and Ec (p=-0.48; R=0.0348) was observed. Therefore the time of sensorial privation had an influence on the overall score (p=- 0.53; R=0.0174). CONCLUSION: The language profile of children who use CI for five years is devious and similar to that of five year old hearing children regarding Expression and to that of four year old hearing regarding Comprehension; time of sensorial privation was statistically significant for the score obtained in C--receptive language--and for the score obtained in the E section (Ec)--expressive language, as well as in the overall score of RDLS.

Linguagem oral de crianças com cinco anos de uso do implante coclear / Oral language of children with five years of experience using cochlear implant

TEMA: implante coclear (IC) em crianças. Objetivo: traçar um perfil de linguagem oral receptiva e expressiva de crianças usuárias de implante coclear há cinco anos a cinco anos e onze meses; verificar a influência do tempo de privação sensorial na linguagem oral receptiva e expressiva dessas crianças. MÉTODO: 19 crianças deficientes auditivas usuárias de IC com deficiência auditiva pré-lingual, com tempo de uso do IC variando de 5a a 5a11m e média do tempo de privação sensorial de 3a (desvio padrão um ano) foram avaliadas por meio da Reynell Developmental Language Scales (RDLS) (Reynell e Gruber, 1990) que é composta pela Escala de Compreensão (C), Escala de Expressão (E) e suas Sub-Escalas Estrutura (Ee), Vocabulário (Ev) e Conteúdo (Ec). RESULTADOS: a mediana e os valores do quartil 75 e quartil 25 encontrados foram: 44, 57 e 54 para C; 48, 60 e 55 para E; 20, 21 e 20 para Ee; 15, 19 e 17 para Ev; 15, 22 e 18 para Ec; 96, 116 e 108 para a pontuação total. Houve correlação estatística entre o tempo de privação sensorial e a pontuação de C (p = - 0,62; R = 0,0044) e Ec (p = - 0,48; R = 0,0348) tornando o tempo de privação influente na pontuação total (p = - 0,53; R = 0,0174). CONCLUSÃO: o perfil de linguagem das crianças usuárias de implante coclear há cinco anos é desviante e semelhante ao perfil das crianças ouvintes de cinco anos para a Expressão e ao das crianças ouvintes de quatro anos para a Compreensão; a influência do tempo de privação sensorial foi estatisticamente significante na pontuação da C - linguagem receptiva - e na pontuação de uma seção (Ec) da E - linguagem expressiva, sendo significante na pontuação total da RDLS.

BACKGROND: cochlear implant (CI) in children. AIM: 1) to delineate a profile of receptive and expressive verbal language of children who have been using cochlear implant for five years and five years and eleven months; 2) to verify the influence of time of auditory sensorial privation in the receptive and expressive verbal language of these children. METHOD: 19 children users of CI with auditory deficiency acquired before language development, who have been using CI for 5y - 5y11m and who have an average time of sensorial privation of 3y (standard deviation of 1 year). These children were assessed using the Reynell Developmental Scales (RDLS) (Reynell e Gruber, 1990) which is composed of: Comprehension Scale (C), Expression Scale (E) and its Structure Sub-Scales (Es), Vocabulary (Ev) and Content (Ec). RESULTS: the median values and the values found for quartile 75 and quartile 25 were:.44, 57 and 54 for C; 48, 60 and 55 for E; 20, 21 and 20 for Es; 15, 19 and 17 for Ev; 15, 22 and 18 for Ec; 96, 116 and 108 for the total score. A statistical correlation between the time of sensorial privation and the score obtained for C (p= - 0.62; R= 0.0044) and Ec (p= - 0.48; R = 0.0348) was observed. Therefore the time of sensorial privation had an influence on the overall score (p= - 0.53; R = 0.0174). CONCLUSION: the language profile of children who use CI for five years is devious and similar to that of five year old hearing children regarding Expression and to that of four year old hearing regarding Comprehension; time of sensorial privation was statistically significant for the score obtained in C - receptive language - and for the score obtained in the E section (Ec) - expressive language, as well as in the overall score of RDLS.

Social play development in pre-weaning olfactory deprived or stimulated rats.

The effect of neonatal unilateral restriction or increased olfactory stimulation upon the development of social play behavior in Wistar strain rats was investigated. Pups were unilaterally thermocauterized in one of the nares on postnatal day 3 (experiment 1), or exposed to amyl acetate from 3 to 19 days of age (experiment 2). Unilateral odor deprivation significantly increased the frequency of boxing, wrestling and pinning in rats of both sexes. However, amyl acetate exposure significantly decreased the frequency of wrestling and pinning in females with no effects in males. The alterations in the development of social play behavior are concurrent with gross physical olfactory bulb modifications that may reflect a significant interference with the integration and transmission of olfactory stimuli to central structures such as septal, entorhinal, cingulate and midline frontal cortices subserving social play behavior. Data suggest that early in life brain mechanisms underlying social play behavior are sensitive to manipulation of neonatal olfactory cues and may participate in the modulation of this behavior.

Auditory deprivation modifies biological rhythms in the golden hamster.

To assess to what extent auditory sensory deprivation affects biological rhythmicity, sleep/wakefulness cycle and 24 h rhythm in locomotor activity were examined in golden hamsters after bilateral cochlear lesion. An increase in total sleep time as well as a decrease in wakefulness (W) were associated to an augmented number of W episodes, as well as of slow wave sleep (SWS) and paradoxical sleep (PS) episodes in deaf hamsters. The number of episodes of the three behavioural states and the percent duration of W and SWS increased significantly during the light phase of daily photoperiod only. Lower amplitudes of locomotor activity rhythm and a different phase angle as far as light off were found in deaf hamsters kept either under light-dark photoperiod or in constant darkness. Period of locomotor activity remained unchanged after cochlear lesions. The results indicate that auditory deprivation disturbs photic synchronization of rhythms with little effect on the clock timing mechanism itself.

Auditory deprivation modifies sleep in the guinea-pig.

After destruction of both cochleae, a significant enhancement of both paradoxical sleep and slow wave sleep together with decreased wakefulness, were observed for up to 45 days. The sleep augmentation consisted of an increment in the number of episodes of both slow wave and paradoxical sleep rather than in the duration of single episodes. The partial isolation provoked by deafness is postulated as explanation. We suggest that the suppression of one input to a complex set of networks related to the sleep-waking cycle, introduce an imbalance that leads to sleep enhancement.

Morphological differences in neuromasts of the blind cave fish Astyanax hubbsi and the sighted river fish Astyanax mexicanus.

Vital staining and scanning electron microscopy were used to study the morphology of superficial neuromasts in the blind cave fish, Astyanax hubbsi, and its sighted congener, Astyanax mexicanus. In blind Astyanax the neuromasts are 80 X 50 microns in size and possess cupulae with an oval basal shape. The length of the cupula is correlated to the location of its neuromast. Head neuromasts were found to have the longest cupulae (up to 300 microns), and caudal neuromasts have the smallest. Cupulae of all lengths have been observed to be easily bent by water movements. The neuromasts are directionally sensitive in that the bending of their cupulae perpendicular to the longer axis of the cupulae provides maximal excitation. A comparison of superficial neuromasts in the blind A. hubbsi to those in sighted A. mexicanus revealed several structural differences. The neuromasts in the blind fish are twice as large. Their cupulae, in particular, are much longer and seem to have supporting attachments at their edges. The greater length of the cupulae in blind cave fish may be of particular importance for the functioning of the lateral line organ, since longer cupulae protrude beyond the boundary layer in faster water currents and thus can increase the sensitivity of the neuromast. The specific morphology of the neuromasts in the blind cave fish appears to reflect an evolutionary adaptation which can serve to improve the functioning of the lateral line system and thereby compensate for the lack of eyes.

Chronic sensory deprivation affects cytochrome oxidase staining and glutamic acid decarboxylase immunoreactivity in adult rat ventrobasal thalamus.

The rodent ventrobasal thalamus (VB) contains groups of vibrissa-related neurons (barreloids) that are highly reactive for the enzyme cytochrome oxidase. The present experiments show that each barreloid also contains a dense accumulation of glutamic acid decarboxylase (GAD) immunoreactive terminals. Chronic vibrissa trimming results in parallel declines in staining for both cytochrome oxidase (CO) and GAD in barreloids associated with the trimmed hairs. Thus, thalamic metabolism like that in the cortex is dependent upon normal sensory input. This includes projection neurons as well as neurons in the reticular nucleus, which are the major source of gamma-aminobutyric acid (GABA)ergic input to the rat VB.