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Functional relationship of lateral hypothalamus and amygdala in control of eating.

Cannulas were stereotactically implanted in the lateral hypothalamus and the ipsilateral amygdaloid cortical nucleus of 7 male albino rats, Wistar strain. After functional checking of the accuracy of implants by adrenergic elicitation of increased food intake, the animals were injected with combinations of noradrenaline, phenoxybenzamine or tolazoline, or placebo under 6 treatment conditions, while food-and water satiated. The elicitation of increased food intake in the satiated rat by adrenergic stimulation of the lateral hypothalamus was confirmed, and it was further found that simultaneous adrenergic stimulation of the amygdaloid cortical nucleus augmented this increase. However, simultaneous anti-adrenergic blockade in the amygdaloid cortical nucleus reduced eating to control level. The lack of response of the amygdaloid cortical nucleus to adrenergic stimulation in the satiated rat, under simultaneous stimulation of the lateral hypothalamus with either placebo or an adrenergic blocker, was also demonstrated. It was concluded that the amygdaloid cortical nucleus has a modulatory influence on eating behavior, which is dependent on the level of activity in the lateral hypothalamus, and further that this modulatory influence is necessary to the behavioral output of the hypothalamic system. This is the same relationship between the hypothalamus and amygdala previously demonstrated in regard to drinking behavior and these results are seen as supporting the behavioral generality of the functional relationships reported.

Amygdala↗
PubMed2004

The maize duplicate genes narrow sheath1 and narrow sheath2 encode a conserved homeobox gene function in a lateral domain of shoot apical meristems.

The narrow sheath (ns) phenotype of maize is a duplicate factor trait conferred by mutations at the unlinked loci ns1 and ns2. Recessive mutations at each locus together confer the phenotypic deletion of a lateral compartment in maize leaves and leaf homologs. Previous analyses revealed that the mediolateral axis of maize leaves is comprised of at least two distinct compartments, and suggest a model whereby NS function is required to recruit leaf founder cells from a lateral compartment of maize meristems. Genomic clones of two maize homeodomain-encoding genes were isolated by homology to the WUSCHEL-related gene PRESSED FLOWER (PRS). PRS is required for lateral sepal development in Arabidopsis, although no leaf phenotype is reported. Co-segregation of the ns phenotype with multiple mutant alleles of two maize PRS homologs confirms their allelism to ns1 and ns2. Analyses of NS protein accumulation verify that the ns-R mutations are null alleles. ns transcripts are detected in two lateral foci within maize meristems, and in the margins of lateral organ primordia. Whereas ns1 and ns2 transcripts accumulate to equivalent levels in shoot meristems of vegetative seedlings, ns2 transcripts predominate in female inflorescences. Previously undiscovered phenotypes in the pressed flower mutant support a model whereby the morphology of eudicot leaves and monocot grass leaves has evolved via the differential elaboration of upper versus lower leaf zones. A model implicating an evolutionarily conserved NS/PRS function during recruitment of organ founder cells from a lateral domain of plant meristems is discussed.

Amino Acid Sequence↗
PubMed2006

Septal ablation in hypertrophic obstructive cardiomyopathy improves systolic myocardial function in the lateral (free) wall: a follow-up study using CMR tissue tagging and 3D strain analysis.

AIMS: Alcohol septal ablation (ASA) has been successful in the treatment of symptomatic hypertrophic obstructive cardiomyopathy (HOCM). The aim of this study is to evaluate the effects of ethanol-induced myocardial infarcts on regional myocardial function using cardiac magnetic resonance (CMR) tissue tagging and 3-dimensional (3D) strain analysis. METHODS AND RESULTS: In nine patients (age 52+/-15 years) who underwent ASA, CMR was performed prior to and 6 months after the procedure. Regional myocardial mass was evaluated using cine imaging. Myocardial tagging was used to calculate systolic 3D myocardial strain values. These strain values were used to calculate the shortening index (SI), a robust parameter for myocardial contraction. Maximum end-systolic (ES) SI and systolic SI rate were quantified in three circumferential segments: septum, adjacent, and remote (lateral) myocardium. Compared with baseline, septal and non-septal mass decreased at follow-up (from 72+/-27 to 59+/-21 g; P=0.008 and from 131+/-34 to 109+/-30 g; P=0.008, respectively). In the septum, maximum ES SI and SI rate remained unchanged after ASA. In adjacent myocardium, ES SI remained unchanged, whereas SI rate improved (from -56.5+/-21.1 to -70.0+/-16.7%/s; P=0.02). Both ES SI and SI rate improved significantly in remote myocardium (from -16.9+/-2.8 to -18.8+/-3.2%; P=0.02 and from -70.3+/-9.2 to -86.1+/-15.0%/s; P=0.01, respectively). CONCLUSION: Reduction of left ventricular (LV) outflow tract obstruction in symptomatic HOCM is associated with a significant reduction in myocardial mass and improvement of intramural systolic function in the lateral (remote) wall, indicating reversed LV remodelling.

Adolescent↗
PubMed1999

Hemodynamic function at rest, during acute stress, and in the field: predictors of cardiac structure and function 2 years later in youth.

Left ventricular hypertrophy is an independent predictor of cardiovascular morbidity and mortality. However, predictors of cardiac structure and function in youth are not completely understood. On 2 occasions (2.3 years apart), we examined 146 youth aged initially 10 to 19 years (mean age, 14.2+/-1.8 years). On the initial visit, hemodynamic function was assessed at rest, during laboratory stress (ie, orthostasis, car-driving simulation, video game, and forehead cold), and in the field (ie, ambulatory blood pressure). Quantitative M-mode echocardiograms were obtained on both visits. On both visits, black compared with white youth had higher resting laboratory systolic blood pressure (P<0.02), greater relative wall thickness (P<0.003), greater left ventricular mass indexed by either body surface area or height(2.7) (P<0.01 for both), and lower midwall fractional shortening ratio (P<0.05). Hierarchical stepwise regression analysis indicated that significant independent predictors of follow-up left ventricular mass/height(2. 7) were the initial evaluation of left ventricular mass/height(2.7), body mass index, gender (males more than females), and supine resting total peripheral resistance (final model R(2)=0.53). Left ventricular mass/body surface area was predicted by initial left ventricular mass/body surface area, weight, gender, mean supine resting total peripheral resistance, and systolic pressure response to car-driving simulation (final model R(2)=0.48). Midwall fractional shortening was predicted by initial midwall fractional shortening, race (white more than black), and lower mean supine total peripheral resistance (final model R(2)=0.13). The clinical significance of these findings and their implications for improved prevention of cardiovascular diseases are yet to be determined.

Adolescent↗
PubMed1976

Personality dysfunction and lateralized deficits in cerebral functions as measured by the MMPI and Reitan-Halstead Battery.

Previous research using the MMPI has failed to show personality differences between right and left hemispheric brain-damaged patients. The purposes of the present study were, first to determine whether lateralized deficits in cortical functioning as measured by neuropsychological testing are systematically associated with neurotic-psychotic distinctions on the MMPI. Secondly, we wished to determine the strength of predictive association in the relationship between lateralized functional deficits and personality organization. A localization key (Russell, et al., 1972) was applied to the "Reitan-Battery" test results for 94 patients who were referred for neuropsychological testing. Based on this approach, 15 pairs of patients were selected who were "left" or "right" hemispheric dysfunctional in terms of test performance. Pairs were matched for age and "average impairment rating" (Russell, et al., 1972). Their MMPIs were also designated "neurotic" or "psychotic" using the Goldberg Psychotic Index (Goldberg, 1972). The results suggest that patients with deficits in left hemisphere functions tend to score in the psychotic range and patients with deficits in right hemispheric functions tend to score in the neurotic range of the MMPI Goldberg Index. In this set of data there was a 38% reduction in error of predicting neurotic-psychotic category but knowing whether the patient was left or right hemispheric dysfunctional in terms of neuropsychological tests.

Adult↗
PubMed1997

[Electromyography studies for objective assessment of loss of function of the lateral pterygoid muscles after dislocation fractures of the mandibular processes].

The aim of treatment for luxation fractures of the mandibular articular processes is not only complete anatomical restitution but also restoration of the mobility. In a retrospective study on 242 patients after operative and conservative treatment, it was possible to demonstrate that there are no correlations between fragment position and functional result. Functional restitution was observed after conservative treatment in 65% of cases and after operative treatment in 57%. In order to establish the causes for dysfunction of the lateral pterygoid muscle an electromyographical technique was developed to dissipate the action potentials of the muscle. Another retrospective study, performed in 23 patients with dysfunction of the mandible revealed loss of activity of the lateral pterygoid muscle after fracture treatment, independent of the treatment method, in 11.5% of cases (two patients). Without any connection to the treatment method, the remaining results permit to conclude that there are preoperative neurological defects. Therefore the pre- and posttherapeutic functions of muscles and nerves were investigated in a prospective study on 18 patients. Before the treatment 16.6% of the patients (n = 3) showed defects of the lateral pterygoid nerve with a resulting loss of muscle function. According to the findings, residual dysfunction of the lateral pterygoid muscle is determined by the extend of the traumatic nerve injury, independent of the treatment method. In the case of axonal defects of the pterygoid nerve, there can be no expectation of a restitutio ad integrum after the operative fragment position.

Adolescent↗
PubMed1994

Form and function relationships in lateral line systems: comparative data from six species of Antarctic notothenioid fish.

The structure and physiology of the anterior lateral line canal systems were studied in six species of fish belonging to two different families within the suborder of antarctic fish Notothenioidei. Many of the canals within the species belonging to the genus Trematomus are relatively straight sided tubes with diameters around 0.4 mm. Some of the canals in Trematomus, and most of the canals in the icefishes (family Channichthyidae) are more complex. Relatively small pores lead into large tubules, the walls of which appear partially membranous, and the canals not much more than constrictions between adjacent tubules. Dissostichus mawsoni, a large species, has canals with distinctive wide and narrow sections, 1.8 mm and 0.48 mm, respectively. Despite these morphological differences the frequency response characteristics of anterior lateral line units are remarkably similar in all six species. In the case of D. mawsoni, this functional similarity results from narrow sections of the canals, which provide the viscous resistance to flow that preserves the mechanical filtering properties of the canal despite the huge size difference between D. mawsoni and the other species. It is argued that the most appropriate way to view canals is as high pass filters which attenuate lower frequencies, and that this effect is best illustrated by comparing the frequency response characteristics of superficial and canal neuromasts using a sinusoidal stimulus that has a constant peak-to-peak velocity. The functional contribution of canals is to attenuate low frequencies and improve the signal-to-noise ratio for biologically important signals in the presence of low frequency noise produced, for example, by the animal's own movements.

Animals↗
PubMed2005

Laterality of brain areas associated with arithmetic calculations revealed by functional magnetic resonance imaging.

BACKGROUND: Asymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions: arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality. METHODS: Using a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping (SPM99) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas. RESULTS: For both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased. CONCLUSIONS: The laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.

Brain↗
PubMed2004

Effects of hyperbaric oxygen therapy on cerebral oxygenation and mitochondrial function following moderate lateral fluid-percussion injury in rats.

OBJECT: In the current study, the authors examined the effects of hyperbaric O2 (HBO) following fluid-percussion brain injury and its implications on brain tissue oxygenation (PO2) and O2 consumption (VO2) and mitochondrial function (redox potential). METHODS: Cerebral tissue PO2 was measured following induction of a lateral fluid-percussion brain injury in rats. Hyperbaric O2 treatment (100% O2 at 1.5 ata) significantly increased brain tissue PO2 in both injured and sham-injured animals. For VO2 and redox potential experiments, animals were treated using 30% O2 or HBO therapy for 1 or 4 hours (that is, 4 hours 30% O2 or 1 hour HBO and 3 hours 100% O2). Microrespirometer measurements of VO2 demonstrated significant increases following HBO treatment in both injured and sham-injured animals when compared with animals that underwent 30% O2 treatment. Mitochondrial redox potential, as measured by Alamar blue fluorescence, demonstrated injury-induced reductions at 1 hour postinjury. These reductions were partially reversed at 4 hours postinjury in animals treated with 30% O2 and completely reversed at 4 hours postinjury in animals on HBO therapy when compared with animals treated for only 1 hour. CONCLUSIONS: Analysis of data in the current study demonstrates that HBO significantly increases brain tissue PO2 after injury. Nonetheless, treatment with HBO was insufficient to overcome injury-induced reductions in mitochondrial redox potential at 1 hour postinjury but was able to restore redox potential by 4 hours postinjury. Furthermore, HBO induced an increase in VO2 in both injured and sham-injured animals. Taken together, these data demonstrate that mitochondrial function is depressed by injury and that the recovery of aerobic metabolic function may be enhanced by treatment with HBO.

Animals↗
PubMed2006

Negatively correlated firing: the functional meaning of lateral inhibition within cortical columns.

Lateral inhibition is a well documented aspect of neural architecture in the main sensory systems. Existing accounts of lateral inhibition focus on its role in sharpening distinctions between inputs that are closely related. However, these accounts fail to explain the functional role of inhibition in cortical columns, such as those in V1, where neurons have similar response properties. In this paper, we outline a model of position tracking using cortical columns of integrate-and-fire and Hodgkin-Huxley-type neurons which respond optimally to a particular location, to show that negatively correlated firing patterns arise from lateral inhibition in cortical columns and that this provides a clear benefit for population coding in terms of stability, accuracy, estimation time and neural resources.

Action Potentials↗
PubMed2004

Evaluation of a functional position for lateral radiograph acquisition in adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective examination of lateral spine radiographs of 50 patients with adolescent idiopathic scoliosis (AIS) was performed to evaluate the sagittal profile of patients in two different standing positions. OBJECTIVES: To evaluate segmental and global changes in the sagittal profile of the spine associated with two standing radiographic positions and determine if one position represents a more functional stance for accurate sagittal balance evaluation. SUMMARY OF BACKGROUND DATA: Studies of spinal sagittal balance during relaxed standing have indicated that the sagittal vertical axis (SVA), as determine by the horizontal displacement of a C7 plumb line from the posterior superior corner of the sacrum, is neutral or slightly positive. However, standing with the arms forward flexed to allow radiographic visualization of the spine results in a negative shift in SVA. METHODS.: Measurements were obtained from standing lateral radiographs in patients with AIS in two different standing positions: arms forward flexed to 45 degrees with elbows fully extended versus elbows fully flexed with fists resting on clavicles. Sagittal plane parameters were analyzed using correlation analyses and repeated-measures analyses of variance with significance set at 0.005. RESULTS: The study cohort included 25 patients who had undergone solely nonoperative treatment (without progression) and 25 patients who had undergone operative intervention for their scoliosis. In all patients, SVA was more negative (C7 shifted more posterior with respect to the sacrum) when the arms were in the forward flexed position compared to the fists on clavicles position (-4.2 +/- 2.5 cm vs. -1.3 +/- 2.4 cm, P < 0.001). In operative patients, the shoulder forward flexed position was associated with relative posterior rotation of the pelvis represented by an average increase of 2.7 +/- 3.8 degrees in pelvic tilt (P = 0.002) and an average decrease of 3.2 +/- 4.5 degrees in sacral slope (P = 0.002). There was no correlation between the degree of arm forward flexion and changes in sagittal measures between the two positions. CONCLUSIONS: The fists on clavicles position for lateral radiograph acquisition has less negative shift in SVA, and in patients with spinal instrumentation, less compensatory posterior rotation of the pelvis. This position is more representative of a patient's functional balance while still allowing adequate lateral radiographic visualization of the spine.

Adolescent↗
PubMed1983

Functional dissociation between lateral and medial entorhinal cortex in memory processes in mice.

The effects of lesions of the medial or the lateral entorhinal cortex in mice were examined on acquisition, retention and extinction of an operant-conditioning task in a Skinner box. Compared with the control animals, lesions in the medial entorhinal had no behavioral effects whereas lesions in the lateral entorhinal enhanced retention and increased resistance to extinction but did not change acquisition of this task. These results suggest a functional dissociation between the two parts of the entorhinal cortex.

Animals↗
PubMed2000

Functional instability following lateral ankle sprain.

Lateral ankle sprain (LAS) is an extremely common athletic injury. Despite extensive clinical and basic science research, the recurrence rate remains high. Functional instability (FI) following LAS is hypothesised to predispose individuals to reinjury because of neuromuscular deficits which result following injury. This paper provides an overview of the potential causes of FI which may manifest themselves clinically. The theoretical explanations of FI are discussed, as are implications for assessment and treatment of FI following LAS. When LAS occurs, structural damage not only occurs to the ligamentous tissue, but also to the nervous and musculotendinous tissue around the ankle complex. While injury to the ligaments may result in laxity of the joints of the ankle complex, neuromuscular deficits are also likely to occur due to the injury to the nervous and musculotendinous tissue. These neuromuscular deficits may be manifested as impaired balance, reduced joint position sense, slower firing of the peroneal muscles to inversion perturbation of the ankle, slowed nerve conduction velocity, impaired cutaneous sensation, strength deficits and decreased dorsiflexion range of motion. Additionally, the abnormal formation of scar tissue after injury may lead to sinus tarsi syndrome or anterolateral impingement syndrome, which may also lead to FI of the ankle complex. Assessment of patients with LAS must address not only joint laxity and swelling, but should include examination for neuromuscular deficits as well. The treatment and rehabilitation goals must also address restoration of neuromuscular function, as well as restoration of mechanical stability to the injured joints.

Ankle Injuries↗
PubMed1985

Autonomic function in amyotrophic lateral sclerosis: a study of cardiovascular responses.

Autonomically mediated cardiovascular responses were evaluated in 15 ALS patients and compared with 15 healthy subjects. The respiratory sinus arrhythmia, the heart rate response to a Valsalva manoeuvre, to isometric handgrip and to a dive reflex test was normal, indicating a normal function of vagal nerves. The heart rate and blood pressure responses during an orthostatic test were normal, indicating a normal function of sympathetic nerves. The increase in blood pressure and blood flow in the contralateral forearm which occurs on handgrip in healthy subjects was reduced in the ALS patients. The cause of this is unclear, but could be related to decreased function of "ergoreceptors" or altered vascular reactivity in atrophic muscle.

Aged↗
PubMed1994

Reticular thalamic inhibitory input to lateral hypothalamic neurons: a functional and histochemical determination.

Both the lateral hypothalamus (LH) and reticular thalamus (RT) have been implicated in the integration of a variety of vital functions. To determine relevant connections more specifically between cells of these two regions in the rat, functional neurophysiological and horseradish peroxidase (HRP) histochemical techniques were utilized. Single pulse electrical stimulation of the RT modified the discharge frequency of the majority of LH neurons tested. LH neuronal responses to RT stimulation included; inhibition (66.32%), excitation followed by inhibition (6.12%), and excitation (7.14%). Because RT stimulation resulted primarily in the inhibition of LH neuronal activity with a relative short mean latency of 1.87 +/- 0.23 ms, the existence of a possible direct inhibitory pathway from the RT to LH also was evaluated using HRP histochemistry. Retrogradely HPR labeled soma were identified in the RT after HRP was ejected extracellularly onto LH neurons, which exhibited a decrease in spontaneous activity in response to RT stimulation. These data demonstrate direct projections from the RT to the LH. In addition, HRP labeling of neurons and axons in the zona incerta-LH area following LH HRP ejections suggest this route as a synaptic pathway from RT to LH.

Action Potentials↗