Some Behavioral Differences in Mice Genetically Selected for High and Low Brain Weight

1966 ◽  
Vol 19 (3) ◽  
pp. 675-681 ◽  
Author(s):  
Cynthia Wimer ◽  
Lee Prater

Learning ability, exploratory behavior, and emotionality were measured in mice genetically selected for high and low total brain weight. The high selection lines scored significantly higher than the low lines in locomotor activity in the open field and discrimination learning performance in a water maze, and these findings were supported by correlations between brain weight and behavioral scores within unselected control lines. There is some evidence that these behavioral differences are associated with general changes in brain size produced by genetic selection.

1969 ◽  
Vol 25 (2) ◽  
pp. 363-368 ◽  
Author(s):  
Cynthia Wimer ◽  
T. H. Roderick ◽  
R. E. Wimer

Locomotor activity and performance on several different learning tasks were measured in mice genetically selected for high brain weight and in unselected control lines. Brain size was found to be positively related to locomotor activity in an open field and to performance on brightness discrimination-learning and active avoidance tasks and negatively related to passive avoidance performance. The results provide support for the findings of a previous study on these animals and add further information on the nature of the brain size and behavior relationship.


2018 ◽  
Author(s):  
Dhruva V. Raman ◽  
Timothy O’Leary

AbstractHow does the size of a neural circuit influence its learning performance? Intuitively, we expect the learning capacity of a neural circuit to grow with the number of neurons and synapses. Larger brains tend to be found in species with higher cognitive function and learning ability. Similarly, adding connections and units to artificial neural networks can allow them to solve more complex tasks. However, we show that in a biologically relevant setting where synapses introduce an unavoidable amount of noise, there is an optimal size of network for a given task. Beneath this optimal size, our analysis shows how adding apparently redundant neurons and connections can make tasks more learnable. Therefore large neural circuits can either devote connectivity to generating complex behaviors, or exploit this connectivity to achieve faster and more precise learning of simpler behaviors. Above the optimal network size, the addition of neurons and synaptic connections starts to impede learning performance. This suggests that overall brain size may be constrained by the need to learn efficiently with unreliable synapses, and may explain why some neurological learning deficits are associated with hyperconnectivity. Our analysis is independent of specific learning rules and uncovers fundamental relationships between learning rate, task performance, network size and intrinsic noise in neural circuits.


1980 ◽  
Vol 29 (4) ◽  
pp. 401-407 ◽  
Author(s):  
Norio HASEGAWA ◽  
Ryojiro FURUOKA ◽  
Takuo AOYAMA ◽  
Tomonori IMAMICHI

1969 ◽  
Vol 28 (3) ◽  
pp. 707-712 ◽  
Author(s):  
Merrill F. Elias

Spatial reversal learning was explored for mice genetically selected for high brain weight and unselected control mice with lower brain weights. Original learning and two reversals were presented in a water maze. There were no differences for original learning, but the high brain-weight mice were superior to the unselected controls for both reversals. Since all controls had lower brain weights than the highs, it was concluded that these data support a positive relation between brain size and spatial reversal learning.


Author(s):  
Felicity Muth ◽  
Amber D Tripodi ◽  
Rene Bonilla ◽  
James P Strange ◽  
Anne S Leonard

Abstract Females and males often face different sources of selection, resulting in dimorphism in morphological, physiological, and even cognitive traits. Sex differences are often studied in respect to spatial cognition, yet the different ecological roles of males and females might shape cognition in multiple ways. For example, in dietary generalist bumblebees (Bombus), the ability to learn associations is critical to female workers, who face informationally rich foraging scenarios as they collect nectar and pollen from thousands of flowers over a period of weeks to months to feed the colony. While male bumblebees likely need to learn associations as well, they only forage for themselves while searching for potential mates. It is thus less clear whether foraging males would benefit from the same associative learning performance as foraging females. In this system, as in others, cognitive performance is typically studied in lab-reared animals under captive conditions, which may not be representative of patterns in the wild. In the first test of sex and species differences in cognition using wild bumblebees, we compared the performance of Bombus vancouverensis nearcticus (formerly bifarius) and Bombus vosnesenskii of both sexes on an associative learning task at Sierra Nevada (CA) field sites. Across both species, we found that males and females did not differ in their ability to learn, although males were slower to respond to the sucrose reward. These results offer the first evidence from natural populations that male bumblebees may be equally as able to learn associations as females, supporting findings from captive colonies of commercial bees. The observed interspecific variation in learning ability opens the door to using the Bombus system to test hypotheses about comparative cognition.


1980 ◽  
Vol 238 (1) ◽  
pp. R76-R81 ◽  
Author(s):  
H. F. Cserr ◽  
M. Bundgaard ◽  
J. K. Ashby ◽  
M. Murray

The size of choroid plexuses and cerebral ventricles relative to brain varies widely among vertebrates. The functional significance of this variability has attracted little attention since Herrick's original proposal that large choroid plexuses might enhance oxygen delivery to the brain and therefore be of adaptive value in the transition of vertebrates from water to air breathing. We compared choroid plexus and brain weight or ventricular and brain volume in 40 species from nine vertebrate groups. Both choroid plexus weight and ventricular volume were unrelated to brain size. Plexus weight ranged from 0 to 5.2% of brain weight and ventricular volume from 0.9 to 132% of brain volume. Amid this diversity the dipnoans, chondrosteans, holosteans, amphibians, and crossopterygian examined in this study are exceptional in uniformly having large plexuses. The adaptive significance of large choroid plexuses may lie in the presence of specific homeostatic mechanisms and their role in the response to the increases in PCO2 that accompany the transition to air breathing.


Author(s):  
Jia Zhang

In general, over 70% of students can adapt to this blended learning model after experiencing the blended learning model for some time, which can satisfy the in-dividual differences of students in a better way, attain some assistance from it and help to improve learning performance and learning ability. It can be discovered from this research that the blended learning model is superior to the single and traditional teaching mode or the pure network teaching mode in the aspects of in-spiring the learning interest of students, exercising self-management capability of students and self-evaluation ability. It can be seen from the specific situation of investigation data that it is feasible to implement the blended learning model in colleges and universities even though the overall level of students’ ability in the blended learning is low. As this is a preliminary investigation into the blended learning model, specific solutions or strategies have not been provided for some problems. However, it is believed to achieve greater effects if the research is con-tinued on the practice.


2017 ◽  
Vol 61 (4) ◽  
pp. 5-11 ◽  
Author(s):  
C. S. Ibe ◽  
S. O. Salami ◽  
N. Wanmi

Abstract As a sequel to the current advancement in ethology, this study was designed to provide information on the brain size of the African grasscutter at specific postnatal periods and to extrapolate these findings to the behaviour of the rodent in its natural habitat. Brain samples were extracted from African grasscutter neonates on postnatal day 6, juveniles on postnatal day 72 and adults on postnatal day 450 by basic neuro-anatomical techniques. The weight, volume and dimensions of the brain samples were determined in absolute and relative terms. Their encephalisation quotient was also computed. There was a very strong positive correlation between nose-rump length and brain length in the neonates. The relative brain weight of neonates, juveniles and adults were 3.84 ± 0.12 %, 2.49 ± 0.07 % and 0.44 ± 0.03 %, respectively. The differences were significant (P < 0.05). The encephalisation quotient of juveniles was 1.62 ± 0.03 while that of the adult was 0.49 ± 0.02. The difference was significant (P < 0.05). The results were extrapolated to the animal’s cognitive ability, and compared with other rodents. It was concluded that the juvenile African grasscutter may have higher cognitive ability than the adult rodent, thus, juveniles should be preferred in physiological studies of memory and cognition.


Author(s):  
Pankaj Phukan ◽  
Sanjit Namasudra ◽  
Meenakshi Bawari ◽  
Mahuya Sengupta

Objective: This study aims to assess the effects of the aqueous extract of Hydrocotyle javanica (HJ) in ameliorating mercury-induced neurobehavioral toxicity.Methods: For the study, 36 adult male Swiss albino mice of 25–30 g in weight were taken. They were equally divided into six groups. Group I was treated with distilled water, Group II was treated with mercuric chloride (1.5 mg/kg), Group III was treated with HJ extract low dose (100 mg/kg), Group IV was treated with HJ extract high dose (200 mg/kg), Group V was treated with mercuric chloride plus HJ extract low dose, and Group VI was treated with mercuric chloride plus TB extract high dose. In all the groups, the doses were administered orally through oral gavage tube and the treatment lasted for 14 days. The behavioral effects evaluated were locomotor activity in the open field test, immobility in forced swimming test and anxiety in elevated plus maze test, spatial learning ability, and memory in the Morris water maze test.Results: The present study showed that mercury exposure significantly decreased the locomotor activity (p<0.001), number of annulus crossovers (p<0.001), number of open arm entries (p<0.01), time spent in open arms (p<0.001), and increased escape latency (p<0.01), path length (p<0.001), and immobility (p<0.001) in mice. The aqueous extract of HJ significantly alleviated the neurotoxic effects of mercury. The aqueous extract of HJ showed to increase the locomotor activity (p<0.01), number of annulus crossovers (p<0.001), number of open arm entries (p<0.05), and time spent in open arms (p<0.05), which was decreased in mercury-exposed mice. The HJ extract also showed to decrease the immobility (p<0.001), escape latency (p<0.05), and path length (p<0.001) in mercury-exposed mice.Conclusion: The result of the study shows that neurobehavioral changes induced by mercuric chloride were significantly reversed by the aqueous extract of HJ. Thus, base on the present study, it is concluded that HJ is effective in ameliorating the neurobehavioral deficits induced by mercury.


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