Sensitive Method for the Detection of Experimental Brain Lesions

1973 ◽  
Vol 36 (2) ◽  
pp. 584-586 ◽  
Author(s):  
Serena S. Besley ◽  
Charles L. Sheridan
Keyword(s):  
Pattern Discrimination ◽  
Brain Lesions ◽  
Albino Rats ◽  
Traditional Methods ◽  
Anterior Cortex ◽  
Sensitive Method

Small anterior lesions were placed unilaterally in 7 albino rats whose opposite hemispheres had previously been trained in diametrically opposed pattern-discrimination habits. Performances mediated by the lesioned hemisphere were significantly impaired, implicating extrastriate anterior cortex in the mediation of pattern discrimination. Traditional methods entailing the use of far more massive anterior lesions have failed to detect similar effects.

Further Evaluation of a Sensitive Method for Detecting Experimental Brain Lesions

1975 ◽  
Vol 41 (2) ◽  
pp. 407-410 ◽  
Author(s):  
Terry J. Hottman ◽  
Robert E. Sanders ◽  
Christine M. Rinck ◽  
Charles L. Sheridan
Keyword(s):  
Pattern Discrimination ◽  
Brain Lesions ◽  
Extrastriate Cortex ◽  
Albino Rats ◽  
Cortical Lesions ◽  
Sprague Dawley ◽  
Posterior Cortex ◽  
Eyes Open ◽  
Sensitive Method

Small, unilateral cortical lesions were placed in either medial-anterior, lateral-anterior, or posterior cortex of 20 male, Sprague-Dawley, albino rats. In addition, unilateral sham operations were performed on 8 rats from the same stock. All subjects had been trained prior to surgery with diametrically opposed visual habits mediated by opposite cerebral hemispheres. The opposing habits were, insofar as possible, evenly matched prior to surgery. After surgery, lesioned hemispheres, regardless of locus of lesion, were slower in acquiring the habit they mediated, than were unlesioned hemispheres. Further, unlesioned hemispheres dominated in test trials in which subjects chose one of the two cue doors with both eyes open. These findings confirm that the “interocularly conflicting discrimination” baseline detects a role of extrastriate cortex in mediation of pattern discrimination habits. They further indicated that losses occur without regard to the various locations of lesion employed.

Detection of a Deficit in Visual Discrimination of Pattern following Lesions of Anterior Cortex: Role of Type of Motivation

1976 ◽  
Vol 42 (2) ◽  
pp. 616-618
Author(s):  
Christine M. Rinck ◽  
Robert E. Sanders ◽  
Terry J. Hottman ◽  
Charles L. Sheridan
Keyword(s):  
Visual Discrimination ◽  
Pattern Discrimination ◽  
Albino Rats ◽  
Anterior Cortex ◽  
Appetitive Motivation ◽  
Surgical Errors ◽  
Surgical Recovery ◽  
Aversive Motivation ◽  
Selective Impairment

6 albino rats were trained under appetitive motivation to perform diametrically opposed visual discriminations of pattern via opposite eyes. Small lesions were subsequently placed unilaterally in anterior neocortex. Following a period of post-surgical recovery, subjects were re-trained on the diametrically opposed discriminations in alternating 10-trial blocks. Every subject made more post-surgical errors on the discrimination mediated by the eye contralateral to the lesion. Since albino rats have virtually complete decussation of the visual system, this indicates selective impairment in mediation of performance of pattern discrimination in the part of the lesioned hemispheres. Thus, findings previously obtained in studies involving aversive motivation are general to appetitively motivated tasks.

scholarly journals The Effect of Patterned Sound Deprivation upon Auditory Discrimination in Albino Rats

2021 ◽  
Author(s):  
◽  
Robin Fraser Patchett
Keyword(s):  
Discrimination Task ◽  
Prior Experience ◽  
Pattern Discrimination ◽  
Field Testing ◽  
Frequency Discrimination ◽  
Auditory Discrimination ◽  
Sensitive Period ◽  
Albino Rats ◽  
Sprague Dawley ◽  
Auditory Pattern

<p>To test the hypothesis that prior patterned or varied auditory experience was necessary for the development of auditory frequency discrimination and auditory pattern discrimination, groups of sprague-Dawley albino rats were deprived of patterned sound from birth by the novel technique of rearing them in 'white' noise. The sound deprived rats learned a frequency discrimination as easily as controls reared in varied sound conditions, but showed inferior performance on an auditory pattern discrimination task. Supporting experiments showed that the inferiority of varied sound deprived animals on the pattern discrimination task was not likely to have been due to their emotional state at the time of the testing nor to their inferiority in learning to respond in a discrimination task compared with non-deprived controls. Open-field testing showed that the sound deprived subjects did not differ from non-deprived controls in 'emotionality'. The sound deprived rats were not inferior, either, to controls on a complex visual discrimination task. Experiments were also carried out to explore the effect of various durations of patterned sound deprivation and the effect of the deprivation at various times in the life cycle of the rat on auditory pattern discrimination. The results of these experiments favoured an explanation for the effect of varied sound experience which proposed that patterned auditory discrimination development depended, simply, on prior experience with varied sound rather than an explanation which proposed that the effect depended on varied sound experience during a particular sensitive period in the life of the rat. The research involved a total of seven different experiments, the similarities in the findings of which when compared with those of other investigators working in the area of the effects of deprivation of patterned light on visual discriminations were noted. The present experiments support generalizations about the role of prior experience on later behaviour, based largely on experiments in the visual mode, by supplying evidence from another sensory mode.</p>

scholarly journals История развития методов и интерференционных приборов для измерения малой разности оптических фаз (обзор)

2021 ◽  
Vol 129 (2) ◽  
pp. 174
Author(s):  
Г.Б. Малыкин
Keyword(s):  
Harmonic Analysis ◽  
Photoelectric Effect ◽  
Traditional Methods ◽  
Small Phase ◽  
Interferometry Method ◽  
Physical Phenomena ◽  
Sensitive Method ◽  
Internal Photoelectric Effect ◽  
Phase Differences

Methods of interferometry, which are used to measure very small phase differences, are considered. in fundamental and applied problems. It is shown that the first improvements in interferometric methods for measuring small phase differences for recording various physical phenomena in the second half of the XIX - early XX centuries. carried out by I.A. Fizeau, A.A. Michelson, E. Morley, Lord Rayleigh, D.C. Miller and J.M. Sagnac. It was also shown that the most sensitive method of modulation interferometry was created in the period 1949-1952. Soviet radiophysicists A.A. Andronov, I.L. Berstein and G.S. Gorelik. It is noted that the modulation interferometry method could be implemented even in 1914 with a photocell on an external photoelectric effect, or in 1923 with a photocell on internal photoelectric effect (photodiode). However, then professional opticians used traditional methods for measuring small phase differences, and radiophysics as a science was just beginning its formation. It is shown that the methods of electrical and photoelectric harmonic analysis developed in late XIX - early XX centuries could find successful application in interferometry, but by that time, when they could find practical use, they were almost completely forgotten.

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