Auditory frequency discrimination and generalization following lesions of the amygdaloid area in rats.

Abstract

Rats trained in a bar-pressing situation to discriminate between either 2 tones or tone and no-tone, based upon intermittent food reinforcement in the presence of S*, displayed consistent and often severe impairment on retention performance after large bilateral lesions in the amygdaloid area. Histological analysis also implicated the putamen in these effects. Amygdaloid impairment was closely associated with increased responding under nonreinforced conditions, with no concomitant increases in responding to S" 1 ". Hippocampal lesions, by contrast, increased responding to S* without seriously affecting responding to S~. Amygdaloid impairment on stimulus generalization occurred after 2tone but not after tone-no-tone training, and seemed to reflect a defect in generalization of S~ or in behavioral contrast as part of a basic disturbance in S" control of behavior.

Caudate Nucleus Lesions Impair the Ability of Rats to Learn a Simple Straight-Alley Task

“…deficits in caudotomized animals have utilized relatively complex learning tasks: including, delayed and alternation responding, escape and active avoidance, lever-pressing and similar operant tasks, successive discrimination and reversal learning, and different types of maze problems (Chorover & Gross, 1963;Divac, et dl., 1978;Kirkby, 1969Kirkby, , 1978Kirkby & Kimble, 1968;Kirkby & Polgar, 1974;Mikulaus & Isaacson, 1965;Sanberg, et al, 1978;Schmaltz & Isaacson, 1968;Schwartzbaum, et al, 1964). However, most of the studies showing learning.…”

Behavioural Contrast and Peak Shift in Children

“…Other frustration-related phenomena have been observed in pigeons (Staddon & Innis, 1966), rats (Amsel & Roussel, 1952), monkeys (Davenport & Thompson, 1965) and children (Ryan & Watson, 1968). Behavioural contrast has so far been reported in pigeons (Reynolds, 1961) and retardate children (O'Brien, 1968), while peak shift has been reported in the pigeon (Hanson, 1959) and in the rat (Schwartzbaum et al, 1964;Pierrel & Sherman, 1960, 1962. Landau (1968) has looked for peak shift in normal children, but failed to find it.…”

The Hippocampus as a Cognitive Map

“…* * Similarly, Wild and Blampied (1972) and Woodruff, Means, and Isaacson (1973) report that hippocampal rats are impaired both on retention and acquisition of go-no-go. On the other hand, Schwartzbaum, Thompson, and Kellicutt (1964) showed that hippocampal rats could retain a preoperatively acquired go-no-go discrimination, the only abnormality in * We have already discussed the fact that when the cue is at a remove from the lever normal animals perform less well than do hippocampals (p. 268). * * In this study the hippocampal rats did not make more S -responses than did a control group which received bilateral hippocampal injections of sodium sulphadiazine, a drug assumed not to elicit seizures.…”

“…As regards the use of external cues, in both Schwartzbaum et al (1964) and Gaffan (1973) separate tones were used as S + and S -and normal performance was seen in both cases. In all the other studies only one cue was used, with the exception of Mering and Mukhin (1973) who also reported normal performance.…”

“…In five of the studies (Schwartzbaum et al 1964, Wild and Blampied 1972, Gaffan 1973Freeman and Kramarcy 1974) go-no-go training was followed by tests of the generalization gradients established to the discriminative * This deficit might relate to the difference seen in intact animals between feature-positive and feature-negative tasks. When the S + is a discrete stimulus learning is faster than when this stimulus is the S -.…”