280 BRAIN MECHANISMS AND LEARNING 



DISCRIMINATION 



I. DIFF T ON SS 

 A GENERALIZATION B DIFFERENTIATION 



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Fig. II 

 SPECIFICITY OF TONE EFFECTS. I. Specificity for T frequency (DIFF. T ON SS). a (or A) 

 GENERALIZATION stage: both 'reinforced' (i6oo c.p.s. -CESS SS) and non-' reinforced' 

 (i6o c.p.s.) tones affected responses, b (or B) DIFFERENTIATION stage: only i6oo c.p.s. 

 tones were effective. II. Specificity for localization (T ON SS TO DIFF. LEG). No differentia- 

 tion was established : T affected both types of response, those on right sensory cortex (RSC) 

 after left foreleg stimuli (SSLF) (currently cut off after T) and those on left sensory cortex 

 (LSC) after right foreleg stimuli (SSRF) (currently not cut off after T). III. Specificity for 

 modality (T ON DIFF. MODALITY). Differentiation was estabhshed: T affected responses 

 on right sensory cortex after left foreleg stimuli occurring on right visual cortex (RVC) after 

 repetitive flashes (FL.) (currently not cut off after T). DIFF., different; FL., flashes; LSC, left 

 somatic sensory cortex; RSC, right sensory cortex; RVC, right visual cortex; SSLF, sub- 

 cutaneous stimulus to left foreleg; SSRF. subcutaneous stimulus to right foreleg. 



