J. OLDS AND M. E. OLDS 



I8l 



IV 



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Fig. 20 

 Localizations of microclectrode points yielding various effects. I. Point in or near maninnllo 

 thalamic tract yielding reinforcement to contmiioiis firing (schematically symbolized by unit- 

 sinewave pairings followed by repetitive vmit discharge). II. Point in fimbria yielding rein- 

 forcement to continuous firing, plus three cortical points yielding negative results. III. Point 

 in anterior rhinencephalon which augmented firing rate greatly during reintorccment 

 procedure. IV. Point in hippocampus where reinforcement caused firing after the stimulus; 

 and point in mammillo-thalamic tract region of thalamus where reinforcement yielded 

 continuous firing. V. Point in dorsal posterior hypothalamus where stimulation elicited unit 

 firings. 



larger integration which we proceed to condition. However, wc do have 

 anecdotes which suggest that a unit discharge started by pressure (as our 

 microclectrode enters an area) can be maintained active by reinforcement. 

 If stimulation with the microclectrode can be performed systematically, it 

 will at least be shown whether the unit response needs to be started by 

 some afferent system to be conditioned. 



