1382 



HANDBOOK OF PHYSIOLOGY 



NEUROPHYSIOLOGY II 



this work, and in emotional phenomena by Brady in 

 Chapter LXIII. 



Sponlaneims Electrical Activity mid Rtiatinii 

 to 'Aroi/sar Mechanisms 



Using the Hess implanted electrode technique, 

 Jung & Kornmiiller (60) observed a theta rhythm 

 discharge of 4 to 7 per sec. waves in the rabbit hippo- 

 campus following afferent stimuli. In an exploration 

 of subcortical electrical activity in the cat brain, 

 Gerard et al. (38) noted somewhat similar rhythms in 

 the cat brain. MacLean and co-workers (77) noticed 

 olfactory-like "responses' in the cat hippocampus fol- 

 lowing a variety of stimuli. These changes were seen 

 in the pyriform cortex and in the hippocampus but 

 the majority of the changes they reported were fast, 

 perhaps to be explained from the fact that they ob- 



served animals under anesthesia. They mention, how- 

 ever, that they also saw a theta rhythm response 

 similar to that of Jung & Kornmiiller (60). Robinson 

 & Lennox (93) .saw evoked potentials following hip- 

 pocampal stimulation. Liberson & Akert (67) ob- 

 served a theta rhythm in the guinea-pig brain follow- 

 ing what they term "social intercourse.' Green & 

 Arduini (46) studied the theta rhythm in the rabbit. 

 They found that it could be elicited by a variety of 

 stimuli, including visual, auditory, .somatic and 

 olfactory, as shown in figure 5. It was also seen in the 

 cat, but with considerably more difficulty. In the 

 monkey the evoked potential was not difficult to ob- 

 serve but the theta rhythm was virtually impossible 

 to .see, excepting under conditions likely to produce 

 extreme emotional reactions. [This accords with the 

 observations of Grey Walter (113) on man which are 

 discussed in Chapter XI in this Handbook.'] This 



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SOMATIC 



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FIG. 5. Afferent responses in the liippocampu.s. .Vute rabbit preparations under curare and local 

 anesthesia, showing various afferent responses. O//., olfactory bulb; Atol., motor cortex; L. and 

 R. Hip., left and right hippocampi. Note characteristic hippocampal responses to various modalities 

 of stimulation. [From Green & .Arduini (4G).] 



