I'll'' 



II WllHi l( Ik (IF I'HYSK II I KJY 



\i i koi'IIYSlol.OGY III 



of real and manipulate entities. Other visual experi- 

 ments extend the occipital lobe results already men- 

 tioned. 

 Thus, when the optic chiasm has been cut in cats 



so tha 1\ the ipsilateral projection area is activated 



from each eye, a discrimination learned through, say, 

 the lefl eye is correctly performed when stimuli reach 

 only the right one. After further section of the corpus 

 callosum, however, the discrimination is retained only 

 for stimuli presented to the left eye, not for those to 

 the right eye. Clearly, the learned pattern has re- 

 mained localized to the left side of the nervous 

 system, although it could effectively he engaged by 

 the right side so long as major connecting paths were 

 intact (59). (The above findings were for pattern 

 vision; results for color vision did not indicate Mich 

 sharp lateralization.) Learning 'set" also fails to 

 transfer from the side that learned, even when 

 specific discrimination does, with intact callosum 

 268). In this connection, the finding of Land (166) 

 that all spectral colors can he experienced l>y a 

 normal subject on looking at two superposed images of 

 a 1 ene, each taken at a different fairly pure spectral 

 frequency, is relevant. (Also, rotating hlack-white 

 disks can give colors, as described by Bartley.) The 

 qualitative experiences are generated from quantita- 

 tive differences in intensity, and the various shades 

 plot as geometrical displacements from a black-while 

 axiv 



On the motor side, also, not only is much of the 

 cortex involved in language use, but temporal lobe 



Stimulation can interfere with word choice or can 

 even block speech (Zangwill), just as frontal lobe 

 stimulation can lead 10 maintained reiteration of a 

 wind ( ;in. (Such findings would seem (o demand 

 cortical action rather than the subcortical control 

 urged b\ some, including Paillard.) Ii would be 

 naive to think too simply in terms of gross regional 

 memory chunks (102); witness the aphasic loss of 

 onh one language in a bilingual person [e.g. Lam- 

 bert & Fillenbaum (165) Such subjective findings, 

 related to the objective evidence from electrophysi- 

 ological localization in projection and association 

 areas, afford ways of actually plotting anatomically 

 the pattern 1 >l expei ien< e and conception. Die) 

 fragmenl ol the total representation of external 

 r . , 1 li t \ in a microreality internal to the brain, as 

 developed l>\ Craik (49), and go a considerable 

 distance to re ve the mystery ol qualitative sub- 

 jective experience and to link solidly our subjective 

 world in a real external one in a pretty good one-to- 

 one relationship a resolution ol the problems that 



•Mil Bel kef A .111(1 I I I I 



.\//i hanism 



The nature of the material trace, and the conditions 

 for its establishment, are also being explored. Not 

 only can memories be localized, they can be favored 

 or hindered by the activity of specific neural regions 

 [the reticular formation and amygdala, considered b\ 

 French and Gloor; the hypothalamus by Doi\ 

 and Gellhorn (80)] and, once laid down, can be 

 brought into clear or blurred recall by stimulation 

 of other particular brain regions (26, 149, 222, 259, 

 275; Galambos & Morgan). Hippocampus stimulation 

 blocks learning at first, large slow waves appear in it 

 with habituation but des\ nchronize with the novel 

 (126). Large slow spindles in response to a condition- 

 ing stimulus predict failure to learn (21). Early in 

 training, hippocampal potentials appear before 

 entorhinal ones; later the time order is reversed (3). 

 Loss of recent memory after damage to the amygdala, 

 mamillary bodies I _* -, 7 1 or fornix (-'74) has been 

 noted. These regions presumably act via modulating 

 impulses that favor or hinder the initial flow and 

 reverberation of impulses laving down traces, or the 

 subsequent How involved in recall. 



The problem of specific recall, like that of directed 

 attention or of selected action, is not yet clearly 

 related to particular brain mechanisms. Some sort of 

 exploring or scanning-type process, that runs through 

 categories as a card-sorting machine, may be involved. 

 The vast detail that is retrievable, especially under 

 hypnosis, is well known, but the process of its re- 

 trieval remains mysterious. Serious workers report, 

 for example, tli.it a hypnotized adult can recall 

 details of a classroom attended when 6 years old, but 

 only after being lirsi given the suggestion, "You are 

 now six" (262). Abo, details of a conversation held by 

 a surgeon and assist. mis during the period of full 

 surgical anesthesia have been subsequently reported 

 by the patient under hypnosis 1 ;i \. Recall is perhaps 

 more important relative in storage than has been 

 generally belie\ ed. 



III. 11 activity of a neuron and junction leaves 



behind an altered state lias been known since the 

 recognition of a refractory period ol nerve. Even 

 earlier, ii was well established that after-potentials 

 were markedly prolonged and enhanced In a te- 

 tanization .is compared 10 a single action (28g 

 Tetanizing presynaptic fibers can enhance for a long 

 lime reflex responses evoked through them; con- 

 versely, weeks of inactivity can practically abolish a 

 response (62, [86). following .1 single nerve fibei 

 action, after-potentials may last seconds, chemical 

 activity, minutes, and ion pumping, hums, \liei .i 



