PMID-14090522[0] The Brains record of auditory and visual experience -- A final summary and discussion
- 102 pages. basically, this is a book.
- Electrical stimulation causes 'hallucinations of things previously seen or heard or experienced.'
- 'Both the experience and the interpretation are produced by discharge in the temporal cortex and not in other areas'
- Experiential responses only followed stimulation in the temporal lobe.
- These tests were done in an effort to locate the source of a seizure.
- Damn, references the Caliph at Cordova as the first to document epileptic hallucinations (1519!)
- And Hughlings Jackson (1888)!
- Extirpation of memories elicited by ustim to an area persist after removal of that area.
- Performed 1,288 surgeries, 520 of them for seizures in the temporal lobes, 40 of these with experiential responses, and 24 of those with experiential epileptic hallucinations.
- Many of the patients' epilepsy was caused by ischemia, perhaps developmental; others by glioma..
- Stimulation of the white matter has never produced an experiential response. Deep stimulation in the amygdala or hippocampus (??) also failed to elicit experiential responses.
- Talks about 'difficult birth' -- was/is this the cause of some epilepsy? Or has that been discounted?
- Buncha stuff on human cortical anatomy / topology, which is not so interesting to me.
- Walker on the chimpanzee (1938) showed that the temporal cortex has no direct connections to the thalamus except posteriorly, where projections are received from nucleus lateralis posterior and pulvinar (visual attention), and within the transverse temporal gyri which receive auditory afferent projections from the medial geniculate body.
- Also receives large fiber projections from the hippocampus.
- This is absolutely fascinating. Memories, art, songs (music, so much music -- temporal lobe!), childbirth, counting, childhood molestation, a whole host of experiences were brought forth by electrical stimulation.
- Case 9. E. Le. This 44-year old woman began to have seizures at age 22 during a pregnancy. The attack pattern was: (1) flushing of face and neck (2) automatism; (3) occasional generalized seizure. During and automatism she was apt to say, "I am alright". Then she would walk about the room and show marked affection toward anyone who happened to be present.
- Repeated without warning: She said, "Yes, another experience, a different experience." Then she added, "A true experience. This man, Mr. Meerburger, he, oh well, he drinks. Twice his boy has run away. I went to the store once for an ice cream cone and I saw that he was back, and I said 'Hmm, he is back,' and the lady asked me 'What is the matter,' and I didn't know how to explain so I said, 'Well you know Mr. Meerburger drinks.' I thought that was the easiest way but later mother told me, no, and it made it a lot worse."
- What surprises me is the relative lack of breadth in these --many of the responses to stimulation are quite similar, over a wide range of cortex, many of them very dream-like in features and recall.
- Their impression: It is often evident that ''each stimulation leaves behind a facilitating influence so that the same response follows each stimulation and this facilitation may cause a given response to follow stimulation at one to three centimeters distance. Illustrated by the case 5, D.F
- This deserves far more experimentation! E.g. ask the patient to think about something, and see if the same stimulation elicits different memories.
- Another patient had a series of experiential hallucinations which all involved some aspect of 'grabbing' -- a man grabbing a rifle from a cadet during a parade, a man snatching his hat from the hat-check girl, grabbing a stick from a dog's mouth. In this epileptic, an instance of 'grabbing' was the ictal focus. Amazing.
- Points out that stimulation must activate a great number of neural circuits, only one specific memory is recalled -- indicating that there is strong inhibition for mutual-exclusion.
- Non-dominant, non-speech temporal cortex is almost always involved in interpretation: stimulation produces visual experiences, or visual interpretive illusions (change in distance or speed).
- Stimluation also produces changes in the state-of-mind.
- Certain sorts of experiences seem absent:
- The times of making up ones mind
- Times of carrying out skilled acts, writing messages or adding figures,
- Eating food
- Sexual excitement and experience (unless the patients may have self-censored this?)
- Intense pain or suffering.
- These things do not involve interpretation, and the focus of attention is not on the way that things are heard or seen.
- They would remove quite large sections of the temporal lobe!
- Still, the excision of these areas does not abolish memory: it does not contain a record of the past.
- Yet stimulation in the temporal lobe recalls memories as nowhere else does.
- There is a sharp frontier / boundary between auditory and visual temporal cortices and interpretive -- millimeters movement may change phosphenes into recall of a familiar person.
- Note the comparison between speech cortex (dominant) and interpretive -- stimulation of speech cortex produces no speech, only aphasia, whereas stimulation of non-dominant termporal cortex forces recall.
- "He who is faithfully analysing many cases of epilepsy is doing far more than studying epilepsy"
____References____
[0] PENFIELD W, PEROT P, THE BRAIN'S RECORD OF AUDITORY AND VISUAL EXPERIENCE. A FINAL SUMMARY AND DISCUSSION.Brain 86no Issue
595-696 (1963 Dec) |
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