PMID-14347624[0] Conditioned reflexes elicited by Eletrical Stimulation of the Brain in Macaques
- "The relation of neural to mental processes is nowhere more clearly and directly deominstrated than in the elicitation of subjective experience in human patients by electrical stimluation of their brains"
- Difference between sensory and motor thresholds heretofore unexplained. I guess they were in S1 -- and higher current activates more axons (?)
- Ewald (42) perfected the means, introduced by Simonoff (40) of stimulating the brain in freely moving, unanesthetized animals. Have to look this up.
- Movement could be elicited by stimulation of any part of the cerebral cortex of dogs.
- Loucks: any neocortical or subcortical locus could serve as a CS in rats.
- permanent chairing due to fear of herpes B: "With ten laboratory workers dying in the past decade if virus B encephalitis following monkey bites (11), it was felt that all possible steps should be taken to protect techinall personel form this danger, and the monkeys were permanently restrained." (in a chair)
- Several changes had to be made to the chair to fix this.
- even the pigtail monkeys, which are more gentile, would become aggressive and recalcitrant when the task became more difficult.
- Simple classical conditioning test in monkeys.
- CR = lever pressing to aviod US (shock).
- All electrical stimuli were fed through RF isolation units to prevent ground loop.
- Beast of a study: Stimulation proved effective as SA-or FRCS in all areas of the brain assayed, covering 38 cortical (Table 1 and Fig. 2) and 31 subcortical loci. The latter included the optic tract, lateral and medial geniculate nuclei, pulvinar, lateral posterior nucleus, posterior hypothalamus, tegmentum dorsal to nucleus ruber, brachium of the superior colliculus, and the periaqueductal gray.
- Threshold for response varied with both time (facilitation and habituation) and with the attentive & motivational state of the animal.
- Can discriminate electrodes 1-3mm apart.
- Quote: Judicious and limited use of punishment (electric shock) was required to mantain performance without making the monkey "neurotic". (This as they were testing various currents, and some were below threshold).
- A fully trained monkey can respond to one pulse.
- Hard to train monkeys on anything below 20Hz. (Recall anything in the ~6Hz range puts cats to sleep).
- Subthreshold precentral ICMS would induce movement if activation was increased, eg. US, or a loud and unfamiliar sound, e.g. a truck horn.
- Much lower threshold for ICMS in monkeys as compared to cats. But they were not controlling the critical parameter, e.g. current intensity or delivered charge.
____References____
[0] DOTY RW, CONDITIONED REFLEXES ELICITED BY ELECTRICAL STIMULATION OF THE BRAIN IN MACAQUES.J Neurophysiol 28no Issue
623-40 (1965 Jul) |
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