Acetylcholine‐sensitive cells in the cerebral cortex

Krnjević, K.; Phillis, John W.

doi:10.1113/jphysiol.1963.sp007106

Cited by 402 publications

(69 citation statements)

References 63 publications

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“…Accordingly, evidence from human studies suggests that increased cortical ACh can enhance the selectivity of perceptual processing in the extrastriate cortex during encoding in a visual working memory task (Furey et al, 1997(Furey et al, , 2000, and scopolamine has been shown to reduce encodingrelated activity in the temporal lobes (including PRh) during visual delayed matching to sample (Schon et al, 2005). Moreover, reports indicate that direct application of cholinergic agents can fine-tune the receptive fields of cortical pyramidal cells (Krnjevic and Phillis, 1963;Sillito and Kemp, 1983;Murphy and Sillito, 1991;Rasmusson, 2000), and such findings have long been suggested as evidence for a role of cortical ACh in facilitating information acquisition, perhaps by amplifying the cortical processing of sensory stimuli (Hasselmo and Bower, 1993;Everitt and Robbins, 1997;Sarter and Bruno, 1997;Weinberger, 2003;Hasselmo and McGaughy, 2004). Thus, a local effect on stimulus acquisition within PRh might explain the impairment caused by presample scopolamine.…”

Section: Discussionmentioning

confidence: 99%

Paradoxical Facilitation of Object Recognition Memory after Infusion of Scopolamine into Perirhinal Cortex: Implications for Cholinergic System Function

Winters¹,

Saksida²,

Bussey³

2006

J. Neurosci.

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The cholinergic system has long been implicated in learning and memory, yet its specific function remains unclear. In the present study, we investigated the role of cortical acetylcholine in a rodent model of declarative memory by infusing the cholinergic muscarinic receptor antagonist scopolamine into the rat perirhinal cortex during different stages (encoding, storage/consolidation, and retrieval) of the spontaneous object recognition task. Presample infusions of scopolamine significantly impaired object recognition compared with performance of the same group of rats on saline trials; this result is consistent with previous reports supporting a role for perirhinal acetylcholine in object information acquisition. Scopolamine infusions directly before the retrieval stage had no discernible effect on object recognition. However, postsample infusions of scopolamine with sample-to-infusion delays of up to 20 h significantly facilitated performance relative to postsample saline infusion trials. Additional analysis suggested that the infusion episode could cause retroactive or proactive interference with the sample object trace and that scopolamine blocked the acquisition of this interfering information, thereby facilitating recognition memory. This is, to our knowledge, the first example of improved recognition memory after administration of scopolamine. The overall pattern of results is inconsistent with a direct role for cortical acetylcholine in declarative memory consolidation or retrieval. Rather, the cholinergic input to the perirhinal cortex may facilitate acquisition by enhancing the cortical processing of incoming stimulus information.

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Section: Discussionmentioning

confidence: 99%

Paradoxical Facilitation of Object Recognition Memory after Infusion of Scopolamine into Perirhinal Cortex: Implications for Cholinergic System Function

Winters¹,

Saksida²,

Bussey³

2006

J. Neurosci.

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“…The actions of some of the compounds were also tested on the antidromic spikes of corticospinal neurones (Betz cells). In these instances the medullary pyramidal tracts were exposed and stimulated with bipolar needle electrodes (Phillips, 1956;Krnjevic & Phillis, 1963b …”

Section: Methodsmentioning

confidence: 99%

“…Compounds in these three groups were also tested on the antidromically evoked spikes of single Betz cells (Phillips, 1956(Phillips, , 1959Krnjevic & Phillis, 1963b). It has already been reported that, unlike the antidromic invasion of motoneurones in the spinal cord (Curtis et al, 1959), the antidromic invasion of Betz cells is not readily blocked by y-aminobutyric acid (Krnjevic & Phillis, 1963a), although enormous doses of y-aminobutyric acid may partially block invasion (Krnjevic, 1963).…”

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confidence: 99%

Actions of Certain Amines on Cerebral Cortical Neurones

Krnjević

Phillis

1963

British Journal of Pharmacology and Chemotherapy

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202

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A number of derivatives of tryptamine and phenethylamine, and certain other compounds, were tested on neurones in the cerebral cortex of cats by iontophoretic release from micro-pipettes. The characteristic action of many of these compounds was a depression of the neuronal discharge initiated by synaptic activity or by the application of L-glutamate; imidazolylacetic acid, dopamine, ephedrine and ergometrine were particularly effective. Catechol amines, hydroxytryptamines and imidazolylacetic acid had a relatively quick and rapidly reversible action, not unlike that of y-aminobutyric acid, whereas ephedrine and derivatives of lysergic acid diethylamide caused a slower and more prolonged depression of the amplitude of spikes, rather like atropine. Several compounds, including 5-hydroxytryptamine, adrenaline and ergometrine, could also excite the same neurone when larger amounts were applied. A few substances, such as dopa and methylergometrine, had a predominantly excitant action.There has been much speculation during the course of the last decade concerning the significance of several indole and catechol amines which occur naturally in the brain. Interest in these substances has increased as a result of recent developments in the study of psychotropic compounds, some of which are structurally related to the indole and catechol amines (lysergic acid diethylamide, bufotenine, mescaline and others).Evaluation of the importance of these compounds in central nervous mechanisms (Marrazzi & Hart, 1955;Marrazzi, 1957). These findings were substantiated by Ochs, Booker & Aprison (1960), who showed that 5-hydroxytryptamine, applied topically, depressed cortical responses to direct stimulation;

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“…This is quite a remarkable correspondence considering that only 14±16% of cortical cells appear to be cholinoceptive. KrnjevicÂ and Phillis (1963) recorded from 1367 cortical cells, including the ordinarily``silent'' cells, and found that only 14.6% of cortical neurons respond to acetylcholine. Counts of cell bodies reacting to antibodies against muscarinic receptor or acetylcholin-esterase histochemistry similarly showed that 15.6% or 14.7% of cells in cerebral cortex are cholinoceptive (Woolf, 1993).…”

Section: Introductionmentioning

confidence: 99%

A structural basis for memory storage in mammals

Woolf

1998

Progress in Neurobiology

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AbstractÐIt is proposed that altered dendrite length and de novo formation of new dendrite branches in cholinoceptive cells are responsible for long-term memory storage, a process enabled by the degradation of microtubule-associated protein-2. These memories are encoded as modality-speci®c associable representations. Accordingly, associable representations are con®ned to cytoarchitectonic modules of the cerebral cortex, hippocampus, and amygdala. The proposed sequence of events leading to long-term storage in cholinoceptive dendrites begins with changes in neuronal activity, then in neurotrophin release, followed by enhanced acetylcholine release, muscarinic response, calcium in¯ux, degradation of microtubule-associated protein-2, and ®nally new dendrite structure. Hypothetically, each associable representation consists of altered dendrite segments from approximately 5000±15 000 cholinoceptive cells contained within one or a few module(s). Simultaneous restructuring during consolidation of long-term memory is hypothesized to result in a similar infrastructure among dendrite sets, facilitating co-activation of those dendrite sets by neurotransmitters such as acetylcholine, and conceivably enabling high energy interactions between those dendrites by phenomena such as quantum optical coherence. Based on the speci®c architecture proposed, it is estimated that the human telencephalon contains enough dendrites to encode 50 million associable representations in a lifetime, or put another way, to encode one new associable representation each minute. The implications that this proposal has regarding treatments for Alzheimer's disease are also discussed. #

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Acetylcholine‐sensitive cells in the cerebral cortex

Cited by 402 publications

References 63 publications

Paradoxical Facilitation of Object Recognition Memory after Infusion of Scopolamine into Perirhinal Cortex: Implications for Cholinergic System Function

Paradoxical Facilitation of Object Recognition Memory after Infusion of Scopolamine into Perirhinal Cortex: Implications for Cholinergic System Function

Actions of Certain Amines on Cerebral Cortical Neurones

A structural basis for memory storage in mammals

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