Sensory connexions to the hypothalamus and mid‐brain, and their role in the reflex activation of the defence reaction

Abrahams, V. C.; Hilton, S. M.; Malcolm, J. L.

doi:10.1113/jphysiol.1962.sp006998

Cited by 62 publications

(13 citation statements)

References 22 publications

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“…arousal have a cholinergic component, the widespread evoked release of ACh may be the result of activation of this system. This is supported by studies which show that the mid-brain reticular formation receives non-specific visual projections (French, von Amerongen & Magoun, 1952;Fillenz, 1953;Ingvar & Hunter, 1955;Abrahams, Hilton & Malcolm, 1962) and that visual stimulation can desynchronize the e.e.g. (Wilson & Wilson, 1959;Erwin, Lerner, Wilson & Wilson, 1961).…”

supporting

confidence: 53%

The central release of acetylcholine during stimulation of the visual pathway

Collier¹,

Mitchell²

1966

The Journal of Physiology

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SUMMARY1. -In rabbits anaesthetized with Dial ACh has been collected from the surface of the cerebral cortex during stimulation of the visual pathways.2. The spontaneous release of ACh from the visual and non-visual areas of the cortex was found to be similar.3. Stimulation of the retinae by diffuse light produced a large increase in ACh release from the primary visual receiving areas (4.3 times the spontaneous release) and a smaller increase (1.9 times the spontaneous release) from other parts of the cortex.4. Direct unilateral electrical stimulation of the lateral geniculate body evoked a large increase in ACh release (3.4 times the spontaneous release) from the ipsilateral visual cortex and a smaller increase (1.7 times the spontaneous release) from the contralateral visual area and other regions of the cerebral cortex. The evoked increase from the contralateral cortex was not mediated by transcallosal pathways.5. The increase in ACh release evoked from the visual cortex by stimulation of the ipsilateral lateral geniculate body was dependent on the frequency of stimulation. The evoked release was smallest at low stimulus frequencies and increased to a maximum at 20 stimuli/sec.The evoked ACh release from other areas of the cortex was independent of the frequency at which the lateral geniculate body was stimulated.6. The possible central nervous pathways associated with the spontaneous release of ACh and the release evoked by stimulation of the eyes by light and by direct stimulation of the lateral geniculate body are discussed.7. It is concluded that two ascending cholinergic systems may be involved; the non-specific reticulo-cortical pathways responsible for the e.e.g arousal response, and the more specific thalamo-cortical pathways associated with augmenting and repetitive after-discharge responses. The first system is thought to be concerned with the small but widespread

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supporting

confidence: 53%

The central release of acetylcholine during stimulation of the visual pathway

Collier¹,

Mitchell²

1966

The Journal of Physiology

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“…There is every reason to believe that the extra-lemniscal afferent pathway, which has been shown to connect with the hypothalamic and mid-brain areas integrating the defence reaction (Abrahams, Hilton & Malcolm, 1962) would be at least as effective in exciting the caudal strip, located in the present experiments. Thus, during a defence reaction elicited by a sufficiently intense noxious stimulus in the normal, non-anaesthetized animal the whole brain stem area from the hypothalamus rostrally to the medulla caudally would be activated together, so that, in skeletal muscle, inhibition of the on-going vasoconstrictor activity would accompany activation of the vasodilator nerve supply.…”

Section: Discussionmentioning

confidence: 87%

The pontomedullary area integrating the defence reaction in the cat and its influence on muscle blood flow

Coote¹,

Hilton²,

Zbrożyna³

1973

The Journal of Physiology

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119

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SUMMARY1. In anaesthetized cats the effects were investigated of electrical stimulation of regions in the caudal mesencephalon, pons and medulla on muscle blood flow, skin blood flow and arterial blood pressure.2. It was found that within the dorsal part of the well known pressor area there is a narrow strip, 2-5 mm lateral from the mid line, starting ventral to the inferior colliculus and ending in the medulla close to the floor of the IV ventricle, from which vasodilatation in skeletal muscles is selectively obtained. This strip is quite separate from the more ventral, efferent pathway for active vasodilatation running from the hypothalamic and rostral mesencephalic 'defence centre'.3. As in the case of the hypothalamic and rostral mesencephalic 'defence centre', the muscle vasodilatation obtained from the caudal strip is accompanied not only by a rise of arterial blood pressure, but also by tachycardia, vasoconstriction in the skin, pupillary dilatation and piloerection.

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“…Cutaneous, visual and auditory pathways converge on the brain-stem regions integrating the defence reaction; and the active muscle vasodilatation is a component of the pseudaffective reflex elicited in the highdecerebrate cat when these regions of the brain stem have been spared (Abrahams et al 1960b; Abrahams et al 1962). We therefore regard the integrative centre for the defence reaction as a reflex centre in the classical sense, and hence we would class this pattern of cardiovascular response as a preparatory reflex reaction.…”

Section: Discussionmentioning

confidence: 99%