Sensory stimuli

Table 1. Stevens Law Exponents for Different Sensory Stimuli ...

Fig. 48.—Diagrammatic Representation of Independent and Inter>related Responses to Sensory Stimuli, Emphasizing the Distinction between Analytical and Affective Judgments. ...

Many electrophysiological studies have shown that single-unit activity of noradrenergic neurons in the locus coeruleus is increased by sensory stimuli. Effective stimuli range from those causing physical discomfort (e.g. footshock) and interoceptive... 

Collaterals from neurons of neighbouring specific thalamo-cortical relay nuclei. Because these neurons are themselves activated by sensory inputs transmitted along the spinothalamic tract, this provides one way in which sensory stimuli can influence cortical activity generally, as well as specifically. 

The generally accepted view is that the stimulatory drive for the ARAS comes from collaterals of the classical ascending sensory pathways. Indeed, this is another way in which sensory stimuli can affect our state of arousal (Fig. 22.5). The diffuse activating... 

Some of the TRPs are activated directly by sensory stimuli, but others are activated by a variety of intracellular chemical messengers [12] Initial... 

All animals exhibit innate behaviors in response to specific sensory stimuli that are likely to result from the activation of developmentally programmed neural circuits. Even the activation of single classes of olfactory neurons can trigger complex behaviors [10]. The authors observed that Drosophila exhibit robust avoidance to odors released by stressed flies. When stressed, the flies emit an odorant mixture that elicits avoidance in other flies. C02 is the active component of this mixture. Specific blockade of the activation of a particular odorant receptor... 

The midbrain (mesencephalon) is the top of the brain stem. The dorsal midbrain is the tectum, which is involved in eye movements and reflexive reactions to sensory stimuli. The mesencephalic reticular formation projects upward to the forebrain and is involved in arousal and attention. The periaqueductal gray area surrounds the cerebral aqueduct, and integrates analgesic, defensive/aggressive, sexual, and autonomic responses. The red nucleus and substantia nigra are important structures in motor function. 

Inglis EM, Fibiger HC. 1995. Increases in hippocampal and frontal cortical acetylcholine release associated with presentation of sensory stimuli. Neuroscience 66(1) 81-86. 

Holling, C. S. (1958). Sensory stimuli involved in the location and selection of sawfly cocoons by small mammals. Canadian Journal of Zoology 36,633-653. 

It contracts in response to an impulse of its motor nerve. In executing motor programs, the brain sends impulses to the spinal cord. These converge on a-moto-neurons in the anterior horn of the spinal medulla. Efferent axons course, bundled in motor nerves, to skeletal muscles. Simple reflex contractions to sensory stimuli, conveyed via the dorsal roots to the motoneurons, occur without participation of the brain. Neural circuits that propagate afferent impulses into the spinal cord contain inhibitory interneurons. These serve to prevent a possible overexcitation of motoneurons (or excessive muscle contractions) due to the constant barrage of sensory stimuli. 

This relationship explains why sensory stimuli that are conducted via 2000 Thieme... 

Earlier theories of attention such as that proposed by Broadbent (1958) suggested that some physical property of sensory stimuli dictates whether or not they are available to further processing (Fig. 1). Crucially Broadbent considered attention to be a real physical property of the nervous system, not a convenient psychological construct or metaphor. In this formulation early selection of stimuli is performed by a limited capacity filter and only selected stimuli are encoded. While this and similar models paved the way for experimental re-... 

Ketamine and also tiletamine are structurally and pharmacologically related to phencyclidine. Its mechanism of action is not well understood. It has been suggested that it blocks the membrane effects of the excitatory neurotransmitter glutamic acid. Ketamine produces dissociative anesthesia, which means that the patient seems to be awake but there are no responses to sensory stimuli. Ketamine, which can be administered IV or IM, has strong analgesic activity. It is especially indicated for interventions of short duration without any need for skeletal... 

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