Behavioral and Neural Signatures of Visual Imagery Vividness Extremes: Aphantasia versus Hyperphantasia.

Although Galton recognized in the 1880s that some individuals lack visual imagery, this phenomenon was mostly neglected over the following century. We recently coined the terms "aphantasia" and "hyperphantasia" to describe visual imagery vividness extremes, unlocking a sustained surge of public interest. Aphantasia is associated with subjective impairment of face recognition and autobiographical memory.

Phantasia-The psychological significance of lifelong visual imagery vividness extremes.

Visual imagery typically enables us to see absent items in the mind's eye. It plays a role in memory, day-dreaming and creativity. Since coining the terms aphantasia and hyperphantasia to describe the absence and abundance of visual imagery, we have been contacted by many thousands of people with extreme imagery abilities.

Two kinds of tryptamine receptor. 1957.

There are two kinds of tryptamine receptor in the guinea-pig ileum, namely the M receptors which can be blocked with morphine and the D receptors which can be blocked with dibenzyline. Atropine, an atropine-like drug, cocaine, and methadone inhibit effects due to the M receptors, even after dibenzyline, but have no additional effect after morphine. Lysergic acid diethylamide, dihydroergotamine and 5-benzyloxygramine inhibit effects due to the D receptors, even after morphine, but have no additional effect after dibenzyline.

AN IMPROVED MICROBATH.

A method is described for the study of the actions of drugs and tissue extracts on small pieces of smooth muscle suspended in a bath with a capacity of 0.027 ml. The small size of the bath is an advantage when the total amount of active substance is small.

Assay of substance P on goldfish intestine in a microbath.

A technique is described for testing the effects of drugs on the intestine of goldfish in a microbath (0.05 ml.).

Assay of substance P on the fowl rectal caecum.

The optimum conditions for the assay of substance P on fowl rectal caecum have been studied. Effective concentrations vary from 0.01 to 0.

A comparison of the kallikrein-kinin system in sheep and dogs.

Three preparations of kallikrein, made from the urine of man, dog and sheep, all formed active kinins when incubated with the plasma of sheep or dogs. The six kinins could not be distinguished from one another by parallel assays on guinea-pig ileum, rat uterus and rat duodenum; they are thought to be identical, or nearly so. As judged by the amount of kinin produced, a sample of dog plasma appeared to contain about 4.

The extraction of human urinary kinin (substance Z) and its relation to the plasma kinins.

Human urinary kinin (substance Z) has been extracted by modifications of the methods previously described by Gomes (1955) and Jensen (1958). The separation of two oxytocic fractions from such extracts by paper pulp chromatography (Walaszek, 1957; Jensen, 1958) could not be confirmed. Substance Z could not be distinguished from kallidin, bradykinin or glass-activated kinin by parallel quantitative assays, thus confirming that these four substances are very closely related.

A microbath.

A microbath, with a volume of less than 50 cubic millimetres, for testing the effects of drugs on small pieces of smooth muscle, is described. Drugs are applied automatically in any desired order and the record of their effects is amplified electrically. In this apparatus the response of small pieces of rat uterus to drugs is apt to be nearly all-or-none.

Two kinds of tryptamine receptor.

There are two kinds of tryptamine receptor in the guinea-pig ileum, namely the M receptors which can be blocked with morphine and the D receptors which can be blocked with dibenzyline. Atropine, an atropine-like drug, cocaine, and methadone inhibit effects due to the M receptors, even after dibenzyline, but have no additional effect after morphine. Lysergic acid diethylamide, dihydroergotamine and 5-benzyloxygramine inhibit effects due to the D receptors, even after morphine, but have no additional effect after dibenzyline.