The most prominent sensory effects are buzzing in the visual and auditory senses. I understand this as a kind of ringing or hysteresis caused by slowed decay of transmitter signaling. Light and sound also seem amplified such that bright lights and noises are disturbing. There was a sort of synesthesia -- Unlike that of L in which deepening understanding of the the relationships among sensory data renders the source modality irrelevant, with P.H. synesthesia, it's as though the sensations are sloshing around so violently they spill over into each other's containers. Vertigo is very strong (whether or not caused by the visual and auditory effects) and it tends to elicit feelings of sickness. Usually these can be abated by lying down and closing ones eyes.

The Harmala alkaloids harmine, harmaline, and tetrahydroharmine are found in a variety of plants of which the most popular is the Banisteriopsis caapi vine. The most concentrated source of Harmala alkaloids is the seed of Peganum harmala, commonly known as Syrian Rue. The chemicals tend to produce bright colored imagery as it changes continually in a flowing transformation of dream-like sequences.

HARMINE -- 7-methoxy-1-methyl-9H-pyrido (3,4-b) indole.
Material: Indole-based alkaloid found in several places including
_Banisteriopsis caapi_ (from which the South American hallucinogenic
brew yage is prepared), _Peganum harmala_ (Syrian rue), _Zygophyllum
fabago_ and _Passiflora incarnata._
Usage: 25-750 mg harmine (see effects) is ingested on an empty
stomach. In its hydrochloride form harmine may be snorted (20-200
mg). Injection dosges are smaller: SC 40-70 mg, IV 10-30 mg.
Absorbed poorly through stomach. Small doses (20-200 mg) effective
intrabuccally and sublingually.
Effects: Harmine and related alkaloids are serotonin antagonists,
hallucinogen, CNS stimulants, and short-term MAO inhibitors (100 x MAO
inhibition of improniazid but lasting only several hours). Small
doses (25-50 mg) act as mild and therapeutic cerebral stimulant,
sometimes producing drowsy or dreamy state for 1-2 hours. Larger
doses up to 750 mg may have hallucinogenic effect, the intensity of
which varies widely with the individual. Doses of 25-250 mg taken
with LSD or psiolcybin alter the quality of the experience of the
latter. Telepathic experiences have been reported with this
combination.
Contraindications: Harmine is a brief MAO inhibitor. It should
not be used with alcohol and certain foods and drugs (see list). When
snuffed, harmine may be slightly irritating to nasal passages. Large
amounts may depress CNS. Since individual sensitivity varies this may
occur with 250-750 mg.
Supplier: CS.
Note: Notes on other harmala alkaloids: Different harmala
alkaloids vary in potency. The equivalent of 10 mg harine is 50 mg
harmaline, 35 mg tetrahydraharman, 25 mg harmalol or harmol, 4 mg
methoxyharmalan. Harmal alkaloids are synergistic (mutually
potentiating) and are therefore most effective when combined in an
appropriate balance. Tropines (belladonna alkaloids) also potentiate
harmals. Harmol and harmalol (phenols) in overdoses can cause
progressive CNS paralysis.

Susceptibility to Seizures

A persons susceptibility to having photosensitive seizures is influenced by several factors. Genetics plays a definite role, sex is a factor, and the persons general physical condition and current physical state also play a part.

Photosensitivity is more prevalent among females, about 1.69:1. A photosensitive mother has a one in four chance of having a photosensitive child, and having a photosensitive sibling raises the odds of photosensitivity. Evidence of photosensitivity passing through the father's genes is inconclusive.

Physical factors that have been suspected as an influence are tiredness, influenza, alcohol and premenstrual state.

Light/sound machines are probably stronger seizure triggers than TV sets, because of the regularity of the stimulation, but the population using light/sound is minuscule compared to the one using TV, so relatively little research has been devoted to comparisons.