Sleep/Wake Cycle
The state of being aware of and able to perceive one's thoughts, feelings, sensations, and surroundings.
Consciousness
Drugs that alter perception, mood, and cognitive processes, often causing hallucinations or profound changes in consciousness.
Hallucinogens
Minimum level of stimulus needed for detection.
Determines if a stimulus can be noticed at all.
Absolute Threshold
The measure of the intensity or loudness of a sound wave, represented by the height of its peaks.
Amplitude
Central area of the retina responsible for sharp central vision. It contains a high concentration of cone cells (no rods), enabling detailed and color vision.
Fovea
A sleep disorder characterized by excessive daytime sleepiness, sudden episodes of muscle weakness (cataplexy), sleep paralysis, and hallucinations during sleep onset or awakening.
Narcolepsy
Drugs that slow down neural activity and bodily functions. They induce relaxation, sedation, and can lower inhibitions
Depressants
The process by which sensory receptors become less responsive to constant stimuli over time.
Sensory Adaptation
The brain's ability to determine the location of a sound source in space. It relies on cues such as differences in arrival time and intensity between the ears, as well as spectral cues, to accurately locate sounds.
Sound Localization
Neurons in the retina that receive visual information from bipolar cells and transmit it to the brain via the optic nerve. They play a crucial role in processing visual signals and relaying them to the brain for further interpretation.
Ganglion Cells
The phenomenon where the body increases the time spent in REM sleep after a period of REM deprivation.
REM Rebound
A highly addictive opioid drug derived from morphine. It produces intense euphoria, pain relief, and sedation by binding to opioid receptors in the brain.
Heroin
A condition in which stimulation of one sensory pathway leads to automatic, involuntary experiences in another sensory pathway.
Synesthesia
In the ear this occurs in the cochlea, where hair cells convert sound vibrations into electrical signals that are sent to the brain.
Transduction
A type of color vision deficiency where an individual has only two types of functioning cone cells instead of the normal three. This condition typically results in difficulty distinguishing between certain colors, especially reds and greens.
Dichromatism
A theory proposing that dreams are the result of random neural activity in the brainstem during REM sleep, which is then interpreted and synthesized by the cerebral cortex into a narrative or story.
Activation-Synthesis (Dreams)
Medications that block the reabsorption of neurotransmitters by the sending neuron, thereby increasing the concentration of neurotransmitters in the synaptic cleft and enhancing neurotransmission.
Reuptake Inhibitors
Fluid-filled structures in the inner ear that detect rotational movements of the head. They play a crucial role in the vestibular sense, helping to maintain balance and coordination by sending signals to the brain about changes in head position and movement.
Semicircular Canals
Idea that different parts of the inner ear detect different sound frequencies. High pitches are sensed near the entrance, low pitches near the end.
Place Theory
A neurological condition characterized by the inability to recognize familiar faces, including one's own face, despite intact vision and intellect. It's often referred to as face blindness.
Prosopagnosia
A sleep disorder commonly known as sleepwalking, characterized by walking or performing other activities while still asleep. It typically occurs during non-REM sleep stages and can result in injuries or accidents.
Somnambulism
Substances that bind to neurotransmitter receptors without activating them, blocking the effects of neurotransmitters
Antagonists
The sense of body movement and position, including the awareness of muscle and joint sensations. It allows us to perceive and control our body's movements, providing feedback to the brain about the position and orientation of body parts.
Kinesthesis
A theory of pitch perception proposing that the frequency of a sound wave directly corresponds to the rate at which auditory nerve fibers fire. Higher frequency sounds lead to faster firing rates, resulting in higher perceived pitches.
Frequency Theory
A theory proposing that color vision is based on pairs of opposing color processes (red-green, blue-yellow, and black-white).
Opponent-Process Theory