Review Flashcards on Nervous System, Sensation, Perception, Hearing

Flashcards to review key concepts from lecture notes on the nervous system, sensation, perception, and hearing.

What are the three components of the hierarchy in the nervous system?

Cortex, brainstem, and spinal cord

What does the neocortex do in the motor system?

Plans and initiates movements

What is species-typical behavior?

Actions produced by every member of a species

What is a monosynaptic reflex?

Reflex requiring one synapse between sensory input and movement

What was the significance of Fritsch and Hitzig's experiment in 1870?

Electrical stimulation of a dog’s cortex produced movement of mouth, limbs, and paws

What did Wilder Penfield confirm about the motor cortex?

Confirmed the role of primary motor cortex in producing movement in humans using electrical stimulation.

What is the motor homunculus?

Topographical representation of the human body in the sensory or motor cortex

What is the function of the lateral corticospinal tract?

Moves the digits and limbs on the opposite side of the body

What is the function of the ventral corticospinal tract?

Moves the muscles of the midline body (trunk) on the same side of the body

Laterally located motor neurons project to muscles that control what?

Fingers and hands

Intermediately located motor neurons project to muscles that control what?

Arms and shoulders

Medially located motor neurons project to muscles that control what?

The trunk

What is the function of an extensor muscle?

Moves (extends) the limb away from the trunk

What is the function of a flexor muscle?

Moves the limb toward the trunk

What is Sensory Transduction?

Transformation of stimulus energy into nerve signals in our sense organs

What is perception?

The interpretation and processing of sensations (i.e., nerve signals).

What are the 4 common features across all sensory systems?

1) Receptors 2) Sensory pathways (sensory receptor-> Thalamus-> Cortex ) 3) Sensory processing and representation (sensory maps) 4) Perception, attention (awareness) and recognition (interpretation)

What is proprioception?

Information on the relative positions of the parts of the body

Define nociception.

Signals near-damage or damage to tissue concerning pain

Which sense maintains postural equilibrium and balance?

Vestibular sense

What is the main determinant of sensitivity of a sensory system?

Receptor density

What is light?

Electromagnetic energy that we see

What range of electromagnetic energy is visible to humans?

400 to 700 nanometers

What is refraction in the context of the eye?

Necessary to focus light rays and this is accomplished by the cornea and lens

What is accommodation in the eye?

The process in which the lens changes its shape, thus altering its refractive power

What is myopia?

When the light entering the eye is focused in front of the retina and distant objects cannot be seen sharply; nearsightedness

What is hyperopia?

When light entering the eye is focused behind the retina; farsightedness

What is the fovea?

Retina location with high photoreceptor (cones) density that is specialized for high acuity vision

What are the types of neurons in the retina?

Photoreceptors (Rods & Cones), Bipolar cells, Retinal ganglion cells (RGC), Horizontal cells, Amacrine cells

What are the functions of rods?

Used for dim light vision. Highly sensitive to light. Low spatial resolution. Achromatic vision, with more emphasis on detecting motion

What are the functions of cones?

Used for day vision. 1/10th of the rods' light sensitivity. High spatial resolution. Color vision, with more emphasis on detecting fine details

What is a receptive field?

The distinct region in the retina in which stimuli will activate a sensory neuron

How do on-center ganglion cells respond to light?

These cells are excited by light that falls on their center and inhibited by light that falls in their surround

How do off-center ganglion cells respond to light?

The cells are inhibited when light falls in their center and excited when light falls in their surround

What is topographical mapping in the visual cortex?

Close by areas in the visual field are ‘mapped’ onto close by areas in the cortex

What do V1 neurons behave like?

Feature detectors – Excited by bars of light oriented in particular directions

Where does the dorsal visual stream project to and what is its function?

Projects to the parietal cortex. The “how” or “where” pathway (how action is to be guided toward objects)

Where does the ventral visual stream project to and what is its function?

Projects to the temporal cortex. The “what” pathway (identifies what an object is)

What are the three types of cone pigments and their maximal absorptions?

419 nm (“blue” or short wavelength), 531 nm (“green” or middle wavelength), 559 nm (“red” or long wavelength)

What is the trichromatic theory of color vision?

Explanation of color vision based on the coding of three primary colors: red, green, and blue. The color we see is determined by the relative responses of the different cone types. Can explain different types of color blindness

What is the opponent-process theory of color vision?

Explanation of color vision that emphasizes the importance of the opposition of colors: Red versus green and Blue versus yellow. Opponent processing occurs in retinal ganglion cells.

What does the trichromatic theory explain?

Explains the responses of the cones in the retina, i.e., how different light wavelengths are detected.

What does the opponent-process theory explain?

Explains how color information is efficiently encoded at the level of the ganglion cells and LGN.

What are the functions of hearing?

Identification of sounds, localization of sounds, and communication

What defines the intensity (loudness) of a sound stimulus?

Sound pressure amplitude, usually measured in decibels (dB)

What is frequency in the context of sound?

Number of cycles within a given time period. Measured in Hertz (Hz) - 1 Hz is 1 cycle per second. Perception of pitch is related to frequency

What is a fundamental frequency?

The rate at which the complex waveform pattern repeats

What are overtones (harmonics)?

Set of higher frequency sound waves that vibrate at whole-number (integer) multiples of the fundamental frequency

What is the function of the outer ear?

Capture sounds

What is the function of the middler ear?

Transformer

What is the function of the inner ear?

Biological amplifier and analyzer

What is the tympanic membrane?

The eardrum; a thin sheet of skin at the end of the outer ear canal. Vibrates in response to sound

What is the cochlea?

Spiral structure of the inner ear filled with watery fluids in three parallel canals

What does the middle canal contain?

The basilar membrane with the organ of Corti

What happens at the basilar membrane when it is displaced?

Bends stereocilia against tectorial membrane and causes the release of neurotransmitters

What is the function of stereocilia?

Hairlike extensions on the tips of hair cells in the cochlea that initiate the release of neurotransmitters when they are flexed

What is tonotopic organization?

An arrangement in which neurons that respond to different frequencies are organized anatomically in order of frequency

What is the medial geniculate nucleus?

The part of the thalamus that relays auditory signals to the temporal cortex and receives input from the auditory cortex

What is Broca's area responsible for?

Anterior speech area in the left hemisphere that functions with the motor cortex to produce the movements needed for speaking

What is Wernicke's area responsible for?

Posterior speech area at the rear of the left temporal lobe that regulates language comprehension; also called the posterior speech zone

Where does analysis of speech take place?

Largely in the left hemisphere

Where does analysis of musical sounds take place?

Largely in the right hemisphere

What are binaural cues?

Location cues based on the comparison of the auditory signals received by the left and right ears

What is interaural time difference (ITD)?

Brain compares the difference in the time that a sound reaches the left and right ears

What is interaural level difference (ILD)?

Brain compares the difference in sound pressure level (intensity) of the sound that reaches the left and right ears. The head blocks some of the energy reaching the opposite ear