How can relay neurons have very large or very small receptive fields?

Many primary neurons can converge on one secondary signaling neuron or just one or a few primary neurons can reach the trasmitting neuron. In the later case, more signals are generated given the same stimulus applied to the same area

The process by which stimulus energy from a neurological input is converted into the electrochemical energy used by signaling neurons is called what?

Stimulus transduction

What is the principle called by which key attributes of a stimulus must be represented in the signals of the primary sensory neuron?

This is neural encoding

This is the concept where sensory information much be fine-tuned to achieve maximal discriminative capacity

Lateral inhibition

What is important to note about the waveform of the signal that comes from a sensory neuron with regard to the source?

The waveform is a function of the stimulus and the receptor type

The amplitude of a sensory stimulus is simply a function of what?

The strength of the stimulus

How does the process of lateral inhibition work and how does it contribute to sensory discrimination?

The sensory neuron that receives the strongest signal from a given input sends a negating inhibitory signal right to the neighboring terminals which prevents them from firing; this highlights the primary input and lowers the amount of sensory noise

To what part of the brain are most sensory pathways routed?

The thalamus; this then modifies and relays the information it receives to the cortical centers

These function as stretch receptors in skeletal muscle and function to detect stretching and pattern changes in body parts

Muscle spindles

What is interesting to note about the different response rates of primary and secondary sensory neurons in muscle spindles?

Primary sensory neurons adapt rapidly while secondary neurons adapt more slowly

For sound waves and their sinusodal form, what is a cycle?

A cycle is defined as the distance from one sound wave peak to the next peak

This is the part of the outer ear that collects sound waves and directs them to the auditory canal. This also aids in sound localization and amplifies high-frequency sounds

The pinna

This part of the ear contains the tympanic membrane (which vibrates when struck by sound waves) which then moves to activate the malleus, incus and stapes (in that order)

The middle ear

The malleus-incus-stapes structure of the middle ear leads directly to the oval window which serves what function?

It is the opening of and transmits sound energy to the cochlea of the inner ear

What are the key biomechanics of a cross section of the cochlea?

Its movement is based on the movement of 2 membranes in an alternating motion which stretch then relax bundles of nerves

In the auditory system, where are hair cells found and what functions do they serve?

They are found in the cochlea (of the inner ear) and are key to detection of the position and movement of the head and they also direct compensationary movements of the eyes and help to maintain balance, all in addition to their fuction in sound tranduction

What happens when there is "tension" applied to the hair cells?

Ion channels open in response to the physical stimulation and and depolarization results

What is critical to note about the de- and repolarization of hair cells by the endolymph fluid?

Both are achieved through potassium

In the graphs of characteristic frequencies, what appears when higher frequency sounds are analyzed?

A wide, single peak appears which is not present in the graphs of lower frequency sounds

As you go along the length of the basilar membrane, how do the encoded frequency and physical structure of the cochlea change?

The frequency decreases in compression and the structure becomes more "floppy"

What is important to note about auditory cortex input?

The auditory complex in each hemisphere receives inputs from both ears

This is the first place where signals from the two ears come together and can be compared

The superior olive

Cells in the lateral superior olive look for differences in what?

Sound intensity

Cells in the medial superior olive look for what?

Particular timing differences in auditory signals

In terms of sound localization cues, intensity differences work best for (blank) frequencies while timing differences work best for (blank) frequencies

High, low

How doesthe MSO compute the location of a sound by interaural time differences?

The leading neuron along the x axis to which the two signals arrive as close to simultaneously as possible produces the strongest effective signal which occurs at a specific point along said axis