BMS1052 – Lesson 4a: Sensory Systems Introduction

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Questions and Answers

What initial change occurs in sensory receptor cells when stimulated?

Membrane potential change (correct)

Intracellular calcium increase

Chemical neurotransmitter release

Hyperpolarization of the cell

Which type of channel opens in response to stretch, leading to depolarization?

Stretch-sensitive Na+ channels (correct)

Ligand-gated Cl- channels

Calcium channels

Voltage-gated K+ channels

How do sensory neurons encode information from different stimuli?

By changing the type of neurotransmitter released

Via the length of the axon

By varying the amplitude of action potentials

Through the rate and timing of action potentials (correct)

In sensory coding, what does a rate code indicate?

Distinct firing rates correspond to various stimuli Signup and view all the answers

What is represented by neuronal spiking or firing in a sensory neuron?

Action potentials per second Signup and view all the answers

What aspect of action potentials is noted as being unpredictable or stochastic?

The timing of individual action potentials Signup and view all the answers

Which receptor type is activated by light energy?

G-protein coupled receptors Signup and view all the answers

What is the relationship between stimulus orientation and action potentials in a neuron?

Orientation influences the rate of action potentials produced Signup and view all the answers

What coding method is primarily focused on in sensory systems, except for the auditory system?

Rate coding Signup and view all the answers

Which one of the following accurately describes a somatotopic map?

A spatial representation of the skin surface in the somatosensory cortex Signup and view all the answers

In the visual cortex (V1), what do adjacent groups of neurons encode?

Adjacent spatial locations Signup and view all the answers

What does auditory cortex map in terms of sensory information?

Sound frequencies (pitch) Signup and view all the answers

Which of the following correctly describes a factor influencing sensory transmission?

The strength of the stimulus Signup and view all the answers

Which concept relates to the orderly representation of structures in sensory systems?

Topographic maps Signup and view all the answers

Which statement is true about rate and temporal codes in sensory systems?

Different neuronal systems might use either rate or temporal codes. Signup and view all the answers

What is the primary role of sensory neurons in sensory systems?

To extract information from the environment Signup and view all the answers

What does sensory coding suggest about neuron responses to identical stimuli across trials?

Responses are highly variable and unreliable across trials. Signup and view all the answers

Which statement correctly describes how different neurons respond to stimuli?

Neurons can be tuned for multiple stimulus features. Signup and view all the answers

What does rate coding theory propose about action potentials?

Only the total number of spikes in a time window matters. Signup and view all the answers

What is the primary difference between sensation and perception?

Sensation is the process of encoding stimuli, while perception interprets that information. Signup and view all the answers

How do temporal coding theories differ from rate coding theories?

They emphasize the timing of action potentials over the number. Signup and view all the answers

Which of the following accurately describes transduction in sensory systems?

Transduction is the conversion of one form of energy into another, such as light into neural signals. Signup and view all the answers

Which of the following is not a stimulus feature for neurons in the auditory cortex?

Motion direction Signup and view all the answers

What does the concept of a population of neurons encoding every stimulus help accommodate?

Variability and unreliability in neuron responses to stimuli. Signup and view all the answers

How does sensory receptor stimulation influence action potentials?

It produces a change in membrane potential called a receptor potential. Signup and view all the answers

In the context of sensory coding, what might affect the action potentials in somatosensory neurons?

Pressure and vibration frequency Signup and view all the answers

What role do physical structures like the eyeball and outer ear play in sensory systems?

They influence the transmission of stimulus energy to receptor cells. Signup and view all the answers

What is a significant characteristic of the mean response across trials in sensory coding?

It reflects the average variability of neuron responses. Signup and view all the answers

What is one example of sensation as described in the content?

Encoding sound pressure waves into action potentials. Signup and view all the answers

Which of these factors does NOT affect sensory transmission?

Personal cognitive experiences. Signup and view all the answers

Which of the following sensory modalities involves the detection of molecules and ions?

Taste and smell Signup and view all the answers

What is a key feature of sensory neurons as they relate to encoding stimulus information?

They are arranged in topographic maps representing sensory modalities. Signup and view all the answers

Study Notes

Sensation vs. Perception

Sensation encodes events and stimuli through the nervous system, relying on physical, biochemical, and neural events.
Perception interprets sensory information based on the brain's previous experiences.

Learning Objectives

Understand factors influencing sensory transmission and transduction.
Learn how stimulus information is encoded in action potentials.
Describe functional organization of sensory neurons into topographic maps.

Transduction

Transduction refers to converting one energy form into another (e.g., sound pressure waves for hearing, light energy for vision).
Physical structures like the eyeball and skin impact how stimulus energy reaches receptor cells.
Sensory receptors generate a change in membrane potential, called receptor potential, upon stimulus reception.

Sensory Coding

Sensory neurons encode information through the rate and timing of action potentials.
Rate code: Different stimuli lead to varied firing rates of action potentials.
Temporal coding: Timing of action potentials can provide additional stimulus information.

Neuronal Responses

A single neuron can respond variably to identical stimuli, necessitating encoding through a population of neurons for reliability.
Neurons can be tuned for various stimulus features, e.g., visual neurons respond to orientation and motion, while auditory neurons react to sound frequency and intensity.

Topographic Maps

Maps represent spatial information systematically, placing adjacent physical features nearby in the map.
Areas in the somatosensory cortex reflect a somatotopic map of the skin, while auditory cortex maps sound frequency and visual cortex represents visual space.

Overall Concepts

Action potential rates can vary, leading to representational differences of sensory information.
Both rate and temporal coding may be employed by different neuronal systems for effective communication of sensory data.

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Description

Explore the foundational concepts of sensation and perception in sensory systems. This quiz delves into how the nervous system encodes sensory stimuli and the brain's interpretation of these signals. Engage in understanding the differences and connections between sensation and perception.