Fundamentals of Sensory Systems Flashcards

Vocabulary practice flashcards generated from lecture notes on sensory systems, covering receptors, coding, pathways, cortical areas, and pathology.

Sensory System

The afferent arm of the nervous system consisting of sensory receptors, neural pathways, and brain areas that detect, conduct, and process information from the internal and external environment.

Sensory Information

Any information from the internal or external environment that is processed by the sensory system.

Sensation

Sensory information that successfully reaches conscious awareness.

Perception

The conscious understanding and interpretation of the meaning of a sensation.

Transduction

The process by which sensory receptors convert stimulus energy from one form into electrical signals known as receptor potentials.

Photoreceptors

Sensory receptors located in the eye that detect light stimuli to enable vision.

Mechanoreceptors

Sensory receptors in skin, joints, muscles, and inner ear that transmit mechanical deformation such as touch, pressure, hearing, and balance.

Thermoreceptors

Sensory receptors specialized for detecting changes in temperature.

Chemoreceptors

Receptors that detect chemical concentrations, responsible for smell and taste as well as monitoring internal factors like pH, $\text{CO}_2$, and $\text{O}_2$.

Nociceptors

Specialized sensory receptors that detect painful stimuli.

Sensory Unit

A single afferent neuron together with all of its peripheral sensory endings or associated specialized receptor cells.

Receptive Field

The specific region of the body where stimulation leads to electrical activity in a particular primary afferent neuron.

Modality

The specific form of physical energy represented by a stimulus, such as light, temperature, sound, or pressure.

Adequate Stimulus

The specific stimulus modality to which a particular sensory receptor is designed to respond best.

Threshold

The minimum stimulus intensity required to activate a receptor and trigger an action potential in a sensory neuron.

Recruitment

The activation of additional sensory units and afferent neurons in response to stronger stimulus intensities.

Sensory Adaptation

A decrease in the magnitude of the receptor potential and action potential firing frequency over time during continuous, constant stimulation.

Phasic Receptors

Rapidly adapting sensory receptors that fire action potentials primarily at the onset and end of a stimulus to track changes in the environment.

Tonic Receptors

Slowly adapting sensory receptors that maintain action potential firing throughout the entire duration of a sustained stimulus.

Acuity

The spatial precision with which a sensory stimulus can be localized and discriminated from an adjacent stimulus.

Divergence

A neuronal arrangement where a single presynaptic neuron branches to make synaptic contact with two or more postsynaptic neurons.

Convergence

A neural circuit pattern where multiple presynaptic neurons synapse onto a single postsynaptic neuron.

Lateral Inhibition

A mechanism in sensory processing where excited primary afferents activate inhibitory interneurons that suppress adjacent peripheral pathways, enhancing sensory contrast and acuity.

First-Order Neuron

The primary afferent sensory neuron that transduces stimuli in the periphery and carries signals into the CNS, with its cell body located in a dorsal root ganglion or cranial nerve ganglion.

Second-Order Neuron

An interneuron in the spinal cord or brainstem that receives synaptic input from first-order sensory neurons and ascends to synapse in the thalamus.

Third-Order Neuron

A neuron originating in the thalamus that receives input from second-order sensory neurons and projects directly to the primary sensory cortex.

Somatosensory Cortex

The primary brain region responsible for processing somatic sensations, located in the postcentral gyrus of the parietal lobe.

Cortical Association Areas

Brain regions adjacent to primary sensory cortices that perform complex processing, integration, and interpretation of sensory information.

Limbic System

A brain structure network that incorporates emotional significance and memory context into processed sensory information.

Synesthesia

A sensory processing disorder featuring crossovers between senses, where stimulation in one sensory modality triggers automatic experiences in another modality.

Sensory Neuron Diseases (SND)

Peripheral nervous system disorders caused by the degeneration of short and long peripheral axons and afferent sensory projections.