Sensory Systems vocab

Action

Motor activities such as moving the head or the eyes, and locomoting through the environment. Action is one of the major outcomes of the perceptual process

Action potential

Rapid increase in positive charge in a nerve fiber (axon) that travels down the fiber. Also called nerve impulse or spike.

Afferent neurons

Neurons that carry action potentials from receptors in the sensory organs towards the central nervous system.

Auditory perception

The sense of "hearing", one of the five traditional senses

Bottom-up processing …

Processing that is based on stimulation of the receptors. Also called data-based processing.

Efferent neurons

Neurons that carry action potentials away from the central nervous system to effectors such as muscles.

Environmental stimulus

The stimulus "out there", in the external environment.

Dualism

A major philosophical approach stating that the mind has an existence separate from the material world of the body. mind and brain are two separate phenomena.

Gustatory perception

The sense of "tasting", one of the five traditional senses

Homunculus

A map-like representation of regions of the body in the brain

Materialism

A major philosophical approach stating that the only thing that exists is matter, and that all things, including the mind and consciousness, are the result of interaction between bits of matter. argue that mind and brain are both physical mediums.

Neuron

One of two cell types in the nervous system (along with the glial cells). Neurons are responsible for processing sensory, motor, cognitive, and affective information.

Olfactory perception

The sense of "smelling", one of the five traditional senses

Perception

The organization, identification, and interpretation of sensory information in order to represent, understand, and interact with the environment.

Primary receiving areas

Areas of the cerebral cortex that are first to receive most of the signals initiated by a sense's receptors. For example, the occipital cortex is the site of the primary receiving area for vision, and the temporal lobe is the site of the primary receiving area for hearing.

Receptive field

The area on the receptor surface (e.g., the retina for vision or the skin for touch) that, when stimulated, affects the firing of that neuron.

Receptor

A cell sensitive to environmental energy which changes this energy into electrical signals in the nervous system

Recognition

The ability to place an object in a category that gives it meaning - for example, recognizing a particular red object as a tomato or giving a physical sound a semantic meaning.

Sensory organs

Specialized organs that interact with environmental stimuli and that contain receptors that transduce a specific type of stimulus energy into nerve activity (e.g., the eye in vision or the skin in touch).

Sensory systems

The parts of the nervous system, which are responsible for processing sensory information (e.g., the somatosensory system is a sensory system).

Tactile perception

The sense of "touching", one of the five traditional senses.

Top-down processing

Processing that starts with the analysis of high-level information, such as knowledge a person brings to a situation. Also called knowledge-based processing. Distinguished from bottom-up, or data-based processing, which is based on incoming data.

Topographic maps

The ordered projection of a sensory surface (e.g., the retina or the skin) or an effector system (e.g., the musculature) to one or more structures of the central nervous system. Can be found in all sensory systems and in many motor systems.

Transducer

A "device" that converts a signal in one form of energy to another form of energy.

Transduction

In the senses, the conversion of environmental energy into electrical energy. For example, receptors in the eye transduce light energy into electrical energy.

Visual perception

The sense of "seeing", one of the five traditional senses.

Anterior

Toward the front end (antonym of posterior)

Autonomic nervous system (ANS)

The part of the PNS that influences the function of internal organs. Acts largely unconsciously and regulates the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.

Brainstem

The posterior part of the brain, adjoining and structurally continuous with the spinal cord. In humans, it is usually described as including the medulla oblongata, pons, and midbrain.

Brodmann area

A region of the cerebral cortex that is defined by its cytoarchitecture, or histological structure and organization of cells.

Central nervous system (CNS)

The brain and the spinal cord.

Cerebellum

A large, highly convoluted (in-folded) structure located dorsal to the brainstem at the level of the pons. Also known as "little cerebrum".

Cerebral cortex

The layered sheet of neurons that covers the surface of the brain and contains the machinery for creating perception, as well other functions, such as language, memory, and thinking. It is divided in two (lateral) hemispheres, each containing four major lobes.

Contralateral

On the opposite side of the body (antonym of ipsilateral)

Coronal plane

A plane that shows brain structures as seen from the front. Also called frontal plane.

Distal

Located more distant from the point of origin or attachment (antonym of proximal).

Dorsal

Toward the back, away from the ventral (stomach) side. The top of the brain is considered dorsal because it has this position in four-legged animals (antonym of ventral).

Dorsal

Toward the back, away from the ventral (stomach) side. The top of the brain is considered dorsal because it has this position in four-legged animals (antonym of ventral).

Gray matter

A major component of the central nervous system that contains primarily neuronal cell bodies.

Inferior

Below another part (antonym of superior)

Ipsilateral

On the same side of the body (such as two parts on the left, antonym of contralateral).

Lateral

Away from the midline of the body, toward the side

Medial

Toward the midline of the body, away from the side

Occipital lobe

One of the four major lobes of the cerebral cortex, which holds amongst others the primary visual cortex.

Parietal lobe

One of the four major lobes of the cerebral cortex, which holds amongst others the primary somatosensory cortex.

Peripheral nervous system (PNS)

The part of the nervous system apart from the brain and the spinal cord

Posterior

Toward the rear end (antonym of anterior).

Proximal

Located close (approximate) to the point of origin or attachment (antonym of distal)

Sagittal plane

A plane that shows brain structures as seen from the side.

Somatic nervous system

The part of the PNS that is associated with body movements through the control of skeletal (voluntary) muscles and with the reception of external stimuli.

Superior

above another part

Temporal lobe

One of the four major lobes of the cerebral cortex, which holds amongst others the primary auditory cortex

Thalamus

A group of nuclei, which provide primary sensory relay for somatosensory, gustatory, auditory, visual, and vestibular sensory inputs to the cerebral cortex.

Transverse plane

A plane that shows brain structures as seen from above. Also called horizontal plane.

Ventral

Toward the stomach, away from the dorsal (back) side (antonym of dorsal)

White matter

A major component of the central nervous system that contains millions myelinated axons (i.e., the wires between neuronal cell bodies).

Axon

A long projection of a neuron that typically conducts action potentials away from the neuron's cell body, also known as a nerve fiber

dendrite

Branching extensions of the neuron's plasma membrane that increase the surface area of the neuron and collect neuronal activity from other cells

Equilibrium potential

The membrane potential at which a particular type of ion has no driving force to diffuse through the plasma membrane in either direction. At the equilibrium potential, chemical and electrical gradients are equal in magnitude.

glia cells

Non-neuronal cells in the nervous system that provide support and protection for neurons.

Graded potential

A relatively small change in membrane potential, for example by opening ligand-gated ion channels. The strength of a graded potential is given relative to the strength of stimulation (compare action potential).

Neuron doctrine

The concept proposing that the neuron is the fundamental unit of the nervous system. Compare Reticular theory.

Postsynaptic

Referring to the neuron (or parts thereof) after the synapse with respect to the flow of information. Compare presynaptic.

Postsynaptic potential

Changes in the membrane potential of the postsynaptic neuron of a synapse. Postsynaptic potentials are graded potentials that are either excitatory or inhibitory.

Presynaptic

Referring to the neuron (or parts thereof) before the synapse with respect to the flow of information. Compare postynaptic

Reticular theory

An obsolete scientific theory in neurobiology that stated that the nervous system is made up of a single interlinking network. Compare Neuron doctrine.

Amygdala

A subcortical structure that is involved in emotional responding and in processing olfactory signals.

Chemotopic map

The pattern of activation in the olfactory system in which chemicals with different properties create a "map" of activation based on these properties. aka odor map

Glomeruli

Small structures in the olfactory bulb that receive signals from similar olfactory receptor neurons. One function of each glomerulus is to collect information about a small group of odorants.

Mitral cell

A neuron in the olfactory bulb that receives signals from olfactory receptor neurons and relays them to the brain. There are about 50,000 of these neurons in the human olfactory bulb.

Olfactory bulb

The structure that receives signals directly from the olfactory receptors. Contains glomeruli, which receive these signals from the receptors.

Olfactory epithelium

The region inside the nose that contains the receptors for the sense of smell.

Olfactory receptor

A protein string that responds to odor stimuli. Different olfactory receptor neurons are equipped with different olfactory receptors.

Oral capture

The condition in which sensation from both olfaction and taste are perceived being located in the mouth.

Papillae

Ridges and valleys on the tongue, some of which contain taste buds. There are three types of papillae: fungiform, foliate, and circumvallate.

Population coding

A general principle of sensory processing, according to which different values of perceptual attribute are coded by different patterns of activity in a whole population of neurons.

Recognition profile

The pattern of olfactory activation for an odorant, indicating which olfactory receptor neurons are activated by the odorant.

Retronasal Route

The opening from the oral cavity, through the nasal pharynx, into the nasal cavity. This route is the basis for the way smell combines with taste to create flavor.

Taste bud

A structure located within papillae on the tongue that contains the taste cells

Taste Cells

Cells located in taste buds that cause the transduction of chemical or electrical energy when chemicals contact receptor sites or channels located at the tip of this cell.

Taste pore

An opening in the taste bud through which the tips of taste sells protrude. When chemicals enter, they stimulate the taste cells and result in transduction.

Active touch

Touch in which the observer plays an active role in touching and exploring an object, usually with his or her hands.

Cortical magnification

The exaggerated cortical representation of one part of a sensory dimension or surface compared to another.

Cutaneous senses

The ability to perceive sensations, such as touch, temperature, and pain that are based on stimulation of receptors in the skin.

Dermis

The layer of skin below the epidermis

Epidermis

The outer layers of the skin, including a layer of dead skin cells

Kinesthesis

The perception of body movements. It involves being able to detect changes in body position and movements based on proprioception and the vestibular system

Mechanoreceptor

Receptor that responds to mechanical stimulation, such as pressure, stretching, or vibration.

Meissner corpuscle

A rapidly adapting mechanoreceptor in the skin. It has been proposed that the Meissner corpuscle is important for perceiving tactile slip and for controlling the force needed to grip objects.

Merkel receptor

A disk-shaped mechanoreceptor in the skin connected to slowly adapting sensory neurons. Associated with the perception of fine details.

Pacinian corpuscle

A mechanoreceptor in the skin with a distinctive elliptical shape. It transmits pressure to the sensory neurons inside it only at the beginning and the end of a pressure stimulus. Associated with the perception of vibration and the fine textures that are perceived when moving the fingers over a surface.

Passive touch

. A situation in which a person passively receives tactile stimulation.

Proprioception

The sensing of the position and movement of the limbs.

Rate code

A neuronal coding principle in which the firing rate of a neuron carries information about the stimulus. It is often associated with neural coding of magnitude (intensity of pressure, stretch, light intensity, or loudness).

Rapidly adapting (RA) receptor

Mechanoreceptors that respond with bursts of firing just at the onset and offset of a pressure stimulus. The Meissner corpuscle and the Pacinian corpuscle are rapidly adapting receptor.

Ruffini cylinder

A mechanoreceptor structure in the skin connected to slowly adapting sensory neurons. It has been proposed to be involved in perceiving "stretching".

Slowly adapting (SA) receptors

Mechanoreceptors located in the epidermis and the dermis that respond with prolonged activity to continued pressure. The Merkel receptor and the Ruffini cylinder are slowly adapting mechanoreceptors.

Somatosensory system

The system that includes the cutaneous senses (senses involving the skin) and proprioception (the sense of the position and movement of the limbs).

Two-point threshold

The smallest separation between two points on the skin that is perceived as two points; a measure of acuity on the skin.

Acoustic signal

The pattern of frequencies and intensities of the sound stimulus.