Behavioral Neuroscience Vocabulary

Vocabulary flashcards based on lecture notes on Behavioral Neuroscience, Tenth Edition by S. Marc Breedlove and Neil V. Watson.

Accommodation

The variation in the eye’s optical power brought about by temporary changes in the shape of the lens.

Amacrine Cell

A type of cell in the retina that transmits electrical signals from the bipolar cells to the ganglion cells, influencing the rate at which those signals are generated over time.

Amblyopia

A developmental disorder of the visual system in which an eye fails to achieve normal visual acuity, despite the absence of structural abnormalities.

Bipolar Cells

Type of cell in the retina that transforms electrical signals from the photoreceptors into action potentials; these cells play a crucial role in generating ON and OFF responses.

Blind Spot

The region of the eye where the optic nerve penetrates the retina; also, the region where major blood vessels enter and exit the eye’s interior.

Ciliary Muscle

A muscle in the eye that controls the shape of the lens, enabling accommodation.

Complex Cortical Cell

A category of visual cortical cell whose receptive field layout makes the cell responsive to the length of a contour and, in some instances, the presence of contours forming angles and corners.

Cones

Photoreceptors that are specialized for daylight and color vision.

Cornea

The transparent portion of the eye’s front surface, which refracts light and allows it to pass into the eyeball.

Extraocular Muscles

In humans, six large muscles attached to the globe of the eye; by rotating the eyeball within the orbit, the coordinated contractions of these muscles control the direction of gaze.

Extrastriate Cortex

Areas of cortex outside V1 that are involved in vision.

Fovea

Pit or depression in the retina; the region of sharpest vision.

Ganglion Cells

Cells within the retina with center/surround receptive field organization; axons of the retinal ganglion cells constitute the optic nerve.

Horizontal Cells

A type of cell in the retina that modulates the strength of signals generated by neighboring photoreceptors.

Hue

Dominant wavelength of color.

Iris

The two-layered ring of tissue that gives the eye its characteristic color.

Lateral Geniculate Nucleus (LGN)

A group of nerve cell bodies arranged in layers in the thalamus, each layer receiving input from either the left eye or the right eye; the major relay station between the eye and the visual cortex.

Lateral Inhibition

The capacity of an excited neuron to reduce the activity of its neighbors, increasing contrast and sharpness in visual response.

Lens

The transparent, flexible, and curved structure in the eye that focuses light onto the retina.

Macular Degeneration

A relatively common ocular disorder in which fluid pressure builds up within the eyeball, eventually causing blindness if not corrected.

Magnocellular

Referring to the large cells in the lateral geniculate nucleus that are involved in processing motion and spatial information.

Mirror Neuron

A type of neuron that fires both when an individual performs an action and when the individual observes the same action performed by another.

Myopia

Referring to an abnormally long eye, in which the retinal image is blurred because the eye’s focal point lies in front of the retina.

Occipital Lobe

The region of the brain located at the back of the head that is primarily responsible for visual processing.

Ocular Dominance Column

A perpendicular column of neurons in V1 with similar ocular dominance characteristics.

Ocular Dominance Slab

A section of visual cortex containing a set of ocular dominance columns that together represent the full range of ocular dominance characteristics.

Off-Center Bipolar Cell

A type of bipolar cell in the retina that is inhibited by light in the center of its receptive field and excited by light in the surrounding area.

Off-Center Ganglion Cell

A type of ganglion cell in the retina that is inhibited by light in the center of its receptive field and excited by light in the surrounding area.

Off-Center/On-Surround

A receptive field organization where the center is inhibited by light and the surround is excited by light.

On-Center Bipolar Cell

A type of bipolar cell in the retina that is excited by light in the center of its receptive field and inhibited by light in the surrounding area.

On-Center Ganglion Cell

A type of ganglion cell in the retina that is excited by light in the center of its receptive field and inhibited by light in the surrounding area.

On-Center/Off-Surround

A receptive field organization where the center is excited by light and the surround is inhibited by light.

Opponent-Process Hypothesis

A theory proposing that color perception is controlled by the activity of two opponent systems: a blue-yellow mechanism and a red-green mechanism.

Opsin

The non-light-absorbing component of rhodopsin.

Optic Ataxia

A disorder characterized by difficulty in reaching for objects under visual guidance, often due to damage in the dorsal stream of visual processing.

Optic Chiasm

The X-shaped structure located at the base of the brain where the optic nerves from each eye partially cross. This crossing allows visual information from the right visual field of both eyes to be processed in the left hemisphere of the brain, and vice versa.

Parvocellular

Referring to the small cells in the lateral geniculate nucleus that are involved in processing color and fine detail.

Photon

A particle representing a quantum of light or other electromagnetic radiation.

Photopic System

The visual system that operates under well-lit conditions and is responsible for color vision and high visual acuity; primarily involves cone photoreceptors.

Photoreceptor Adaptation

The process by which photoreceptors adjust their sensitivity to light levels, allowing the visual system to operate effectively under varying illumination conditions.

Photoreceptors

Specialized cells in the retina (rods and cones) that detect light and initiate the process of vision.

Primary Visual Cortex (V1)

The first cortical area involved in processing visual information, located in the occipital lobe.

Pupil

The central opening of the iris that regulates the amount of light entering the eye.

Range Fractionation

A hypothesis suggesting that different sensory receptors specialize in detecting different ranges of stimulus intensities, allowing the system to cover a wide range of intensities.

Receptive Field

The specific region of sensory space (e.g., visual field) to which a sensory neuron responds.

Refraction

The bending of light as it passes through different media, such as from air into the eye, which helps focus images on the retina.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors and other neurons involved in processing visual information.

Retinal

A form of vitamin A aldehyde; one of the two components of photopigments in the retina.

Rhodopsin

The photopigment found in rod photoreceptors that is responsible for detecting low-light conditions.

Rods

Photoreceptors in the retina that are sensitive to low light levels and are responsible for night vision.

Saccades

Rapid, jerky movements of the eyes that shift the focus of gaze from one point to another.

Scotoma

An area of partial or complete loss of vision surrounded by a field of normal vision, often resulting from damage to the retina or visual pathways.

Scotopic System

The visual system that operates under low-light conditions and is responsible for black-and-white vision; primarily involves rod photoreceptors.

Simple Cortical Cell

A neuron in the visual cortex that responds to specific features such as edges, bars, or gratings of a particular orientation.

Spatial-Frequency Filter Model

A model of visual processing that suggests the visual system analyzes images by decomposing them into spatial frequency components.

Spectrally Opponent Cell

A visual receptor cell that has opposite firing responses to different regions of the spectrum, contributing to color vision.

Trichromatic Hypothesis

The theory that color vision is based on the activity of three types of cone photoreceptors, each sensitive to different wavelengths of light (short, medium, and long).

Visual Acuity

The sharpness or clarity of vision, typically measured by the ability to distinguish fine details.

Visual Field

The entire area that can be seen when the eyes are fixed in one position, encompassing the central and peripheral vision.

Wavelength

The distance between successive peaks of a wave, such as a light wave, which determines the color perceived in vision.

α-Synuclein

A protein predominantly found in the brain that is associated with the regulation of neurotransmitter release. Abnormal accumulation of α- synuclein is a hallmark of several neurodegenerative diseases, including Parkinson’s disease.

Acetylcholine (Ach)

A neurotransmitter that plays a crucial role in both the central and peripheral nervous systems. It is involved in muscle activation at the neuromuscular junction and also functions in various brain regions related to attention, learning, and memory.

Actin

A globular protein that polymerizes to form microfilaments, which are part of the cytoskeleton in eukaryotic cells. Actin filaments are involved in various cellular processes, including muscle contraction and cell division.

Acute Flaccid Myelitis (AFM)

A rare but serious neurological condition characterized by sudden onset of arm or leg weakness, often associated with viral infections that affect the spinal cord.

Alpha Motor Neuron

Large motor neurons located in the spinal cord and brainstem that innervate extrafusal muscle fibers, leading to muscle contraction. They are the final common pathway for motor commands from the central nervous system to skeletal muscles.

Amyotrophic Lateral Sclerosis (ALS)

A progressive neurodegenerative disease that affects motor neurons, leading to muscle weakness, paralysis, and eventually respiratory failure.

Antagonist

A substance that binds to a receptor and blocks or dampens the biological response that would normally be elicited by an agonist.

Apraxia

A motor disorder caused by brain damage, characterized by the inability to perform purposeful movements or use objects correctly, despite having the physical ability to do so.

Ataxia

A neurological sign consisting of lack of voluntary coordination of muscle movements, which can affect gait, posture, and speech.

Autoimmune Disorder

A condition in which the immune system mistakenly attacks the body’s own tissues, leading to inflammation and damage.

Ballistic Movement

Rapid, involuntary movements that are performed without feedback from sensory information during the movement, such as a reflex.

Basal Ganglia

A group of subcortical nuclei involved in the regulation of voluntary motor movements, procedural learning, and routine behaviors or habits.

Bovine Spongiform Encephalopathy (BSE)

A prion disease affecting cattle, characterized by spongy degeneration of the brain and associated with the consumption of contaminated feed.

Central Pattern Generator

Neural circuits that produce rhythmic outputs in the absence of rhythmic input, responsible for generating repetitive movements such as walking or breathing.

Cerebrocerebellum

The part of the cerebellum involved in the planning and execution of voluntary movements, particularly those requiring fine motor control.

Closed-Loop Control Mechanism

A system in which the output is fed back into the system to regulate its own activity, maintaining stability and accuracy in motor control.

Cre-Recombinase

An enzyme used in genetic research to induce recombination between specific DNA sequences, facilitating gene knockout or modification in targeted cells.

Creutzfeldt-Jakob Disease (CJD)

A rare, degenerative, and fatal brain disorder caused by prions, leading to rapid cognitive decline, motor dysfunction, and death.

Decomposition of Movement

A condition where complex movements are broken down into simpler components, often due to neurological disorders affecting motor planning.

Deep Brain Stimulation (DBS)

A neurosurgical procedure involving the implantation of a device that sends electrical impulses to specific brain regions, used to treat movement disorders like Parkinson’s disease.

Dystrophin

A protein that helps maintain the structural integrity of muscle cells; mutations in the gene encoding dystrophin lead to muscular dystrophies.

Electromyography (EMG)

A diagnostic procedure that measures the electrical activity of muscles at rest and during contraction, used to assess the health of muscles and the nerve cells that control them.

Extrafusal Fiber

The standard muscle fibers that generate force and are responsible for muscle contraction; they are innervated by alpha motor neurons.

Extrapyramidal System

A network of brain structures involved in the regulation of involuntary movements and coordination, including the basal ganglia and related pathways.

Fast-Twitch Muscle Fiber

Muscle fibers that contract quickly and powerfully but fatigue rapidly; they are adapted for short bursts of strength or speed.

Final Common Pathway

The last route through which all motor commands pass before reaching the muscles; it includes the alpha motor neurons.

Flaccid Paralysis

A type of paralysis characterized by weakness or loss of muscle tone, leading to limp muscles; often due to damage to lower motor neurons.

Gamma Motor Neuron

Motor neurons that innervate intrafusal fibers within muscle spindles, playing a role in muscle tone regulation and proprioception.

Golgi Tendon Organ

Sensory receptors located at the junctions between muscles and tendons that detect changes in muscle tension and help prevent muscle damage.

Huntingtin

A protein encoded by the HTT gene; mutations in this gene lead to Huntington’s disease, characterized by motor dysfunction and cognitive decline.

Huntington’s Disease

A neurodegenerative disorder caused by a genetic mutation leading to progressive motor dysfunction, cognitive decline, and psychiatric symptoms.

Ideational Apraxia

A disorder characterized by the inability to conceive or plan a series of motor actions needed to perform a task, despite having the physical ability to do so.

Ideomotor Apraxia

A condition where individuals can perform automatic or habitual movements but struggle with

Innervation Ratio

The number of muscle fibers innervated by a single motor neuron. Muscles that require fine control (like those in the eye) have a low innervation ratio, while those involved in gross movements (like the legs) have a high innervation ratio.

Intrafusal Fiber

Specialized muscle fibers found inside muscle spindles that detect changes in muscle length and are innervated by gamma motor neurons.

L-dopa

A precursor to dopamine that is used as a treatment for Parkinson’s disease; it crosses the blood-brain barrier and is converted to dopamine in the brain.

loxP

A specific DNA sequence recognized by Cre-recombinase, allowing scientists to insert, delete, or rearrange genes at targeted sites in genetic engineering.

Motor Unit

A single motor axon and all the muscle fibers that it innervates.

Muscle Spindle

A specialized sensory organ found in most skeletal muscles that provides mechanosensory information about muscle length.

Muscular Dystrophy (MD)

A group of genetic disorders characterized by progressive muscle weakness and degeneration due to defects in muscle proteins.