Acadeca '23-'24

5-HT (5-hydroxytryptamine)

5-HT (5-hydroxytryptamine)

neurotransmitter that is also known as serotonin; notable for its function in mood and emotion

Absolute refractory period

the interval of time immediately following an action potential during which a second action potential cannot be initiated, as the voltage-gated sodium channels have not returned to their closed state and are not ready to be opened again

Absorption spectra

the specific wavelengths of light absorbed by a particular substance; in neuroscience, this refers to the opsins found in cone photoreceptors, each of which absorbs and transduces a different wavelength of light.

Action potential

the basic event nerve cells use to transmit information from one place to another; a brief and drastic change in the membrane potential of a neuron, caused by the rapid opening and closing of ion channels

Active transport

the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration, meaning against the concentration gradient; energy is required to achieve this movement.

Active zone

the site of neurotransmitter release

Afferents

nerves/axons that bring information to the central nervous system or brain

Afterhyperpolarization

the phase of a neuron's action potential when the cell's membrane potential falls below the normal resting potential; commonly referred to as the undershoot phase

Agonist

a substance that binds to a receptor and causes the same action as the substance that normally binds to the receptor

Akinetopsia

a condition defined by the inability to detect motion

All-or-none principle

This principle refers to the fact that a nerve signal is sent at the same intensity regardless of the intensity of the initial impulse as long as an initial threshold is met, and thus the neuron fires at full strength or not at all.

Allosteric site

a binding site on a protein where molecules can bind that is different from the main binding site that the usual binding partner uses (used by non-competitive agonists and antagonists)

AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor

a type of ionotropic receptor for glutamate that allows sodium influx, depolarizing the cell and mediating excitatory neurotransmission

Amygdala

a subcortical structure in the temporal lobe of the brain that is associated with regulating emotion; a major component of the limbic system

Antagonist

a substance that prevents the binding or the action of a substance that normally binds to a receptor

Anterolateral spinothalamic system

one of the ascending systems that brings sensory information from the body to the brain (specifically, pain and temperature)

Arachnoid membrane

the middle layer of the three protective membranes (meninges) that cover the brain and spinal cord; characterized by long, stringy components that look like spider webs

Area MT

a region in the parietal lobe of the cortex that is involved with motion perception

Artificial intelligence

computer systems that are able to perform tasks that typically require human intelligence

Artificial neural networks

Developed to allow computers to mimic existing networks of neurons in the brain, these networks involve layers of nodes that are analogous to neurons.

Astrocyte

a large, star-shaped glial cell in the brain

Autonomic nervous system

a component of the peripheral nervous system that regulates involuntary physiologic processes, including heart rate, blood pressure, respiration, digestion, and sexual arousal

Axon

a long cord-like portion of the neuron's structure that conducts electrical impulses or action potentials away from the cell body

Axon hillock

the site of transition between the cell body and the axon; controls the initiation of an electrical impulse

Axon terminal

the end region of an axon that contains neurotransmitters for neural communication

Barrel field

an area of a rodent's primary somatosensory cortex representing the touch or somatosensory inputs of each of their whiskers

Basal ganglia

a cluster of nuclei deep in the cerebral hemispheres of the brain that is critical for voluntary bodily movement and motivation

Basilar membrane

the flexible membrane inside the cochlea where auditory transduction takes place, which encodes the frequency or pitch of a sound based on its position along the membrane

Binocular vision

vision that incorporates inputs from both eyes into a single image

Bipolar cells

cells that connect photoreceptors to ganglion cells in the retina

Blood brain barrier

a highly selective lining of the blood vessels in the brain that keeps certain molecules or infectious agents from gaining access to the central nervous system

BOLD imaging

a mechanism that functional MRI (fMRI) uses to record neural activity by tracking oxygenated blood flow in the brain; BOLD is an acronym for Blood Oxygen Level Dependent.

Brain-machine interface (BMI)

a system that allows a person to control a device or machine with their own brain by way of implanted electrodes

Brainstem

a stalk-like structure that connects the brain to the spinal cord; regulates many of the body's critical functions, including breathing, heart rate, coordination, and reflexes

Calcium calmodulin-dependent protein kinase (CaMKII)

a protein kinase activated by an increase in internal Ca²⁺ concentration; involved in several mechanisms that result in LTP

Center-surround receptive field

a visual receptive field with a circular center region and a surround region; stimulation of the center produces a response opposite of the response generated by stimulation of the surround.

Central canal

a narrow tube through the length of the entire spinal cord that contains the cerebrospinal fluid (CSF); part of the ventricular system

Central nervous system (CNS)

the part of the nervous system that is encased in bone; made up of the brain and spinal cord

Cerebellar deep nuclei

nuclei found deep within the cerebellum that provide the output from this structure

Cerebellum

a structure at the rear of the brain that is responsible for controlling balance and other complex motor functions

Cerebral aqueduct

a conduit that allows cerebrospinal fluid to flow between the third and fourth ventricle of the brain; part of the ventricular system

Cerebral cortex

the outermost, wrinkly layer of the brain that plays an important role in memory, thinking, learning, reasoning, problem-solving, emotions, consciousness, and functions related to the senses

Cerebral hemispheres

each of the two parts of the cerebrum (left and right) in the brain

Cerebrospinal fluid (CFS)

fluid that cushions and protects the brain; produced by the choroid plexus; flows through the ventricular system to the subarachnoid space

Cervical spinal cord

the top section of the spinal cord that carries information to and from (innervates) the arms, neck, and shoulders

Channel

an opening or passageway for an ion to pass from one side of a membrane to the other

Channelrhodopsin-2 (ChR2)

a light-sensitive cation channel, which was originally isolated from green algae; can be artificially expressed in neurons and then used to control the activity of that neuron using specific wavelengths of light

Chemical driving force

a force that is a result of an ion concentration gradient across the cell membrane which encourages ions to move

Chemical synapses

a type of synapse in which presynaptic activity stimulates the release of neurotransmitters, activating receptors in the postsynaptic membrane

Choroid

a network of blood vessels located between the sclera and the retina; brings oxygen and nutrients to the retina

Choroid plexus

a network of blood vessels in each ventricle of the brain that produce the cerebrospinal fluid

Classical conditioning

a learning procedure in which a stimulus that evokes a response is paired with another neutral stimulus that normally does not evoke this response; an association between these stimuli is then learned.

Cochlea

the section of the inner ear where auditory transduction takes place, translating sound waves into electrochemical signals

Competitive agonist

a substance that competes for the same receptor binding site as the endogenous neurotransmitter

Competitive antagonist

a molecule that competes for the same binding site as the natural (endogenous) neurotransmitter and has the opposite effect as that transmitter

Computational neuronal modeling

the use of computer algorithms to model the behavior of neurons to learn more about their processes

Computational psychiatry

a field of psychiatry that uses computer algorithms in behavior testing to provide clinicians with more data about psychiatric patients and gather insight about the effect of treatments

Concentration gradient

the difference in concentration of a substance between one location and another

Cone

a photoreceptor type concentrated in the fovea of the retina; specialized for daytime vision and responsible for color vision

Conformation

the shape of a receptor

Congenital analgesia

insensitivity to pain, or pain blindness, present from birth

Connectome

a map of the neural circuit structure and function within the human brain

Consolidation

the process by which recent learned experiences are transformed into long-term memory

Cornea

the transparent external surface of the eye that is responsible for the majority of the refraction (bending/focusing) of light

Cortical magnification

the effect created by the number of neurons in the visual cortex varying as a function of the location of the stimulus in the visual field; items appearing in the central part of the visual field are represented larger in the visual cortex than objects at the edge of the visual field.

Corticospinal tract

one of the descending motor pathways bringing motor information down from the brain to the muscles (specifically, voluntary movement commands for most parts of the body, including limbs and digits)

Cranial nerves

twelve pairs of nerves entering or exiting the brain at the brainstem that connect the central nervous system with the head, face, and neck

CREB

a transcription factor that is critical in producing new proteins necessary for maintaining structural changes in the synapse; activated by CAMKII

Cribriform plate

the part of the skull that divides the brain and olfactory bulb from the sinuses; contains tiny holes for olfactory axons to pass through, carrying smell information to the brain

Critical periods

lmited periods of time when an aspect of brain development is particularly sensitive to inputs from the external environment

DAG (diacylglycerol)

a secondary messenger that activates the enzyme protein kinase C and is involved in many signaling cascades

Decussation

the crossing of nerve pathways from one side of the nervous system to the other

Deep neural network

a complex version of an artificial neural network that is capable of highly advanced problem solving

Degenerate

to lose structure or function

Delayed rectifier

a voltage-gated potassium channel named for its delay in returning the neuron membrane potential to rest following afterhyperpolarization

Dendrite

a projection of a neuron that receives signals from other neurons

Dendritic arbor

the size and shape of the branching dendrites from one neuron

Dentate gyrus

a region of the hippocampus that is notable for evidence of neurogenesis in adults

Deoxygenated

not carrying oxygen

Depolarization

a change in the membrane potential that takes it from the value at rest to a less negative (more positive) value

Dermatome

an area or stripe of skin whose neurons all send their input to the brain via the same spinal nerve and have their cell bodies in the same dorsal root ganglion

Diffuse

to move from a region of high concentration to low concentration, resulting in a more even distribution of a given ion

Dipole

an area of negative charge next to an area of positive charge

Direction-selective neurons

In the visual system, these neurons fire action potentials maximally when they detect movement in a particular direction.

Dopamine

a type of catecholamine (derived from the molecule tyrosine) neurotransmitter that is involved in movement, mood, attention, and internal organ function; produced mainly in the ventral tegmental area and the substantia nigra of the basal ganglia

Dopaminergic

describes a cell that produces dopamine

Dorsal column medial lemniscal system

one of the ascending systems that brings sensory information from the body to the brain (specifically, fine detailed touch information, vibration, and texture)

Dorsal root ganglion

the part of the spinal nerves that contains the cell bodies for somatosensory neurons bringing information from the skin and tissues to the brain

Dura mater

the tough, outermost layer of the three protective membranes (meninges) that cover the brain and spinal cord

Effector protein

selectively binds to a protein to regulate its biological activity; can alter enzyme activity, gene expression, or other protein functions

Efferents

nerves/axons that bring information down from the central nervous system or brain

Efflux

flow out of a cell

Electrical driving force

the force created by the separation of charge across the membrane; tends to move ions in a direction determined by its charge, as like charges repel and opposite charges attract

Electrical potential

the force exerted on an electrically charged particle; represented by the symbol V and measured in volts; also called voltage or potential difference

Electrical synapses

synapses in which electrical current flows directly from one cell to another via a junction that allows ions to pass directly (gap junction)

Electrodes

small, wire-based devices designed to read the electrical signals that the brain uses to process information

Electroencephalogram (EEG)

a test that measures electrical activity generated by the brain and recorded from the scalp using electrodes

Electrophysiological recordings

recordings of the electrical activity of neurons

Endocytosis

a process that brings substances into the cell; material to be internalized is surrounded by an area of cell membrane, which buds off inside the cell to form a vesicle containing the ingested material.

Endogenous

naturally occurring