Modality-specific deficit in recognizing objects that occurs in the absence of major deficits in basic sensory processing.
Loss of the ability to write, as a consequence of brain damage.
alexia (acquired dyslexia)
Loss of the ability to read, as a consequence of brain damage.
Front; in front of.
Inability to link skilled motor movement to ideas or representations; inability to perform skilled, sequential, purposeful movement that cannot be accounted for by disruptions in more basic motor processes such as muscle weakness, abnormal posture or tone, or movement disorders; most common after damage to the left hemisphere.
Area of the brain where information from multiple modalities is processed.
Major structure of the neuron, along which information is carried from the cell body to the synaptic cleft.
Complex collection of subcortical nuclei located near the thalamus, consisting of the caudate nucleus, putamen, and nucleus accumbens (known collectively as the striatum); the globus pallidus (or pallidum); the substantia nigra; and the subthalamic nucleus. Important in motor control.
Both sides; two-sided.
Mechanism by which substances are prevented from reaching the brain; consists of tightly packed glial cells between blood vessels and neurons, which create a physical obstruction that keeps materials in the bloodstream from directly reaching the nervous system.
Map (named after its creator) that divides the brain into distinct areas based on similarities in the laminar organization and nature of cells.
Toward the back (in an animal, toward the tail).
Part of the cell containing the nucleus and other cellular apparatus responsible for manufacturing the proteins and enzymes that sustain cell functioning.
Split or chasm that separates each hemisphere of the brain in an anterior-posterior dimension; sometimes called the Rolandic fissure.
central nervous system (CNS)
Body system encompassing the brain and the spinal cord.
Region at the back of the brain, located posterior to the medulla, that plays a major role in motor control through the regulation of muscle tone and guidance of motor activity; especially important in the coordination of muscle movement timing, the planning of movements, and the learning of motor skills.
One of two physically separated halves of the cortex.
cerebrospinal fluid (CSF)
Fluid found between neurons and their bony encasements; similar in composition to blood plasma.
Field of study comprised of investigations of all mental functions that are linked to neural processes.
On the opposite side.
Planar view of the brain in which the brain is sliced ear-to-ear to separate the front from the back.
Twelve major nerves originating in the brain; some are responsible for receipt of sensory information and motor control of the head, others are responsible for the neural control of internal organs.
Part of the neuron that receives input from other cells.
Brain structure that contains the thalamus and hypothalamus.
Above or superior (in a four-legged animal, toward the animal's back).
Episodes in which synchronous activity of nerve cells increases so that a gigantic hyperpolarization of neurons spreads over a large area in an atypical and abnormal manner; during a seizure, neurons in the brain fire in an abnormal manner typified by great bursts or volleys, often called spikes. May be generalized or partial.
Deep valley between brain convolutions or gyri.
Brain area in front of the central fissure.
Cells of the nervous system that serve as support cells; although they do not convey information like neurons, they can nonetheless influence neuronal transmission; in addition, they are involved in processes that occur in response to brain damage.
Convolution, or bump, of the brain formed by a giant sheath of neurons wrapped around other brain structures (plural: gyri).
Term synonymous with hemineglect; syndrome in which patients ignore, or do not pay attention to, information on one side of space (usually the left), and act as if that side of the world does not exist, despite having intact sensory and motor functioning.
Term synonymous with hemi-inattention; syndrome in which patients ignore, or do not pay attention to, information on one side of space (usually the left), and act as if that side of the world does not exist, despite having intact sensory and motor functioning.
Paralysis of the side of the body contralateral to the site of brain damage.
Superior portion of the posterior temporal lobe where the human primary auditory cortex is located.
Condition in which the entire occipital cortex of one hemisphere is damaged, so that no visual information can be detected in the contralateral visual field.
Planar view of the brain in which the brain is sliced so that the top of the brain is separated from the bottom; also called axial or transverse.
Field of study that emphasizes examination of the changes in behavior as a result of brain trauma to understand mental processes in humans.
Brain area controlling behaviors that help the body maintain equilibrium including the control of eating, drinking, fleeing and fighting.
Bottom; underneath; below.
One of two dorsal midbrain structures; acts as a relay point for auditory information and contributes to reflexive movements of the head and eyes in response to sound.
On the same side.
Toward the outside (of the brain).
lateral corticospinal tract
One of two major sets of pathways that link the brain to muscle. This tract, whose cell bodies are located mainly in primary motor cortex, crosses entirely from one side of the brain to the opposite side of the body in the medulla; thus, damage to this tract results in profound deficits in motor movement on the opposite side of the body, including the ability to reach, grasp, and manipulate objects.
left visual field
Area/information to the left of the fixation point of gaze.
Series of subcortical structures—including the amygdala, hypothalamus, cingulate cortex, anterior thalamus, mammillary body, and hippocampus—that sit below the neocortex; contributes to emotional and other functions.
Fissure in the brain that separates the right cerebral hemisphere from the left.
In the middle or center (of the brain).
Section of the brain directly superior to the spinal cord; contains the cell bodies of most cranial nerves and controls many vital functions and reflexes.
Brain region superior to the pons; contains the nuclei of some of the cranial nerves. Also contains the inferior and superior colliculi, which are important in orientation to stimuli in the auditory and visual modalities, respectively.
Planar view of the brain in which the brain is cut down the middle, separating the left side from the right side.
Nervous system cells that carry information from one place to another by means of a combination of electrical and chemical signals.
Distinct groups of neurons whose cell bodies are all situated in the same region.
Brain region behind the parieto-occipital sulcus; involved in processing visual information.
Thin strand of neural tissue located directly below the frontal lobe; one of two bulbs (one in each hemisphere) that receive and project sensory information about smells.
Crossover point where some information from the left eye is transmitted to the right side of the brain, and vice versa; place where information from the inside half of each retina crosses the midline of the body and projects to the contralateral lateral geniculate.
Brain region directly behind the central fissure and above the Sylvian fissure.
peripheral nervous system
All neural tissue beyond the central nervous system, such as neurons that receive sensory information from the body or send information to muscles, and neurons that relay information to or from the spinal cord or the brain.
To perform a behavior repeatedly.
Multifunctional brain area directly superior to the medulla and anterior to the cerebellum. Contains the superior olive (which relays auditory information from the ear to the brain); acts as the main connective bridge from the rest of the brain to the cerebellum; is the point of synapse of some cranial nerves; and acts to control certain types of eye movements and vestibular functions.
primary motor cortex
Cortical region that is the final exit point for neurons responsible for fine motor control of the body's muscles.
primary sensory cortex
Cortical region that initially receives information about a particular sensory modality from receptors in the periphery.
Perception of the position of body parts and their movements.
Disorder in which one quadrant of the visual world is lost; caused by damage to a dorsal or ventral portion of the occipital cortex in one hemisphere.
Region of the brain whose neurons receive information from one area of the brain and then go on to synapse elsewhere in the brain; often a site where information is combined or recoded.
reticular activating system (RAS)
Set of brainstem neurons that projects diffusely to many other regions of the brain; relies on the excitatory neurotransmitter glutamate. Important for overall arousal and attention, and for regulation of sleep-wake cycles.
right visual field
Area/information to the right of the fixation of gaze.
Toward the front (in an animal, toward the head).
Planar view of the brain in which the brain is cut so that the left side is separated from the right side.
Blind spots; particular regions of the visual field in which light-dark contrast cannot be detected. Caused by damage to small portions of the visual cortex.
Portion of the nervous system through which many sensory neurons relay information to the brain, and through which motor commands from the brain are sent to the muscles.
Valley between brain convolutions (plural: sulci).
Dorsal midbrain structures that allows orientation of eyes toward large moving objects in the periphery, so that the object falls in the center of vision. Also permits one to move the focus of visual attention from one position or object to another.
Sylvian (lateral) fissure
Separates each hemisphere of the brain in the dorsal-ventral dimension; sometimes called the fissure of Sylvius.
Brain area below the Sylvian fissure; plays an important role in memory, emotion, and auditory perception.
Part of the diencephalon; a large relay center for almost all sensory information coming into the cortex and almost all motor information leaving it.
Organized with regard to the frequency of a tone or sound.
One side; one-sided.
Below or inferior (in a four-legged animal, toward the animal's stomach).