Achromatopsia
Colorblindness that causes inability to discriminate among different hues; caused by damage to the visual association cortex.
Agnosia
Agnosia is the inability to identify objects.
Agnostic alexia
An inability to recognize text.
Amygdala
An almond-shaped structure in the temporal lobe; part of the
limbic system. The amygdale is thought to play a prominent role in the
integration of brain systems that are responsible for emotional behavior.
Appreceptive agnosia
Apperceptive agnosia is more severe type of visual agnosia and represents an inability to categorize or manipulate an object that that can only be seen. A person with apperceptive agnosia may be unable to distinguish shape or even say if they have seen a similar object before. People with apperceptive agnosia have difficulty copying simple drawings
Appreceptive component of prosopagnosia
Loss of the ability to perceive even the individual characteristics of a face.
Asperger's syndrome
A syndrome similar to Autistic Psychopathy characterized by severe and sustained impairment in social interaction, development of restricted and repetitive patterns of behavior, interests, and activities. These characteristics result in clinically significant impairment in social, occupational, or other important areas of functioning.
In contrast to Autistic disorder (Autism), there are no clinically significant delays in language or cognition or self help skills or in adaptive behavior, other than social interaction.
Associative agnosia
Associative agnosia is less severe form of visual agnosia because a limited understanding of the relevance of a visual object is retained. People with associate visual agnosia can copy drawings but remain unaware of what the drawing is of. They also have difficulty in transferring visual information into verbal mechanisms (they have trouble giving words to what they see).
Associative component of prosopagnosia
The inability to pair facial features to get a vision of the entire face, even though a person can recognize the individual features.
Astereognosia or Somatosensory Agnosia
An agnosia connected to tactile sense - that is, touch. Patient finds it difficult to recognize objects by touch based on its texture, size and weight. However, they may be able to describe it verbally or recognize same kind of objects from pictures or draw pictures of them. Thought to be connected to lesions or damage in somatosensory cortex.
Auditory Agnosia
Auditory agnosia refers to similar symptoms with environmental, nonverbal auditory cues. This is separate from word deafness which is agnosia connected to auditory information. Receptive amusia is agnosia for music. Cortical deafness refers to people who do not respond to any auditory info but their hearing is intact.
Axon
Axons are the parts of the neurons which transmit an electrical signal from one part of the body to another. This electrical signal is propagated by a wave of voltage gated channels that open letting charged atoms in thus opening voltage gated channels further down the axon. They are like wires for the nervous system.
Congenital
Something that is inherited.
Cone Photoreceptors
Cones are receptor cells of the retina; meximally sensitive to one of three different wavelengths of light and hence encodes color vision.
Colorblindness
Colorblindness is the inability to discriminate among different hues; caused by damage to the visual association cortex.
Color Agnosia
There is a distinction between color perception versus color recognition. Central Achromatosia refers to deficiency in color perception.
Color anomia
Color anomia is the inability to name colors of common objects.
Covert
Not openly practiced, avowed, engaged in, accumulated, or shown.
Dementia
Deterioration of intellectual faculties, such as memory, concentration, and judgment, resulting from an organic disease or a disorder of the brain. It is sometimes accompanied by emotional disturbance and personality changes.
Dendrite
The part of a nerve cell which will receive information
from the terminal buttons of an axon relay it towards the body of the cell.
Once the information reaches the body it can then be sent through the axon
and ultimately to another cell.
Depth Perception
Depth Perception is the ability to see how far things are away from your face.
Encephalitis
Inflammation of the brain.
Enzyme
Any one of the complex proteins produced by living cells
which acts as a catalyst (increases the likelihood that a reaction will occur)for
specific biochemical reactions. MAO is an example of this. It causes the
breakdown of dopamine inside the terminal buttons of nerve cells.
Hemiachromatopsia
Hemiachromatopsia is one-sided colorblindness due to damage to only one half of the brain that detects color.
Hemisphere
One side of the brain (left or right).
Hippocampus
This structure, located in the temporal lobe, is thought to
be the area in the brain where information is processed and integrated into
memories. The hippocampus contains cells that change in a way that corresponds
to learning.
Ion
Ions are groups of atoms which carry either a positive
or a negative electric charge due to the loss or gain of an electron. Ions
are important in information transmission in nerve cells because their movement
in and out of the plasma membrane allows for the alteration in electric
potential and ultimately the production of an action potential.
Lesion
A wound or injury, generally disrupting function.
Medulla
The medulla is the primary are in which many of the motor
tracts cross as they come up through the spinal cord. Being that it is a
very basic part of the brain, it controls many of our most basic functions
such as reflexes, gagging, coughing, vomiting, and swallowing.
Mescaline
The hallucinogenic drug that is the active component of mescal buttons.
Midbrain
Located in the same area as the midbrain (the brainstem)
the midbrain is also considered one of the basic and primal brain structures.
It is in change are visual and auditory reflexes and serves as the nerve
pathway between the two hemispheres.
Neuroimaging
Neuroimaging is the overarching name for all ways of viewing neural activity, such as PET Scans and MRIs.
Neurotransmission
Neurotransmission is the passage of information (electrical
impulses) across a synapse. This process involves the neurotransmitters
being released into the synapse from the vesicle due to a change in the
electric potential of an axon. Some of the neurotransmitters will traverse
the synapse and bind with the dendrite of another nerve cell located on
the other side. If enough neurotransmitters bind to the dendrite, the dendrite
will experience a change in its electrical potential resulting in the production
of an action potential. This will allow the continuation of the information
to other nerve cells.
Neurotransmitter
A neurotransmitter is a substance such as dopamine or serotonin which will
carry information (electrical impulses) across a synapse when stimulated
by an electrical impulse.
neurotransmitter binding
Neurotransmitter binding occurs when the neurotransmitters,
released from the vesicles, connect with the receptors of the dendrite and
cause an action potential to occur.
Neuron
A neuron is a nerve cell which normally consists of an
axon, a dendrite and a cell body. These cells allow the body to experience
the external environment by translating the information in the external
world into something which can be processed internally, namely electric
impulses.
Nucleus Accumbens
The nucleus accumbens receives input from dopamine-secreting
neurons that originate in the ventral tegmental area. This nucleus is thought
to be the primary target of neurons involved in the brain's natural reinforcement
circuit.
Object Agnosia
Object agnosia is an inability to recognize objects. Subtypes: Form agnosia: Patients perceive only parts of details, not the whole object.
Occipitotemporal lobes
Both the occipital lobes (the back most lobes of the brain) and the temporal lobes (the lobes under your temples) - see diagram on the causes page under Agnosia
Photoreceptors
Photoreceptors are receptor cells of the retina; tranduces light energy into electrical potentials.
PET scan
A PET scan is a method of measuring the level of activity
in a certain brain region during a mental task. If we wanted to measure
what happens when someone speaks we would first 1) inject a small amount
of harmless radioactive material with sugar into the brain which will emit
particles that can be measured by a PET scanner, 2) have the patient speak
about what is on their mind while their head is in the PET machine 3) examine
the printout which will show that the regions with the most activity used
the most sugar and since the sugar was connected to the radioactive material
we can deduce that the most particles were emitted from the areas that were
most active.
Pons
The pons is the structure in the brain which connects the medulla
with the higher cortical areas of the brain. The higher cortical areas are
the areas of the brain which form associations and are thought to coordinate
the importance and order in which information will be processed and acted
upon. Thus, if a person fighting four grown men in a bar brawl were to gag
on their saliva (a process caused by the medulla) it would have less of
an effect due to the decision of the higher cortical areas to dedicate all
energies to the task at hand.
Posterior cerebral artery stroke
A stroke in a specific blood vessel in the back of the head.
Prosopagnosia
Prosopagnosia is the inability to recognize faces.
Rod photoreceptors
Rods are receptor cells of the retina; sensitive to light of low intensity.
Putamen
A region that supplies input to the basal ganglia, which
scientists believe control movement. The putamen is thought to control voluntary
movement.
Receptive Amusia
Receptive amusia is agnosia for music. Cortical deafness refers to people who do not respond to any auditory info but their hearing is intact.
Reuptake
The process by which terminal buttons of axons will take
certain neurotransmitters out of the synapse in order to clean up or to
reduce their concentration. Reuptake is inhibited with drugs such as Prozac
which is a well known SSRI (selective serotonin reuptake inhibitor).
Serotonin
Serotonin is a neurotransmitter that is implicated in
the control of many functions of the body including sexuality, hunger, sleep
cycles, and mood. It is the primary neurotransmitter which MDMA affects.
Sex-lined trait
A sex-linked trait is carried on either the X or the Y chromosome. If it is carried on only the Y then only males can have it and all fathers will give it to their sons. If it is on the X chromosome then mothers can be carriers and give it to their sons and daugthers.
Simultagnosia
Patients recognize objects or details but only one at the time. They cannot make out the scene they belong to or make out a whole image out of the details. They literally cannot see the forest for the trees.
Somatosensory Agnosia or Astereognosi
An agnosia connected to tactile sense - that is, touch. Patient finds it difficult to recognize objects by touch based on its texture, size and weight. However, they may be able to describe it verbally or recognize same kind of objects from pictures or draw pictures of them. Thought to be connected to lesions or damage in somatosensory cortex.
Stroke
A sudden loss of brain function caused by a blockage or rupture of a blood vessel to the brain, characterized by loss of muscular control, diminution or loss of sensation or consciousness, dizziness, slurred speech, or other symptoms that vary with the extent and severity of the damage to the brain.
Subliminal Messages
Subliminal Messages are messages that your brain picks up from stimuli but your consciousness does not. They can affect behavior without people being aware of them.
Temporal lobectomy
Removal of the temporal lobe (s) of the brain.
Temporal lobe atrophy
A wasting away or decreasing in size of the temporal lobe of the brain.
Transient ischemic attack
A temporary blockage of the blood supply to the brain caused by a blood clot and usually lasting ten minutes or less, during which dizziness, blurring of vision, numbness on one side of the body, and other symptoms of a stroke may occur. Also called ministroke.
Wavelength
Light is a narrow band of the spectrum of electromagnetic radiation with a wavelength between 380 (purple) and 760 (red) nm.