Central Nervous System 1

ventricle

4 cavities in the brain; central hollow cavities that lie deep within the brain. They are continuous with one another and with the central canal of the spinal cord. They are filled with cerebrospinal fluid and lined by ependymal cells, a type of neuroglia.

encephalitis

Inflammation of the brain

auditory association area

It is more posterior; permits the perception of the sound stimulus, which we "hear" as speech, a scream, music, thunder, noise, and so on. Memories of sounds heard in the past appear to be stored here for reference. Wernicke's area, includes parts of the auditory cortex.

primary auditory cortex

Located in the superior margin of the temporal lobe abutting the lateral sulcus. Sound energy exciting the hearing receptors of the inner ear causes impulses to be transmitted to the primary auditory cortex, where they are interpreted as pitch, loudness, and location.

visceral sensory area

The cortex of the insula just posterior to the gustatory cortex is involved in conscious perception of visceral sensations. These include upset stomach, full bladder, and the feeling that your lungs will burst when you hold your breath too long.

vestibular cortex

This part of the cortex responsible for conscious awareness of balance. It is located in the posterior part of the insula and adjacent parietal cortex.

cerebral cortex

the "executive suite" of the nervous system, where our conscious mind is found. It enables us to be aware of ourselves and our sensations, to communicate, remember, understand, and initiate voluntary movements. It is composed of gray matter but no fiber tracts. It contains billions of neurons arranged in six layers. It accounts for roughly 40% of total brain mass and has many convolutions effectively tripling its surface area.

anencephaly

"without the brain" the cerebrum and part of the brain stem never develop because the neural folds fail to fuse rostrally. The child is totally vegetative, unable to see, hear, or precess sensory inputs. Muscles are flacid and no voluntary movement is possible. Mental life as we know it does not exist. Death occurs soon after birth.

diencephalon

(interbrain) That part of the forebrain between the cerebral hemispheres and the midbrain including the thalamus, the epithalamus, and the hypothalamus; forming the central core of the forebrain and surrounded by the cerebral hemispheres. These gray matter areas collectively enclose the third ventricle

dyslexia

A learning disability in 5 to 15% of the population that specifically affects the ability of otherwise intelligent people to read. This deficit in visual symbol and language processing is thought to result from errors arising in one hemisphere. Several genes that predispose children to dyslexia have been identified, but dyslexia can also be acquired by brain injury or degeneration.

thalamus

A mass of grey matter in the diencephalon of the brain; Consists of bilateral egg-shaped nuclei, which form the superolateral walls of the third ventricle. means "inner room" which well describes this deep, well hidden, brain region that makes up 80% of the diencephalon. The thalamus is the relay station for information coming into the cerebral cortex. Information is sorted and edited in this structure. Plays a key role in mediating sensation, motor activities, cortical arousal, learning and memory.

gustatory cortex

A region involved in perceiving taste stimuli, is located in the insula just deep to the temporal lobe.

Alzheimer's disease

Degenerative brain disease resulting in progressive loss of memory(particularly for recent events),shortened attention span, disorientation, motor control, eventual language loss and increasing dementia; patients represent nearly half of the people living in nursing homes. Between 5 and 15% of people over 65 develop this condition, and for up to half of those over 85 it is a major contributing cause in their deaths. Hallucinations may occur and over a period of several years, formerly good natured people become irritable, moody, and confused. Examintions of the brain reveal senile plaques( consisting of beta amyloid peptide cut from a normal membrane precursor protein, APP) littering the brain between neurons.

epithalamus

The most dorsal portion of the diencephalon;Forms the roof of the third ventricle; Extending from its posterior border and visible externally is the pineal gland or body which secretes the hormone melatonin. Helps regulate sleep/wake cycle.

Huntington's disease

a fatal hereditary disorder that strikes during middle age. Mutant huntingtin protein accumulate in brain cells and the tissue dies, leading to massive degeneration of the basal nuclei and later of the cerebral cortex. Its initial symptoms in many are wild, jerky, almost continuous flapping movements called chorea. (Movements are involuntary) .Late in the disease, marked mental deterioration occurs. Progressive and usually fatal within 15 years of onset of symptoms. Hyperkinetic manifestations are overstimulation of the motor drive.Treated with drugs that block dopamine's effects.

frontal eye field

is located partially in and anterior to the premotor cortex and superior to Broca's area. This cortical region controls voluntary movement of the eyes.

primary visual cortex

is seen on the the extreme posterior tip of the occipital lobe, but most of it is buried in the calcarine sulcus in the medial aspect of the occipital lobe. The largest cortical sensory area, and receives visual info. that originates on the retina of the eye.

Broca's area

lies anterior to the inferior region of the premotor area. It has long been considered to be 1) present in one hemisphere only (usually the left) and 2) a special motor speech area that directs the muscles involved in speech production. However, imaging studies indicate this area to also become active as we prepare to speak and even as we think about(plan) many voluntary motor activities other than speech.

somatosensory

lies just posterior to the primary somatosensory cortex and has many connections with it. The major function of this area is to integrate sensory inputs (temperature, pressure, and so forth) relayed to it via the primary somatosensory cortex to produce an understanding of an object being felt: its size, texture, an the relationship of its parts.

prefrontal cortex

It is the most complicated and cortical region of all. It is involved with intellect, complex learning abilities, recall, and personality. It contains working memory, judgment, reasoning, persistence, and planning. These abilities develop slowly in children, which implies that the prefrontal cortex matures slowly and depends heavily on positive and negative feedback from out social enviroment.

premotor cortex

Just anterior to the precentral gyrus in the frontal lobe and it helps plan movements. This region selects and sequences basic motor movements into more complex tasks, such as playing a musical instrument or typing. Using highly processed sensory info. received from other cortical areas, it can control voluntary actions that depend on sensory feedback, such as moving an arm through a maze to grasp a hidden object. It coordinates the movement of several muscle groups mainly by sending activating impulses to the primary motor cortex. Think of this region as the stagin area for skilled motor activities.

olfactory cortex

Lies on the medial aspect of the temporal lobe in a small region called the piriform lobe which is dominated by the hooklike uncus. Afferent fibers from smell receptors in the superior nasal cavities send impulses along the olfactory tracts that are ultimately relayed to the olfactory cortices. The outcome is conscious awareness of different odors. The olfactory cortex is part of the primitive rhinencephalon.

Wernicke's area

Patients with lesions involving this are able to speak but produce a type of nonsense often referred to as "word salad". They have great difficulty understanding language.

multimodal association areas

Receives inputs from multiple senses and send outputs to multiple areas. This allows us to give meaning to the information that we receive, store it in memory, tie it to previous experience and knowledge, and decide what action to take. It seems to be where sensations, thoughts, and emotions become concvious.

hypothalamus

Region of the diencephalon forming the floor of the third ventricle of the brain; Named for its position below the thalamus; caps the brain stem and forms the inferolateral walls of the third ventricle. Merges into the midbrain inferiorly, and extends from the optic chiasma (crossover point of the optic nerves) to the posterior margin of the mammillary bodies. Main visceral control center of the body and is vitally important to overall body homeostasis. Controls the autonomic nervous system, initiates physical responses to emotion, regulates body temp, regulates food intake, regulates water balance and thirst, regulates sleep/wake cycles, controls edocrine system function. disturbances in this structur cause disturbances such as: severe body wasting, obestiy, sleep disturbances, dehydration, and emotional imbalances. Can be implicated in failure to thrive in children.

primary motor cortex

motor areas of the cortex, which control voluntary movement, line in the posterior part of the frontal lobes and is specifically located in the precentral gyrus of the frontal lobe of each hemisphere. Large neurons, called pyramidal cells, in these gyri allow us to consciously control the precise or skilled voluntary movements of our skeletal muscles. Their long axons, which projects to the spinal cord, form the massive voluntary motor tracts called pyramidal tracts or corticospinal tracts.

basal nuclei

Specific grey matter areas located deep within the white matter of the cerebral hemispheres. Each basal nuclei include the caudate nucleus, putamen, and globus pallidus.

primary somatosensory cortex

resides in the postcentral gyrus of the parietal lobe, just posterior to the primary motor cortex. Neurons in this gyrus receive information from the general (somatic) sensory receptors in the skin and from proprioceptors (position sense receptors) in skeletal muscles, joints, and tendons. The neurons then identify the body region being stimulated, an ability called spatial discrimination.

Parkinson's disease

results from a degeneration of the dopamine releasing neurons of the substantia nigra. As those neurons deteriorate, the dopamine- deprived basal nuclei they target become overactive. Affected individuals have a persistent tremor at rest (exhibited by "pill rolling"movements of the fingers and wrist), a forward-bent walking posture and shuffling gait, and a stiff facial expression.They are slow initiating and executing movement. Cause is unknown but evidence points to abnormalities in certain mitochondrial proteins and protein degradation pathways. Treatment includes drugs L-dopa, deprenyl, deep brain stimulation(to allevaite tremors), and gene therapy

visual association area

surrounds the primary visual cortex and covers much of the occipital lobe. Communicating with the primary visual cortex, this area uses past visual experiences to interpret visual stimuli (color, form, and movement), enabling us to recognize a flower or a person's face and to appreciate what we are seeing.