Eppp Terms Physiology

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Hippocampus

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The hippocampus is a part of the forebrain, located in the medial temporal lobe. It belongs to the limbic system and plays major roles in short term memory and spatial navigation.

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Medulla Oblongata

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The medulla oblongata is the lower portion of the brainstem. It deals with autonomic functions, such as breathing and blood pressure. The cardiac center is the part of the medulla oblongata responsible for controlling the heart rate.

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Pons

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The pons relays sensory information between the cerebellum and cerebrum; aids in relaying other messages in the brain; controls arousal, and regulates respiration (see respiratory centres). In some theories, the pons has a role in dreaming.

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Cerebellum

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The cerebellum is a region of the brain that plays an important role in the integration of sensory perception, coordination and motor control. In order to coordinate motor control, there are many neural pathways linking the cerebellum with the cerebral motor cortex (which sends information to the muscles causing them to move) and the spinocerebellar tract (which provides proprioceptive feedback on the position of the body in space). The cerebellum integrates these pathways, like a train conductor, using the constant feedback on body position to fine-tune motor movements

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Spinal Cord

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The spinal cord is a long, thin, tubular bundle of nerves that is an extension of the central nervous system from the brain and is enclosed in and protected by the bony vertebral column. The main function of the spinal cord is transmission of neural inputs between the periphery and the brain.

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Ventricles

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There are four cerebral ventricles: the paired lateral ventricles, and midline the third and fourth ventricles. The two lateral ventricles, located within the cerebrum, are relatively large and C-shaped, roughly wrapping around the dorsal aspects of the basal ganglia. It is in the lateral ventricles of the embryo that the successive generation of neurons gives rise to the 6-layered structure of the neocortex, constructed from the inside out during development. Each lateral ventricle extends into the frontal, temporal and occipital lobes via the frontal (anterior), temporal (inferior), and occipital (posterior) horns, respectively.

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Pituitary Gland

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The pituitary gland secretes hormones regulating homeostasis, including tropic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamus by the median eminence.

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Hypothalamus

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The hypothalamus is responsible for certain metabolic processes and other activities of the Autonomic Nervous System. It synthesizes and secretes neurohormones, often called hypothalamic-releasing hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones. The hypothalamus controls body temperature, hunger, thirst, [1] fatigue, anger, and circadian cycles.

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Thalamus

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The hypothalamus is responsible for certain metabolic processes and other activities of the Autonomic Nervous System. It synthesizes and secretes neurohormones, often called hypothalamic-releasing hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones. The hypothalamus controls body temperature, hunger, thirst, [1] fatigue, anger, and circadian cycles.

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Pineal Gland

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The pineal gland (also called the pineal body, epiphysis cerebri, or epiphysis) is a small endocrine gland in the vertebrate brain. It produces melatonin, a hormone that affects the modulation of wake/sleep patterns and photoperiodic (seasonal) functions.[1][2] It is shaped like a tiny pine cone, and is located near the center of the brain, between the two hemispheres, tucked in a groove where the two rounded thalamic bodies join.

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Cerebral Cortex

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The cerebral cortex is a structure within the brain that plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. In dead, preserved brains, the outermost layer of the cerebrum has a grey color, hence the name grey matter. Grey matter is formed by neurons and their unmyelinated fibers, whereas the white matter below the grey matter of the cortex is formed predominantly by myelinated axons interconnecting different regions of the central nervous system. The human cerebral cortex is 2-4 mm (0.08-0.16 inches) thick.

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Corpus Callosum

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The corpus callosum is a structure of the mammalian brain in the longitudinal fissure that connects the left and right cerebral hemispheres. It is the largest white matter structure in the brain, consisting of 200-250 million contralateral axonal projections. It is a wide, flat bundle of axons beneath the cortex. Much of the inter-hemispheric communication in the brain is conducted across the corpus callosum.

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Caudate Nucleus

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The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate, originally thought to primarily be involved with control of voluntary movement, is now known to be an important part of the brain's learning and memory system.

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Basal Ganglia

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The basal ganglia (or basal nuclei) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. Mammalian basal ganglia are associated with a variety of functions: motor control, cognition, emotions, and learning. In modern use the term 'ganglia' is in this instance considered a misnomer; 'ganglion' refers to concentrations of neural nuclei in the periphery only (for example those of the autonomic nervous system), and the term 'basal nuclei' is preferred.

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Putamen

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The putamen is a structure in the middle of the brain which, together with the caudate nucleus, forms the dorsal striatum. It appears to play a role in reinforcement learning.

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Globus Pallidus

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The globus pallidus (Latin for "pale globe") is a sub-cortical structure of the brain. It is a major element of the basal ganglia system. In this system, it is a major constituent of the basal ganglia core, which consists of the striatum and its direct targets: globus pallidus and substantia nigra. The last two are made up of the same neuronal elements, have a similar main afferent (the dorsal striatum), have a similar synaptology, and do not receive cortical afferents. It was recently discovered [1] to play an active part in pre-filtering external stimuli and may help reduce the amount of irrelevant information the brain can store.

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Substantia Nigra

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The substantia nigra (Latin for "black substance", Sömmering) or locus niger is a heterogeneous portion of the midbrain, separating the pes (foot) from the tegmentum (covering), and an accessory to the basal ganglia system. The substantia nigra compacta and surrounding is responsible for dopamine production in the brain, and therefore plays a vital role in reward and addiction.

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Nucleus Accumbens

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The nucleus accumbens (NAcc), also known as the accumbens nucleus or as the nucleus accumbens septi (Latin for nucleus leaning against the septum), is a collection of neurons within the forebrain. It is thought to play an important role in reward, laughter, pleasure, addiction, fear, and the placebo effect.

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Midbrain

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In biological anatomy, the mesencephalon (or midbrain) comprises the tectum (or corpora quadrigemini), tegmentum, the ventricular mesocoelia (or "iter"), and the cerebral peduncles, as well as several nuclei and fasciculi. Caudally the mesencephalon adjoins the pons (metencephalon) and rostrally it adjoins the diencephalon (Thalamus, hypothalamus, et al).

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Red Nucleus

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The red nucleus is a structure in the rostral midbrain involved in motor coordination. It comprises a caudal magnocellular and a rostral parvocellular part. In humans, the red nucleus mainly controls the muscles of the shoulder and upper arm, but it has some control over the lower arm and hand as well. It is less important in its motor functions for humans than in many other mammals, because, in humans, the corticospinal tract is dominant. However the crawling of babies is controlled by the red nucleus, as is arm-swinging in normal walking.

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Prefrontal Cortex

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This brain region has been implicated in planning complex cognitive behaviors, personality expression, and moderating correct social behavior. The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals.
The most typical neurologic term for functions carried out by the pre-frontal cortex area is executive function. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social "control" (the ability to suppress urges that, if not suppressed, could lead to socially-unacceptable outcomes).

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Frontal Lobe

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The executive functions of the frontal lobes involve the ability to recognize future consequences resulting from current actions, to choose between good and bad actions (or better and best), override and suppress unacceptable social responses, and determine similarities and differences between things or events.
The frontal lobes also play an important part in retaining longer term memories which are not task-based. These are often memories associated with emotions derived from input from the brain's limbic system. The frontal lobe modifies those emotions to generally fit socially acceptable norms.
Psychological tests that measure frontal lobe function include Finger tapping, Wisconsin Card Sorting Task, and measures of verbal and figural fluency.

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Parietal Lobe

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The parietal lobe plays important roles in integrating sensory information from various parts of the body, knowledge of numbers and their relations[1], and in the manipulation of objects. Portions of the parietal lobe are involved with visuospatial processing. Much less is known about this lobe than the other three in the cerebrum.

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Occipital Lobe

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The occipital lobe is divided into several functional visual areas. Each visual area contains a full map of the visual world. Although there are no anatomical markers distinguishing these areas (except for the prominent striations in the striate cortex), physiologists have used electrode recordings to divide the cortex into different functional regions.
The first functional area is the primary visual cortex. It contains a low-level description of the local orientation, spatial-frequency and color properties within small receptive fields. Primary visual cortex projects to the occipital areas of the ventral stream (visual area V2 and visual area V4), and the occipital areas of the dorsal stream - visual area V3, visual area MT (V5), and visual area DP.

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Temporal Lobe

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The temporal lobes are parts of the cerebrum that are involved in speech, memory, and hearing. They lie at the sides of the brain, beneath the lateral or Sylvian fissure. Seen in profile, the human brain looks something like a boxing glove. The temporal lobes are where the thumbs would be.
The temporal lobe is involved in auditory processing and is home to the primary auditory cortex. It is also heavily involved in semantics both in speech and vision. The temporal lobe contains the hippocampus and is therefore involved in memory formation as well.

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Reticular Activating System

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The reticular activating system (or ARAS, for Ascending Reticular Activating System) is the name given to the part of the brain (the reticular formation and its connections) believed to be the center of arousal and motivation in mammals (including humans). The reticular activating system (RAS) has received attention from neuroscientists interested in various pathological conditions affecting behaviour, such as Alzheimer's Disease. More recently, results of research on the area has prompted extrapolations from the data into attention-deficit hyperactivity disorder (ADHD). The reticular activating system is believed to cause ADD and ADHD due to the imbalance of norepinephrine in the cells

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Suprachiasmatic Nucleus

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The suprachiasmatic nucleus (SCN) is a bilateral region of the brain, located in the hypothalamus, that is responsible for controlling endogenous circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions over a 24-hour period.
The SCN contains several cell types and several different peptides (including vasopressin and vasoactive intestinal peptide) and neurotransmitters, and interacts with many other regions of the brain.

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Amygdala

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Limbic System. In complex vertebrates, including humans, the amygdalae perform primary roles in the formation and storage of memories associated with emotional events. Research indicates that, during fear conditioning, sensory stimuli reach the basolateral complexes of the amygdalae, particularly the lateral nuclei, where they form associations with memories of the stimuli. The association between stimuli and the aversive events they predict may be mediated by long-term potentiation, a lingering potential for affected synapses to react more readily.[3]
Memories of emotional experiences imprinted in reactions of synapses in the lateral nuclei elicit fear behavior through connections with the central nucleus of the amygdalae. The central nuclei are involved in the genesis of many fear responses, including freezing (immobility), tachycardia (rapid heartbeat), increased respiration, and stress-hormone release. Damage to the amygdalae impairs both the acquisition and expression of Pavlovian fear conditioning, a form of classical conditioning of emotional responses.[3]

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Locus Coereleus

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The locus ceruleus (or "LC") is located within the dorsal wall of the rostral pons in the lateral floor of the fourth ventricle. This nucleus is the principal site for synthesis of norepinephrine in the brain, and is composed of mostly medium-size neurons. Melanin granules inside the LC contribute to its blue color; it is thereby also known as the nucleus pigmentosus pontis, meaning "heavily pigmented nucleus of the pons." The neuromelanin is formed by the polymerization of norepinephrine and is analogous to the black dopamine-based neuromelanin in the substantia nigra. The locus ceruleus is studied in relation to clinical depression, panic disorder, and anxiety. Some antidepressant medications including reboxetine, venlafaxine, and bupropion, as well as ADHD medication atomoxetine, are believed to act on neurons in this area. This area of the brain is also intimately involved in REM sleep.

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Broca's Area

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People suffering from damage to this area may show a condition called Broca's aphasia (sometimes known as expressive aphasia, motor aphasia, or nonfluent aphasia), which makes them unable to create grammatically-complex sentences: It's often described as telegraphic speech and contains little but content words. Patients are usually aware that they cannot speak properly. Comprehension in Broca's aphasia is relatively normal, although many studies have demonstrated that Broca's aphasics have trouble understanding certain kinds of syntactically-complex sentences.[

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Wernicke's Area

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Wernicke's area is named after Carl Wernicke, a German neurologist and psychiatrist who, in 1874, discovered that damage to this area could cause a type of aphasia that is now called Wernicke's aphasia or receptive aphasia.
This condition results in a major impairment of language comprehension, and in speech that has a natural-sounding rhythm and a relatively normal syntax but is largely meaningless (a condition sometimes called fluent or jargon aphasia).

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Primary Motor Cortex

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The primary motor cortex (or M1) works in association with pre-motor areas to plan and execute movements. M1 contains large neurons known as Betz cells which send long axons down the spinal cord to synapse onto alpha motor neurons which connect to the muscles. Pre-motor areas are involved in planning actions (in concert with the basal ganglia) and refining movements based upon sensory input (this requires the cerebellum).

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Primary Somatosensory Cortex

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Brodmann areas 3, 1 and 2 comprise the primary somatosensory cortex of the human brain. Because Brodmann sliced the brain somewhat obliquely, he encountered area 1 first; however, from rostral to caudal the Brodmann designations are 3, 1 and 2, respectively.

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Seratonin

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In the central nervous system, serotonin plays an important role as a neurotransmitter in the modulation of anger, aggression, body temperature, mood, sleep, sexuality, appetite, and metabolism, as well as stimulating vomiting.

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Dopamine

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Dopamine is a hormone and neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D1, D2, D3, D4 and D5, and their variants. Dopamine is produced in several areas of the brain, including the substantia nigra and the ventral tegmental area.[1] Dopamine is also a neurohormone released by the hypothalamus. Its main function as a hormone is to inhibit the release of prolactin from the anterior lobe of the pituitary.
Dopamine can be supplied as a medication that acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure. However, because dopamine cannot cross the blood-brain barrier, dopamine given as a drug does not directly affect the central nervous system. To increase the amount of dopamine in the brains of patients with diseases such as Parkinson's disease and dopa-responsive dystonia, L-DOPA (levodopa), which is the precursor of dopamine, can be given because it can cross the blood-brain barrier.

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Acetylcholine

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Acetylcholine has functions both in the peripheral nervous system (PNS) and in the central nervous system (CNS) as a neuromodulator.
In the PNS, acetylcholine activates muscles, and is a major neurotransmitter in the autonomic nervous system.
In the CNS, acetylcholine and the associated neurons form a neurotransmitter system, the cholinergic system, which tends to cause excitatory actions.

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Epinephrine

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Epinephrine (also referred to as adrenaline; see Terminology) is a hormone and neurotransmitter. It is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine. Epinephrine is a "fight or flight" hormone, and plays a central role in the short-term stress reaction. It is released from the adrenal glands when danger threatens or in an emergency. Such triggers may be threatening, exciting, or environmental stressor conditions such as high noise levels, or bright light

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Melatonin

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Melatonin is a naturally occurring hormone found in most animals, including humans, and some other living organisms, including algae.[1] Circulating levels vary in a daily cycle, and melatonin is important in the regulation of the circadian rhythms of several biological functions. Production of melatonin by the pineal gland is under the influence of the suprachiasmatic nucleus (SCN) of the hypothalamus, which receives information from the retina about the daily pattern of light and darkness. Both SCN rhythmicity and melatonin production are affected by non-image-forming light information traveling through the recently-identified retinohypothalamic tract (RHT).

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GABA

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Gamma-aminobutyric acid (GABA) is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays an important role in regulating neuronal excitability throughout the nervous system. GABA is also directly responsible for the regulation of muscle tone.Disrupted GABAergic signaling has been implicated in numerous and varied neurological and psychiatric pathologies including movement and anxiety disorders, epilepsy, schizophrenia, and addiction.