Medial Forebrain Bundle
Self Stimulation
Oxidopamine
Hypothalamus, Anterior
Adrenergic Agents
Parkinson Disease, Secondary
Substantia Nigra
Dopamine
Parkinsonian Disorders
Corpus Striatum
Sympatholytics
Hypothalamus
Dyskinesia, Drug-Induced
Tyrosine 3-Monooxygenase
Haloperidol
Mesencephalon
Rats, Sprague-Dawley
Neurons
Levodopa
Reward
Evoked Potentials
Brain
Brain-stimulation reward thresholds raised by an antisense oligonucleotide for the M5 muscarinic receptor infused near dopamine cells. (1/98)
Oligonucleotides targeting M5 muscarinic receptor mRNA were infused for 6 d into the ventral tegmental area of freely behaving rats trained to bar-press for lateral hypothalamic stimulation. The bar-pressing rate was determined at a range of frequencies each day to evaluate the effects of infusions on reward. M5 antisense oligonucleotide (oligo) infusions increased the frequency required for bar pressing by 48% over baseline levels, with the largest increases occurring after 4-6 d of infusion. Two control oligos had only slight effects (means of 5 and 11% for missense and sense oligos, respectively). After the infusion, the required frequency shifted back to baseline levels gradually over 1-5 d. Antisense oligo infusions decreased M5 receptors on the ipsilateral, but not the contralateral, side of the ventral tegmentum, as compared with a missense oligo. Therefore, M5 muscarinic receptors associated with mesolimbic dopamine neurons seem to be important in brain-stimulation reward. (+info)Dynamics of hippocampal ensemble activity realignment: time versus space. (2/98)
Whether hippocampal map realignment is coupled more strongly to position or time was studied in rats trained to shuttle on a linear track. The rats were required to run from a start box and to pause at a goal location at a fixed location relative to stable distal cues (room-aligned coordinate frame). The origin of each lap was varied by shifting the start box and track as a unit (box-aligned coordinate frame) along the direction of travel. As observed by Gothard et al. (1996a), on each lap the hippocampal activity realigned from a representation that was box-aligned to one that was room-aligned. We studied the dynamics of this transition using a measure of how well the moment-by-moment ensemble activity matched the expected activity given the location of the animal in each coordinate frame. The coherency ratio, defined as the ratio of the matches for the two coordinate systems, provides a quantitative measure of the ensemble activity alignment and was used to compare four possible descriptions of the realignment process. The elapsed time since leaving the box provided a better predictor of the occurrence of the transition than any of the three spatial parameters investigated, suggesting that the shift between coordinate systems is at least partially governed by a stochastic, time-dependent process. (+info)Hippocampal place-cell firing during movement in three-dimensional space. (3/98)
"Place" cells of the rat hippocampus are coupled to "head direction" cells of the thalamus and limbic cortex. Head direction cells are sensitive to head direction in the horizontal plane only, which leads to the question of whether place cells similarly encode locations in the horizontal plane only, ignoring the z axis, or whether they encode locations in three dimensions. This question was addressed by recording from ensembles of CA1 pyramidal cells while rats traversed a rectangular track that could be tilted and rotated to different three-dimensional orientations. Cells were analyzed to determine whether their firing was bound to the external, three-dimensional cues of the environment, to the two-dimensional rectangular surface, or to some combination of these cues. Tilting the track 45 degrees generally provoked a partial remapping of the rectangular surface in that some cells maintained their place fields, whereas other cells either gained new place fields, lost existing fields, or changed their firing locations arbitrarily. When the tilted track was rotated relative to the distal landmarks, most place fields remapped, but a number of cells maintained the same place field relative to the x-y coordinate frame of the laboratory, ignoring the z axis. No more cells were bound to the local reference frame of the recording apparatus than would be predicted by chance. The partial remapping demonstrated that the place cell system was sensitive to the three-dimensional manipulations of the recording apparatus. Nonetheless the results were not consistent with an explicit three-dimensional tuning of individual hippocampal neurons nor were they consistent with a model in which different sets of cells are tightly coupled to different sets of environmental cues. The results are most consistent with the statement that hippocampal neurons can change their "tuning functions" in arbitrary ways when features of the sensory input or behavioral context are altered. Understanding the rules that govern the remapping phenomenon holds promise for deciphering the neural circuitry underlying hippocampal function. (+info)Independence of firing correlates of anatomically proximate hippocampal pyramidal cells. (4/98)
In neocortex, neighboring neurons frequently exhibit correlated encoding properties. There is conflicting evidence whether a similar phenomenon occurs in hippocampus. To assess this quantitatively, a comparison was made of the spatial and temporal firing correlations within and between local groups of hippocampal cells, spaced 350-1400 microm apart. No evidence of clustering was found in a sample of >3000 neurons. Moreover, cells active in two environments were uniformly interspersed at a scale of <100 microm, as assessed by the activity-induced gene Arc. Independence of encoding characteristics implies uncorrelated inputs, which could enhance the capacity of the hippocampus to store arbitrary associations. (+info)Relapse to cocaine-seeking after hippocampal theta burst stimulation. (5/98)
Treatment efforts for cocaine addiction are hampered by high relapse rates. To map brain areas underlying relapse, we used electrical brain stimulation and intracranial injection of pharmacological compounds after extinction of cocaine self-administration behavior in rats. Electrical stimulation of the hippocampus containing glutamatergic fibers, but not the medial forebrain bundle containing dopaminergic fibers, elicited cocaine-seeking behavior dependent on glutamate in the ventral tegmental area. This suggests a role for glutamatergic neurotransmission in relapse to cocaine abuse. The medial forebrain bundle electrodes supported intense electrical self-stimulation. These findings suggest a dissociation of neural systems subserving positive reinforcement (self-stimulation) and incentive motivation (relapse). (+info)Forced limb-use effects on the behavioral and neurochemical effects of 6-hydroxydopamine. (6/98)
Rats with unilateral depletion of striatal dopamine (DA) show marked preferential use of the ipsilateral forelimb. Previous studies have shown that implementation of motor therapy after stroke improves functional outcome (Taub et al., 1999). Thus, we have examined the impact of forced use of the impaired forelimb during or soon after unilateral exposure to the DA neurotoxin 6-hydroxydopamine (6-OHDA). In one group of animals, the nonimpaired forelimb was immobilized using a cast, which forced exclusive use of the impaired limb for the first 7 d after infusion. The animals that received a cast displayed no detectable impairment or asymmetry of limb use, could use the contralateral (impaired) forelimb independently for vertical and lateral weight shifting, and showed no contralateral turning to apomorphine. The behavioral effects were maintained throughout the 60 d of observation. In addition to the behavioral sparing, these animals showed remarkable sparing of striatal DA, its metabolites, and the expression of the vesicular monoamine transporter, suggesting a decrease in the extent of DA neuron degeneration. Behavioral and neurochemical sparing appeared to be complete when the 7 d period of immobilization was initiated immediately after 6-OHDA infusion, only partial sparing was evident when immobilization was initiated 3 d postoperatively, and no sparing was detected when immobilization was initiated 7 d after 6-OHDA treatment. These results suggest that physical therapy may be beneficial in Parkinson's disease. (+info)Restorative plasticity of dopamine neuronal transplants depends on the degree of hemispheric dominance. (7/98)
The ability of dopaminergic (DA) transplants to restore complex sensorimotor behaviors in experimental Parkinson's disease is dependent on graft survival and reinnervation and is likely to be further modified by complex functional graft-host interactions. Here, we examined the impact of hemispheric dominance and extensive testing regimes on the functional capabilities of DA transplants to restore skilled forelimb movements in rats with unilateral 6-hydroxydopamine lesions. Interestingly, a near complete recovery was observed in DA-grafted animals that did not exhibit a strong hemispheric lateralization for paw use before lesion and implantation surgery, whereas animals with a clear lateralization of paw use and grafted into the contralateral hemisphere exhibited only moderate recovery. Finally, animals grafted ipsilateral to the preferred paw were most resistant to functional improvements in skilled forelimb use. However, the influence of hemispheric dominance on the degree of functional DA graft-induced restoration was specific for skilled forelimb use, whereas no such differences were observed in other tests for motor and sensory functions related to the DA system. Furthermore, functional recovery of DA-grafted animals in skilled forelimb use was significantly promoted by extensive behavioral testing regimes indicative of a "learning how to use" the transplant effect. These findings indicate the importance of the underlying functional architecture of complex sensorimotor behaviors, such as skilled forelimb use, and the DA neurotransmitter system for the plasticity of DA transplants to promoting a more complete behavioral recovery in experimental, and potentially, also in clinical forms of Parkinson's disease. (+info)Preferential increases in nucleus accumbens dopamine after systemic cocaine administration are caused by unique characteristics of dopamine neurotransmission. (8/98)
In vivo voltammetry was used to investigate the preferential increase of extracellular dopamine in the nucleus accumbens relative to the caudate-putamen after systemic cocaine administration. In the first part of this study, cocaine (40 mg/kg, i.p.) was compared with two other blockers of dopamine uptake, nomifensine (10 mg/kg, i.p.) and 3beta-(p-chlorophenyl)tropan-2beta-carboxylic acid p-isothiocyanatophenylmethyl ester hydrochloride (RTI-76; 100 nmol, i.c.v.), to assess whether the inhibitory mechanism of cocaine differed in the two regions. All three drugs robustly increased electrically evoked levels of dopamine, and cocaine elevated dopamine signals to a greater extent in the nucleus accumbens. However, kinetic analysis of the evoked dopamine signals indicated that cocaine and nomifensine increased the K(m) for dopamine uptake whereas the dominant effect of RTI-76 was a decrease in V(max). Under the present in vivo conditions, therefore, cocaine is a competitive inhibitor of dopamine uptake in both the nucleus accumbens and caudate-putamen. Whether the preferential effect of cocaine was mediated by regional differences in the presynaptic control of extracellular DA that are described by rates for DA uptake and release was examined next by a correlation analysis. The lower rates for dopamine release and uptake measured in the nucleus accumbens were found to underlie the preferential increase in extracellular dopamine after cocaine. This relationship explains the paradox that cocaine more effectively increases accumbal dopamine despite identical effects on the dopamine transporter in the two regions. The mechanism proposed for the preferential actions of cocaine may also mediate the differential effects of psychostimulant in extrastriatal regions and other uptake inhibitors in the striatum. (+info)The medial forebrain bundle (MFB) is a group of fiber tracts in the brain that carries various neurotransmitters, including dopamine, serotonin, and norepinephrine. It plays a crucial role in reward processing, motivation, and reinforcement, as well as regulation of motor function, cognition, and emotion.
The MFB is located in the ventral part of the forebrain and extends from the ventral tegmental area (VTA) in the midbrain to the prefrontal cortex, nucleus accumbens, amygdala, and other limbic structures in the basal forebrain.
Damage to the MFB can result in various neurological and psychiatric symptoms, such as motor impairment, mood disorders, and addiction. Stimulation of the MFB has been shown to produce rewarding effects and is implicated in the reinforcing properties of drugs of abuse.
'Self-stimulation' is more commonly known as "autoeroticism" or "masturbation." It refers to the act of stimulating one's own genitals for sexual pleasure, which can lead to orgasm. This behavior is considered a normal part of human sexuality and is a safe way to explore one's body and sexual responses. Self-stimulation can also be used as a means of relieving sexual tension and promoting relaxation. It is important to note that self-stimulation should always be a consensual, private activity and not performed in public or against the will of another individual.
Oxidopamine is not a recognized medical term or a medication commonly used in clinical practice. However, it is a chemical compound that is often used in scientific research, particularly in the field of neuroscience.
Oxidopamine is a synthetic catecholamine that can be selectively taken up by dopaminergic neurons and subsequently undergo oxidation, leading to the production of reactive oxygen species. This property makes it a useful tool for studying the effects of oxidative stress on dopaminergic neurons in models of Parkinson's disease and other neurological disorders.
In summary, while not a medical definition per se, oxidopamine is a chemical compound used in research to study the effects of oxidative stress on dopaminergic neurons.
The anterior hypothalamus is a region in the brain that has various functions related to endocrine regulation, autonomic function, and behavior. It contains several nuclei, including the paraventricular nucleus and the supraoptic nucleus, which are involved in the release of hormones from the pituitary gland. The anterior hypothalamus helps regulate body temperature, hunger, thirst, fatigue, and sleep-wake cycles. It also plays a role in processing emotions and stress responses. Damage to the anterior hypothampus can result in various endocrine and behavioral disorders.
Adrenergic agents are a class of drugs that bind to and activate adrenergic receptors, which are cell surface receptors found in the nervous system and other tissues. These receptors are activated by neurotransmitters such as norepinephrine and epinephrine (also known as adrenaline), which are released by the sympathetic nervous system in response to stress or excitement.
Adrenergic agents can be classified based on their mechanism of action and the specific receptors they bind to. There are two main types of adrenergic receptors: alpha and beta receptors, each with several subtypes. Some adrenergic agents bind to both alpha and beta receptors, while others are selective for one or the other.
Adrenergic agents have a wide range of therapeutic uses, including the treatment of asthma, cardiovascular diseases, glaucoma, and neurological disorders. They can also be used as diagnostic tools to test the function of the sympathetic nervous system. Some examples of adrenergic agents include:
* Alpha-agonists: These drugs bind to alpha receptors and cause vasoconstriction (narrowing of blood vessels), which can be useful in the treatment of hypotension (low blood pressure) or nasal congestion. Examples include phenylephrine and oxymetazoline.
* Alpha-antagonists: These drugs block the action of alpha receptors, leading to vasodilation (widening of blood vessels) and a decrease in blood pressure. Examples include prazosin and doxazosin.
* Beta-agonists: These drugs bind to beta receptors and cause bronchodilation (opening of the airways), increased heart rate, and increased force of heart contractions. They are used in the treatment of asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders. Examples include albuterol and salmeterol.
* Beta-antagonists: These drugs block the action of beta receptors, leading to a decrease in heart rate, blood pressure, and bronchodilation. They are used in the treatment of hypertension, angina (chest pain), and heart failure. Examples include metoprolol and atenolol.
* Nonselective alpha- and beta-antagonists: These drugs block both alpha and beta receptors and are used in the treatment of hypertension, angina, and heart failure. Examples include labetalol and carvedilol.
Secondary Parkinson's disease, also known as acquired or symptomatic Parkinsonism, is a clinical syndrome characterized by the signs and symptoms of classic Parkinson's disease (tremor at rest, rigidity, bradykinesia, and postural instability) but caused by a known secondary cause. These causes can include various conditions such as brain injuries, infections, drugs or toxins, metabolic disorders, and vascular damage. The underlying pathology of secondary Parkinson's disease is different from that of classic Parkinson's disease, which is primarily due to the degeneration of dopamine-producing neurons in a specific area of the brain called the substantia nigra pars compacta.
The Substantia Nigra is a region in the midbrain that plays a crucial role in movement control and reward processing. It is composed of two parts: the pars compacta and the pars reticulata. The pars compacta contains dopamine-producing neurons, whose loss or degeneration is associated with Parkinson's disease, leading to motor symptoms such as tremors, rigidity, and bradykinesia.
In summary, Substantia Nigra is a brain structure that contains dopamine-producing cells and is involved in movement control and reward processing. Its dysfunction or degeneration can lead to neurological disorders like Parkinson's disease.
The preoptic area (POA) is a region within the anterior hypothalamus of the brain. It is named for its location near the optic chiasm, where the optic nerves cross. The preoptic area is involved in various functions, including body temperature regulation, sexual behavior, and sleep-wake regulation.
The preoptic area contains several groups of neurons that are sensitive to changes in temperature and are responsible for generating heat through shivering or non-shivering thermogenesis. It also contains neurons that release inhibitory neurotransmitters such as GABA and galanin, which help regulate arousal and sleep.
Additionally, the preoptic area has been implicated in the regulation of sexual behavior, particularly in males. Certain populations of neurons within the preoptic area are involved in the expression of male sexual behavior, such as mounting and intromission.
Overall, the preoptic area is a critical region for the regulation of various physiological and behavioral functions, making it an important area of study in neuroscience research.
Dopamine is a type of neurotransmitter, which is a chemical messenger that transmits signals in the brain and nervous system. It plays several important roles in the body, including:
* Regulation of movement and coordination
* Modulation of mood and motivation
* Control of the reward and pleasure centers of the brain
* Regulation of muscle tone
* Involvement in memory and attention
Dopamine is produced in several areas of the brain, including the substantia nigra and the ventral tegmental area. It is released by neurons (nerve cells) and binds to specific receptors on other neurons, where it can either excite or inhibit their activity.
Abnormalities in dopamine signaling have been implicated in several neurological and psychiatric conditions, including Parkinson's disease, schizophrenia, and addiction.
Parkinsonian disorders are a group of neurological conditions characterized by motor symptoms such as bradykinesia (slowness of movement), rigidity, resting tremor, and postural instability. These symptoms are caused by the degeneration of dopamine-producing neurons in the brain, particularly in the substantia nigra pars compacta.
The most common Parkinsonian disorder is Parkinson's disease (PD), which is a progressive neurodegenerative disorder. However, there are also several other secondary Parkinsonian disorders, including:
1. Drug-induced parkinsonism: This is caused by the use of certain medications, such as antipsychotics and metoclopramide.
2. Vascular parkinsonism: This is caused by small vessel disease in the brain, which can lead to similar symptoms as PD.
3. Dementia with Lewy bodies (DLB): This is a type of dementia that shares some features with PD, such as the presence of alpha-synuclein protein clumps called Lewy bodies.
4. Progressive supranuclear palsy (PSP): This is a rare brain disorder that affects movement, gait, and eye movements.
5. Multiple system atrophy (MSA): This is a progressive neurodegenerative disorder that affects multiple systems in the body, including the autonomic nervous system, motor system, and cerebellum.
6. Corticobasal degeneration (CBD): This is a rare neurological disorder that affects both movement and cognition.
It's important to note that while these disorders share some symptoms with PD, they have different underlying causes and may require different treatments.
The corpus striatum is a part of the brain that plays a crucial role in movement, learning, and cognition. It consists of two structures called the caudate nucleus and the putamen, which are surrounded by the external and internal segments of the globus pallidus. Together, these structures form the basal ganglia, a group of interconnected neurons that help regulate voluntary movement.
The corpus striatum receives input from various parts of the brain, including the cerebral cortex, thalamus, and other brainstem nuclei. It processes this information and sends output to the globus pallidus and substantia nigra, which then project to the thalamus and back to the cerebral cortex. This feedback loop helps coordinate and fine-tune movements, allowing for smooth and coordinated actions.
Damage to the corpus striatum can result in movement disorders such as Parkinson's disease, Huntington's disease, and dystonia. These conditions are characterized by abnormal involuntary movements, muscle stiffness, and difficulty initiating or controlling voluntary movements.
Neural pathways, also known as nerve tracts or fasciculi, refer to the highly organized and specialized routes through which nerve impulses travel within the nervous system. These pathways are formed by groups of neurons (nerve cells) that are connected in a series, creating a continuous communication network for electrical signals to transmit information between different regions of the brain, spinal cord, and peripheral nerves.
Neural pathways can be classified into two main types: sensory (afferent) and motor (efferent). Sensory neural pathways carry sensory information from various receptors in the body (such as those for touch, temperature, pain, and vision) to the brain for processing. Motor neural pathways, on the other hand, transmit signals from the brain to the muscles and glands, controlling movements and other effector functions.
The formation of these neural pathways is crucial for normal nervous system function, as it enables efficient communication between different parts of the body and allows for complex behaviors, cognitive processes, and adaptive responses to internal and external stimuli.
Sympatholytics are a class of drugs that block the action of the sympathetic nervous system, which is the part of the autonomic nervous system responsible for preparing the body for the "fight or flight" response. Sympatholytics achieve this effect by binding to and blocking alpha-adrenergic receptors or beta-adrenergic receptors located in various organs throughout the body, including the heart, blood vessels, lungs, gastrointestinal tract, and urinary system.
Examples of sympatholytic drugs include:
* Alpha blockers (e.g., prazosin, doxazosin)
* Beta blockers (e.g., propranolol, metoprolol)
* Centrally acting sympatholytics (e.g., clonidine, methyldopa)
Sympatholytics are used to treat a variety of medical conditions, including hypertension, angina, heart failure, arrhythmias, and certain neurological disorders. They may also be used to manage symptoms associated with anxiety or withdrawal from alcohol or other substances.
The hypothalamus is a small, vital region of the brain that lies just below the thalamus and forms part of the limbic system. It plays a crucial role in many important functions including:
1. Regulation of body temperature, hunger, thirst, fatigue, sleep, and circadian rhythms.
2. Production and regulation of hormones through its connection with the pituitary gland (the hypophysis). It controls the release of various hormones by producing releasing and inhibiting factors that regulate the anterior pituitary's function.
3. Emotional responses, behavior, and memory formation through its connections with the limbic system structures like the amygdala and hippocampus.
4. Autonomic nervous system regulation, which controls involuntary physiological functions such as heart rate, blood pressure, and digestion.
5. Regulation of the immune system by interacting with the autonomic nervous system.
Damage to the hypothalamus can lead to various disorders like diabetes insipidus, growth hormone deficiency, altered temperature regulation, sleep disturbances, and emotional or behavioral changes.
Drug-induced dyskinesia is a movement disorder that is characterized by involuntary muscle movements or abnormal posturing of the body. It is a side effect that can occur from the long-term use or high doses of certain medications, particularly those used to treat Parkinson's disease and psychosis.
The symptoms of drug-induced dyskinesia can vary in severity and may include rapid, involuntary movements of the limbs, face, or tongue; twisting or writhing movements; and abnormal posturing of the arms, legs, or trunk. These symptoms can be distressing and negatively impact a person's quality of life.
The exact mechanism by which certain medications cause dyskinesia is not fully understood, but it is thought to involve changes in the levels of dopamine, a neurotransmitter that plays a key role in regulating movement. In some cases, adjusting the dose or switching to a different medication may help alleviate the symptoms of drug-induced dyskinesia. However, in severe cases, additional treatments such as deep brain stimulation or botulinum toxin injections may be necessary.
Electric stimulation, also known as electrical nerve stimulation or neuromuscular electrical stimulation, is a therapeutic treatment that uses low-voltage electrical currents to stimulate nerves and muscles. It is often used to help manage pain, promote healing, and improve muscle strength and mobility. The electrical impulses can be delivered through electrodes placed on the skin or directly implanted into the body.
In a medical context, electric stimulation may be used for various purposes such as:
1. Pain management: Electric stimulation can help to block pain signals from reaching the brain and promote the release of endorphins, which are natural painkillers produced by the body.
2. Muscle rehabilitation: Electric stimulation can help to strengthen muscles that have become weak due to injury, illness, or surgery. It can also help to prevent muscle atrophy and improve range of motion.
3. Wound healing: Electric stimulation can promote tissue growth and help to speed up the healing process in wounds, ulcers, and other types of injuries.
4. Urinary incontinence: Electric stimulation can be used to strengthen the muscles that control urination and reduce symptoms of urinary incontinence.
5. Migraine prevention: Electric stimulation can be used as a preventive treatment for migraines by applying electrical impulses to specific nerves in the head and neck.
It is important to note that electric stimulation should only be administered under the guidance of a qualified healthcare professional, as improper use can cause harm or discomfort.
Tyrosine 3-Monooxygenase (also known as Tyrosinase or Tyrosine hydroxylase) is an enzyme that plays a crucial role in the synthesis of catecholamines, which are neurotransmitters and hormones in the body. This enzyme catalyzes the conversion of the amino acid L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by adding a hydroxyl group to the 3rd carbon atom of the tyrosine molecule.
The reaction is as follows:
L-Tyrosine + O2 + pterin (co-factor) -> L-DOPA + pterin (oxidized) + H2O
This enzyme requires molecular oxygen and a co-factor such as tetrahydrobiopterin to carry out the reaction. Tyrosine 3-Monooxygenase is found in various tissues, including the brain and adrenal glands, where it helps regulate the production of catecholamines like dopamine, norepinephrine, and epinephrine. Dysregulation of this enzyme has been implicated in several neurological disorders, such as Parkinson's disease.
Haloperidol is an antipsychotic medication, which is primarily used to treat schizophrenia and symptoms of psychosis, such as delusions, hallucinations, paranoia, or disordered thought. It may also be used to manage Tourette's disorder, tics, agitation, aggression, and hyperactivity in children with developmental disorders.
Haloperidol works by blocking the action of dopamine, a neurotransmitter in the brain, which helps to regulate mood and behavior. It is available in various forms, including tablets, liquid, and injectable solutions. The medication can cause side effects such as drowsiness, restlessness, muscle stiffness, and uncontrolled movements. In rare cases, it may also lead to more serious neurological side effects.
As with any medication, haloperidol should be taken under the supervision of a healthcare provider, who will consider the individual's medical history, current medications, and other factors before prescribing it.
The mesencephalon, also known as the midbrain, is the middle portion of the brainstem that connects the hindbrain (rhombencephalon) and the forebrain (prosencephalon). It plays a crucial role in several important functions including motor control, vision, hearing, and the regulation of consciousness and sleep-wake cycles. The mesencephalon contains several important structures such as the cerebral aqueduct, tectum, tegmentum, cerebral peduncles, and several cranial nerve nuclei (III and IV).
Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.
Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.
These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.
Neurons, also known as nerve cells or neurocytes, are specialized cells that constitute the basic unit of the nervous system. They are responsible for receiving, processing, and transmitting information and signals within the body. Neurons have three main parts: the dendrites, the cell body (soma), and the axon. The dendrites receive signals from other neurons or sensory receptors, while the axon transmits these signals to other neurons, muscles, or glands. The junction between two neurons is called a synapse, where neurotransmitters are released to transmit the signal across the gap (synaptic cleft) to the next neuron. Neurons vary in size, shape, and structure depending on their function and location within the nervous system.
Levodopa, also known as L-dopa, is a medication used primarily in the treatment of Parkinson's disease. It is a direct precursor to the neurotransmitter dopamine and works by being converted into dopamine in the brain, helping to restore the balance between dopamine and other neurotransmitters. This helps alleviate symptoms such as stiffness, tremors, spasms, and poor muscle control. Levodopa is often combined with carbidopa (a peripheral decarboxylase inhibitor) to prevent the conversion of levodopa to dopamine outside of the brain, reducing side effects like nausea and vomiting.
Denervation is a medical term that refers to the loss or removal of nerve supply to an organ or body part. This can occur as a result of surgical intervention, injury, or disease processes that damage the nerves leading to the affected area. The consequences of denervation depend on the specific organ or tissue involved, but generally, it can lead to changes in function, sensation, and muscle tone. For example, denervation of a skeletal muscle can cause weakness, atrophy, and altered reflexes. Similarly, denervation of an organ such as the heart can lead to abnormalities in heart rate and rhythm. In some cases, denervation may be intentional, such as during surgical procedures aimed at treating chronic pain or spasticity.
In the context of medicine, particularly in behavioral neuroscience and psychology, "reward" is not typically used as a definitive medical term. However, it generally refers to a positive outcome or incentive that reinforces certain behaviors, making them more likely to be repeated in the future. This can involve various stimuli such as food, water, sexual activity, social interaction, or drug use, among others.
In the brain, rewards are associated with the activation of the reward system, primarily the mesolimbic dopamine pathway, which includes the ventral tegmental area (VTA) and the nucleus accumbens (NAcc). The release of dopamine in these areas is thought to reinforce and motivate behavior linked to rewards.
It's important to note that while "reward" has a specific meaning in this context, it is not a formal medical diagnosis or condition. Instead, it is a concept used to understand the neural and psychological mechanisms underlying motivation, learning, and addiction.
'Animal behavior' refers to the actions or responses of animals to various stimuli, including their interactions with the environment and other individuals. It is the study of the actions of animals, whether they are instinctual, learned, or a combination of both. Animal behavior includes communication, mating, foraging, predator avoidance, and social organization, among other things. The scientific study of animal behavior is called ethology. This field seeks to understand the evolutionary basis for behaviors as well as their physiological and psychological mechanisms.
Evoked potentials (EPs) are medical tests that measure the electrical activity in the brain or spinal cord in response to specific sensory stimuli, such as sight, sound, or touch. These tests are often used to help diagnose and monitor conditions that affect the nervous system, such as multiple sclerosis, brainstem tumors, and spinal cord injuries.
There are several types of EPs, including:
1. Visual Evoked Potentials (VEPs): These are used to assess the function of the visual pathway from the eyes to the back of the brain. A patient is typically asked to look at a patterned image or flashing light while electrodes placed on the scalp record the electrical responses.
2. Brainstem Auditory Evoked Potentials (BAEPs): These are used to evaluate the function of the auditory nerve and brainstem. Clicking sounds are presented to one or both ears, and electrodes placed on the scalp measure the response.
3. Somatosensory Evoked Potentials (SSEPs): These are used to assess the function of the peripheral nerves and spinal cord. Small electrical shocks are applied to a nerve at the wrist or ankle, and electrodes placed on the scalp record the response as it travels up the spinal cord to the brain.
4. Motor Evoked Potentials (MEPs): These are used to assess the function of the motor pathways in the brain and spinal cord. A magnetic or electrical stimulus is applied to the brain or spinal cord, and electrodes placed on a muscle measure the response as it travels down the motor pathway.
EPs can help identify abnormalities in the nervous system that may not be apparent through other diagnostic tests, such as imaging studies or clinical examinations. They are generally safe, non-invasive procedures with few risks or side effects.
The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:
1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.
The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.
"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.
Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.
Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.
Medial forebrain bundle
Hypothalamotegmental tract
Maria Carmela Lico
Leonard Sax
Neuromodulation
Ferguson reflex
Reward system
Olfactory tubercle
Deep brain stimulation
Ventral tegmental area
Hypothalamus
Grandiose delusions
Septal area
Stimulant
Fasciculus retroflexus
Mesolimbic pathway
Brain stimulation reward
Nigrostriatal pathway
Guided rat
Foix-Chavany-Marie syndrome
Index of anatomy articles
Monoamine nuclei
MFB
Neural pathway
Limbic system
Histamine
Remote control animal
Jean-Charles Schwartz
List of regions in the human brain
Diagonal band of Broca
Medial forebrain bundle - Wikipedia
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Deep brain stimu8
- Subjects that receive the deep brain stimulation treatment in the medial forebrain bundle have been reported to have high remission rates with normative functioning and no adverse side effects. (wikipedia.org)
- Researchers implanted pacemaker electrodes into the medial forebrain bundle of patients suffering from major depression and performed deep brain stimulation. (neurosciencenews.com)
- The researchers implanted the deep brain stimulation systems in the patients medial forebrain bundle (blue) of the brain, a part of the brains reward system. (medicalfair-india.com)
- Prof. Dr. Volker A. Coenen, first author of the study and director of the Stereotactic and Functional Neurosurgery Unit at the Department of Neurosurgery of the Medical Center - University of Freiburg, and his team implanted the deep brain stimulation systems in the patients medial forebrain bundle of the brain and used them to stimulate the medial forebrain bundle. (medicalfair-india.com)
- Deep brain stimulation of the medial forebrain bundle: distinctive responses in resistant depression. (bvsalud.org)
- The scientist's investigation covers issues in Deep brain stimulation, Depression, Medial forebrain bundle, Treatment-resistant depression and Neuroscience. (research.com)
- The medial forebrain bundle as a target for deep brain stimulation for obsessive-compulsive disorder. (research.com)
- Deep brain stimulation, Medial forebrain bundle, Depression, Neuroscience and Diffusion MRI are his primary areas of study. (research.com)
Midbrain4
- The MFB is one of the two major pathways connecting the limbic forebrain, midbrain, and hindbrain. (wikipedia.org)
- Swanson LW , Hahn JD , Sporns O . Structure-function subsystem model and computational lesions of the central nervous system's rostral sector (forebrain and midbrain). (neurotree.org)
- This view is related to the theory that all positive reinforcers activate a common biological mechanism associated with approach behaviors and that this mechanism has as one of its components dopaminergic fibers that project up the medial forebrain bundle from the midbrain to limbic and cortical regions. (baristaexchange.com)
- 10. Describe the main structures of the brain stem, the midbrain, and forebrain, including the basal ganglia, the limbic system and the cerebral cortex. (meganursingwriters.com)
Ventral4
- The medial forebrain bundle (MFB) is a neural pathway containing fibers from the basal olfactory regions, the periamygdaloid region and the septal nuclei, as well as fibers from brainstem regions, including the ventral tegmental area and nigrostriatal pathway. (wikipedia.org)
- The anatomic targets include the subgenual cingulate cortex, ventral capsule/ventral striatum, nucleus accumbens, and superolateral branch of the medial forebrain bundle. (psychiatrist.com)
- The reward centre gets lit up through the nucleus accumbens, the amygdala, the insular and the ventral medial prefrontal cortex, as well as the medial forebrain bundle (all of these are deep brain structures): and we experience happiness or joy or sexual pleasure. (sparklinghill.com)
- Other cells were seen on the base of the hypothalamus, within the median forebrain bundle, dorsal and ventral aspects of the ventromedial nucleus, zona incerta and dorsal part of the dorsomedial nucleus. (elsevierpure.com)
Hypothalamus3
- The MFB passes through the lateral hypothalamus and the basal forebrain in a rostral-caudal direction. (wikipedia.org)
- Olfactory afferent: Fibers from olfactory pathway pass to hypothalamus as medial forebrain bundle. (kypho.com)
- Projections to areas caudal to the hypothalamus go through the medial forebrain bundle, the mammillotegmental tract and the dorsal longitudinal fasciculus. (sciencebeta.com)
Dorsal1
- [4] [5] Ascending sensory tracts in the dorsal column-medial lemniscus pathway (DCML) carry information from the periphery to the cortex of the brain. (wikipedia.org)
Lesions3
- In animal studies studying the effects of Levodopa-induced dyskinesia, a major complication in the treatment of Parkinson's disease, lesions in the medial forebrain bundle show a maximum level of severity and sensitivity to levodopa and provide insight into the mechanisms of Levodopa-induced dyskinesia. (wikipedia.org)
- Estudis previs del nostre grup demostren que l'estimulació reforçant del feix prosencefàlic medial (MFB-ICSS) facilita l'aprenentatge i la memòria en rates sanes o amb determinades lesions cerebrals. (udg.edu)
- Bissonette GB, Martins GJ, Franz TM, Harper ES, Schoenbaum G, Powell EM (2008) Double dissociation of the effects of medial and orbital prefrontal cortical lesions on attentional and affective shifts in mice. (springer.com)
Prefrontal cortex1
- The impact of 6-OHDA (8, 12, 16μg/4μl) administered unilaterally into the medial forebrain bundle on the sucrose solution intake (a measure of anhedonia) and on the tissue levels of noradrenaline (NA), dopamine (DA) and serotonin (5-HT) in the striatum (STR), substantia nigra (SN), prefrontal cortex (PFC) and hippocampus (HIP) was examined in rats pretreated or non-pretreated with desipramine. (nih.gov)
Nucleus4
- Microinjections of a glutamate AMPA antagonist (DNQX) in medial shell of nucleus accumbens (NAc) can cause either intense appetitive motivation (i.e., 'desire') or intense defensive motivation (i.e., 'dread'), depending on site along a flexible rostrocaudal gradient and on environmental ambience. (jneurosci.org)
- Localized neuropharmacological glutamate blockade at sites in the medial shell of nucleus accumbens (NAc), by microinjections of the glutamate AMPA antagonist, DNQX, produce either intense appetitive behavior or fearful behavior. (jneurosci.org)
- These axon bundles are known as tuberoinfundibular tract which transports two hormones liberated by neurons of tuberal nucleus. (kypho.com)
- The concept of MDD as a dysfunction of neuronal networks rather than of distinct brain areas has led to the clinical investigation of a number of DBS targets, including the subgenual cingulate (Cg25), nucleus accumbens (NAcc) and medial forebrain bundle (MFB). (fu-berlin.de)
Lemniscus3
- 8. Describe the formation and termination of the medial lemniscus of brain. (dentaldevotee.com)
- To pass through the brainstem, before reaching their primary destination to thalamus, the tracts present compact bundle known as spinal lemniscus. (kypho.com)
- Similarly, medial lemniscus is another compact bundle destined to thalamus while passing through brainstem. (kypho.com)
Unilaterally1
- Male Sprague Dawley rats were lesioned unilaterally with 6-hydroxydopamine at the medial forebrain bundle. (erowid.org)
Stimulate1
- minute to stimulate its medial forebrain bundle (the part of I had reached a stage in my career where I felt like the brain that generates pleasure sensations). (medlineplus.gov)
Electrodes1
- Rewarding electrical stimulation was delivered via electrodes stereotaxically implanted in the medial forebrain bundle-lateral hypothalamic area of the rat brain. (erowid.org)
Axon1
- Neurons are connected by a single axon, or by a bundle of axons known as a nerve tract , or fasciculus . (wikipedia.org)
Tract1
- These fiber bundles are known as hypothalamohypophyseal tract. (kypho.com)
Pathway2
- Furthermore, reduced integrity within another pathway called the medial forebrain bundle also showed a relationship to patient-reported physical health impairments. (technologynetworks.com)
- A neural pathway connects one part of the nervous system to another using bundles of axons called tracts. (wikipedia.org)
Rats2
- In a study with rats, using intracranial self-stimulation implanted in the medial forebrain bundle, rats treated with nicotine and methamphetamine showed an increased speed at which they pressed a lever to induce self-stimulation. (wikipedia.org)
- Previous studies from our group have demonstrated that rewarding stimulation of the medial forebrain bundle (MFB-ICSS) facilitates learning and memory in healthy and brain-lesioned rats. (udg.edu)
Behavior2
- The study indicates that the medial forebrain bundle may be directly linked to motivational behavior that is induced by drugs. (wikipedia.org)
- Swanson LW , Hahn JD , Sporns O . Structure-function subsystem models of female and male forebrain networks integrating cognition, affect, behavior, and bodily functions. (neurotree.org)
Velocities1
- Conduction velocities are extremely slow, and support is provided in bundles by a single Schwann cell. (medscape.com)
Stimulation2
- Electrical stimulation of the medial forebrain bundle is believed to cause sensations of pleasure. (wikipedia.org)
- The medial forebrain bundle may also serve to study abuse-related drug effects through intracranial self-stimulation. (wikipedia.org)
Target1
- The medial forebrain bundle may serve as a target in treating treatment-resistant depression. (wikipedia.org)
Rates1
- En aquesta tesi, s'avalua per primera vegada l'efecte de la MFB-ICSS sobre molècules associades amb l'AD i la relació amb la millora cognitiva en rates, incloent els models d'AD esporàdic de β-amiloide i d'estreptozotocina. (udg.edu)
Neurons2
- 26. Progressive loss of dopaminergic neurons induced by unilateral rotenone infusion into the medial forebrain bundle. (nih.gov)
- The spinal cord houses millions of neurons, and their bundled fibers are running as tracts that are either ascending or descending. (endinglines.com)
Limbic3
- The MFB is one of the two major pathways connecting the limbic forebrain, midbrain, and hindbrain. (wikipedia.org)
- Chergui K, Nomikos GG, Mathé JM, Gonon F, Svensson TH (1996) Burst stimulation of the medial forebrain bundle selectively increase Fos-like immunoreactivity in the limbic forebrain of the rat. (yale.edu)
- Describe the main structures of the brain stem, the midbrain, and forebrain, including the basal ganglia, the limbic system and the cerebral cortex. (elitecollegessays.com)
Ventral tegm4
- The medial forebrain bundle (MFB) is a neural pathway containing fibers from the basal olfactory regions, the periamygdaloid region and the septal nuclei, as well as fibers from brainstem regions, including the ventral tegmental area and nigrostriatal pathway. (wikipedia.org)
- Notice how the ventral tegmental area (VTA) connects via the medial forebrain bundle (MFB) to the nucleus accumbens (NAcc). (harley.com)
- Link between structural connectivity of the medial forebrain bundle, functional connectivity of the ventral tegmental area, and anhedonia in unipolar depression. (unibe.ch)
- 5. Furlanetti LL, Coenen VA , Döbrössy MD . Ventral tegmental area dopaminergic lesion- induced depressive phenotype in the rat is reversed by deep brain stimulation of the medial forebrain bundle. (uni-freiburg.de)
Basal1
- The MFB passes through the lateral hypothalamus and the basal forebrain in a rostral-caudal direction. (wikipedia.org)
Lateral8
- Four major projection pathways are described: (1) local projections within the arcuate nucleus bilaterally, (2) projections to the median eminence including the lateral palisade zone, (3) projections to a periventricular pathway extending rostrally to multiple hypothalamic nuclei, the septal region and BNST and dorsally to the dorsomedial nucleus and (4) Projections to a ventral hypothalamic tract to the lateral hypothalamus and medial forebrain bundle. (brainmaps.org)
- Deep brain stimulation of the supero-lateral branch of the medial forebrain bundle does not lead to changes in personality in patients suffering from severe depression. (uni-koeln.de)
- The part of the hypothalamus posterior to the middle region consisting of several nuclei including the medial mamillary nucleus, lateral mamillary nucleus, and posterior hypothalamic nucleus (posterior hypothalamic area). (nih.gov)
- Loose heterogeneous collection of cells in the anterior hypothalamus, continuous rostrally with the medial and lateral preoptic areas and caudally with the tuber cinereum. (nih.gov)
- The medial edge of the internal capsule and the subthalamic region form its lateral boundary. (nih.gov)
- It contains the lateral hypothalamic nucleus, tuberomammillary nucleus, lateral tuberal nuclei, and fibers of the medial forebrain bundle. (nih.gov)
- In male zebra finches, the circuit connecting the medial dorsolateral nucleus of the thalamus (DLM) and its cortical target, the lateral magnocellular nucleus of the anterior neostriatum (lMAN), is crucial for the acquisition of a normal vocal pattern during the sensitive period for song learning. (jneurosci.org)
- The linear nucleus (Li) is found in the medullary reticular formation surrounding the middle segment of the compact part of the ambiguus nucleus (AmbC) in dorsal, medial and/or lateral aspects. (biomedcentral.com)
Brainstem1
- On the other hand, connectivity to the thalamus and brainstem through the medial forebrain bundle (MFB) was only observed in SO patients. (ox.ac.uk)
Preoptic1
- MSG activated the medial preoptic area, dorsomedial nucleus of the hypothalamus , and habenular nucleus. (brainmaps.org)
Anterior1
- Associations between anterior cingulate thickness, cingulum bundle microstructure, melancholia and depression severity in unipolar depression. (unibe.ch)
Severity1
- METHOD: The neurotoxin of 6-OHDA was injected into medial forebrain bundle of right hemisphere and behavioral tests were carried out to eight weeks thereafter to evaluate severity of PD and its progress. (bvsalud.org)
Sensations1
- If you've ever seen a rat press a lever 100 times per minute to stimulate its medial forebrain bundle (the part of the brain that generates pleasure sensations)…I was hooked. (medlineplus.gov)
Depression2
- The medial forebrain bundle may serve as a target in treating treatment-resistant depression. (wikipedia.org)
- The medial forebrain bundle and its role in the circuitry of depression. (uniklinik-freiburg.de)
Study1
- The study indicates that the medial forebrain bundle may be directly linked to motivational behavior that is induced by drugs. (wikipedia.org)