Limbic System & Limbic System Neurotransmitters

"Hippo Hat" HIPPO - hippocampus H - hypothalamus A - Amygdala T - thalamus

The purpose of the limbic system is

Feelings underlying love, altruism, morals, as well as anger, resentment, jealousy and greed are all generated by the limbic system.

The limbic system is an [blank_start]integrative[blank_end] system that utilizes information from and has complex connections with, many different subsystems (motor, sensory, and autonomic systems).

The following are functions of the limbic system

Which functions are the limbic system involved in?

limbic lobe was identified as consisting of a ring-like area of cortex on the medial surface of each cerebral hemisphere, including the cingulate gyrus, parahippocampal gyrus and septal cortex – all three of which are interconnected by a white matter pathway called the [blank_start]cingulum[blank_end]

The Papez Circuit includes the following areas of the brain:

Label the diagram:

The Papez Circuit: Hippocampus connects to [blank_start]Mammillary Bodes (Hypothalamus)[blank_end] through the fornix Mammillary Bodes (Hypothalamus) connect to the [blank_start]Anterior nuclei of the thalamus[blank_end] through the mammilo-thalmic tract Anterior nucli of the thalamus connect to [blank_start]cingulate gyrus[blank_end] through internal capsule Cingulate gyrus connects to [blank_start]hippocampus[blank_end] through cingulum

In the Papez circuit, the hippocampus is connected to the Mamillary Bodies (Hypothalamus) by the

In the Papez Circuit, the Mammillary Bodies (hypothalamus) are connected to the anterior nuclei of the thalamus by the

In the Papez Circuit, the anterior nuclei of the thalamus is connected to the cingulate gyrus by the

In the Papez Circuit, the cingulate gyrus is connected to the hippocampus by the

The functions of the limbic system can be divided into four basic categories:

One of the things that makes the olfactory system unique is that smells evoke strong feelings, emotionally enhance our experiences, and facilitate the establishment of memories (all key limbic system functions).

Olfactory cortex includes a part of the orbitofrontal cortex and the medial aspect of the temporal lobe known as the pyriform cortex that includes a medial bulge known as the uncus.

The uncus is of clinical significance because:

The limbic system modulates and, at times, directly activates the hypothalamus.

[blank_start]Explicit[blank_end] memory refers to the conscious recollection of facts [blank_start]Implicit[blank_end] memory refers to the subconscious learning of skills, habits or behaviors

Explicit memory includes

The main structure in the limbic system that is important for establishing explicit memories is the

Implicit memory refers to the subconscious learning of skills, habits or behaviors (e.g., how to ride a bike), and occurs through circuits of the

Severe memory deficit is usually observed only when the damage is [blank_start]bilateral[blank_end]

When lesions/damage create issues in the consolidation process of placing short-term memories into long-term storage this is referred to as [blank_start]anterograde[blank_end] amnesia while [blank_start]retrograde[blank_end] amnesia refers to the loss of previously formed long-term memories.

What brain structure is a major target in Alzheimer's Disease

What nutritional deficiency causes Wernicke-Korsakoff Syndrome-

Thiamine deficiency in Wernicke-Korsakoff Syndrome, which is usually caused by ETOH can be manifested in

Prefrontal cortex: [blank_start]Dorsolateral[blank_end] = executive, problem solving and analyzing [blank_start]Ventomedial[blank_end] = role in emotional processing [blank_start]Orbitofrontal cortex (OFC)[blank_end] = regulate impulses, compulsions, and drives [blank_start]Anterior cingulate cortex (ACC)[blank_end] = selective attention, emotions, depression, and anxiety

In the limbic system, the ________is responsible for constructing the perceptions of emotional feelings, making judgements about our experiences, and determining actions in response to the emotional value we place on our experiences

The ________, which is part of the prefrontal cortex, is involved in impulse control, moral judgement, abstracting the rules of social interaction, and the ability to appreciate the consequences of one's actions

The _________ is involved primarily in executive functions, contributing to our ability to prioritize and carry out actions, and adapt to change.

[blank_start]Mood[blank_end] is an internal subjective state that fluctuates in response to physiological and environmental circumstances [blank_start]Temperament[blank_end] refers to the relatively stable characteristics and personality traits of individuals and how they engage with the world throughout their lifetime

When there is dysfunction of the limbic system circuits that give rise to mood and temperament, there can be a significant change in how an individual reacts in the world and with others.

The endogenous reward system involves which structures in the brain

Ventral tegmental area (VTA) is a tiny group of dopaminergic (releasing or involving dopamine as a neurotransmitter) neurons located in the midbrain that gives rise to two major projections or pathways:

Mesolimbic:

Mesocortical pathway:

VTA and its projections to the nucleus accumbens is involved in virtually every type of addiction

The ability to attach negative emotions to experiences, which then drive behavior, is what underlies survivability for all animals, including humans.

The major structure of the brain that pairs experience with emotion, including fear, is the __________, a subcortical nuclear complex located in the temporal lobe.

Functions of the amygdala include:

Kluver-Bucy Syndrome is a clinical condition where the removal of the bilateral temporal lobes (including the amygdala) leads to:

The amygdala has widespread and often reciprocal connections to many areas of the brain, including the neocortex, hippocampus, hypothalamus, nuclei of the extrapyramidal motor system, and thalamus.

Amygdala receives direct projections from sensory relay nuclei of the [blank_start]thalamus[blank_end], bypassing the [blank_start]cortex,[blank_end] so that emotional significance can be paired with incoming sensory information even before there is a conscious perception of what the stimulus actually is.

The amygdala is involved in quickly reacting to acute threatening situations by:

If the amygdala and associated limbic system circuits are continuously responding to perceptually stressful stimuli, such as in the setting of chronic stress, there can be negative consequences, including dysfunction of the immune system, the cardiovascular system, and parts of the nervous system.

Each of the nuclei in the limbic system uses a specific neurotransmitter to communicate with other parts of the brain.

[blank_start]Glutamate[blank_end] = turns brain on; builds memory; regulates awareness, movement, sensation & mood [blank_start]GABA[blank_end] - turns brain off; involved in sleep, sedation, relaxation, reducing anxiety & decreasing muscle tension [blank_start]Endocannabinoids[blank_end] = regulate pain, appetite [blank_start]Serotonin[blank_end] = regulate mood, anxiety, appetite, sleep cycle [blank_start]Noradrenaline[blank_end] = feelings of alertness, attention, concentration, raising BP, lifts mood, can cause anxiety [blank_start]Dopamine[blank_end] = creates feelings of motivation and drive, liking, attention, pleasure & enjoyment in food [blank_start]Acetylcholine[blank_end] = regulates sleep cycle and alertness and builds memory

Within the CNS, there are high concentrations of cholinergic neurons in

Acetylcholine acts on target neurons in the _________ and the __________, strengthening the neural circuits that are involved in memory formation.

Serotonin (5–HT) is a monoamine (specifically, an indoleamine) that is produced by [blank_start]raphe[blank_end] nuclei, small groups of serotonergic neurons in the reticular formation extending from the medulla to the midbrain

Dopamine is a monoamine (specifically, a catecholamine) that is produced by several different nuclear groups in the brain. One of these nuclear groups – the [blank_start]ventral tegmental area[blank_end] – is located in the midbrain, and has major connections to limbic system structures via the mesolimbic and mesocortical pathways

[blank_start]Mesolimbic pathway[blank_end] (VTA nucleus accumbens and other limbic system structures such as the amygdala) – involved in pleasure and reward; stimulation of this pathway results in a sense of pleasure. [blank_start]Mesocortical pathway[blank_end] (VTA prefrontal cortex) – involved in motivational behavior; tied to pleasure and reward.

Dopamine (via the mesolimbic & mesocortical pathways) plays a major role in addiction. Any drug that elicits the subjective sense of pleasure or joy acts on these dopaminergic pathways (i.e., the endogenous reward system); and such drugs can be physiologically and/or psychologically addicting.

Norepinephrine is a monoamine (specifically, a catecholamine) that, in the CNS, is produced by the ____________, a tiny, paired nucleus that lies dorsolaterally in the pontine reticular formation.

Monoamine neurotransmitters modulate our emotional response to the world and our mood. If the levels of the monoamines are increased, there is a feeling of well-being. If levels are decreased, the result can be depression.

The standard classes of medications used to treat depression modulate monoamine neurotransmitters. These drugs might facilitate the transmission of monoamine synaptic connections by:

The four categories of "antidepressant" medications are:

Tricyclic antidepressants work by

Glutamate is the [blank_start]most[blank_end] used neurotransmitter in the nervous system and is [blank_start]always[blank_end] thought to cause an excitatory postsynaptic response.

Neurons that release opioids are also involved in limbic system circuits; in fact, the highest density of opioid receptors is in limbic system structures.

Papez Circuit