Physiology II: Nervous system IV - Basal Ganglia, Thalamus, Hypothalamus and Limbic system

Subcortical regions: … (2)

Basal ganglia, diencephalon

Diencephalon is composed of: … (2)

thalamus, hypothalamus

…: role in starting, stopping, and modulating motor pathways, inhibit muscles tone, select and maintain purposeful and suppress/unwanted movements patterns, monitor/coordinate slow, sustained contractions especially posture and support

Basal ganglia

Complex integrative role of basal ganglia, involved in … involving motor cortex and thalamus

important feedback loop

Thalamus …

reinforces motor action

Basal ganglia modulate the thalamus by: … (2)

inhibitory effect on thalamus, inhibition through brain stem neurons

…: gradual destruction of dopamine releasing neurons in basal ganglia (substantia nigra → lack of dopamine)

Parkinson’s disease

Motor disorders associated with parkinson’s disease: … (5)

rigidity, resting tremor, hesitation, bradykinesia, postural instability

…: increased muscle tone

rigidity

…: involuntary movements

resting tremor

…: slowness in initiation of movement

hesitation

…: slowness in preforming a movement

bradykinesia

…: impaired balance and frequent falls

postural instability

…: a dopamine precursor which enters blood and then the brain, where it is converted to dopamine

levodopa (L-dopa)

The thalamus serves as a relay station for …. on its way to cortex

preliminary processing of sensory input

The thalamus … and routes important signals to appropriate areas of the cortex

screens out insignificant signals

Along with the brain stem and cortical association areas the thalamus is important in … to stimuli of interest

directing attention

Thalamus role in motor control: …

positive reinforcement of voluntary motor activity by initiated by cortex

The hypothalamus controls: … (9)

body temp, thirst/urine, food intake, anterior pituitary hormone secretion, posterior pituitary hormones, uterine contraction/milk production, autonomic nervous system, emotional/behavioral patterns, sleep-wake cycles

Hypothalamus is most involved in …

directly regulating internal environment

Limbic system is a …, consists of a ring of forebrain structures that surround the brain stem, interconnected by intricate white matter pathways

functional system

Functions of the limbic system: … (4)

emotions, basic behavioral patterns, motivation, learning, memory

…: subjective emotional feelings and moods (ex. anger, fear, sadness, joy)

emotion

there is a … associaed with feelings

physical response

Cortical association areas also involved in …

conscious emotion

… → reinforced

gratifying behaviors

… → suppress behaviors

unpleasant experiences

…: stimulation leads to pleasant sensations, in regions involved in highly motivated behaviors (eating, drinking, sexual activity)

“reward” centers

…: stimulation leads to unpleasant stimulation

“punishment” centers

…: ability to direct behavior toward specific goal

motivation

…: subjective urges associated with specific bodily needs → motivate appropriate behavior to satisfy these needs

Homeostatic drives

Example of homeostatic drives: thirst due to water deficit → … → …

drinking behavior, primary motives

…: achievement, power, motivation, desire for wealth, are complex networks involving limbic system reward punishment centers and associative cortex

Secondary (learned) behaviors

Neurotransmitters associated with behavior, emotion, and motivation: … (3)

norepinephrine (noradrenaline), dopamine, serotonin

… (2): belong to a class of catecholamines, found in reward centers with the highest rate of self-stimulation

norepinephrine, dopamine

…: affect moods, some influence self-stimulation in experimental animals

psychoactive drugs

…: stimulates dopamine release → increased rate of stimulation (upper drug)

amphetamines

Most drugs abused recreationally boost effectiveness of … → initially intense sensation of pleasure

dopamine in the pleasure pathway

…: blocks the reuptake of dopamine at synapses making it more available in synaptic cleft

cocaine

…: psychiatric mood disorder associated with prevalent negative mood, loss of interests, inability to experience pleasure, suicidal tendencies

depression

Depression results from a …

deficiency of serotonin and noradrenaline

Areas involved in depression: … (3)

hippocampus, amygdala, medial prefrontal cortex

…: most often increase serotonin or noradrenaline efficacy

antidepressant drugs

Four types of antidepressant drugs: …

selective serotonin uptake inhibitors, serotonin noradrenaline reuptake inhibitors, tricyclic antidepressants, monoamine oxidase inhibitors

…: Prolong serotonin activity at synapses by inhibiting reuptake (Prozac)

selective serotonin uptake inhibitors

…: prolong activity of both neurotransmitters at synapses (effexor, cymbalta)

serotonin noradrenaline reuptake inhibitors

…: block reuptake of serotonin, norepinephrine at synapses but unlike SSROs and SNRIs also affect autonomic nervous system → side effects

tricyclic antidepressants

…: raise levels of serotonin, norepinephrine and dopamine by inhibiting enzyme MAO which breals these down. more side effects, especially when combined with certian foods such as cheese

Monoamine oxidase inhibitors

Antidepressants immedialy boost neurotransmitter concentation, yet a reduction of symptoms typically takes …

several weeks

…: acquisition of knowledge as a result of experiences instruction or both

learning

…: storage of acquired knowledge for later recall

memory

Memory laid down in stages: … (4)

memory trace, short-term memory, long-term memory, consolidation, working memory

…: neural change underlying storage of knowledge

memory trace

…: seconds to hours

Short-term memory

…: days to years

long-term memory

…: transferring and fixing STM traces into LTM

consolidation

…: temoirarily holds and interrelates information relevant to surrent task; crucual for mental functioning

working memory

…: inability to recall recent past events, usually follows a traumatic event such as a concussion or stroke

retrograde amnesia

…: inability to consolidate new memory in long-term storage for later retrieval, medial temporal lobe (hippocampus) lesions, cannot form new memories but can recall old memories

anterograde

Short-term memory involves … in preexisting synapse function

transient modifications

Long-term memory involves relatively … changes bwtween existing neurons in the brain

permanent functional or structural

transient modifications in the function of preexisting synapse in STM include: ...

change in amount of neurotransmitter released, change in responsiveness of postsynaptic cell

…: decreased responsiveness to repetitive exposure to an indifferent stimulus → depresses synaptic activity

habituation

In habituation the … do not open as readily

voltage-gated Ca+ channels

…: increased responsiveness to a mild stimulus following a strong or noxious stimulus → enhances synaptic activity

Sensitization

Sensitization happens through …

presynaptic facilitation through serotonin

…: consolidation of STM to LTM, connections get stronger the more often it is used (more and stronger EPSPs in postsynaptic neuron)

Long-term potentialtion

Long-term potentiation lasts for days/weeks; especially prevalent in hippocampus, involves NMDA … ad .. → insertion of more …

glutamate receptors, Ca2+ signaling, postsynaptic glutamate receptors

Formation of new permanent synaptic connections by activation of … that control synthesis of proteins needed for lasting structural or functional changes at specific synapses (cAMP plays a role)

specific genes

…: conscious memories depend on hippocampus and medial temporal lobe

declarative memories

Declarative memory can be grouped into: … (2)

semantic memories, episodic memories

…: unconscious “how to” perform a motor skill/routine depend on cerebellum and sensory/motor systems

procedural memories

…: executive functions of manipulation, integration, juggling with competing priorities, problem solving, making choices, organizing activities, inhibiting impulses, these functions carried out with association and sensory areas

prefrontal cortex

Working memory is …

temporary and erasable