Final exam flash cards

Basic functions of the limbic system

Basic survival functions

• Feeding

• Fight or flight

• Aggression

• Sexual response cycle

What are the gyri of the limbic lobe?

• Parahippocampal gyrus

• Subcallosal gyrus

• Cingulate gyrus

Functions of the parahippocampal gyrus

• memory encoding/retrieval

• Spatial memory/navigation

• Scene regocnition

Functions of the subcallosal gyrus

• Mood regulation (long term affect)

Functions of the cingulate gyrus

• Emotional regulation (ant)

• Attentional mechanisms (ant)

• Emotional aspects of pain

• Memory retrieval (post)

• Social behavior and empathy

Which gyrus helps remember how to get to school and back?

The parahippocampal gyrus helps remember how to get to school and back due to its spatial memory and navigation feature

Which gyrus is associated w/ clinical depression?

The subcallosal gyrus is associated with clinical depression, as it plays a significant role in mood regulation.

Which gyrus helps me not yell when I’m angry, pay attention to rewarding stimuli, and be empathetic?

The cingulate gyrus helps regulate emotional responses, maintain attention to rewarding stimuli, and enhance empathy.

Hippocampal formation

Consolidates STM → LTM.

Explicit memory

Easy to describe, stored in the hippocampus.

Implicit memory

motor memory biases, hard to describe (like how to ride a bike), not usually stored in hippocampus.

What are the types of explicit memories (associated with the hippocampus)

• Declarative (episodic and semantic)

• Contextual

• Emotional

• Spatial

• Associative

• Prospective

Declarative memory

Facts or events that can be consciously recalled w/ 2 subtypes

• episodic: autobiographical (your experience of an event

• Semantic: general knowledge (jeopardy)

Contextual memory

Matching experiences with time and place (matching a person with where you usually see them)

Emotional memory

Storage of emotionally charged memories

Spatial memory

Cognitive map of locations, routes, spatial relationships (for navigating the environment)

Associative memory

Forming links between different pieces of information (helps in school)

Prospective memory

Remembering to perform tasks in the future

What is the Papez circuit?

The pathway of emotional regulation and memory consolidation

Draw the path of the papez circuit

Starts at the subiculum (part of the hippocampus) → through the fornix → mammillary bodies for recollection → Through the anterior thalamic nucleus (relay station) → cingulate gyrus for emotional regulation and decision-making → Entorhinal cortex (part of the parahippocampal gyrus) for memory consolidation → back to where it started at the hippocampus.

What is the function of the amygdala?

• Emotional detection

• Emotional generation

• Emotional memory

Describe emotional detection w/ the amygdala

The amygdala recognizes emotional stimuli from the environment. It is more sensitized to threat and reward experiences

Describe emotional generation with the amygdala

There are two main pathways

• Fear/fight/flight response goes through the hypothalamus (we are more sensitized to this pathway)

• Pleasure and reward are processed through the ventral striatum (which is in the basal ganglia)

Describe emotional memory in the amygdala

The amygdala attaches emotional significance to memories. It is more primed to fear conditioning, where it pairs two previously unrelated stimuli (a fearful response w/ a previously unrelated stimulus) through associative learning

It also consolidates emotional memories (this process is improved when we have moderate levels of cortisone, but impaired by too much or too little)

What is the septal area?

The pleasure center of the brain

What are the functions of the septal area?

• Positive emotional regulation (feeling pleasurable stimuli)

• Reward reinforcement (like a dopamine surge w/ certain actions)

• Modulating memory processing

• Regulating aggression (down regulation)

• Autonomic regulation

• Social bonding behaviors (new born/mother have inc. oxytocin levels together)

What condition deals with an overactive septal area?

Kluver Busey syndrome: hyperactive social, hypersexuality, anti-inhibition

What are the steps to olfactory transduction?

• Odorants dissolve in mucosal layer

• Odorant binds to receptor proteins on cilia of olfactory sensory neurons

• action potential generated on olfactory nerve

• olfactory nerve synapse w/ mitral cells in olfactory bulb

What parts does the lateral olfactory tract have?

• Piriform cortex: identifying odors

• Amygdala: processing smells emotionally

• Entorhinal cortex: consolidating olfactory memory (part of parahippocampal gyrus)

• olfactory tubercle: Integrating olfaction w/ reward/motivation systems

What parts does the medial olfactory tract have?

• CL olfactory bulb: coordinates bilateral processing of smell

• Anterior olfactory nucleus: modulates olfactory info (becoming accustomed to a candle in a room)

Describe the medial dorsal nucleus of the thalamus

Since info from the olfactory bulb doesn’t get relayed through the thalamus on its way to the cortex (it does go through the thalamus on it’s way back afferent), the medial dorsal nucleus relays olfactory info to other cortical regions for higher order processing.

What is the function of the orbitofrontal cortex

This integrates olfaction, taste, and somatosentation to create FLAVOR. Info coming to this cortex does have to go through the thalamus during its efferent pathway.

What are the 3 input nuclei?

• Putamen

• Caudate

• Nucleus accumbens

Function of the putamen

Input nucleus. Regulates movements especially in response to sensory feedback. Motor control

Function of the caudate

Input nucleus. Cognitve processing, motor planning, associative learning

Function of the nucleus accumbens

Input nucleus. Reward processing, motivation and emotional responses.

What are the output nuclei of the basal ganglia?

• Globus pallidus internus (GPi)

• Substantia nigra pars reticulata (SNPR)

Function of the globus pallidus internus (GPi)

Inhibitory signals to the thalamus to regulate/fine tune movement

Function of the substantia nigra pars reticulata

Inhibitory to thalamus and brainstem controlling eye movement and posture

What are the associated nuclei in the basal ganglia?

• Globus pallidus externus (GPe)

• Subthalamic nucleus (STN)

Function of globus pallidus externus (GPe)

Inhibitory to STN to help regulate movement and prevent excessive movement

Function of subthalamic nucleus (STN)

Modulates output of basal ganglia. Excitatory to GPi and SNPR (both inhibitory output nuclei) to control movement precision.

What comprises the striatum?

• caudate nucleus

• putamen

• nucleus accumbens

What comprises the ventral striatum

Nucleus accumbens is in the ventral part of the striatum, so another name for it is ventral striatum

What comprises the corpus striatum?

• caudate nucleus

• putamen

• nucleus accumbens

• globus pallidus

What comprises the lentiform nucleus?

• putamen

• globus pallidus

Where do the basal ganglia receive blood supply from?

Perforating arteries originating from the circle of Willis

What part of the basal ganglia do the posterior cerebral and posterior communicating arteries supply?

• Subthalamic nucleus (STN)

• Substantia nigra

What branches supply the striatum?

Lenticulo striate branches (which are branches of the middle cerebral artery).

• Note, these branches are small, but have a disproportionate effect since they supply the striatum which is a crucial structure.

What artery supplies the globus pallidus?

Anterior choroidal artery

What areas are supplied by the anterior cerebral artery?

Nucleus accumbens plus the head of the caudate

What are the basal ganglia loops?

2 Motor loops

• Motor

• Oculomotor

2 Sensory

• Executive/associative

• Emotion/motivation

Function of the motor loop of the basal ganglia

• Selecting/planning, then executing voluntary movement

• Modulating (determining “bigness”) of movement

• Maintaining “automatic” movements (walking while talking, it takes care of walking part so you don’t have to consciously think about it.)

• Starting (via direct pathway) & stopping (via indirect pathway) movements

Function of the oculomotor loop of the basal ganglia

Helps w/ saccades (visual attention mechanisms). This loop is how basal ganglia connects to sup. colliculus (through SNPR) to get to the brainstem for reflexive eye movement.

Function of the executive loop of the basal ganglia

Facilitates goal-directed and socially acceptable behaviors. Aids in learning, attention, complex cognitive tasks

Function of the limbic loop of the basal ganglia

Modulates reward expectancy behaviors. Helps reward-based learning/motivation.

What parts comprise the motor loop of the basal ganglia?

Begins at Primary motor cortex/motor areas → putamen for motor control → SNPR/GPi (motor territory) to limit excessive motion → Nuclei of thalamus for relay back to cortex, then start over

What parts comprise the oculomotor loop of the basal ganglia?

Begins at frontal/supplementary eye fields → head of caudate nucleus for planning/learning movement → SNPR/GPi (oculomotor territory) to inhibit excess motion → Several nuclei of thalamus

What parts comprise the executive/associative loop of the basal ganglia?

Begins in the prefrontal cortex → caudate nucleus for motor planning/learning → SNPR/GPi (associative territory) to inhibit excess motion → Several nuclei of thalamus for relay back to cortexW

What parts comprise the emotion/motivation loop of the basal ganglia?

Starts in ant. cingulate and Pre-frontal cortex → to ventral striatum for motivation/reward processing → SNPT/GPi (limbic territory) to reduce excessive motion → to several nuclei of the thalamus to relay back to cortex.

What is the purpose of parallel motor circuits in the basal ganglia?

Balance direct/indirect pathways to allow flexibility and precision of controlled movement

What is parkinson’s disease?

A movement disorder that results from idiopathic degeneration of the sunstantia nigra pars compacta (produces dopaming to striatum to regulate direct/indirect pathways)

Symptoms of parkinson’s disease

Parkinson’s is a loss of dopamine leading to: hypokinetic disorder

• Tremor (involuntary movement)

• Rigidity (too much muscle tone)

• Akinesia/bradykinesia

• Postural instability (common fall risk)

• Non-motor dysfunction

What is the cause of huntington’s disease?

It is genetically inherited striatal degeneration leading to hyperkineticism due to excessive dopamine

Symptoms of huntington’s disease

Over production of dopamine causing:

• Motordysfunction: Chorea - inability to inhibit involuntary. movement

• Cognitive impairment

• Behavioral disorder

• Motor impersistence - can’t sustain voluntary muscle contraction

What neurophychiatric disorders are associated w/ the basal ganglia?

• Obsessive-compulsive disorder

• Addiction disorders

• Major depression disorder

• Generalized anxiety disorder

• Schizophrenia

Describe obsessive-compulsive disorder (OCD) and what causes it

Chronic thoughts/impulses w/ ritualistic/repetitive behavior

Caused by: Abnormalities in nucleus accumbens/cortical communication causing behaviors that usually aren’t associated with reward to become associated with reward

Describe addiction disorders and what causes them

Compulsive patterns of substance seeking and taking

Dysfunctional reward pathway regulation (hypo/hyperactivity). Basically either you don’t experience as much reward in every day life so you seek out more, or you experience more than usual which causes you to seek it our more.

Describe major depression disorder and what causes it

Low mood “affect”, decreased motivation

Altered dopamine (the “want” neurotransmitter) signaling (D1/D2 receptors)

Describe generalized anxiety disorder and what causes it

Persistent worrying, autonomic arousal (fight/flight), fatigue, nausea (constant state of worry)

Caused by decreased metabolic activity in the striatum

Describe schizophrenia and what causes it

Altered perception of reality, abnormal decision making/behavior. Hallucination (visual/auditory), percusatory thoughts

Caused by reduced corticostriatal connectivity

What system is the cerebellum part of?

Extrapyramidal motor system, so it has no direct connection to lower motor neurons, has to communicate w/ other structures for movement.

What separates the anterior and posterior lobes of the cerebellum?

The primary fissure

What separated the flocculonodular lobe from the cerebellar body?

The posterolateral fissure.

What artery supplies the posterior inferior cerebellar artery (PICA)?

Vertebral artery

What artery (ies) does the basilar artery supply with relation to the cerebellum?

Anterior inferior cerebellar artery (AICA) and superior cerebellar artery (SCA)

What portions of the cerebellum to the various cerebellar arteries supply?

• Posterior inferior cerebellar artery (from vertebral artery) supplies the posterior inferior cerebellum

• Anterior inferior cerebellar artery (from basilar artery) supplies the anterior inferior cerebellum

• Superior cerebellar artery (from basilar artery) supplies the superior cerebellum

What is the overarching function of the superior cerebellar peduncle?

It helps ensure smooth, precise, well timed motor activity

Describe the efferent pathway of the sup. cerebellar peduncle

Leaves the cerebellum and travels to the red nucleus and the thalamus. Allows communication between cerebellum/cortex

Describe the afferent pathway of the superior cerebellar peduncle

It receives info from the spinocerebellar tracts (spinal cord to cerebellum) to integrate sensory/motor data to help improve voluntary movement

What is the overarching function of the middle cerebellar peduncle?

Fine tunes voluntary movement so that we do the actions we planned to do (smooth execution)What

Describe the pathway of the middle cerebellar peduncle

How cortex talks to cerebellum. Cortex → pons → cerebellum (via corticopontine projections)

• Afferent projections from CL pontine nuclei to cerebellum carrying info re intended actions to compare w/ actual movement to fine tune voluntary movement

What is the overarching function of the inferior cerebellar peduncle?

Integrates sensory/motor to maintain equilibrium for balance/posture

Describe the afferent pathway of the inferior cerebellar peduncle

Afferent projections from brain and spinal cord to cerebellum w/ proprioceptive info for balance/posture

Describe the efferent pathway of the inferior cerebellar peduncle

Cerebellum → vestibular nuclei & reticular formation regarding balance/posture regulationWhat

What are the 3 cerebellar cortical layers?

Deep → superficial: Granual → Purkinje → Molecular

What does the Granular layer of the cerebellum house?

Granule and golgi cell bodies

What does the purkinje layer of the cerebellum house?

Purkinje neuron cell bodies

What does the Molecular layer of the cerebellum house?

Axons, dendrites, cell bodies of basket and stellate cells

Function of climbing fibers

Convey error signal to cerebellum by exciting purkinje neuron dendrites and deep cerebellar nuclei.

Function of Mossy fibers

Convey magnitude and duration of sensory information by exciting deep cerebellar nuclei, and purkinje fibers.

Function of stellate, basket, and golgi cells

Talk to neurons w/in their own system, inhibit purkinje neurons

Function of granule cells

talk to neurons w/in their own system, excite purkinje neurons

Function of Purkinje neurons

Only source of cerebellar cortical output.

• Inhibited by stellate, basket, or golgi cells

• Excited by granule cells or climbing fibers

Function of deep cerebellar nuclei

Source of cerebellar output

• Inhibited by purkinje neurons

  • Excited by mossy fibers

What is the function of the deep cerebellar nuclei as a whole, and what are the 3 nuclei?

Source of output to extra-cerebellar structures

• Fastigial

• Interposed

• Dentate

Function of the fastigial nucleus

Located most medially. Associated w/ vermis. Vermal region uses this nucleus to report on how the trunk is moving compared to what was planned.

Function of the interposed nuclei

Pair of nuclei. Lateral to fastigial nucleus. Associated w/ paravermal region. Globose is the medial nucleus, emboliform is the lateral nucleus. Report on how limbs are moving compared to what was planned.

Function of the dentate nucleus

Most lateral. Source of most efferent info from sup. cerebellar peduncle to plan motor movement. Associated w/ lateral hemisphere.

What are the cerebellar zones?

There are longitudinal zones of the cerebellum with specific motor functions

• Vestibulocerebellum

• Spinocerebellum

• Cerebrocerebellum