Neuroscience BIG CUMULATIVE Exam Prep

Central Lateral Thalamus

Stimulating this roused monkeys from anesthesia

Direct connection to consciousness

synapse

junction point between pre and post synaptic neurons where NTs are secreted and bind to receptors

dendritic spine

protrusions from dendrites that receive input from an axon at the synapse.

suprachiasmatic nucleus

controls circadian rhythms

circadian rhythms

The 24-hour self-sustaining biological cycles (sleep, hormones, etc)

optic nerve

nerve that carries neural impulses from the eye to the visual cortex AND the superchiasmatic nucleus

pineal gland

secretes melatonin

electroencephalography (EEG)

sleep-screening that records action potentials in the outer cortices of the brain (the cap)

Waking

pattern that has beta waves, high frequency, small, influenced by activity of neural networks

stage 1 sleep

stage of sleep where a person's pulse slows and muscles relax, breathing becomes uneven and the brain produces theta waves

stage 2 sleep

stage of sleep characterized by a slower, more regular wave pattern, along with momentary interruptions of "sleep spindles" and "K complexes"

stage 3 sleep

deep sleep characterized by low frequency, high amplitude delta waves

REM

sleep with vivid dreams, beta waves like awakeness, and increased activity in some "awakeness" areas

Structures active in REM

Anterior cingulate, ventral striatum, hypothalamus, amygdaga, Ventral tegmental area (LIMBIC SYSTEM), Secondary visual cortex (SEEING IN DREAMS), and motor/premotor area (SLEEP MOVEMENT).

Structures inactive in REM

Primary visual cortex (NO REAL SEEING), Orbitofrontal cortex, post-cingulate precuneus, parietal cortex (DISORIENTATION AND FIRST/THIRD PERSON IN DREAMS), and dorsolateral prefrontal cortex (dlPFC) (LACK OF INSIGHT/DECISION MAKING)

primary visual cortex

cortex for raw visual information (what and where) (inhibited in REM sleep)

secondary visual cortex

cortex for interpreting visual information (direction? sleep? orientation? etc) (active in REM sleep, how we dream)

acetylcholine

Originates in the pedunculopontine (PPT) and laterodorsal tegmental (LDT) nuclei. Projects to the hippocampus, amygdala, frontal lobes, basal ganglia, and thalamus. Functions to promote REM, neural plasticity, arousal, and award

pedunculopontine (PPT) and laterodorsal tegmental (LDT) nuclei

generate acetylcholine

Noradrenaline

Originates in the locus coeruleus. Projects to the forebrain, brainstem, cerebellum, and spinal cord. Functions to mediate arousal/activity of neurons in the CNS

locus coeruleus

generates noradrenaline

Serotonin (5-HT)

Originates in the raphe nuclei. Projects to the medulla, spinal cord, cerebellum, limbic system, striatum, and cortex. Functions to regulate regulating mood, sleep, and digestion

raphe nuclei

generate serotonin

median preoptic nucleus and ventrolateral preoptic nucleus

sleep promoting areas (activate GABAergic neurons)

arousal areas

PPT and LDT nuclei, locus coeruleus, and raphe nuclei

narcolepsy

a disease caused by a loss of hypocretin (orexin) producing neurons in the hypothalamus, which is important for transitioning between sleep and wakefulness

hypocretin (orexin)

neurotransmitter where a deficiency of this causes narcolepsy. Likely works to activate the dorsolateral cortex (not active during REM) and the lateral tegmental nucleus (AKA Pedunculopontine area)

Amygdala

A limbic system structure involved in memory, decision-making, and emotion, particularly fear and aggression. (Overactivity leads to unregulated negative emotions associated with a specific memory)

Hippocampus

A neural center located in the limbic system that helps consolidate information from short term memory to long-term memory and spatial navigation. (active in neurogenesis in adults, specifically the dentate gyrus)

Neurogenesis

the formation of new neurons

BrdU

How to measure Neurogenesis

Thalamus

Sensory relay station and connecting to other brain regions involved in cognitive functions. It influences sensory perception, motor control, and emotional regulation (If under-regulated, hallucinations)

Hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

HPA Axis (Hypothalamic-pituitary-adrenal axis)

axis that stimulates stress response; controls release of cortisol and adrenaline through adrenocorticotropic hormone (ACTH)

Benzodiazepines

fast-acting drug to treat anxiety/panic attacks that enhances GABA release either with high intensity or low intensity - addictive bc GABAergic signalling can lead to DA release

Lithium effect on glutamate

Lithium effects this neurotransmitter by inhibiting the activation of it's NMDA receptor, and inhibiting the activation of the system that generates secondary messengers to create the glutamatergic response

lithium effect on dopamine

lithium effects this neurotransmitter by inhibiting the release of the NT in the synaptic cleft, inhibiting acticity of receptors by inhibiting the intracellular response, and inhibiting the generation of cAMP which contributes to mania

lithium

a drug commonly used to treat schizophrenia; a mood-stabilizer

Dopamine theory of schizophrenia

Theory explaining how hyperactivity of the D2 (inhibitory DA) receptor causes symptoms of Schizophrenia like hypofrontality and memory loss (cAMP system dysfunction)

positive symptom

a behavior that is gained, such as a delusion/hallucination or mania

negative symptom

a behavior that is removed or lost, such as a lack of motivation to engage in activities, reduced speech, and inability to experience pleasure

serotonin

neurotransmitter crucial for the formation of short term memories through enhancing neurotransmitter release between sensory and motor neurons

dopamine

neurotransmitter crucial for the formation of long term memories. Involves synaptic growth via gene activation that induces physical/anatomical changes

Implicit memory

the memory we can't vocalize and explain, like motor/perceptual skills like how to bike or walk. This involves the amygdala, the cerebellum, and reflex pathways. This is extremely conserved across species

explicit memory

the memory we can explain/declare, (also known as declarative memory). This includes things like names, places, facts, events, things you can "recall". This involves the hippocampus and the medial temporal lobe, and is impossible without the hippocampus.

Long term potentiation

a long-lasting enhancement of a neural signal that occurs after repeated stimulation to strengthen connections; the physiological process of memory formation; as you strengthen connections, it’s easier to access info

early LTP

enhancement for short-term memory through enhancing neurotransmitter release with serotonin

late LTP

enhancement for long-term memory, and happens through a change in gene expression

cyclic AMP

A second messenger derived from ATP and triggers specific cellular changes in gene regulation, kinase activation, and metabolic regulation

cAMP system

cAMP → protein kinase A → nucleus (CRE and CREB systems) → transcription → proteins → strengthened post-synaptic response of the neuron

a greater post-synaptic response can be triggered by the same signal/action potential from the pre-synaptic neuron.

tri-synaptic pathway

pathway of the hypothalamus. enters thru perforant path → dentate gyrus (DG) → mossy fiber path → CA3 → Schaffer collateral path → CA1 → cortex .

allows for the hippocampus to organize and amplify a neural signal such that we can store a memory.

Resting Membrane Potential

State of neuron maintained by Na+/K+ pump. Electrostatic forces & Concentration gradient also influence the resting potential

Stimulus

Neurotransmitter that triggers neuron response.

EPSP

Excitatory post-synaptic potential from Na+ influx that increases likelihood of firing.

IPSP

Inhibitory post-synaptic potential from Cl- influx that decreases likelihood of firing.

ligand-gated ion channel

Gate that requires a stimulus to open. Opens during initial excitation

voltage-gated channel

open and close in response to changes in membrane potential during depolarization

Depolarization

Process when membrane potential reaches -55 mV (threshold of excitation). Na+ flows in.

Threshold of Excitation

Membrane potential level to trigger action potential.

Absolute Refractory Period

Period when neuron cannot fire another action potential.

Repolarization

Return to resting potential after peak excitation. K+ ions leave.

Relative Refractory Period

Period when stronger stimulus can trigger action potential.

Hyperpolarization

Increased negativity of membrane potential post-repolarization. NA+/K+ pump reactivates to bring cell back to resting action potential.

Na+/K+ Pump

Transports 2 K+ in for every 3 Na+ out

Saltatory Conduction

Action potential jumps between Nodes of Ranvier.

Nodes of Ranvier

Gaps in myelin sheath facilitating rapid conduction. Contains high density of voltage gated Na+ channels

1st Step of synaptic transmission

arrival of action potential at axon terminal

2nd step of synaptic transmission

activation of voltage gated calcium chanels

3rd step of synaptic transmission

synaptic vesicle fuses with presynaptic membrane to release neurotransmitters into cleft

4th step of synaptic transmission

Neurotransmitters bind to post-synaptic receptors to induce an EPSP (Na+) or IPSP (Cl-)

5th step of synaptic transmission

Neurotransmitters are released from receptors and either a) diffuse b) are transported back to presynaptic cell or c) are broken down by enzymes

Ionotropic Receptors

Receptors that open ion channels directly upon binding.

Metabotropic Receptors AKA GPCR (G Protein Coupled Receptor)

Receptors that activate second messenger systems upon binding

Dendrites

Receive signals from other neurons. Input zones

Cell Body

Contains nucleus, decides neuron type, and combines/transforms inputs. Integration zone.

Axon

Transmits electrical signals away from the cell body. Conduction zone.

Axon Terminals

Send signals to other neurons. Output zones.

Myelin Sheath

Insulates axon; speeds up signal transmission.

Oligodendrocytes

Myelinating cell in the CNS. (insulate and protect)

Astrocytes

Support neurons; transport oxygen from blood in CNS

Microglia

Immune cells in the CNS.

Glutamate Receptors

AMPA (ionotropic)

Kainate (ionopropic)

NMDA (ionotropic)

mGluR (Metabotropic)

GABA Receptors

GABAa (ionotropic)

GABAb (metabotropic)

hypothalamus (hormone release), ventral tegmental area (motivation), substantia nigra (movement)

3 producers of dopamine

alzheimer's disease

a progressive and irreversible brain disorder characterized by gradual deterioration of memory, reasoning, language, and, finally, physical functioning (amyloid beta plaques and neurofibrillary tangles)

neurogenesis hypothesis

preceding plaque formation in patients with AD, there is a disregulation in the neurogenesis of the hippocampus , thus contributing to the cognitive deficits observed in MCI (Mild Cognitive Impairment) or early AD

pathology of AD

amyloid plaques and neurofibrillary tangles, preceded by deficits of neurogenesis in Dentate Gyrus

Parkinson's disease

A disorder of the central nervous system that affects movement, often including tremors because of a lack of DA in the substantia nigra

lewy bodies

clumps of mutated protein (alpha-synuclein) in DA neurons in Parkinson's patients

striatum

structure in basal ganglia to coordinate movement: broken into caudate nucleus and putamen

Amyotrophic Lateral Sclerosis (ALS)

degenerative disorder of motor neurons in the spinal cord and brainstem, leading to muscle weakness and atrophy.

Generalized anxiety disorder

persistent, excessive anxiety and worry; overactive amygdala makes negative memories more prominent than happy ones

Regions affected by anxiety

amygdala (fear response, processing memory, decision making, emotional reaction)

hippocampus (consolidation of info from short to long term memory and spatial navigation)

SSRI

Drugs used to treat anxiety and depresion by blocking the transporter for serotonin (binds for logner)

5HT-1 receptor

inhibitory serotonin receptor, GPCR, decrease in intracellular concentration of cAMP (secondary messenger)

5HT-2 receptor

excitatory serotonin receptor, increase in intracellular concentration of IP-3 and DAG (important in downstream pathways)

major depressive disorder

mood disorder where the patient has a pervasive and persistent low mood that is accompanied by low self-esteem and a loss of interest or pleasure in normally enjoyable activities

Regions affected by depression

anterior singulate cortex (limbic system; motivation, reward, feelings)

Dorsolateral prefrontal cortex (decision-making, personality, executive function, goal-oriented behavior)

hypothalamus

amygdala

monoamine hypothesis

A deficiency in the availability of monoamines (serotonin, norepinephrine, dopamine) in the synapses contributes to depression

monoamine oxidase (MAO)

an enzyme that oxidizes/breaks down monoamine transmitters -- could be used to treat depression