Neurotransmitters, Brain Nuclei, and Memory: Key Concepts for Neuroscience

What is the primary excitatory neurotransmitter in the brain?

Glutamate

What is the primary inhibitory neurotransmitter in the brain?

GABA (Gamma-Aminobutyric Acid)

Which nucleus produces norepinephrine?

Locus coeruleus

Which nucleus produces serotonin?

Raphe nuclei (brainstem)

Which nucleus produces histamine?

Tuberomammillary nucleus (TMN) of hypothalamus

Which nucleus produces dopamine?

Ventral tegmental area (VTA) and Substantia nigra

Where are orexin-producing neurons located, and how many are there?

Lateral hypothalamus; only 10,000-20,000 neurons

What disorder is caused by decreased/absent orexin?

Narcolepsy (with cataplexy)

How does caffeine reduce sleepiness?

Caffeine blocks adenosine receptors on ACh cells

What triggers melatonin secretion from the pineal gland?

DECREASING daylight

What is episodic memory?

Memory of a specific moment in time and place

What is the role of the hippocampus in memory?

Memory consolidation and formation of new episodic memories

What cellular changes occur during long-term potentiation (LTP)?

1. Proliferation of synaptic spines; 2. Spines become broader with more surface area; 3. Increase in NT receptors on postsynaptic neuron

What is required for LTP to occur?

1. Presynaptic glutamate release; 2. Postsynaptic depolarization

What is classical conditioning?

Associating unconditioned and conditioned stimuli

What brain structures are involved in eyeblink conditioning?

Cerebellum and Red nucleus

What is the dentate gyrus involved in?

1. Formation of new episodic memories; 2. Regulation of mood; 3. High levels of neurogenesis, LTP, and LTD

Which type of ACh receptor is at the neuromuscular junction?

Nicotinic receptors (ionotropic)

What are ionotropic receptors?

Fast, direct ion channels

What are metabotropic receptors?

Slow, G-protein coupled, second messenger systems

Which serotonin receptor is ionotropic?

5-HT3

What neurotransmitter is decreased in Alzheimer's disease?

Acetylcholine (ACh)

What neurotransmitter is decreased in Parkinson's disease?

Dopamine

What neurotransmitter is increased in schizophrenia?

Dopamine (in mesolimbic pathway)

What neurotransmitters are decreased in depression?

Serotonin, Dopamine, Norepinephrine

What is increased in epilepsy?

Glutamate (excess excitation); decreased GABA (reduced inhibition)

What is the only single-synapse reflex?

The STRETCH reflex

Where does transduction occur in the visual system?

In rods and cones (photoreceptors)

What hormone is involved in the HPA axis stress response?

Cortisol

HPA (Hypothalamus-Pituitary-Adrenal Axis)

- Innate differences in baseline cortisol may predispose to PTSD

What is the role of amygdala?

Fear conditioning and emotional learning

How do SSRIs work?

Block reuptake of serotonin

- They increase 5HT in the synapse (Agonist)

What NT is decareased in Alzheimer's disease?

- Loss of ACh in basal forebrain > memory loss

What are metobotropic receptors? (MINE?)

Slow, G-protein couples and second messenger systems

When 5HT receptor is iontropic? (MINE)

5-HT3 (mine)

Are all DA receptors iontriooic or metabotropic?

ALL are METABOTROPIC

What NT is decreased in Parkinson's disease? (mine)

DA

- Loss in substantia nigra > motor problems

What NT is increased in schizophernia? (MINE)

DA (in mesolimbic pathway)

- Also decrease in glutamate

What NT are decreased in depression? (MINE)

- 5HT

- DA

- NE (norepinephrine)

What is increased in epliepsy? What is decreased? (MINE)

Increase: Glutamate (excess excitation)

Decreased: GABA (reduced inhibition)

What is a sensory unit?

A primary afferent neuron all the receptors that define its receptive field.

- One neuron receives input from multiple receptors.

How do receptive field sizes relate to spatial resolution>

Smaller receptive fields = HIGHER spatial resolution

Larger receptive fields = better sensitivity but lower resolution