Unit 4: Neuroscience and conciousness

Genotype

An organism's genetic makeup, or allele combinations, determines phenotype

Phenotype

An organism's physical appearance, or visible traits.

Dendrites

Branchlike parts of a neuron that are specialized to receive signals from other neurons

Axon

The extension of a neuron, ending in branching terminal fibers, helps transmit signals

myelinated sheath

Fatty materials that insulate axon and increase the speed of a signal

Nodes of Ranvier

Gaps in the myelin sheath to which voltage-gated sodium channels are confined.

Cell body (soma)

The part of a neuron that contains the nucleus, coordinates information-processing tasks and keeps the cell alive

Neuron cell membrane

Selectively permeable barrier of neuron that will allow for ions to flow in and out to cause action potential (lets in small molecules with no electrical charge)

Nervous system is made of

Glial cells and neurons

Glial cells

help neurons line up closely with each other to allow neural communication, provide insulation to neurons, transport nutrients and waste products, and mediate immune responses

Neurons

Interconnected information processors that are essential for all of the tasks of the nervous system

Polygenic

Controlled by more than one gene

Synpatic cleft

Small space between neurons where communication occurs

What type of information do neurons transmit?

Sensory and motor

What direction does sensory information travel?

PNS to CNS

What direction does motor information travel?

CNS to PNS

What ions are involved in membrane potentials?

Potassium, sodium, and chloride

Membrane potential

Difference in charge across the membrane provides energy for a signal

What does "resting membrane potential" mean?

When a neuron is not receiving a signal, ions line up on either side of the cell. Different parts of the cell prepare to move to places that need them (positive ions go to negative ion areas, Na+ to inside of cell)

What factors affect the movement of ions in and out of the cell?

When a signal is received in the dendrites, positive ions move in the cell, making it positively charged and active (once reaching threshold of excitation)

How do ions move across the membrane?

Through ion (protein) channels that move down their concentration gradient and create a flow of electrical energy

Action potential

The electrical signal that typically moves from the cell body down the axon to the axon terminals

What are the steps of an action potential?

1. Neuron is in normal resting potential of -70 mV

2. Action potential - A stimulus opens gated ion channels to let Na+ into the cell, depolarizing it. Once it reaches -50, action potential causes more Na+ channels to open down the whole neuron

3. Repolarization - K+ channels open in response to Na+ influx

4. Hyperpolarization - when all channels close, there is too much K+ released so the potential is -80 mV

5. Refractory period - Neuron is dormant until Na/K pump levels are returned to normal

What is meant by the all-or-nothing property? (Neuron communication)

a neuron either fires a complete action potential or it doesn't fire at all. If the stimulus is strong enough to reach the threshold potential, the neuron will generate a full-strength action potential. If the stimulus is too weak and doesn't reach the threshold, no action potential will be generated

What is the gap between an axon and another neuron called?

Synaptic cleft

Which cell sends the signal and which one receives the signal?

The presynaptic neuron sends the signal, and the postsynaptic neuron receives the signal

Neurons use chemical messengers to communicate. What are they called?

Neurotransmitters

What causes neurotransmitters to be released into the synaptic cleft?

When an action potential reaches the presynaptic terminal, it causes neurotransmitter to be released from the neuron into the synaptic cleft, a 20-40nm gap between the presynaptic axon terminal and the postsynaptic dendrite (often a spine).

Where do neurotransmitters attach themselves to on the post-synaptic neuron?

Neurotransmitters attach to receptor proteins embedded in the plasma membrane (outer surface) of the postsynaptic neuron, specifically in the region of the dendrites or the cell body, where the synapse occurs

What mechanisms terminate the action of neurotransmitters in the synapse? Why would this be important?

Neurotransmitter action in the synapse is terminated through reuptake, enzymatic degradation, or diffusion away from the synaptic cleft. This is important to ensure that the signal does not continue indefinitely, allowing for precise and controlled communication between neurons, preventing overstimulation, and maintaining proper neural function.

Where is Broca's area located in the brain and what does it do?

Broca's area, located in the left hemisphere, is associated with speech production and articulation. Our ability to articulate ideas, as well as use words accurately in spoken and written language, has been attributed to this crucial area.

Where is Wernicke's area located in the brain and what does it do?

It has been identified as 1 of 2 areas found in the cerebral cortex that manages speech

What is the prefrontal cortex?

part of frontal lobe responsible for thinking, planning, and language

What is the prefrontal cortex responsible for?

- many higher order functions, everything that distinguishes humans. Executive control - solving problems, making decisions, and how you act in social situations

- undergoes most development from birth

- helps manage how you behave in social situations

Function of hypothalamus

Homeostasis: body temperature, sleep, appetite, emotions, control of the pituitary gland

Function of cerebral cortex

Higher level cognitive functions: complex perceptual, cognitive, and behavioral processes

Function of hippocampus

memory, learning, and emotion. Its largest job is to hold short-term memories and transfer them to long-term storage in our brains. It also plays a role in emotional processing, including anxiety and avoidance behaviors

Function of brain stem

It is responsible for many vital functions of life, such as breathing, consciousness, blood pressure, heart rate, and sleep, connects to spinal cord

Function of cerebellum

Balance and coordination

function of corpus callosum

Band of neural fibers allowing to hemispheres of brain to communicate

Function of thalamus

Collect, Sort, and Direct sensory impulses to particular areas of the brain

What part of the brain helps with memory?

Hippocampus

What structure connects the two hemispheres and is critical for communication between both sides of the brain? How do we know?

The corpus callosum is the structure that connects the two hemispheres of the brain and is critical for communication between them. We know this through various lines of evidence, including anatomical studies, research on split-brain patients, and functional imaging studies

How is somatosensory cortex organized?

The somatosensory cortex is organized into layers, areas, and columns, and is arranged in a somatotopic manner. This means that specific parts of the body are represented in specific areas of the cortex

How are hormones distinct from neurotransmitters?

Hormones are produced in endocrine glands and are secreted into the blood stream. Neurotransmitters: Neurotransmitters are released by presynaptic nerve terminal into the synapse. Hormones: Hormones are transmitted through blood. Neurotransmitters: Neurotransmitters are transmitted across the synaptic cleft

Which two regions/structures interact closely to control the endocrine system?

The nervous system and the immune system

What do psychologists mean when they talk about consciousness? What are some examples of states of consciousness?

In psychology, consciousness refers to your awareness of yourself and your environment, encompassing your thoughts, feelings, sensations, and perceptions. It's essentially the subjective experience of being alive and aware of your surroundings and internal states

Describe sleep stage 1

Beginning of sleep

- transition phase between sleep and wakefulness

- easily awoken

Describe sleep stage 2

most of our nights sleep

- heart rate slows

- body temp drops

- associated with EEG waves that represent sleep-maintaining neural activity

Describe sleep stage 3

deep sleep or slow-wave sleep

- associated with delta waves

- slow-waves decline with age

- most over age 60 have very little stage 3 sleep

Describe REM sleep

Great EEG activation, muscle atonia, rapid eye movements, muscle twitches, and breathing irregularities.

How does homeostasis relate to sleep?

Sleep affects homeostasis by helping to maintain a balance between the need for sleep and the need for wakefulness. This balance is called sleep/wake homeostasis

What signal induces sleep hormone release?

Melatonin?

What brain regions are involved in the signal, the release, and action of sleep hormones?

Pineal gland

Describe the relationship between sleep debt and states of consciousness

Sleep debt, the cumulative effect of insufficient sleep over time, significantly impacts states of consciousness, primarily by decreasing alertness, impairing cognitive function, and altering emotional regulation, all of which are integral aspects of conscious experience

How do genes and environment interact with regard to incidence of schizophrenia?

Genes and environment interact in a complex interplay to influence the incidence of schizophrenia, with both genetic predisposition and environmental factors playing significant roles in the development of the disorder

Agonists

chemicals that mimic a neurotransmitter at the receptor site

Antagonists

Drugs that block the function of a neurotransmitter

What are the two parts of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

Central nervous system

Brain and spinal cord

Peripheral nervous system

Somatic NS (concious motor, involves sending motor and sensory neurons to CNS) Automatic NS (involuntary, contains parasympathetic and sympathetic NS)