Psychology Unit 3 AOS 1 -NS functioning

Nervous system

100

CNS and PNS

What are the two main divisions of the human nervous system?

200

Explain the role of the parasympathetic nervous system in the body.

Rest and digest": The PNS  counterbalances the effects of  your sympathetic nervous system (responsible for the "fight-or-flight" response) and helps your body return to a calm state after a stressful situation has passed.

300

Distinguish between fight, flight and freeze, referring to the appropriate division of the Autonomic Nervous system

• Fight: This response involves confronting the threat head-on. The body prepares for physical action by:

  • Autonomic nervous system division: Primarily driven by the sympathetic nervous system (SNS).
  • Physiological changes: Increased heart rate, blood pressure, and muscle tension, dilated pupils, release of adrenaline and other stress hormones.
  • Behavior: Becomes assertive, aggressive, and focused on defending oneself.

• Flight: This response involves escaping the threat and running away from it. The body prioritizes speed and agility by:

  • Autonomic nervous system division: Primarily driven by the sympathetic nervous system (SNS).

• Freeze: This response involves remaining completely still and motionless in the hope of avoiding detection by the threat. The body minimizes movement and energy expenditure by:

  • Autonomic nervous system division: Primarily driven by the parasympathetic nervous system (PNS).

400

Describe the process of neural transmission

• Synapse: The action potential reaches the axon terminal, where it meets a small gap called a synapse before reaching the next neuron.
• Neurotransmitter release: The electrical signal triggers the release of chemical messengers called neurotransmitters that are stored in vesicles.
• Crossing the synapse: Neurotransmitters diffuse across the synaptic cleft and bind to receptors on the dendrites (the receiving branches) of the postsynaptic (next) neuron.
• Excitatory or inhibitory: Binding of neurotransmitters can either excite the postsynaptic neuron (raising its potential towards threshold) or inhibit it (making it less likely to fire an action potential).

500

Describe a scenario that involves all divisions of the human nervous system

Maya is hiking alone in a remote forest when she stumbles upon a bear cub foraging for berries. Here's how the different divisions of her nervous system come into play:

1. Peripheral Nervous System (PNS):

• Sensory division: Maya's eyes register the sight of the bear cub, sending visual information through the optic nerve to the brain. Simultaneously, her ears pick up the cub's rustling sounds, relayed through the auditory nerve.
• Motor division: As Maya realizes the danger, her muscles tense up (increased muscle tone) in preparation for action, facilitated by motor neurons carrying signals from the spinal cord.

2. Central Nervous System (CNS):

• Spinal cord: Sensory information from the PNS reaches the spinal cord, triggering the "fight-or-flight" response.
• Brain- The prefrontal cortex, involved in higher cognitive functions, helps Maya assess the situation and plan a course of action.

3. Autonomic Nervous System (ANS):

• Sympathetic nervous system (SNS):
  • Released adrenaline increases Maya's heart rate, blood pressure, and breathing, preparing her body for action (fight or flight).
• Parasympathetic nervous system (PNS):
  • Despite the SNS dominance, the PNS may still be active to some degree, trying to maintain some level of homeostasis. For instance, some digestive processes might continue, though at a reduced rate.

Outcome:

Depending on Maya's assessment and available options, her reaction could be:

Neurons

100

Describe the structure of a neuron and its main components.

Cell Body (Soma):

• The central "core" of the neuron, containing the nucleus and other essential organelles like mitochondria and ribosomes.
• The nucleus houses the genetic material (DNA) that dictates the neuron's structure and function.
• The other organelles provide energy and support for the neuron's activities.

2. Dendrites:

• Numerous, branching extensions that project from the cell body, resembling the roots of a tree.
• Function as the receiving end of a neuron, collecting incoming signals from other neurons.
• Each dendrite has many small protrusions called spines that increase its surface area and enhance its ability to receive signals.

3. Axon:

• A single, long, slender fiber that emerges from the cell body.
• Acts as the transmitting end of a neuron, carrying electrical signals away from the cell body towards other neurons.
• Axons can vary greatly in length, from a few millimeters to over a meter in some cases.
• The tip of the axon branches into numerous smaller structures called axon terminals, which form junctions with the dendrites of other neurons at specialized points called synapses.

Additional Structures:

• Myelin sheath: In some neurons, the axon is wrapped in a fatty insulating layer called the myelin sheath. This sheath helps to speed up the transmission of electrical signals along the axon.
• Synapse: The tiny gap between the axon terminal of one neuron and the dendrite of another where the transfer of information occurs through chemical messengers called neurotransmitters.

200

Explain how the neural transmission is electrochemical

Why Electrochemical?

This process is considered electrochemical because:

• Electrical within the neuron: Transmission within a single neuron is electrical – the movement of ions creates a change in electrical potential that travels as a signal.
• Chemical between neurons: Transmission between neurons occurs through chemical means – neurotransmitters that carry the signal across the synapse.

300

Differentiate between sensory neurons, motor neurons, and interneurons.

 

Sensory Neurons:

• Function: Carry information from sensory organs (eyes, ears, skin, etc.) to the central nervous system (CNS).
• Location: Primarily located in the peripheral nervous system (PNS), with cell bodies grouped in clusters called dorsal root ganglia near the spinal cord.
• Structure: Typically have one long dendrite extending to a sensory receptor and one axon projecting towards the CNS.
• Examples: Touch receptors in the skin, photoreceptors in the eyes, taste receptors on the tongue.

2. Motor Neurons:

• Function: Carry information from the CNS (brain and spinal cord) to muscles and glands, causing them to contract or release secretions.
• Location: Found in both the CNS (cell bodies in the brain and spinal cord) and PNS (axons extending to muscles and glands).
• Structure: Usually have multiple short dendrites receiving input from other neurons and one long axon projecting to an effector organ (muscle or gland).
• Examples: Neurons controlling muscle movement for walking, talking, or blinking, neurons stimulating the release of digestive enzymes from the pancreas.

3. Interneurons:

• Function: Act as intermediaries within the CNS, connecting sensory and motor neurons, as well as other interneurons, to process and integrate information.
• Location: Exclusively found in the CNS (brain and spinal cord).
• Structure: Highly variable, can have multiple dendrites and axons, forming complex connections with other neurons.
• Example: Neurons in the spinal cord that integrate sensory information (e.g., pain) and trigger reflex responses (e.g., withdrawing your hand from a hot object).

400

Discuss the lock and key process in neural transmission, using key terms

Neurotransmitters - The Keys

• Neurotransmitters are chemical messengers released by the presynaptic neuron (neuron sending the signal) into the synapse (the gap between neurons).
• Each type of neurotransmitter has a distinct chemical shape. Think of these shapes as unique keys.

2.  Receptor Sites - The Locks

• The dendrites of the postsynaptic neuron (neuron receiving the signal) have specialized proteins embedded in their membrane called receptor sites.
• Receptor sites have specific binding sites that act as "locks" tailored to fit the shape of particular neurotransmitters.

3. The Lock and Key Mechanism

• Binding: When released, neurotransmitters travel across the synapse and fit into the matching receptor site. This is similar to a key fitting precisely into a lock.
• Specificity: The distinct shape of the binding site ensures only the intended neurotransmitter can bind. Other neurotransmitters (with different shapes) won't fit.
• Postsynaptic Effects: The binding event triggers a cascade of changes within the postsynaptic neuron:
  • Excitatory: The neuron may become more likely to fire an action potential.
  • Inhibitory: The neuron may be less likely to fire an action potential.

500

What is neural plasticity and how does it relate to learning and memory?

How does it relate to Learning?

• Formation of new memories: When we learn something new, our brain forms new connections between neurons. These connections create a "memory trace" that allows us to recall the information later.
• Strengthening existing pathways: As we practice or repeat a skill, the neural pathways involved become stronger, making it easier to perform that skill in the future.

3. How does it relate to Memory?

• Consolidation of memories: After a new experience, the memory trace is initially fragile. Over time, the brain strengthens the connections involved, leading to the consolidation of the memory and making it more permanent.
• Memory retrieval: When we try to remember something, the brain reactivates the neural pathways that were involved in the original learning experience. The stronger these connections are, the easier it is to retrieve the memory accurately.

Conscious versus unconscious processes

100

Define consciousness in the context of psychology.

Awareness: It primarily involves being aware of your internal and external environment.

200

Discuss the difference between conscious and unconscious responses.

Conscious Responses:

• Awareness: You are aware of the stimulus and the response you are making. You actively process the information and make a deliberate choice.
• Intentionality: There's a clear intention behind your response. You choose to act in a specific way based on your awareness and reasoning.
• Examples:
  • Deciding to answer a question after carefully considering the answer.
  • Choosing what to eat for breakfast based on your preferences and health considerations.
  • Planning and executing a complex task like solving a math problem.

Unconscious Responses:

• Limited or no awareness: You may not be fully aware of the stimulus or the response you are making. The processing happens implicitly without deliberate thought or conscious control.
• Automatic and reflexive: These responses are often automatic and reflexive, happening without conscious deliberation.
• Examples:
  • Pulling your hand away from a hot stove before you consciously register the pain.
  • Blinking your eyes to remove dust without thinking about it.
  • Reacting with a flinch in response to a sudden loud noise.

300

Describe which divisions of the nervous system control conscious functions

The brain - decision making

CNS - as it includes the brain

400

Describe the process of the spinal reflex

Stimulus:

• An event in the environment triggers a sensory neuron to signal a sensory neuron to send an electrical signal. This could be:
  • Touch: Touching a hot object triggers a receptor in the skin.
  • Stretch: Stretching a muscle pulls on sensory receptors within the muscle.
  • Pain: Pain receptors are activated by tissue damage or other harmful stimuli.

2. Sensory Neuron:

• The activated sensory neuron transmits the electrical signal through its axon towards the spinal cord.

3. Sensory Root:

• The axon enters the spinal cord through the dorsal root, specifically the dorsal root ganglion which contains the cell body of the sensory neuron.

4. Synapse:

• In the spinal cord, the sensory neuron forms a synapse with an interneuron or a motor neuron.

5. Interneuron (Optional):

• In some reflexes, the sensory neuron directly synapses with a motor neuron. However, sometimes, an interneuron acts as an intermediary, receiving the signal from the sensory neuron and then transmitting it to the motor neuron. This allows for more complex processing and integration of information within the spinal cord before triggering a response.

6. Motor Neuron:

• The motor neuron receives the signal from the sensory neuron or interneuron.

7. Motor Root:

• The motor neuron's axon exits the spinal cord through the ventral root.

8. Effector Muscle:

• The axon of the motor neuron reaches the target muscle (effector) and forms another synapse.

9. Muscle Contraction:

• The motor neuron transmits an electrical signal to the muscle, causing it to contract.

10. Response:

• As the muscle contracts, it produces a movement in response to the initial stimulus.

500

Explain how the spinal reflex is adaptive

Spinal reflexes are considered adaptive because they enhance survival and bodily protection in the following ways:

1. Protection from Harm:

• Reflexive withdrawal: Spinal reflexes like the withdrawal reflex allow you to rapidly remove a body part from a source of potential harm (like touching a hot stove or a sharp object). This quick response minimizes tissue damage and promotes survival.

2. Automatic Regulation of Body Functions

• Spinal reflexes help regulate various internal functions without conscious effort. For example:
  • The pupillary light reflex controls the size of the pupil to optimize light intake, protecting the sensitive retina and helping you adapt to different light conditions.

3. Speed and Efficiency:

• Bypassing the brain: Since the reflex arc involves only the spinal cord, responses are initiated much more quickly than if conscious processing in the brain was required. This is crucial in situations where a split-second response might mean the difference between safety and injury.
• Freeing up cognitive resources: By handling basic reflexes automatically, the brain can allocate its processing power to more complex tasks like decision-making and planning, enhancing your overall cognitive efficiency.

Neurotransmitters versus neuromodulators

100

Define neurotransmitters and provide an example of one.

Neurotransmitters are chemical messengers that carry signals between neurons (nerve cells) in the nervous system.e.g. glutamate

200

Compare and contrast the roles of neurotransmitters and neuromodulators in the nervous system.

• Neurotransmitters: Act as specific "messengers" at synapses, directly influencing the firing rate of postsynaptic neurons in a quick and focused manner.
• Neuromodulators: Have broader and more diverse effects, often acting over larger areas of the brain, influencing multiple neurons and their functions over a longer duration. They act more like "modulators" that adjust the overall activity of neural circuits.

300

Explain how the imbalance of neurotransmitters can lead to psychological disorders.

An imbalance of neurotransmitters plays a significant role in the development and manifestation of various psychological disorders. Here's a breakdown of how this works:

1. Neurotransmission and Mental Health:

• Neurotransmitters are crucial for regulating mood, emotions, thought processes, and behavior. A complex balance is needed for healthy mental functioning.
• Disruptions in this system, including imbalances in production, release, uptake, or breakdown of neurotransmitters can contribute to the onset of psychological disorders.

2. Specific Examples:

• Depression: Low levels of serotonin and norepinephrine are often linked to symptoms of depression. Medications like SSRIs (Selective Serotonin Reuptake Inhibitors) work by increasing serotonin availability in the brain.
• Anxiety: Imbalances in neurotransmitters like GABA (inhibitory) and glutamate (excitatory) can contribute to increased anxiety and overactivity in certain brain regions.
• Schizophrenia: Research suggests that excess dopamine activity in specific brain regions may underlie some of the characteristic symptoms of schizophrenia. Antipsychotic medications often target the dopamine system.
• Bipolar Disorder: While the exact mechanisms are still debated, imbalances in various neurotransmitters, including serotonin, dopamine, and glutamate, are likely involved in the extreme mood swings seen in bipolar disorder.

400

Distinguish between serotonin and dopamine as neuromodulators of brain activity

• opamine:
  • Reward and motivation: Dopamine is often associated with reward processing. Its release is associated with pleasurable experiences, motivating us to seek these experiences.
  • Movement and coordination: Dopamine is also essential for controlling and coordinating movements. Deficits in dopamine signaling are implicated in Parkinson's disease.
  • Learning and memory: Dopamine plays a role in reinforcement learning, helping us associate actions with positive outcomes and learn from experiences.
• Serotonin:
  • Mood and emotion: Serotonin is often associated with regulating mood, happiness, and well-being. Low levels of serotonin are linked to symptoms of depression.
  • Sleep and appetite: Serotonin also contributes to sleep regulation and appetite control.
  • Learning and memory: While not as prominent as dopamine, serotonin also plays a role in certain aspects of learning and memory.

500

Explore the role of neuromodulators in shaping long-term neural connections.

Neuromodulators: Shaping the Symphony of the Brain

Neuromodulators, the chemical messengers beyond the realm of traditional neurotransmitters, play a captivating role in orchestrating the long-term dance of neural connections. While neurotransmitters deliver specific, point-to-point messages, neuromodulators act like conductors, influencing the overall tone and volume of neural communication. This influence translates to shaping the formation and strengthening of long-term neural connections, the foundation for learning, memory, and brain plasticity.

Synaptic plasticity

100

Define synaptic plasticity and its importance in neural function

Synaptic plasticity refers to the dynamic ability of synapses, the connections between neurons, to modify their strength and structure over time. This process is crucial for several reasons:

1. Learning and Memory:

• As we learn and form new memories, specific connections between neurons are strengthened through long-term potentiation (LTP), a process that makes them more likely to fire together in the future.
• Conversely, connections that are not frequently used undergo long-term depression (LTD), weakening them and making them less likely to fire together.
• This dynamic process allows the brain to constantly adapt and store new information, forming the basis of learning and memory consolidation.

2. Development and Refinement of Neural Circuits:

• During brain development, synaptic plasticity plays a vital role in establishing and refining neural circuits.

200

Explain the difference between long-term potentiation and long-term depression.

Long-term potentiation (LTP) and long-term depression (LTD) are two opposing forms of synaptic plasticity that play essential roles in learning, memory, and brain function. Here's the breakdown of their differences:

Long-Term Potentiation (LTP)

• Definition: LTP is a persistent strengthening of a synapse. This means after LTP, the connection between two neurons becomes more efficient, so a weaker signal from the presynaptic neuron can cause a stronger response from the postsynaptic neuron.
• Mechanism: LTP typically involves an increase in the number of AMPA receptors (which respond to the neurotransmitter glutamate) embedded on the surface of the postsynaptic neuron. This makes the postsynaptic neuron more sensitive to glutamate released from the presynaptic neuron.
• Effect: LTP amplifies communication between neurons, facilitating future activation of the same neural pathway.
• Relevance: LTP is strongly associated with learning and memory formation. By strengthening connections between neurons that fire together repeatedly, it encodes newly learned information into the brain's network.

Long-Term Depression (LTD)

• Definition: LTD is a persistent weakening of a synapse. After LTD, a stronger signal from the presynaptic neuron is required to elicit a similar response from the postsynaptic neuron.
• Mechanism: LTD often involves a decrease in the number of AMPA receptors on the surface of the postsynaptic neuron, making it less sensitive to glutamate.
• Effect: LTD dampens communication between neurons, making it less likely for a signal to pass across the synapse.

300

Discuss the role of synaptic plasticity in memory formation.

Synaptic Plasticity: The Orchestra of Memory Formation

Memory formation is a complex process involving various parts of the brain, and synaptic plasticity, the dynamic ability of synapses to change their strength and structure, plays a critical role in this intricate dance. Let's delve into how LTP (Long-Term Potentiation) and LTD (Long-Term Depression) contribute to this fascinating phenomenon:

1. The Strengthening Act: Long-Term Potentiation (LTP)

• Imagine learning a new skill like playing the piano. As you repeatedly practice specific motions, the connections between the neurons involved in coordinating these movements are strengthened through LTP.
• This strengthening involves:
  • Enhanced communication: The strengthened connections between neurons allow the signal to flow more efficiently, making it easier to recall the learned skill later.

2. The Pruning Process: Long-Term Depression (LTD)

• Not all experiences are equally important to remember. LTD helps the brain focus and refine its memory storage by weakening unused or irrelevant connections.
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400

How can environmental enrichment influence synaptic plasticity?

Research has shown that environmental enrichment significantly impacts synaptic plasticity, the brain's ability to modify the strength and structure of connections between neurons. Here's how EE influences this critical process:

1. Enhanced LTP and Reduced LTD:

• Studies suggest that EE can promote long-term potentiation (LTP), the strengthening of synapses. This might be achieved through:
  • Increased neurotrophic factors: EE stimulates the production of molecules like brain-derived neurotrophic factor (BDNF) which promotes the growth and survival of neurons and strengthens synaptic connections.
  • Enhanced signaling pathways: EE can activate signaling pathways involved in LTP, such as those involving NMDA receptors and protein kinases.
• Conversely, some studies suggest that EE might decrease long-term depression (LTD), the weakening of synapses. This could contribute to overall strengthening of neural networks.

2. Increased Synaptic Density:

• EE has been shown to increase the number of synapses in specific brain regions, particularly those involved in learning, memory, and sensory processing. This provides more potential pathways for communication between neurons and may enhance cognitive function.

500

Using an example explain how both LTP and LTD can aid with the learning process..

Here's an example that illustrates how both LTP and LTD contribute to the learning process, allowing us to navigate a new environment:

Scenario: Exploring a New City

Imagine you're visiting a new city on vacation. You'll need to learn the layout of the streets, the best places to eat, and the locations of popular attractions to enjoy your time there. How do LTP and LTD help your brain adapt?

LTP: Strengthening Key Connections

• Remembering directions: Each time you successfully navigate from your hotel to a famous landmark, the connections between neurons coding for direction and location in your hippocampus (a brain region involved in spatial memory) are strengthened through LTP. This means the pathways for these important routes become more efficient and easier to activate.
• Favorite Restaurants: When you find a cafe or restaurant with delicious food and excellent service, LTP ensures those connections become stronger as well. These positive experiences create a memorable, reinforced pathway for you to return easily.

LTD: Pruning and Refinement

• Ignoring false leads: Initially, you might get lost, follow confusing directions, or end up at places with long lines or bad reviews. Through LTD, neural connections related to these negative experiences are weakened, making it less likely you'll repeat these detours on future journeys.
• Efficient pathfinding: LTD helps your brain filter out unnecessary details as you discover the city. You may first pay attention to every street sign and building, but LTD will help "erase" those unnecessary connections as you become familiar with the main routes and landmarks. This frees up mental resources to attend to new discoveries.