PSYCH1003 all cards

Broca & Wernicke achievements

Identified language centres in the brain

What fields are within biological psychology

• psychology: study of behaviour/mental processes

• neuroscience: study of the nervous system

5 perspectives (DDDEMA)

1. Describing the behaviour

2. Evolution of the behaviour

3. Development of the behaviour

4. Development of the behaviour over the lifespan

5. Mechanisms of the behaviour

6. Application of biological psychology

the 3 approaches

Somatic intervention, behavioural intervention, correlation

What is somatic intervention?

• approach involving manipulating body structure and function and looking for changes in behaviour

What is behavioural intervention?

approach that involves manipulating behaviour and looking for changes in body structure/function

What is correlation (the approach)

• measures how much a body measure varies with a behavioural measure

Biological explanations for behaviour

1. physiological

2. ontogenetic (course of development in an individual organism)

3. evolutionary

4. Functional

What happened to Phinneas Gage?

He survived an injury where a metal rod pierced his scull, damaging his frontal lobe. This changed his personality and behaviour

What does the nervous system contain

CNS (central nervous system: brain, spinal cord)

AND
Peripheral nervous system (somatic nervous system, autonomic nervous system)

Somatic nervous system

VOLUNTARY.

concerns voluntary control of movement

• sensory input and

• motor output (muscle contraction)

Autonomic nervous system

INVOLUNTARY. Contains the:

• parasympathetic nervous system: vegetative non emergency responses, energy conservation, calming body down, digestion

• sympathetic nervous system: network of nerves that prepares organs for rigorous activity: fight or flight,

Goal: homeostasis (state of balance among all body systems)

Types of neurons in spinal chord

sensory neurons, interneurons, motor neurons

Sensory neurons

carry sensory info from sensory receptors to the CNS

transmit information from receptors to the brain

Interneurons

connect neurons to one-another

Receive the output by sensory neuron

Motor neurons

• transmit commands from the brain to glands and muscles and the body

• transmit the commands from interneurons to the glands and muscles of the body, often through the spinal cord

• carry out voluntary actions like grabbing water, vital bodily functions like digestion and heartbeat

Draw & label a neuron

Dendrite: structure & function

Highly branched, tapering processes extending from the cell body of a neuron.

Receives the electrochemical signal from the previous neuron(s), sends to soma

Cell body/soma structure and function

Contains nucleus, ribosomes and mitochondria

determines how the particular neuron will manipulate input from dendrites, maintains metabolism & health, receives and sends information

Myelin sheath structure & function

Tight coat of cells primarily composing of lipids surrounding axon

Protects axon from other stimuli that may interfere with transmission of nerve impulses, and increases speeds of message transmission

Node of ranvier structure and function

Between the cells that from the sheath are small spaces of bare wire

When a neuron fires, the electrical impulse is transmitted rapidly from node to node

Axon structure and function

Long projection leading from the cell

Conducts the electrochemical signal away from the cell body

Axon terminals structure and function

Finger-like projections leading from the axon to the next neuron(s) or target cells (such as muscle cells).

where the electrochemical signal leaves the neuron so it can be conducted to the next neuron(s) or target cell

Afferent vs efferent axons

• afferent axons bring information INTO the structure (a for admission)

• efferent axon: carry information AWAY from structure (e f or exit)

Pyramidal & multipolar neurons

Bipolar neuron appearance & purpose

Used in specialised sensory systems like vision, hearing

Purkinje neuron structure & role

In cerebellum,

• motor coordination,

• usually inhibitory neurons that fine tune voluntary movements and balance

Unipolar neuron appearance & role

Transmitting sensory information from the periphery to the cns

What are the main roles of glia cells

• support and protect neurons

• maintain homeostasis

• forming myelin

• modulating synaptic activity

• cleaning up synaptic waste

Glia cell-neuron

was believed 10:1, now known its 1:1

Astrocyte role (5)

• supportive / structural,

• nutrient/waste exchange,

• ion balance,

• regulating synaptic activity,

• repair scar formation

Oligendrocyte role

• Found in cns, main role is myelination. One oli can myelinate several axons

Schwann cells role

Found in periphery, also myelinate similar to olis

Microglia & radial glia role

• Microglia

  • Located outside CNS, mylinate axons individually

• radial glia

  • Developing brain, mainly embryo, neurogenesis and helping migration of neurons to correct locations. May differentiate into other cells

Firing of a neuron purpose & overview

Neurones mostly communicate at the synapse by converting an electrical charge in one neurone to a chemical message→ when this is released into the synapse it alters the charge of the next neurone and so forth

• overall pattern of neural activation is distributed over thousands of neurones

• neurones are covered by semi permeable lipid bilayer membrane

Resting polarisation of a neuron

• when a neurone is at rest, its membrane is polarised between inside and outside

  • the inside of the membrane has a NEGATIVE charge whereas fluid outside the cell has a POSITIVE charge

Resting potential: Electrical gradient

•  Na+ and K+ is attracted to negative charge inside neuron

Resting potential: What is it?

Resting potential is the stable negative electrical charge across a cell membrane (~–70 mV)

When the neurone is not firing it is in a state of RESTING POTENTIAL (potential as the cell has stored up energy which has the potential to be used)

Resting potential: Chemical gradient

• distribution of ions across the membrane

  • Na+ is more concentrated outside, more likely to be pulled into the neuron

  • K+ is more concentrated inside so are more likely to be pushed out of the neuron

Resting potential: The 3 factors maintaining

1. Sodium-potassium pump

2. Potassium leak channels

3. Trapped negative ions

Resting potential: Sodium potassium pump

• Actively transports ions using ATP. For every cycle it:

  • Pumps 3 Na+out of the cell

  • pumps 2K+ into the cell

• hence creating a net loss of positive charge inside the cell and creating a negative resting potential

Resting potential: Potassium leak channels

•  Membrane is more permeable to K+ than NA+

  • K+ diffuses out of the cell through leak channels

  • as positive K+ leaves the inside becomes more negative

Resting potential: Trapped negative ions

large negatively charged proteins and molecules inside the cell cannot cross the membrane, contributing to negative charge

Graded potentials: What are they?

Small changes in the membrane potential of a neuron occurring when a stimulus affects the cell membrane

• called graded because their size varies on the strength of the stimulus

• if a threshold is reached, action potential will start

Graded potentials: 4 characteristics

1. Variable size

2. local signals

3. may be depolarising or hyperpolarising

4. can summate

Graded potentials: Variable size

• the response of a graded potential is proportional to stimulus strength; weak stimulus→ small change in voltage and vice versa

Graded potentials: Local signals

• graded potentials can occur in dendrites or the cell body (soma)

• they spread a short distance along the membrane and gradually weaken

Graded potentials: Depolarising

• stimulation can reduce polarisation (depolarise), decreasing voltage discrepancy between the outside and inside

  • excites neuron (renders it more likely to fire with further stimulation)

  • comes from an influx of positive sodium ions→ charge inside cell membrane becomes less negative, makes it more likely to fire if further stimulated

Graded potentials: Hyperpolarising

• stimulation can increase polarisation (hyperpolarise)

  • inhibit neuron and make it less likely to fire

  • outflow of potassium ions, or influx of chloride ions→ potential across membrane becomes more negative, making less likely to fire

Graded potentials: Where do they occur?

most voltage changes occur at synapse along neurones dendrites and cell body, then spread down the cell membrane (like ripples in a pond)

Graded potentials: Summation

• graded potentials are cumulative/additive

  • if a neurone is simultaneously depolarised by -2mV on a dendrite and hyperpolarised by -2mV at an adjacent point, the two graded potentials add up to zero and cancel each other out.

  • if the neuron is depolarised at multiple points, a greater influx of positive ions occurs, producing a ripple all the way down the cell body to the axon

Graded potentials: Types of summation

• spatial: signals from multiple synapses add together

• temporal: signals arrive rapidly from the same synapse and add up

Graded potentials: Threshold

• If the combined graded potentials reach the -55mV threshold they trigger an action potential

Graded potentials: Event sequence

1. Stimulus activates ion channels in dendrites or soma

2. Small voltage change occurs (graded potential)

3. Multiple graded potentials may summate

4. If threshold is reached → action potential starts

Action potentials: What are they

A rapid temporary reversal of membrane potential that allows electrical signals to travel along the axon

• signal used by neurons to communicate with other neurons, muscles and glands

Resting and activation potential requirements

• at rest neurons have a resting membrane potential of -70mV

  • When stimulation reaches -55mV an action potential is triggered

Action potentials: Stages

1. Depolarisation

2. repolarisation

3. hyperpolarisation

4. return to resting potential

Action potentials: Depolarisation

• once stimulus reaches -55mV threshold

• voltage-gated Na+ channels open

• → Na+ rushes into the neuron

Hence:

• membrane potential rapidly rises up to +30mV

• → inside of neuron becomes positive

Action potentials: Repolarisation

• Na+ channels close

• voltage-gated K+ channels open

• K+ ions leave the cell causing the membrane potential to become negative again

Action potentials: Hyperpolarisation

• K+ channels close slowly→ extra K+ leaves the neuron

• membrane potential becomes more negative than resting potential (about -80mV)

Action potentials: Return to resting potential

• K+ channels close

• sodium-potassium pump and leak channels restore normal ion distribution

• neuron returns to -70mV

Action potentials: All or none

•  if threshold is reached, action potential always has same size

  • stronger stimulus doesn’t make it bigger, only more frequent

Action potentials: Refractory periods

• neuron temporarily cant fire another signal)

  • Absolute refractory period: Na+ channels are inactivated, no new AP can occur

  • Relative refractory period: during hyperpolarisation a stronger stimulus is required to trigger another action potential

Action potential: Summary

An action potential is a rapid electrical signal in neurons caused by: Na⁺ rushing into the cell (depolarization) K⁺ leaving the cell (repolarization) Temporary hyperpolarization Return to resting membrane potential This process allows nerve impulses to travel along axons. Rest → Na⁺ In → K⁺ Out → Too Negative → Reset

Neuron firing process

1. Neuron maintains resting potential across the entire neuron, including dendrites, cell body (soma) axon and axon terminals

2. Neuron receives a stimulus (usually via another neuron at a stimulus

• opens ligand-gated ion channels to produce a graded potential (occurs in dendrites and cell body)

3. At the axon hillock all incoming graded potentials are added up.

• if the combined signal reaches -55mV an action potential is triggered

4. action potential occurs along the axon membrane and is propagated along the axon to axon terminals

5. Once action potential reaches axon terminals, voltage gated Ca^2+ channels open, neurotransmitters are released into the synapse

6. next neuron begins its own graded potentials

Neurotransmitter absorption and release

1. Neurotransmitters are synthesised and stored

• synthesised at terminal buttons or soma, then stored in the terminal buttons

2. action potential arrives at terminal button neurotransmitters are realised

• Action potential arrives at the terminal button, opens Ca+ channels and releases neurotransmitters (exocytosis

3. neurotransmitters bind to receptors

• neurons release many types of neurotransmitters

• neurotransmitters can bind to different receptor types, allowing for complex signalling

4. neurotransmitters separate from the receptors

5. neurons are reabsorbed by presynaptic neurons

6. postsynaptic neurons release retrograde neurotransmitters

7. negative feedback sites respond to retrograde neurotransmitters

Neurotransmitter receptors

Types of neurotransmitter receptors

• lock and key model: neurotransmitters and receptors can have different shapes- not all can open to all receptors.

• Two main types:

  • Ionotropic

  • metabotropic

Ionotropic receptors

• receptor binding immediately opens ion channels

• directly affects the membrane

• rapid signalling (1-20ms)

• short duration (100-500ms)

Metabotropic recceptors

• receptor binding activates an intracellular messenger without immediately opening an ion channel

• intracellular messenger opens ion channel

• slower sequence of metabolic reactions >30ms

• longer lasting (seconds to minutes+)

Glutamate neurotransmitter

• One of most common

• excitatory neurotransmitter

• binds to NMDA/AMPA receptors

GABA neurotransmutter

• Also very common

• Inhibitory neurotransmitter

• Binds to GABA receptors

• Causes inhibitory postsynaptic potential

Excitatory post synaptic potential

• post synaptic potential that makes the neuron more likely to produce action pot

• action potential usually requires many excitatory postsynaptic potentials

  • spatial summation: summing potentials that arrive at different synapse

  • temporal summation: summing potentials that arrive at different times at the same synapse

Inhibitory postsynaptic potential

•  makes the postsynaptic potential less likely to produce an action potential

three major divisiions of the brain

• forebrain (prosencephalon)

• midbrain (mescencephalon)

• hindbrain (rhombencephalon)

  • hindbrain and parts of midbrain constitute the brainstem

Hindbrain diagram

Medulla oblongata purpose

Controls vital autonomic functions such as:

• Breathing

• Heart rate

• Blood pressure

• Swallowing, coughing, and vomiting reflexes

Pons purpose

• Acts as a relay station between different parts of the brain.

• Helps regulate:

  • Sleep and arousal

  • Breathing

  • Facial movements and sensations

Cerebellum purpose

• Coordinates voluntary movements.

• Maintains:

  • Balance

  • Posture

  • Motor learning and fine motor control

• Helps movements become smooth and accurate

Midbrain diagram

Superior colliculi purpose (tectum)

Visual reflexes and eye/head orientation

Inferior colliculi purpose (tectum)

Auditory processing and sound orientation

tegmentum purpose (4)

Movement control, arousal, pain modulation, dopamine production

Forebrain structure

Forebrain: Cerebrum vs interbrain structure

Feature	Cerebrum (Telencephalon)	Interbrain (Diencephalon)

Location

Largest, outermost part of the brain

Located beneath the cerebrum, surrounding the third ventricle

Major Structures

Cerebral cortex, basal ganglia, limbic system

Thalamus, hypothalamus, epithalamus, subthalamus

Forebrain: Main components

CCL: Corpus callosum, cerebral cortex, limbic system

Forebrain: Thalamus- where and what

Thalamus

above midbrain

Relays information to the cerebral cortex

Forebrain: Hypothalamus- role

Maintains homeostasis by regulating hunger, thirst, body temperature, sleep, and hormone release.

Forebrain: pituitary gland- role

Releases hormones that control growth, metabolism, reproduction, and other endocrine glands.

Forebrain: basal ganglia role

Helps initiate and regulate voluntary movement, habit formation, and procedural learning.

Forebrain: hippocampus role

Essential for forming new long-term memories and spatial navigation.

Forebrain: Cingulate gyrus role

Involved in emotion, attention, motivation, decision-making, and pain processing.

Amygdala role

Processes emotions, especially fear, threat detection, and emotional learning.

Ventricles role

Fluid-filled spaces that contain and circulate cerebrospinal fluid (CSF), which cushions and nourishes the brain.

Naviagting the brain

Cerebral cortex lobes

Parts of the frontal cortex

Primary motor cortex role

Voluntary movement

Premotor cortex role

Planning movements

Prefrontal cortex role

Decision-making, planning, personality

Broca’s area role

Speech production