Psychobiology 1st yearRevision Guidance

The following slides contain the key concepts covered in the lectures,together with some guidance on how to structure your learning:

means “Just learn it off by heart”

means “Understand this –understand what it means!”

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Psychology as the (experimental) study of human behaviour

What is Psychobiology?- In general: The study of the relationship between

behaviour and biological processes- In particular: The study of the relationship

between behaviour and the brain

Psychobiology aims to get a more complete under-standing of human behaviour:- Whatever you do, you use your body to do it

or in other words:- All behaviour results from biological processes

Behaviour = “The interaction of an organism with its environment”

Three systems that interact with the environment:- The immune system (protects the body)- The endocrine system (maintains and regulates the

body’s internal state)- The nervous system (controls ongoing activity –

biological basis of all ‘cognitive’ functions)

How is behaviour generated?- Register information from the environment- Process (transform) this information- Generate an appropriate response

The more complex the structure of an organism, the more complex the processes involved in generating behaviour

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Why do more complex organisms need a nervous system?

Two systems to co-ordinate cell activities1. Endocrine system2. Nervous system

How are neurons special?- Form & Size: soma, dendrites, axon- Special requirements: no energy storage- Life span: do not divide- Function…

Glia cells- Function: protection & support- Different Types:

- Astrocytes- Microglia- Oligodendroglia

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

NeuronsLecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Electrical Transmission- Resting Potential:

- Ion gradients- Membrane potential- Sodium-potassiom pump

- Signal propagation: - Depolarisation & hyperpolarisation- Electrotonic transmission & action potentials

- Function:- Transmit electrical impulses- Impulses can not be modified!- Information coded by location & firing rate

- Different Types: - Sensory neurons- Motor neurons- Interneurons

Electrical Transmission

- Electrotonic transmission:- Within dendrites & soma- Passive (not self-replicating)- Spatial & temporal summation

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

- Action potential:- Active (self-replicating)- Voltage-gated ion channels- Threshold potential- Depolarisation, repolarisation, hyperpolarisation- Axon hillock- All-or-nothing

- Saltatory conduction: - Myelin sheath- Nodes of Ranvier

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Electro-chemical Transmission- Synapse:

- Pre-synaptic & post-synaptic- Axon terminals & dendritic spines- Electrical & chemical synapse- Excitatory & inhibitory

- Post-synaptic summation- Spatial & temporal- Electrotonic (i.e., full circle!)

- Flow of signals in the nervous system…

Central Nervous System

Brain

SpinalCord

Input: senses & internal organs

Output: skeletal muscles (voluntary control)

Parasympathetic part

‘rest & main-tenance’

Sympathe-tic part

‘fight or flight’

Peripheral Nervous SystemEverything else:

Output: muscles & glands(involuntary control)

No input!

Somatic NS

Autonomic NS

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Function of the NS- Control & co-ordinate:

- From the periphery - via the spinal cord - into the brain - and back

- Detection of sensory signals:- Receptor cells- Sensory neurons- Multiple relay stations & pre-processing stages- Example: retina

- Inside the spinal cord:- Mono-synaptic reflexes- Poly-synaptic reflexes

- Any more complex behaviour requires a brain:

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Cerebellum Movement & Posture

Pons

Medulla

Continuation of spinal cord; autonomic nuclei

Hindbrain

Tectum Perception & Attention

Tegmentum Motor functionsMidbrain

Spinal Cord

Cerebral Cortex (cortical lobes)

Perception, Action,Cognition...

Limbic System Emotion

Basal Ganglia Motor control

Tel-encephalon

Thalamus Central relay station

Hypothalamus Gateway to ES

Forebrain

Di-encephalon

Input – Output – Housekeeping

Signal processing- Primary sensory cortices

- Where?- Representation: retinotopic, somatotopic, etc…

- Higher sensory & association areas- Direction of signal transmission:

- Bottom-up & top-down- Constant feedback = constant modification

Motor output: complex control loops- Cortical motor areas (in the frontal cortex)- Subcortical motor areas

- Basal ganglia- Cerebellum

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Some terminology- Structures:

- Grey matter & white matter- Cortex & nucleus (NOT cell nucleus!)

- Locations & directions:- Anterior, posterior, etc.- Dorsal, ventral, etc.

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Topic: Functional organisation of the brain

- Processing principles:- Input – Integration – Output- Convergence / Divergence- Self-regulation

- These principles in action: Example of visuo-motor control

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Early visual processing- Retina:

- 3 main cell layers- Receptive fields- Visual hemi-field- Temporal & nasal retina

- Into the brain:- Optic nerve- Optic chiasm- LGN of the thalamus- Primary visual cortex

- Tecto-pulvinar system- Superior colliculus of the midbrain- Pulvinar of the thalamus

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Early visual processing- Visual cortex

- Primary visual cortex / V1 / striate cortex- Higher-level processing in the extra-striate

cortex- Specialisation - No single place of “object representation”- Corpus callosum

- Beyond early visual processing- 2 visual streams:

- “Ventral” – temporal lobe – object recognition- “Dorsal” – parietal lobe – object-oriented action

- Evidence:- Dissociation of object recognition / object-

oriented action in patients with brain lesions

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

From perception to action

- Very little is known about what actually happens!

- But some information exists about which structures are involved- Parietal cortex >- Motor areas in frontal lobe >- Primary motor cortex in frontal lobe

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Motor control- Control circuits:

- Cortical areas interconnected with basal ganglia & cerebellum

- Primary motor cortex:- Direct control of voluntary movements- Somatotopic organisation (Homunculus)- Axons cross over (Corpus callosum)

- Hierarchic control:- Primary motor cortex – brainstem – spinal cord- Pyramidal & extra-pyramidal tract- Alpha motor neurons cause muscles to contract

- At every processing stage, ‘feed-forward’ signal transmission can be modified by input from other (perceptual, cognitive, motor…) processing stages!

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Topic: How do ‘higher’ mental functions relate to biological processes

- Memory is the ability to make continuous use of previous experience

- Memory is possible because experiences changethe brain

- Research questions:- How do such changes occur?- How do they affect behaviour?- Which structures are involved?

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

How do changes occur?- Increased neural activity can cause molecular

changes:- Neurotransmitter release etc.

- Sustained activity can cause structural changes- Synapse growth etc.

How do changes affect behaviour?- Optimising existing behaviour- Acquiring new behaviour

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Which structures are involved?- Cortex:

- Lashley’s ‘Law of Mass Action’- No specific place of memory storage!- But brain damage in certain areas can

apparently destroy certain types of memory- Medial temporal lobe:

- Hippocampus, amygdala, and surrounding cortex

- Bilateral removal results in inability to form new conscious memories (anterograde amnesia)

- Diencephalon:- Nuclei of the thalamus & mammillary bodies- Often damaged from alcohol abuse (Korsakoff’s

Syndrome)- Anterograde & retrograde amnesia

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory

Memory & Emotion

- Example: Post-traumatic stress disorder (PTSD)- Amygdala (involved in memory formation) is

‘fear centre’ in the limbic system- Direct connection to hypothalamus- Hypothalamus controls hormone secretion- High activity in amygdala can result in high

levels of stress hormones (adrenaline) and stress neuro-transmitter (noradrenaline)

- These chemicals improve memory!- Evidence: picture & story experiment

- A simplified psychobiological model of (PTSD)

Lecture 1: Basic Concepts

Lecture 2: Neurons

Lecture 3: Nervous System

Lecture 4: Perception & Action

Lecture 5: Learning & Memory