Post on 22-May-2020
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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