Biopsychology

Definition of localisation theory?

• Different parts of the brain are involved in different tasks and are associated to different behaviour.

What is the brain divided into?

• 2 hemispheres and lateralised

What is lateralisation?

• Physical and psychological functions are controlled by a particular hemisphere

What does the left side of the body control?

• Right hemisphere and vice versa

What is the user layer of the brain called ?

Cerebal Cortex

Features and definition of cerebral cortex? (4)

• Covers the inner parts of the brain

• 3mm thick

• Highly developed

• Grey due to location of cell bodies

What are the 4 lobes of the hemispheres?

• Frontal lobe

• Temporal Lobe

• Occipital lobe

• parietal Lobe

What is in the frontal lobe

Motor area : Controls voluntary movements

What happens if their is damage done to the motor area?

Damage may result to loss of control over fine motor skills.

What is in temporal lobe?

Auditory area : Analyse speech based information.

What happens if their is damage done auditory area?

Damage done to this area may produce partial hearing loss - the more extensive the damage the more serious the loss .

What is in the Occipital lobe?

• visual area : Each eye sends information from the right visual field to the left visual cortex and to the right visual field to the left visual cortex.

What is in the Parietal lobe?

• Somatosensory area : Processes sensory information from the skin .

• The amount of somatosensory area devoted to a particular body part represents its sensitivity.

What are the 2 language areas?

• Broca's area

• Wernicke's area

What is Broca’s area ?

Speech production

What does damage to the Broca’s area cause ?

Broca Aphasia

Broca Aphasia characterised by?

• May find it difficult finding words and naming certain objects.

• Slow speech

• laborious

• Lacking in fluency

What is Wernicke's area ?

Language understanding?

What does damage to the Wernicke's area cause ?

• Wernicke's Aphasia

• Produce language but have problems understanding it

• Production of nonsense words

strength : Perterson et al Brain Scan

• Used brain scans to understand how Wernicke's area was active during a listening task and how Broca’s area was active during a reading tasks.

• Suggests that these areas have different functions.

• Study on LTM by Tulving et al revealed that semantic and episodic memory reside in different parts of the prefrontal cortex.

• Provides sound scientific research due to use of highly sophisticated methods.

strength : Neurology

• Lobotomise use to be common practice.Brutal but still controversially used today due to the effectiveness.

• Doughtery et al (2002) had 44 patients with OCD underwent cingulotomy after 32 weeks 1/3 showed a successful response

• success suggest function is localised

weakness : Brain localisation model been questioned.

• Dick Trembley found only few researchers believe language is only in Broca’s area and Wernicke's area

• Advanced techniques has identified regions in right hemisphere and thalamus.

• It‘s not confined and language may be organised more holistically in the brain which contradicts localisation theory.

What are the key features of the nervous system?

• Made up of a network of specialised cells and is our primary communication system

• Electrical impulses and chemical impulses

• Divides into the Central nervous system and the peripheral nervous system.

What are the 2 main functions of the nervous system?

• To collect process and respond to information in the environment

• To co-ordinate the working of different organs and cells in the body.

What is the structure of the Central nervous system?

• Brain

• Spinal Cord

What is the function of the Central Nervous System?

• The brain is a centre of conscious awareness

• The outer layer of the brain, the cerebral cortex is 3mm thick and is highly developed in humans

• Brain is split into hemispheres

• The spinal cord is an extension of the brain snd responsible for reflect actions

• It passes messages to and from the brain and connects nerves to the PNS.

What is the structure of the Peripheral nervous system?

• The PNS transmits messages via millions of neurons to and from the nervous system.

What does the autonomic nervous system do ?

Governs vital functions in the body such as breathing ,heart rate, digestion, sexual arousal and stress responses.

What is the somatic nervous system?

Governs muscle movements and receives information from sensory receptors.

What are key features of the endocrine system?

• Works alongside the nervous system to control vital functions of the body.

• Endocrine system instructs various glands to release hormones in blood.

• Works slower than the nervous system but has widespread and powerful effects.

What are glands?

Glands are organs in the body that produce hormones.

What is the key endocrine gland?

Pituitary gland located in the brain. Refered to as there master gland because it controls the release of hormones from all the other endocrine glands In the body.

What is the hormones function?

They secrete to the bloodstream and affect any cell in the body that has a receptor for that particular hormone.

What happens during the flight or fight response?

• Stressor is perceived by hypothalamus which activates the pituitary.

• The sympathetic nervous system is then aroused

• Adrenaline is then released from the adrenal medulla into the bloodstream.Delivering the aroused state causing changes in target organs in the body.

• Its immediate and automatic - happens as soon as a threat is perceived.

• Parasympathetic nervous system - takes over once the threat has passed.This returns the body to its resting state.Acting as a brake and reduces the activities of the body that were increased by the actions of the sympathetic branch.

What happens during the sympathetic state?

• Increase of heart rate

• increase breathing rate

• dilated pupils

• inhibits digestion

• inhibits saliva production

• contracts rectum

What happens during the parasympathetic state?

• Decease heart rate

• Decrease breathing rate

• constricts pupils

• Stimulates digestion

• stimulates saliva production

• relaxes rectum

What are the 3 types of neurons?

• Sensory neurons

• Relay neurons

• Motor neurons

What is the functions of a sensory neuron?

• Carry messages from the PNS to the CNS.

• Have long dendrites

• short axons

• Ganglias located in the PNS

What is the functions of a relay neuron?

• Connect sensory neurons to motor neurons or other relay neurons

• They have short dendrites and short axons

• 97% are in the brain and visual system.

What is the functions of a motor neuron?

• They connect to effectors such as muscles and glands

• They have short dendrites and long axons

Basic structure of a neuron?

• Cell body - Includes a nucleus which contains the genetic material of the cell.

• Dendrites - Branch like structures that protrude from the cell body.Carry nerve impulse away from neighbouring neuron’s towards the cell body.

• Axons - Carries the electrical impulse away from the cell body down the length of the neuron’s.

• Terminal button- At the end of the axon communicate with the next neuron in the chain across a gap called the synapse.

function and features of a axon?

• Axons - Carries the electrical impulse away from the cell body down the length of the neuron.

• Covered in a fatty layer of myelin sheath that protects the axons.

• gaps in the axon called nodes of ranvier speed up the transmission of the impulse.

what is electrical transmission?

The firing of a neuron.

what is a synapse?

• each neuron is separated from the next by extremely tiny gap

What happens through the synapse?

• Inside a neuron: signals travel electrically (action potential).

• At the presynaptic terminal: the impulse triggers release of neurotransmitters from vesicles.

• Neurotransmitters cross the synaptic cleft.

• They bind to postsynaptic receptors, ensuring the signal goes in one direction.

• The chemical signal is converted back into an electrical impulse in the next neuron.

What are neurotransmitters?

• Neurotransmitters are chemicals that diffuse across the synapse to the next neuron.

• Many different neurotransmitters have been identified.

• Each has a unique molecular structure.

• They fit into postsynaptic receptor sites like a lock and key.

What are the specific functions of a neutrotransmitter?

• Acetylcholine (ACh): found where a motor neuron meets a muscle → causes muscle contraction.

• Serotonin: affects mood and social behaviour (among other functions) → low levels are linked to depression.

What are the excitation and inhibition?

• They have an affect on the neighbouring neuron.

Is Adrenaline inhibitory or excitatoty?

• Usually excitatory increasing the positive charge of the postsynaptic neuron making it more likely the postsynaptic neuron will fire.

Is Serotonin inhibitory or excitatory ?

• Generally inhibitory increasing the negative charge of the postsynaptic neuron making it less likely the postsynaptic neuron will fire.

Is dopamine  inhibitory or excitatory ?

Neurotransmitters are equally likely to have an excitatory or inhibitory effect on the postsynaptic neuron.

What is summation?

• The signals received by a postsynaptic neuron add up (summate) to determine whether it will fire.

• If the total effect reaches the threshold, an action potential is triggered.

• If the net effect is inhibitory, the postsynaptic neuron is less likely to fire because the electrical signal is stopped.

• If the net effect is excitatory, the postsynaptic neuron is more likely to fire, as the electrical signal moves closer to threshold.

What is the holistic theory?

• early 19th century

• suggest that all parts of the brain were involved in processing thought and action.

What is the localisation theory?

• Specific areas of the brain are linked with specific psychological and physical functions.

• If an area of the brain is damaged by illness or injury, the function associated with that area will also be impaired or affected.

What is the brain divided into?

• Its divided into 2 

• Hemispheres and lateralised.

What is lateralisation?

• Some physical and psychological functions that is controlled by a particular hemisphere.

• The left side if body controls the right hemisphere and right side of the body controls the left hemisphere.

What is the outer layer of the Brain called?

• The cerebral cortex

Features of the cerebral cortex?

• The cerebral cortex covers the inner parts of the brain.

• It is around 3mm thick and is highly developed in humans, which separates us from other animals.

• It appears grey in colour because it contains the cell bodies (often called grey matter).

What are the 4 lobes of the cerebral Cortex?

• Motor area

• Somatosensory area

• visual area

• auditory area

What is the motor area?

• The back of the frontal lobe 

• Controls voluntary movement 

• Damage to it may cause loss of control over fine motor skills.

What is the Somatosensory area?

• Front of the parietal lobe

• Process of sensory information from the skin. 

• The amount of Somatosensory area devoted to a particular body part denotes its sensitivity.

What is the visual area?

• The visual cortex is located in the occipital lobe.

• Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex.

What is the auditory area?

• In the temporal lobe 

• Analyses speech based information 

• Damage may result in partial hearing loss.

What is the Broca’s area?

• Aides in speech production

• Identified by Broca in 1880’s

• In the left frontal lobe

What occurs when the Broca area is damaged?

• Damage to Broca’s area causes Broca’s aphasia.

• It is characterised by slow, laborious, and non-fluent speech.

• Individuals may struggle to pronounce certain words and to find the right words.

• They also have difficulty using prepositions (e.g., “in,” “on,” “at”).

What is the Wrenicke’s area?

• The understanding of language

• Identified by Wrenicke in 1880s 

• In the left temporal lobe.

What occurs when the Wrenicke’s area is damaged?

• Damage to Wernicke’s area causes Wernicke’s aphasia.

• Individuals can produce language but have difficulty understanding it.

• Speech is fluent but often meaningless.

• They may also produce nonsense words (neologisms) within their speech.

One strength of localisation theory? neurosurgery.

• Localisation of function is supported through neurosurgery.

• Neurosurgery can be used to treat mental illness by isolating the cingulate gyrus; dysfunction in this area may be linked to OCD.

• Dougherty et al. studied 44 people who had a cingulotomy. At follow-up:

  • 30% showed a successful response.

  • 14% showed a partial response.

• The success of this procedure strongly suggests that behaviours associated with serious mental illness may be localised to specific brain areas.

Strength of localisation theory? brain scan evidence

• Peterson et al. used brain scans to show activity in Wernicke’s area during a listening task and in Broca’s area during a reading task.

• Tulving et al. found that semantic and episodic memories are located in different parts of the prefrontal cortex.

• There are now a number of sophisticated and objective methods (e.g., brain scans) for measuring activity in the brain, providing strong scientific evidence for the localisation of function.

Limitation of localisation ? language model has been questioned

• Dick and Tremblay found that very few researchers now believe language is restricted to Broca’s and Wernicke’s areas.

• Advanced techniques have identified language-related regions in the right hemisphere and the thalamus.

• This suggests that language may be organised more holistically across the brain, which contradicts strict localisation theory.

What is hemispheric lateralisation?

• The brain is lateralised into 2 sides

What is contralateral?

• In the motor area the right hemisphere controls the left side of the body and vice versa.

What is ipsilateral?

• The left visual field (LVF) from both eyes is processed by the right hemisphere (RH), and the right visual field (RVF) from both eyes is processed by the left hemisphere (LH).

• This arrangement allows the visual areas to compare slightly different perspectives from each eye, which aids in depth perception.

• The auditory areas have a similar arrangement, with input from each ear being processed by both hemispheres.

Sperry split brain (1968)

• Split-brain surgery involves surgically separating the two hemispheres by cutting the corpus callosum.

• It is used to treat severe epilepsy, reducing the “electrical storm” across the hemispheres.

• Study setup: 11 patients were shown images projected to the right visual field (RVF) and left visual field (LVF).

  • When an image was presented to one hemisphere, the information could not be conveyed to the other hemisphere.

• Findings:

  • RVF (left hemisphere): participants could describe what they saw.

  • LVF (right hemisphere): participants could not name the object and could not select a matching object behind a screen with the left hand.

  • They could select an object closely associated with the picture.

  • When a pin-up picture was shown to the LVF, participants giggled but reported seeing nothing.

• Conclusion: This demonstrates that certain functions are lateralised:

  • Left hemisphere (LH): verbal, language functions.

  • Right hemisphere (RH): non-verbal, silent, but emotional.

One strength is evidence of lateralised brain functions in neurotypical brains.

• PET scans show that when neurotypical participants attend to global elements of an image, the right hemisphere (RH) is more active.

• When focusing on finer details, the left hemisphere (LH) tends to dominate.

• This suggests that hemispheric lateralisation is a feature of the neurotypical brain as well as in split-brain patients.

One limitation is the idea of analyser versus synthesiser brain may be wrong

• While there are different functions in the right (RH) and left hemispheres (LH), research suggests that people do not have a dominant side that determines personality.

• Nielsen (2013) analysed 1,000 brain scans and found that people used both hemispheres for different tasks, with no evidence of overall dominance.

• This suggests that the popular idea of being “right-brained” or “left-brained” is incorrect.

One strength I support from more recent split brain studies.

• Luck et al. showed that split-brain participants can perform certain tasks better than neurotypical controls.

• In the neurotypical brain, the left hemisphere’s superior processing abilities are sometimes diluted by the less efficient right hemisphere (Kingstone, 1995).

• This supports Sperry’s earlier findings that the left and right hemispheres are distinct in terms of function and abilities.

One limitation is that causal relationships are hard to establish.

• In Sperry’s research, the behaviour of split-brain participants was compared to a neurotypical control group.

• None of the control participants had epilepsy, so some differences between the groups may be due to epilepsy rather than the split-brain procedure.

• This suggests that some of the unique cognitive abilities observed in split-brain participants might be influenced by their epilepsy, not just hemispheric separation.

What is brain plasticity? 

• The brain ability to change and adapt as a result of experience and learning .

During infancy what happens to synaptic connections in the brain?

• The brain experiences a rapid growth in synaptic connections peaking about 15,000 at age 2-3.

What happens to frequently used synaptic connections?

• They’re strengthened

What happens to rarely used synaptic connections?

-They're deleted or pruned (synaptic pruning)

What does research suggest about plasticity in adulthood?

• It is not limited to childhood - plasticity can occur at any time due to learning and experience.

Taxi driver study - To support plasticity(Maguire et al)

• He found significantly more grey matter in the posterior hippocampus in taxi drivers.

• Then he matched to a control group.

• This part of the brain is linked with navigational and spatial development

• the knowledge test is linked to altering the structure of their brains

• The longer into the job the more pronounced was the structural difference.

Research on learning that supports plasticity?

(Draganski ) - imaged the brain of medical students three months before and after final exams 

• Learning induced changes were seen in the posterior hippocampus and the parietal cortex presumably as a result of learning for the exam.

What happens after an area of the brain loses function due to trauma?

• Neural plasticity example: Healthy brain areas can take over functions of damaged, destroyed, or even missing areas.

• Spontaneous recovery: This process happens quickly after brain trauma.

• Slowing down: Recovery then becomes slower over time.

• Rehabilitation therapy: At this stage, therapy (e.g., physio, speech therapy) helps the brain reorganise and continue improving.

Why does the brain rewires itself?

• To form synaptic connections and reorganise itself.

• Closes the area of damage 

• Secondary neural pathways are used to carry out functions.

What are the structural changes in the brain?

• Axonal sprouting – Growth of new nerve endings from surviving neurons. These endings connect with undamaged cells, creating new pathways to restore function.

• Denervation supersensitivity – When some axons are lost, similar axons increase their activity (become more sensitive) to compensate.

• Recruitment of homologous areas – Brain regions on the opposite hemisphere take over tasks (e.g., the right hemisphere supporting language production if the left is damaged).

One limitation of plascity is its possible negative consequences.

• Cognitive decline from drug use – The brain’s adaptation to prolonged drug use can reduce cognitive functioning later in life and increase the risk of dementia.

• Phantom limb syndrome – Around 60–80% of amputees experience sensations (often painful) from the missing limb.

• Not always beneficial – Brain plasticity can sometimes lead to harmful physical or psychological effects, showing that adaptation is not always positive.

One strength of plasticity is thats its a life long ability?

• Bezzola (2012) study – Found that 40 hours of golf training in adults aged 40–60 produced changes in neural representations.

• FMRI findings – Novice golfers showed reduced motor cortex activity compared to a control group, suggesting greater efficiency after training.

• Conclusion – Neural plasticity continues across the lifespan, even in middle and later adulthood.

One strength of functional recovery is its real life world application?

• Neurorehabilitation – Research into plasticity (e.g., axonal growth) has guided the development of therapies to support recovery after brain injury.

• Example: Constraint-induced movement therapy – Patients practice tasks intensively with the affected arm while the unaffected arm is restrained, encouraging recovery of function.

• Conclusion – Research into functional recovery helps medical professionals decide when and how interventions should be introduced.

One limitation is neural plasticity may be related to cognitive reserve?

• Schneider et al. (2014) – Investigated the role of education (as a measure of cognitive reserve) in recovery from brain injury.

• Findings – 40% of patients with more than 16 years of education achieved disability-free recovery, compared to only ~10% of those with fewer than 12 years.

• Conclusion – Cognitive reserve is a crucial factor influencing how well the brain adapts and recovers after trauma.

What are the types of brain scanning and techniques ?

• fMRI

• EEG

• ERP’S

• Post-morterm examinations

fMRI 

• Highlights active areas of the brain

• Detects changes in blood oxygenation and flow linked to neural activity

• More active areas consume more oxygen, so blood flow increases to that region

• Produces a 3D image showing which brain areas are involved in specific mental processes

What is EEG and how does it work?

• Records electrical activity in the brain via electrodes on the scalp

• Measures overall brainwave patterns generated by neurons

• Useful for detecting abnormalities (e.g., epilepsy, sleep disorders)

• Provides high temporal resolution but poor spatial resolution

What are ERPs (Event-Related Potentials) and how do they work?

• A type of EEG that isolates brain activity in response to specific stimuli/events

• Uses statistical averaging to filter out background brain activity

• Identifies types of cognitive processing (e.g., attention, memory)

• High temporal resolution, but requires many trials and skilled analysis

What are post-mortem examinations and how do they work?

• Analysis of the brain after death

• Can link structural abnormalities/damage to observed behaviours or conditions in life

• Provided early foundations for understanding brain function (e.g., Broca’s area)

• Limited as the brain may be affected by death and does not show activity in real time

Strength of fMRI ?

• Risk-free – does not rely on radiation, unlike some other scanning techniques

• Safe for repeated use in participants

• High spatial resolution – produces detailed images by the millimetre

• Provides a clear and accurate picture of how brain activity is localised

Limitation of fMRI ?

• Very expensive compared to other brain-scanning techniques

• Poor temporal resolution – ~5 second lag between neural activity and image

• May not accurately reflect moment-to-moment brain activity