UNIT 1 - TOPIC 1

What is the mind-versus-body problem?

It asks: "is the mind a separate entity from the body and the brain?"

Materialist approach

Claudius Galen. It states that the mind is not separate from the body and the brain. It views the mind as a result of physical interactions between neurons.

Dualistic approach

Rene Descartes. It states that the mind is separate from the body and the brain. It views the mind as our subjective experience (moral values, cultural experience etc.) and is non-physical or non-material like the body.

How did Claudius Galen prove the materialist approach?

He performed experimental surgeries on animals. He wanted to demonstrate that speech was controlled by the brain (and hence the mind) For example, in pigs, he cut the laryngeal cord that controls the vocal cords and the pigs could no longer squeal. He concluded that the mind/brain controls all muscle movements.

How did Rene Descartes support the dualistic approach?

He believed that one's thoughts and feelings ("I think") must be observed because they make us exist in our world ("therefore I am"). He also believed that after death, the physical body dies but the soul (synonymous to the mind) continues to exist.

Phrenology

Franz Gall in 1796. He believed that mental abilities and personality were controlled by 27 (now 37) specific brain organs based on shape (lumps, bumps, indentations), and that the size of each brain organ was determined by how much it was used. The shape was detected by an electric-powered device with 32 probes called a psychograph. It was invented by Henry Lavery and Frank White in 1931. However, Barnum effect could have been caused?

What is included in experimental neurosurgery?

Ablation

Corpus callosotomy

Electrical stimulation of the brain (ESB)

Ablation

Pierre Flourens in the 1820s. It involves destroying or removing a specific area of brain tissue to observe changes in behaviour and cognition. He removed areas of the brain in live animals (mostly rabbits and pigeons) and observed their behaviour and cognition. He discovered that the main areas of the brain had different functions (cerebellum → balance and motor coordination, cerebral cortex → perceptions, motor control and judgment).

ESB

Wilder Penfield in the 1930s. In epileptic patients, he performed the Montreal procedure. It involved a device that sent a mild electrical impulse through a probe to map the functions of various areas of the brain. And, he mapped the brain using ESB by asking patients how they felt (sensory or motor) to avoid damaging healthy parts. This map is called the cortical homunculus. He discovered that the left somatosensory cortex controlled sensation on the right side of the body and vice versa.

What is Positron Emission Tomography (PET)?

It is a neuroimaging technique that measures metabolic processes through blood flow and glucose consumption. It helps show the parts of the brain in action and how it reacts to drugs. It also helps to assess any functional changes in the brain for diseases that are neurodegenerative (alzheimer's, parkinson's) and also schizophrenia. It helps us understand how brain activity changes with mental illness and drug use, linking brain function to behaviour and emotion.

What is Magnetic Resonance Imaging (MRI)?

It is a neuroimaging technique that provides detailed images of brain structure using magnetic fields and radio waves. It detects structural changes associated with cognitive difficulties and volume changes associated with neurodegenerative diseases. It also assesses the impact of traumatic experiences, behavioural interventions, and treatments on brain structures. It helps us see how changes in brain structure relate to memory problems, thinking, and emotional disorders.

What is Functional Magnetic Resonance Imaging (fMRI)?

It is a neuroimaging technique that shows the parts of the brain in action using magnetic fields, radio waves, blood flow and oxygen consumption. It shows the parts of the brain in action during mental processes such as thinking, calculating, and watching a video or a film. It helps us understand which brain areas are active during different cognitive tasks and emotional responses.

What is Electroencephalography (EEG)?

It is a neuroimaging technique that records electrical activity in the brain using electrodes placed on the scalp. It detects change in brain function related to head injuries, epilepsy, consciousness and sleep. It helps us study awareness, sleep, seizures, and how these states affect behaviour and brain function.

What does the nervous system do and include?

It transmits electrical and chemical signals between the brain and the spinal cord, and coordinates actions by sending messages through neurons to specific body parts. It includes Central Nervous System (CNS) and Peripheral Nervous System (PNS).

What is the CNS?

The command centre of the nervous system. t processes information and controls all activities in the body - both voluntary and involuntary. It includes brain and spinal cord. The brain processes sensory information, thoughts and emotions, and controls body functions. The spinal cord sends instructions from the brain to the body and carries sensory information back to the brain. It also coordinates reflexes.

What is the PNS?

It is made up of all the nerves outside the CNS. These nerves branch out from the CNS to all body parts. It receives and sends signals between the body parts and the CNS. It includes Somatic nervous systems (SNS) and Autonomic nervous systems (ANS). The SNS controls voluntary movements. The ANS regulates involuntary movements.

What is the autonomic nervous system (ANS) made up of?

Sympathetic nervous systems - It prepares for stressful/emergency situations - "fight or flight" (not freeze as parasympathetic is mostly freeze)

Parasympathetic nervous systems - It helps relax and recover from stress (responsible for homeostasis and freeze response)

Cell body (soma) structure

Largest part of the neuron containing the nucleus that controls the metabolism and maintenance of the neuron.

Sensory neuron function

Carries sensory information from the body and environment to the CNS

Sensory neuron direction

Afferent (into CNS)

Motor neuron function

Carries messages from CNS to muscles to produce movement

Motor neuron direction

Efferent (away from CNS)

Interneuron function

Transmits information between sensory and motor neurons within the CNS as part of a reflex arc.

Interneuron example

Relaying a reflect signal to pull hand away from a hotplate

What three discrete areas can the brain be viewed as?

1. Hindbrain

2. Midbrain

3. Forebrain

What does the hindbrain do?

It supports bodily functions that are voluntary and involuntary. It is important for movement and balance.

What does the midbrain do?

It supports arousal levels, consciousness and the coordination of movement.

What does the forebrain do?

It supports higher order thinking.

What is the hindbrain made up of?

It contains the medulla, pons and cerebellum.

What is the midbrain made up of?

It includes part of the reticular formation.

What is the forebrain made up of?

It contains the cerebral hemispheres (collectively the cerebrum), hypothalamus and thalamus.

Lobes diagram

What does the temporal lobe do and what does it include?

hearing and language, and includes the primary auditory cortex

What does the occipital lobe do and what does it include?

vision, and includes the primary visual cortex

What does the parietal lobe do and what does it include?

touch, non-verbal thought and spatial orientation, and includes the primary somatosensory cortex

What does the frontal lobe do and what does it include?

abstract thought, social skills and planning, and includes the primary motor cortex

Where is Broca's area, Wernicke's area, and Geschwind's territory located?

Where is the Broca's area located?

frontal lobe near the primary motor cortex

Where is the Wernicke's area located?

temporal lobe near the primary auditory cortex

Where is the Geschwind's territory located?

Parietal lobe between Broca's and Wenicke's areas

What does the Broca's area do?

It controls speech production by coordinating the movements of muscles (e.g. lips, tongue, vocal cords).

What does the Wernicke's area do?

It is responsible for language comprehension - understanding the meaning of spoken and written words. It allows us to form grammatically correct speech.

What does the Geschwind's territory do?

It connects the areas through nerve fibres, helping us understand and produce meaningful language. It uses multimodal neurons to link the sound, look, and meaning of words. It is essential for abstract thinking and classification of concepts.

Example of Broca's area, Wernicke's area, and Geschwind's territory working together

When a word is heard, the primary auditory cortex in the temporal lobe processes the sound. Then, the signal is sent to Wernicke's area, where the word's meaning is interpreted. The meaning is passed through Geschwind's territory, which links word meaning with its sound and visual form. Then, it travels to Broca's area, which plans and coordinates the muscle movements for speech. Finally, the primary motor cortex then activates the relevant muscles to speak the word.