Psychobiology WK 2 Structure and Function

CNS

Brain and Spinal Cord

PNS

Somatic and Autonomic Nervous System

Somatic - Motor neurons and sensory Neurons

Autonomic - Sympathetic and Parasympathetic Nervous System

Benefits of Structure knowledge

Treatment e.g. Vagus nerve activation in post-stroke activation therapy

Corticospinal track from motor cortex to skeletal muscles → TMS can trigger voluntary body movement

Brain

2% of body weight

20% of oxygen and calories consumed

High metabolic activation

Brainstem

Oldest part of brain

Manages life support functions (breathing, heartrate etc) unconsciously

Limbic System

Amygdala, Hippocampus, Thalamus

Emotional regulation, hunger, sleep-wake

Highly specialised neural structures

Cerebellum

Mini brain

Manages movement, posture

Higher learning: motor learning

Contains 80% of brain’s total neurons

Cerebral cortex

2 hemispheres split by corpus callosum

Sensory processing and awareness

90% neocortex, split up by 6 layers (grey matter) ~ 2-4mm thick

Contains 15b neurons

Corpus Callosum

Bundle of neurons connecting two hemispheres of cerebral cortex

Anterior

Front of brain

Rostral

Posterior

Back of brain

Caudal

Superior

Top of brain

Dorsal

Inferior

Bottom of brain

Ventral

Medial

Inner brain

Lateral

Side of brain

Gyrus (gyri)

Upper fold

Sulcus (sulci

Inner fold

Superior Temporal Gyrus (STG)

Gyrus in Wernicke’s area, key for language comprehension

Central sulcus

connects the motor and sensory cortex

Lateral sulcus

Between the temporal lobe and rest of the brain

Differences between human brain and animals brain

Similar function, but different connectivity

Animal brains have less folds and volume, especially in frontal cortex

Chimpanzees are closest to humans, then gorillas

Chimpanzees have less thick and extensive Arcuate Fasciculus (then macaques have none)

Paleoneurology

Study of brain of homo habilis (extinct primate)

Quantum leap approach

Explanation for why our brains have evolved so much

A sudden significant change by various periods of time

Frontal lobe

Responsible for self-management, planning, empathy, impulse control, decision-making

Primary Motor Cortex (M1/Brodmann area 4)

Impulse control and memory also impact personality (Phineas Gage)

People with damage in the frontal lobe struggle to gather information and make fast worthy decisions

Occipital lobe

Visual processing - Depth perception, colour, movement

Primary Visual Cortex - Area V1

Visual information received from retina via Lateral Geniculate Nucleus

Information sent to Temporal lobe (associating meaning)

Information sent to Parietal lobe (Discriminating location)

Parietal lobe

Somatosensory processing - Touch, pain, temperature, any sensation on the body

Sent other sensory information from other areas of the brain (e.g. hearing, visual)

Somatosensory cortex (S1) - discriminates between different sensory inputs

Angular Gyrus - word recognition, symbols, maths

Connected/close to Wernicke’s area for speech comprehension

Temporal lobe

Hearing, information received from ears

Primary Auditory Cortex (Area A1)

Wernicke and Broca’s area

Interacts with amygdala and hippocampus (so memory involved)

Primary motor cortex

Responsible for voluntary movement - kissing, moving hands etc

Each part of the body has a part of the brain connected to it

Methods of investigating the brain

Post-morten dissection - e.g. Broca, stroke studies

Animal studies - different size and structure but functional similarities

Neuroimaging - Functional and structual imaging

fMRI

functional Magnetic Resonance Imaging

Measures oxygen levels in brain regions that are most active

PET

Positron Emission Topography

Radioactive substance injected, which is then tracked in brain based on metabolism and more active brain regions

fUI

functional Ultrasound Imaging

Low-frequency ultrasound probe which measures blood flow in major brain arteries