Anatomy of the brain

Where does the spinal cord start and end?

medulla oblongata to conus medullaris (L1/2)

What does the cerebrum contain?

Cerebral cortex

Basal ganglia

Limbic system

What divides the 2 cerebral hemipsheres?

falx cerebri

What does the left side of the brain control?

• Right sided motor function

• Right sided sensory function

• Right sided body image

• Right side of visual field

• Bilateral audio

• Speech

• Writing

• Language

What does the right side of the brain control?

• Left sided motor function

• Left sided sensory function

• Left sided body image

• Left side of visual field

• Bilateral audio

• Spatial perception

• Facial recognition

Premotor cortex function

• Planning and co-ordination

• Sequential movements

• Supplementary motor cortex

• Postural movements

Primary motor cortex function

• Voluntary, skilled movements of skeletal muscle
• Somatotropic organisation

Prefrontal cortex function

• Higher cortical functions
• Decision-making, problem-solving, planning, organisation, motivation, emotional regulation

Broca’s area function

• Dominant hemisphere
• Production of language

Where is the primary motor cortex located?

within the precentral gyrus

& It gives rise to 60% to 80% of the corticospinal tract (CST)

Function of the Primary somatosensory cortex (post central gyrus)

• Receives and processes sensory information from the contralateral side of the body

• Localisation of sensation

• Pain, temperature, crude touch

• Fine touch, proprioception

Parietal association cortex function

Superior parietal lobule: Interpretation and integration of sensory input

Inferior parietal lobule: Integration of visual and auditory information from the occipital and temporal lobes (includes angular and supramarginal gyrus)

Spatial orientation

Calculation and language

Location and function of the primary auditory cortex

superior temporal gyrus

Perception of sound

Location and function of the auditory association cortex

middle temporal gurus

Processing and interpretation of auditory information

Wernicke’s area – comprehension of language

Location and function of the primary olfactory cortex/ association cortex

inferior temporal gyrus

Awareness and processing of smell

Function of the hippocampus and amygdala

Learning, memory, emotional regulation

What do Lateral geniculate bodies do?

Take part of the raw information from the outer part of the retina to the visual cortex

What do lingula bodies do?

Gathers general info about the field of vision from the inside half of the retina → depth perception

What does the Primary and secondary visual cortex do?

Primary visual cortex:

Visual perception – receives images from the retina → interprets and transmits the info via the ventral and dorsal streams

→ Ventral stream: takes info to the temporal lobe to interpret the image → object recognition

→ Dorsal stream: takes info about an object’s location to the parietal lobe → interprets the space and shape of objects in the field of vision

Secondary Visual Cortex:

receives information from the primary visual cortex

What is part of the limbic system?

hippocampus, fornix, amygdala

What are some surface contributors to the limbic lobe?

cingulate and parahippocampal gyri

What is the Insula and what does it do?

Forms the floor of the lateral sulcus

Has connections with the neocortex, basal ganglia, thalamus, and limbic system

The anterior insula is a cortical centre for pain

The central region is continuous with the frontoparietal and temporal opercular cortex → language function

The posterior insula is interconnected with the entorhinal cortex, and the amygdala → emotional processes

What are the different cortical connections and what do they do?

Association fibres: interconnect cortical sites lying within one cerebral hemisphere

Commissural fibres: run from one cerebral hemisphere to another

Projection fibres: pass between the cerebral cortex and subcortical structures

What are basal Ganglia and what is their function?

a group of deep, interconnected subcortical nuclei

Function: fine-tune voluntary movements via the thalamus

also involved in higher cortical function: planning and modulation of movement, memory, motivation, reward

what are the 5 pairs of basal nuclei?

1. Caudate nucleus

2. Putamen

3. Globus pallidus: External (GPe) and internal (GPi) segments

4. Subthalamic nucleus

5. Substantia nigra
   – Substantia nigra pars reticulata (SNr)
   – Substantia nigra pars compacta (SNc)

What is the lentiform nucleus composed of?

lateral putamen and medial globus pallidus

What is the striatum composed of?

caudate nucleus, putamen

Describe the basal ganglia blood supply

mainly from the striate branches of the middle cerebral artery

The main branches of the middle cerebral arteries are the lenticulostriate arteries (medial and lateral)

The recurrent artery of Heubner is a branch of the anterior cerebral artery and supplies some of the more anterior aspects of the basal ganglia

Posterior cerebral and posterior communicating arteries supply the substantia nigra and the subthalamic nucleus

What can happen if you have a blockage in one of the arteries supplying the basal ganglia?

lacunar strokes

What causes huntington’s and what are some symptoms?

Hereditary loss of basal ganglia and cortical neurons leads to hyperactive state of involuntary movements called chorea

• uncontrolled movements

• slurred speech

• impaired coordination

• balance problems

What causes Parkinson’s and what are some symptoms?

Degeneration of dopamine secreting neurone on the substantia nigra – progressive and results in slower movement.

• tremor (pill rolling)

• rigidity

• stooped posture

• shuffling gait

• mask face