Introduction - Brookes Flashcards
What are the sections of the brain when sliced?
Coronal (frontal) section
- When sliced downwards
Mid sagittal (medial)
- When sliced down the middle
Horizontal section
- When sliced horizontally
What are the brain orientations?
Superior - Dorsal
- Top of brain
Anterior
- Front of brain
Posterior
- Rear of brain
Inferior - Ventral
- Bottom of brain
Regions of the brain and what they give rise to
Telencephalon (Forebrain)
- Cerebral cortex, basal ganglia, limbic system, olfactory bulbs
Diencephalon (Forebrain)
- Thalamus, hypothalamus, epithalamus (pineal gland).
Telencephalon and Diencephalon are derived from the prosencephalon.
Mesencephalon (Midbrain)
- Tectum, tegmentum, cerebral peduncles
Metencephalon (Hindbrain)
- Pons, cerebellum
Myelencephalon (Hindbrain)
- Medulla oblongata.
Metencephalon and Myelencephalon are derived from the Rhombencephalon.
What are brain ventricles?
There are 4 major freely communicating cerebrospinal fluid (CSF) filled cavities called ventricles
There are 2 lateral ventricles
1 ventricle lies below the 2 lateral ventricles
The fourth ventricle is next to the cerebellum
Enlargement of ventricles is seen in neuropsychiatric disorders
What are the lobes of the brain and their uses?
Frontal (Motor control, decision-making, speech, personality)
Parietal (Sensory processing, spatial awareness, touch)
Occipital (Vision processing)
Temporal (Hearing, memory, language comprehension)
What are the cortices of the brain?
Primary motor cortex (Controls voluntary movement)
Primary somatosensory cortex (Processes touch, pain, temperature)
Primary visual cortex (Processes visual information)
Prefrontal cortex (Decision-making, planning, personality)
What does each hemisphere of the brain have more control over?
Left hemisphere is more geared towards abstract and analytical thought, calculation, and linguistic ability.
Right hemisphere is more important for comprehending spatial patterns and complex sounds like music.
Reduced hemispheric asymmetry is a potential risk factor for schizophrenia
What is the thalamus?
The thalamus is a structure in the middle of the brain
It is the relay site for all sensory information coming into the brain
Receives input from spinal chord afferents (brainstem)
It then provides information to the cortex (outer layer of brain)
The cortex can provide information back to the thalamus via a circuit loop that first synapses in the striatum (this is important in regulating input to the cortex)
What is the reticular activating system?
The reticular activating system is a system that provides non-specific sensory information to the thalamus
What do basal ganglia do and what are they?
They are responsible for extrapyramidal motor control
This is the initiation and fine tuning of movement
They are a set of interconnected nuclei
What are the sections of the basal ganglia?
Caudate nucleus
Putamen
Globus pallidus
Substantia nigra
Caudate + Putamen = Striatum
What is the limbic system?
Interconnected areas that regulate emotions and behaviour
May include:
- Hippocampus
- Fornix
- Mammillary body
- Thalamus
- Cingulate gyrus
- Amygdala
- Ventral striatum
What is the amygdala?
It is a small region located at the end of the hippocampus
It is involved in emotional responses to face recognition
Also involved in reward and addiction
How do we know what the amygdala does?
Urbach-Wiethe disease causes calcium build up in the amygdala resulting in a function lesion of the amygdala
Patients with this bilateral amygdala lesion can not discriminate emotion in facial expressions
What are the three catecholamine neurotransmitters?
Adrenaline
Noradrenaline
Dopamine
Catechol group is the benzene ring with 2 hydroxyl groups
Noradenaline neurones structure and role
Has long axonal tracts, small diameter and is highly branched
All originate from a single nucleus (locus coeruleus)
The locus coeruleus is part of the reticular formation and therefore has a role in arousal
The ascending norandrenaline tracts form the medial forebrain bundle
Innervate limbic regions and areas controlling sensory input
They influence hormone secretion from the pituitary
They have a key involvement in perception, attentional processes, mood and behaviour
What areas of the brain produce dopamine neurones and what affect do they each have?
Originate from three major parts of the brain
1: Substantia nigra (affect motor control)
- Project to striatum via nigrostriatal pathway
2: Ventral tegmental area (affect motor control)
- Projects to nucleus accumbens via mesolimbic pathway
- Projects to cortex via mesocortical pathway
3: Hypothalamus (affect hormone secretion)
- Projects to pituitary via tuberoinfundibular pathway
