What is the brain at its most basic sense?
It is mainly a tube of tissue (neural tube) filled with cerebrospinal fluid. Its outer part is crinkled tissue (neocortex) with the folds being gyri and creases sulci. Large suli are fissures (like the longitudinal fissure dividing the two hemispheres and the lateral fissure dividing those in half. Commissures connect the brains hemispheres.
What are the different parts of the neural tube?
- Forebrain - mediates higher/executive functioning
- Brainstem - mediates regulatory functioning like eating/moving.
- Spinal cord - conveys sensory information to the brain and sends information from the brain for the muscles to move.
What is the central nervous system?
Made up of the brain and spinal cord, it connects to the rest of the body via nerve fibers that bring information to and away from the CNS.
What is the peripheral nervous system?
The nerve fibers that share information between the CNS and the rest of the body. The nerve fibers here can regenerate unlike those in the CNS. It is divided into two parts, the somatic and autonomic nervous systems
What are the different parts of the PNS?
- SNS - senses and responds to the external world
- ANS - senses and responds to the body’s organs
> Both have a sensory (connect the sensory receptors) and motor (connect to our muscles and allow response) division.
How is the sensory division of the SNS organised?
Into sensory pathways which are collections of fibers that carry messages from different senses. They carry information collected on one side of the body mainly to the cortex in the opposite hemisphere.
How is the motor division of the SNS organised?
Into motor pathways that produce various movements
How are the sensory and motor pathways of the ANS organised?
They influence the muscles of internal organs like the beating of the heart. They have fewer connections with the CNS, so we have less control over our body’s organs.
What might support the idea that living things are related?
Darwin and Wallace examined many similarities of the structures of living things and their behaviour and suggested that it may be because of animals having a common ancestor
What is a species?
A group of organisms that can breed among themselves
Who discovered genes?
Mendel after experimenting with plant traits; later also determining that environment plays a role which would lead to epigenetics.
What explains epigenetics?
The theory of neuroplasticity where adaptation and learning are due to the brain being able to form new connections and pathways; it also explains how the brain compensates for injury.
Who was Gall and Spurzheim?
Gall and Spurzhem proposed that the cortex and gyri were functioning parts of the brain and not just coverings of the pineal body; discovered where the corticospinal motor pathway leads the cortex of each hemisphere to the opposite side of the body > cortex sends instructions to the spinal cord for movement.
What is the localisation of function?
Gall’s hypothesis which suggested that different parts of the brain had different functions. Individual differences were then connected to head/skull differences to propose the theory. This led to phrenology.
What were the consequences of phrenology?
It was used as a way of making personality assessments (cranioscopy); it was a flop scientifically however as superficial features reveal little on the brain, however it did highlight brain localisation.
What did Bouillaud suggest?
He argued that speech localised and that certain behaviours are lateralised > Auburtin made his dicoveries public. Broca picked this up, researched it and published findings on lateralisation of language on the left hemisphere > Broca’s area and Broca’s aphasia
Who was Wernicke?
He created the first model of how the brain produces language via the auditory cortex connecting to Broca’s area > Wernicke’s area and Wernicke syndrome where people hear but can not repeat; different to Broca as patients could still understand.
What did Wernicke predict?
Conduction aphasia: where the fibres connecting the speech areas are cut leading to one being unable to repeat what was heard > suggested brain areas are interdependent despite localisation
Why is disconnection important in neuropsychology?
- It predicts that complex behaviours are built up in an assembly line fashion of information
- Damage to connecting pathways is similar to damage to the actual structure
What did Flourens and Goltz find?
By experiments with dogs, they determined that many functions are distributed in the brain and that the brain allows recovery of function
What did Hughlings-Jackson discover?
The concept of hierarchical organisation where information is processed serially and organised functionally hierarchical > the nervous system having 3 levels respectfully (spinal cord, brainstem and forebrain).
What did Scoville discover from H.M?
That there are multiple memory systems as H.M could not maintain new memories.
What did the D.F. case highlight?
That we process things more unconsciously than we thought and that the ventral stream mediates actions controlled by conscious visual perception, with the dorsal mediating unconscious visual processes.
