Week 12: Anatomy of the Central nervous system Flashcards
Where has been greatest growth in evolution of brain?
Vison, memory, speech, motor of hand
Rostral
- towards forehead, towards apex
Caudal
Towards occipital lobe, feet, spinal cord
Medulla Oblongata
Breathing - chemoreceptors in carotid body - sends signal here. Reflexes - vomiting, coughing, sneezing, swallowing - motor neurons responsible for mevment of pharynx and tongue. CV funciton - BP and HR
Proreptiliean
Brainstem and hypothalamus = vital funcitons, reliable, instinctive
Pons
Consciousness - regulating wakefulness. Origins of several cranial nerves and large nerve tracts - control voluntary movement
Pons lesions
On motor tracts = locked-in syndrome
Midbrain
Defensive behaviors (fight or flight), Head orienting reflexes (owards visual stimuli - see potentially threatening things), integration of complex movement
Parkinson’s disease
Destruction of substantia nigra
Where specifically are defensive behaviours controlled
Periaqueductal gray matter (midbrain) - integrates motor responses, CV responses, analgesia
Where specifically are head-orienting reflexes controlled
Superior colliculus - columns of neurons respond to specific parts of 3D space
Diencephalon parts (+function)
Thalamus - process sensory information on the way to cortex
Hypothalamus - homeostatic mechanisms
Sub-thalamus - complex movements.
Epithalamus - circadian rhythm
Paleomammalian
Limbic system - early mammalian brains - memories of behaviours as agreeable or disagreeable, responsible for emotions
Limbic brain structures
Hippocampus, amygdala, hypothalamus, cingulate cortex and prefrontal cortex
What does the limbic system process?
Emotions (fear, aggression, pleasure) - records them and integrates them with a motivational system - shapes behaviours to incoming stimuli - based on instincts and past experiences
Amygdala funciton
Responsible for perception of emotions - fear, anger, sadness - sexual acTIVITY AND LIBIDO
Amygdala - lesions
failure to recognise fearful faces, absence of fear during exposure to life-threatening traumatic events
Neocortex
development of language, abstract thought, imagination and conciousness
Occipital lobe
Entire lobe = processing visual information.
Info is retinotopically organised - i.e. one part of visual field is processes in specific part
Parietal lobe
Processes somatosensory information. Language related = ventral portion
Parietal damage
highly complex and unusual - inability to recognise different fingers, inability to write, disturbances in awareness of body image
Primary somatosensory cortex
pOSTCENTRAL GYRUS.
Parietal association cortex dammage can result in
contralateral neglect syndrome
Frontal lobe
Processes motor information, speech related function in ventral portion - rest n multi-sensory info - emotional expression, problem solving, memory, language, judegment
Primary motor cortex
Pre-central gyrus
Frontal lobotomy
1940s, mental illness - reduced tension/adgitation, passivity, lack of initiative, poor conc, depresed depth and intensity of emotions
Temporal lobe
processes auditory information - region in lateral vfissure . Medial temporal lobs - vital for long term memory = hippocampus
LESIONS IN HIPPOCAMPUS
Anterograde amnesia; loss of ability to form new memories, althouh older memories may be safe
Insular lobe
located in deep lateral fissure - processes sensory info from inside body. processes taaste, visercal sens, body temp, pain - integrates with emotions
Lesions to insular lobe
cant taste, emotional disturbances
