Landmarks of the brain Flashcards
ILOS
- list divisions and subdivisions and describe how they originated
- describe basic anatomy and functions of the cortex & cerebellum
- subcortical structures anatomy and functions
1st Neuroanatomists
- ancient egyptians
- Renè Descartes (I think, therefore, I am) 1596-1650
- Thomas Willis (wrote first book about brain -cerebri anatome) 1621-1675
Circle of Willis
-circle where INTERNAL CARTOID artery meets MIDDLE CEREBRAL artery meets BASILAR ARTERY
Divisions of the Brain
Forebrain (PROSENCEPHALON)- Telencephalon, Diencephalon
Midbrain (MESENCEPHALON) - Mesencephalon
Hindbrain(RHOMBENCEPHALON) - Metencephalon, Myelencephalon
-Spinal cord
Forebrain: Telencephalon (cerebral hemispheres)
LABELLED DIAGRAM
- cortex
- basal ganglia
- limbic system
Forebrain: Diencephalon
- thalamus
- hypothalamus
Hindbrain:
LABELLED DIAGRAM
- Pons: cerebellum
- Medulla
Cerebrum:
- frontal lobe
- limbic lobe
- central sulcus
- temporal lobe
- parietal lobe
- occipital lobe
Brodmann Areas:
be able to label on diagram
-Area 41,42 - Temperol lobe (hearing)
-Area 44,45 - Broca’s area (language)
-Area 17,18 - occipital lobe (vision)
Korbinian Brodmann 1868-1918
Primary motor cortex (cerebrum)
- located in percentral gyrus ant. to central sulcus
- controls voluntary movement (hands and face)
- works in conjunction with motor planning areas to control movement of body
Motor planning areas
- primary motor cortex
- premotor area (control of trunk)
- supplementary motor area (initiation of movement etc)
- broca’s area (speech-usually left cerebrum)
What is Apraxia?
- unable to perform movements despite intact muscles
- damage to motor planning areas is cause
what is broca’s aphasia?
- impaired speaking and writing
- caused by damage to motor planning areas
Visual cortex
- visual info travels to PRIMARY VISUAL CORTEX (PVC) from retina via thalamus
- PVC discriminates shape, size, location & texture of objects
- information then conveyed to secondary visual cortex (colour, motion)
- on to rest of cortex for response to visual stimulation
Broca’s Area (language):
1861 assigned motor speech to inferior frontal gyrus on left side
- movement involved in speech (face & tongue)
- lesions are associated with expressive aphasia - speech is slow, laboured and telegraphic
Auditory cortex: (Wernicke’s area)
Carl Wernicke (1848-1905)
- located superior temporal gyrus on left hemisphere
- understanding the spoken word
- lesions are associated with receptive aphasia (difficultty understanding speech of others)
Frontal cortex
- highest brain functions (executive function)
- abstract thought, planning, decision making, social behaviour
- uniquely large in humans
Hypofrontality
schizophrenia -ve symptoms
Corpus Callosum
- large band of white matter connecting left and right cerebral hemispheres
- genu, rostrum, trunk (body), splenium
Cerebellum
- anterior lobe
- posterior lobe
Development of the human brain
25days after conception: head end of neural tube shows 3 divisions
50 days: 5 main divisions of the brain are visible
Lesions of VERMIS (tumours in children: medulloblastoma)
-inability to stand upright, nystagmus, impaired eye scanning
Disease of anterior lobe:
- often associated with chronic alcoholism
- staggering drunken gait when sober
Disease of the neocerebellar cortex, superior cerebellar peduncle-
-incoordination of voluntary movements (particularly of upper limb) - action tremor
Basal Ganglia
-important subcortical system which regulates voluntary movement
Basal Ganglia composed of…
- striatum (caudate nucleus & putamen)
- pallidum (internal & external globus pallidus)
- sub thalamic nucleus
Clinical note :Basal Ganglia
- neurons linking the substantia nigra and the striatum (nigrostriatal pathway) use dopamine during motor activity
- degeneration of nigrostriatal dopamine neurons underline motor symptoms in parkinson’s disease
Limbic system
-emotions, memory, appetite, sleep composed of: -cingulate gyrus -fornix -thalamus -stria terminalis -septal nuclei (social behaviour) -amygdala -hippocampus -hypothalamus
Hippocampus: (limbic system)
- learning, memory, mood, response to stress
- converts short term memory to long-term memory
- lesions of this area result in memory impairments
Amygdala (limbic system):
- located in temporal lobe ant. to hippocampus
- mediates feelings of fear, anxiety, social learning
- lesions lead to fearless behaviour, poor social judgement
- associated with PTSD- hightened activation of amygdala
- often smaller in schizophrenia patients and larger in autistic patients
Hypothalamus (limbic system):
- located anterior/inferior to thalamus
- regulates appetite, body temp etc
Reward pathway of limbic system:
- Neural projection from ventral tegmental area to ventral striatum (nucleus accumbens)
- addiction =loss of behavioural control
Ventricular system:
can only be seen in transparent diagrams- central
