Cerebellum
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- histological
- Leiner et al 1993 - said that the denate nucleus, particularly the ventral region has evolved faster in humans then in monkeys - and that it is histologically different
- White matter
- Jeuptner et al 1997 - suggested that the evoloution of the frontal lobes is mainly in the underlying white matter tracts as opposed to the grey matter of the neocortex
- Zilles et al (1989)
- Suggested that the cerebellum and the frontal lobes have evolved faster then other regions of the brain in humans
- Middleton and Strick 2000
- The cortico-pontine-cerebellar-thalumus system is made up of a series of closed loop modules
- Schmahmann and Pandya 1997
- used an anterograde tracer to track the inputs of the fl into the pontine-cerebellar network - mostly from 46 (dPFC) and 9/45 (vPFC)- but doesnt cross synapses so not the whole way
- Denate connections
- Middleton and Strick 2001 - found that the M1 inputs mainly into dorsal denate nucleus and PFC input mostly into the ventral denate nucleus
- Kelly and Strick 2003
- used a genetically engineered viral, anterograde tracer and found the input from the M1 goes to a particular lobule in the cerebellum and is fed back and the PFC input goes to a different lobule and is fed back
- Ramnani et al 2005
- DTI allows to characterise the inputs into the cerebral peduncle of the human brain - of which the inputs are topographically organised - in macaques as expected the largest input was from the M1 and for humans it was from the PFC- particularly 46.
- Cats
- DeZeeuw - the inferior olive receives both sensory and proprioceptive inputs, and is where climbing fibres originate - signal an event unexpected by sensory input
- Flourens
- Lesioned monkey cerebellum and displayed clinical symptoms of poor coordination of fluid movement - studies like this have helped to establish the textbook conceptualization of the cerebellum as a system for the coordination of movement
- Schmahmann and Pnadya
- Used anterograde tracers from the cortex - the uptake suggesting that the Pontine nucleus gets most of its input from motor areas and parietal - with a bit from the PFCd
- Motor engrams
- Marr 1969 - suggested a physiological model for how thru error based learning and the plasticity of its neural circuits the cerebellum acquires motor engrams - a teaching signal from the climbing fibres alter the synapse between the parallel fibres and purkinje cells
- Schults 1976
- Degeneration studies suggest the cerebral peduncle is topographically organised
- Brodal 1978
- Lesions parts of cortex and showed thru degen that the majority of inputs to the PN are from the M1, PMC and some PFC
- Glickstein 1985
- used a retrograde tracers to see uptake in the cortex from the PN, was mostly M1 and PMC with some PFC
- Only motor
- Glickstein, 1993 suggested that evidence suggests that the cerebellum is purely a motor area !?!?!?
- Tickle
- Blakemore et al 1998 - showed that despite identical tactile stimulation the there was different BOLD activity in the cerebellum in response to self-tickling as opposed to machine
- Von Monokow 1914
- Diachisis - the loss of background excitation form one area leads to the loss of a particular function without that area being associated with that function. The two hemispheres of the cerebellum are contralaterally connected to the hemispheres of the cortex
- Seigfreid et al 1980
- Lesions to the phonogenetically advanced areas of the denate nucleus do not lead to the motor deficits characteristic of cerebellar lesions
- TofH
- Grafman et al 1992 - cerebellar lesions lead to impaired performance in towers of hanoi
- Personality
- Pollack et al 1995 - showed that cerebellar lesions can lead to emo lability and regressive personaltiy changes
- Ramnani and Yeo 1996
- Permenant or temporary inactivations of the cerebellum lead to impairs or abolishes simple/well characterized motor learning
- species difference
- Tucker et al 1997 cerebellar lesions in humans lead to deficits in conditional motor learning whereas in non-human primates it does not - inter-species difference suggests different function
- Schmahmann and Sherman 1998
- cerebellar cognitive affective syndrome - 20 exclusively cerebellar patients and found had lang probs (e.g. agrammatism) exec func probs (e.g. set shift, verb fluency, working mem, abstract thinking) personality probs (disinhibited, blunting of affect) and vis spatial organistation and memory
- Dyslexics
- Nicholson et al 1999 - found dyslexics had problems with balance and coordination
- Stein 2001
- Magnocellular visual system is important for the timing of visual events during reading and the cerebellum plays a role in the timing system - the magnocellular theory of dyslexia
- Miall et al 1985
- Activity in the cerebellum reflects the activity of internal models during motor control
- Rule based word gen
- Petersen and Fiez 1994 - had particpants perform a rule based word gen task and found activity related to motor and cog element were spatially dissociable
- Peg Board
- Kim et al 1994 - had participant do a rule based peg board task in scanner - found 3-4x more activity in lateral denate nucleus for cog component then for simple movement
- Allen et al 1997
- there are over 50% of brains neurons in the cerebellum, yet still commonly held belief that it has a singular functions- despite its receiving input from the pons which contains about 20 million fibres tracts vs the 1 mill of optic or pyramidial tract - did counting task and found motor activity and cognitive activity was dissociable
- Ramnani et al 2000
- the activity in the cerebellum is related to error signals
- Kirschen et al 2005
- did verbal working memory task and as memory load went up so did activity in the cerebellum
- PASAT
- Hayter et al 2007 - PASAT an cognitive task and partialled out mouth move parts to prevent noise - cognitive part led to increased activity in area 46 and lobule VII whereas the motor components led to activity in the M1 and its connected cerebellar lobule
- Ramnani 2006
- suggested that control theory model of cerebellar function can be extended to cognitive control - in that the cerebellum may simulate the processing between the PFC particularly area 46 and its targets in a stimulus specific, rapid, accurate but inflexible way freeing up the PFC for the processing of novel stimulus in a more flexible way
- Balsters and Ramnani 2008
- did a arbitary cue - delayed response task and suggested that activity in crus 1 lobule HVIIA was specific to the processing of information embedded into the arbitary cue as opposed to a different lobule and PMC motor areas for the motor prep