Brainstem: Midbrain - nikolai.lazarov.pro
... Midbrain – general features location – between forebrain and hindbrain the smallest region of the brainstem – 6-7g the shortest brainstem segment ~ 2 cm long ...
... Midbrain – general features location – between forebrain and hindbrain the smallest region of the brainstem – 6-7g the shortest brainstem segment ~ 2 cm long ...
Eye Movements - Center for Neural Science
... Primates, for example, have a highly specialized central region of the retina known as the fovea. The fovea can gather visual information from only 18 of the visual world, but the photoreceptors in the fovea are packed at high density, permitting high resolution. High resolution would be useless, ho ...
... Primates, for example, have a highly specialized central region of the retina known as the fovea. The fovea can gather visual information from only 18 of the visual world, but the photoreceptors in the fovea are packed at high density, permitting high resolution. High resolution would be useless, ho ...
NA EXAM 3 (May 2001)
... auditory perception and reflexes (acoustic startle response) and is laminated, where neurons of lamina are sensitive to specific frequencies. Other nuclei, such as the external nucleus, may be important for acousticomotor function. The inferior colliculus projects to the medial geniculate nucleus of ...
... auditory perception and reflexes (acoustic startle response) and is laminated, where neurons of lamina are sensitive to specific frequencies. Other nuclei, such as the external nucleus, may be important for acousticomotor function. The inferior colliculus projects to the medial geniculate nucleus of ...
Visual signals in the dorsolateral pontine nucleus of the alert
... response was related to the size of the test spot stimulus. For a 1.7 deg test spot moving at about 0.4 Hz + 10 deg, the amplitude of the burst was 283 spikes/s (Fig. 1A). When a 0.6 deg test spot was moved at the same frequency and amplitude, the cell exhibited a peak discharge rate of 176 spikes/s ...
... response was related to the size of the test spot stimulus. For a 1.7 deg test spot moving at about 0.4 Hz + 10 deg, the amplitude of the burst was 283 spikes/s (Fig. 1A). When a 0.6 deg test spot was moved at the same frequency and amplitude, the cell exhibited a peak discharge rate of 176 spikes/s ...
Descending Tracts
... Fibers descend in the corona radiata, then through the anterior two-thirds of the posterior limb of the internal capsule down to the brainstem. In the medulla, fibers collect together to form the medullary "pyramid". In the lower medulla, pyramidal fibers take one of three courses: 1. 90% of the fib ...
... Fibers descend in the corona radiata, then through the anterior two-thirds of the posterior limb of the internal capsule down to the brainstem. In the medulla, fibers collect together to form the medullary "pyramid". In the lower medulla, pyramidal fibers take one of three courses: 1. 90% of the fib ...
the brainstem control of saccadic eye movements
... bottom panel shows the activity of the same cell during and after a leftward saccade. The motor neuron discharges at a constant rate during fixation, generates a burst before and during the rightward saccade, and stabilizes at a higher, tonic rate during the postsaccadic fixation. c | Plot of the ra ...
... bottom panel shows the activity of the same cell during and after a leftward saccade. The motor neuron discharges at a constant rate during fixation, generates a burst before and during the rightward saccade, and stabilizes at a higher, tonic rate during the postsaccadic fixation. c | Plot of the ra ...
Physiology of the Striate Cortex
... • Map of the visual field onto a target structure (retina, LGN, superior colliculus, striate cortex) - overrepresentation of central visual field • Discrete point of light: Activates many cells in the target structure • Perception: Based on the brain’s interpretation of distributed patterns of activ ...
... • Map of the visual field onto a target structure (retina, LGN, superior colliculus, striate cortex) - overrepresentation of central visual field • Discrete point of light: Activates many cells in the target structure • Perception: Based on the brain’s interpretation of distributed patterns of activ ...
Branching Thalamic Afferents Link Action and Perception
... the thalamus. For some cortical areas, such as primary visual or somatosensory areas (V1, S1), this thalamic input is seen to dominate the functional properties of the cortical cells. These thalamocortical afferents pass to the cortex the main, “driving input”1 that the thalamic relay cells receive ...
... the thalamus. For some cortical areas, such as primary visual or somatosensory areas (V1, S1), this thalamic input is seen to dominate the functional properties of the cortical cells. These thalamocortical afferents pass to the cortex the main, “driving input”1 that the thalamic relay cells receive ...
9.14 Questions on chapter 1 of Brain Structure and Its
... 10) The limbic system is characterized by close interconnections with what portion of the upper brainstem? 11) Olfactory input dominated the ancient chordate endbrain, the predecessors of the limbic endbrain structures of mammals. This input was most likely important for two different types of learn ...
... 10) The limbic system is characterized by close interconnections with what portion of the upper brainstem? 11) Olfactory input dominated the ancient chordate endbrain, the predecessors of the limbic endbrain structures of mammals. This input was most likely important for two different types of learn ...
Studies of the Role of the Paramedian Pontine Reticular Formation
... burst neurons in head-restrained monkeys, and (2) reversible inactivation techniques confirmed the traditional view of the importance of PPRF in the control of horizontal eye movements. Reversible inactivation of neurons in the vicinity of identified short-lead burst neurons produced dramatic reduct ...
... burst neurons in head-restrained monkeys, and (2) reversible inactivation techniques confirmed the traditional view of the importance of PPRF in the control of horizontal eye movements. Reversible inactivation of neurons in the vicinity of identified short-lead burst neurons produced dramatic reduct ...
The Motor System of the Cortex and the Brain Stem
... to the spinal cord. It serves postural control and balance, acting on the anti-gravity muscles of the arms and legs. Pontine reticulospinal tract is uncrossed, descends the length of the spinal cord and has direct monosynaptic excitatory inputs on motor neurons innervating anti-gravity muscles of th ...
... to the spinal cord. It serves postural control and balance, acting on the anti-gravity muscles of the arms and legs. Pontine reticulospinal tract is uncrossed, descends the length of the spinal cord and has direct monosynaptic excitatory inputs on motor neurons innervating anti-gravity muscles of th ...
Projections from the superior temporal sulcus to the agranular frontal
... necessary for producing accurate visually guided saccades, but it appears to play an important role in learning conditional oculomotor responses, in encoding saccades relative to an object centred frame of reference, or in monitoring the consequences of eye movements as part of a brain's supervisory ...
... necessary for producing accurate visually guided saccades, but it appears to play an important role in learning conditional oculomotor responses, in encoding saccades relative to an object centred frame of reference, or in monitoring the consequences of eye movements as part of a brain's supervisory ...
Design Features in Vertebrate Sensory Systems
... regional specializations consisting of preferential accumulations of particular subclasses of receptors in specific regions of the receptor sheet. This occurs in the retina where cones accumulate in the foveas of primates or specific subclasses of cones accumulate in the red and yellow retinal field ...
... regional specializations consisting of preferential accumulations of particular subclasses of receptors in specific regions of the receptor sheet. This occurs in the retina where cones accumulate in the foveas of primates or specific subclasses of cones accumulate in the red and yellow retinal field ...
The Optokinetic Uncover TestA New Insight Into Infantile Esotropia
... JAMA Ophthalmol. 2013;131(6):759-765. doi:10.1001/jamaophthalmol.2013.2348 ...
... JAMA Ophthalmol. 2013;131(6):759-765. doi:10.1001/jamaophthalmol.2013.2348 ...
Engines of the brain
... will activate a corresponding “reward expectation” via striosomes. Striosomes will then inhibit SNc as a function of that expected reward. iii) SNc feedback → matrisomes & striosomes (learning): In addition to input from striosomes just described, SNc receives input from the environment conveying “g ...
... will activate a corresponding “reward expectation” via striosomes. Striosomes will then inhibit SNc as a function of that expected reward. iii) SNc feedback → matrisomes & striosomes (learning): In addition to input from striosomes just described, SNc receives input from the environment conveying “g ...
On the importance of the transient visual response in the superior
... [9,11,39,40]. This phenomenon also occurs in cortex, because visual responses in area V4 [41] and frontal eye field [42], particularly the transient component, also diminish with repetition. This type of decrement is not overcome by the stimulus being the target of a saccade [42]. Possibly owing t ...
... [9,11,39,40]. This phenomenon also occurs in cortex, because visual responses in area V4 [41] and frontal eye field [42], particularly the transient component, also diminish with repetition. This type of decrement is not overcome by the stimulus being the target of a saccade [42]. Possibly owing t ...
Visual Dysfunction in Brain Injury
... Superior Colliculus organizing ambient visual spatial process Feed-forward to 99% of the cortex Function for early spatial context for fusion Match with sensorimotor information Receives primary input from brainstem, cerebellum, vestibular system, occipital cortex, thalamus Provides output to occipi ...
... Superior Colliculus organizing ambient visual spatial process Feed-forward to 99% of the cortex Function for early spatial context for fusion Match with sensorimotor information Receives primary input from brainstem, cerebellum, vestibular system, occipital cortex, thalamus Provides output to occipi ...
The visual-oculomotor striatum of the cat: functional relationship to
... in the current analysis is more extensive than reported in previous studies of the caudate nucleus (see Mengual et al. 1999 for a review). The intralaminar as well as several motor-related nuclei have been labeled in most of these earlier studies (as well as in ours), so it is the additional widespr ...
... in the current analysis is more extensive than reported in previous studies of the caudate nucleus (see Mengual et al. 1999 for a review). The intralaminar as well as several motor-related nuclei have been labeled in most of these earlier studies (as well as in ours), so it is the additional widespr ...
Neural Control of Eye Movements
... Donder’s and Lis3ng’s Laws of Torsion • Donder’s Law - Each gaze direcDon has a unique torsional posture, no maeer what path the eye took to get there. • Lis3ng’s Law – Any eye posiDon can be described by rotaDon of the eye from primary posiDon about a single axis lying in a specific fronto-pa ...
... Donder’s and Lis3ng’s Laws of Torsion • Donder’s Law - Each gaze direcDon has a unique torsional posture, no maeer what path the eye took to get there. • Lis3ng’s Law – Any eye posiDon can be described by rotaDon of the eye from primary posiDon about a single axis lying in a specific fronto-pa ...
Link
... threshold. This mask retained the structural information of the T1weighted image and could be utilized for defining normalization parameters. The anatomical images were normalized to a voxel size of 1*1*1 mm. Functional EPIs were corrected for acquisition delay and co-registered to the original T1-w ...
... threshold. This mask retained the structural information of the T1weighted image and could be utilized for defining normalization parameters. The anatomical images were normalized to a voxel size of 1*1*1 mm. Functional EPIs were corrected for acquisition delay and co-registered to the original T1-w ...
MirrorBot Report 6
... place on cortical surface, our model provides a battery of orientation selective filters2, all having the same size, computed according to eccentricity, i.e. according to the ``abscissa'' of the neuron on the cortical sheet (cf. right part of figure 1.4). Orientations of the filters for a specific c ...
... place on cortical surface, our model provides a battery of orientation selective filters2, all having the same size, computed according to eccentricity, i.e. according to the ``abscissa'' of the neuron on the cortical sheet (cf. right part of figure 1.4). Orientations of the filters for a specific c ...
Cerebellum
... afferents to the pontine nuclei arise in the cerebral cortex (M1, S1, SMA, PM and areas 5, 7 of the parietal cortex). All of these areas are, in various ways, active during or before movements. Presumably, the cerebellum thus receives information about movements that are being planned and about the ...
... afferents to the pontine nuclei arise in the cerebral cortex (M1, S1, SMA, PM and areas 5, 7 of the parietal cortex). All of these areas are, in various ways, active during or before movements. Presumably, the cerebellum thus receives information about movements that are being planned and about the ...
Subcortical loops through the basal ganglia
... competing priorities between functional systems represented at cortical and subcortical levels has widespread and profound implications for our understanding of the general issue of behavioural choice. Basal ganglia: connectional architecture The basal ganglia have two primary input ports: the stria ...
... competing priorities between functional systems represented at cortical and subcortical levels has widespread and profound implications for our understanding of the general issue of behavioural choice. Basal ganglia: connectional architecture The basal ganglia have two primary input ports: the stria ...
PDF
... fields do not move when the eyes move [Sl’]. These two areas would therefore seem to form a processing stage immediately before the body-part-centered visual receptive fields in PMv. Another route by which spatial information might reach premotor cortex and guide movement is through parietal areas P ...
... fields do not move when the eyes move [Sl’]. These two areas would therefore seem to form a processing stage immediately before the body-part-centered visual receptive fields in PMv. Another route by which spatial information might reach premotor cortex and guide movement is through parietal areas P ...
Superior colliculus
The superior colliculus, (Latin, upper hill) is a paired structure of the mammalian midbrain. In other vertebrates this is known as the optic tectum or simply tectum, and the adjective tectal may also be used. The superior colliculus forms a major component of the midbrain. The tectum is a layered structure, with a number of layers that varies by species. The superficial layers are sensory-related, and receive input from the eyes as well as other sensory systems. The deep layers are motor-related, capable of activating eye movements as well as other responses. There are also intermediate layers, with multi-sensory cells and motor properties.The general function of the tectal system is to direct behavioral responses toward specific points in egocentric (""body-centered"") space. Each layer of the tectum contains a topographic map of the surrounding world in retinotopic coordinates, and activation of neurons at a particular point in the map evokes a response directed toward the corresponding point in space. In primates, the superior colliculus has been studied mainly with respect to its role in directing eye movements. Visual input from the retina, or ""command"" input from the cerebral cortex, create a ""bump"" of activity in the tectal map, which, if strong enough, induces a saccadic eye movement. Even in primates, however, the tectum is also involved in generating spatially directed head turns, arm-reaching movements, and shifts in attention that do not involve any overt movements. In other species, the tectum is involved in a wide range of responses, including whole-body turns in walking rats, swimming fishes, or flying birds; tongue-strikes toward prey in frogs; fang-strikes in snakes; etc.In some vertebrates, including fish and birds, the tectum is one of the largest components of the brain. In mammals, and especially primates, the massive expansion of the cerebral cortex reduces the tectum (""superior colliculus"") to a much smaller fraction of the whole brain. It remains nonetheless important in terms of function as the primary integrating center for eye movements.Note on terminology: This article follows terminology established in the literature for the analogous structure in mammals/non-mammals (see above), using the term ""superior colliculus"" when discussing mammals and ""optic tectum"" when discussing either specific non-mammalian species or vertebrates in general.