scholarly journals Effects of task and coordinate frame of attention in area 7a of the primate posterior parietal cortex

2011 ◽  
Vol 10 (1) ◽  
pp. 12-12 ◽  
Author(s):  
J. B. Rawley ◽  
C. Constantinidis
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Coordinate Frame ◽  
Area 7A ◽  
Posterior Parietal

scholarly journals Neural Representation During Visually Guided Reaching in Macaque Posterior Parietal Cortex

2010 ◽  
Vol 104 (6) ◽  
pp. 3494-3509 ◽  
Author(s):  
Barbara Heider ◽  
Anushree Karnik ◽  
Nirmala Ramalingam ◽  
Ralph M. Siegel
Keyword(s):  
Firing Rate ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Neural Representation ◽  
Eye Position ◽  
Visually Guided ◽  
Task Condition ◽  
Visually Guided Reaching ◽  
Area 7A ◽  
Posterior Parietal

Visually guided hand movements in primates require an interconnected network of various cortical areas. Single unit firing rate from area 7a and dorsal prelunate (DP) neurons of macaque posterior parietal cortex (PPC) was recorded during reaching movements to targets at variable locations and under different eye position conditions. In the eye position–varied task, the reach target was always foveated; thus eye position varied with reach target location. In the retinal-varied task, the monkey reached to targets at variable retinotopic locations while eye position was kept constant in the center. Spatial tuning was examined with respect to temporal (task epoch) and contextual (task condition) aspects, and response fields were compared. The analysis showed distinct tuning types. The majority of neurons changed their gain field tuning and retinotopic tuning between different phases of the task. Between the onset of visual stimulation and the preparatory phase (before the go signal), about one half the neurons altered their firing rate significantly. Spatial response fields during preparation and initiation epochs were strongly influenced by the task condition (eye position varied vs. retinal varied), supporting a strong role of eye position during visually guided reaching. DP neurons, classically considered visual, showed reach related modulation similar to 7a neurons. This study shows that both area 7a and DP are modulated during reaching behavior in primates. The various tuning types in both areas suggest distinct populations recruiting different circuits during visually guided reaching.

Covert attention suppresses neuronal responses in area 7a of the posterior parietal cortex

1994 ◽  
Vol 72 (2) ◽  
pp. 1020-1023 ◽  
Author(s):  
M. A. Steinmetz ◽  
C. E. Connor ◽  
C. Constantinidis ◽  
J. R. McLaughlin
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Potential Role ◽  
Visual Stimuli ◽  
Covert Attention ◽  
Neuronal Responses ◽  
Central Target ◽  
Match To Sample ◽  
Area 7A ◽  
Posterior Parietal

1. The effect of covert attention was studied in area 7a of the posterior parietal cortex of rhesus monkeys performing a spatial match-to-sample task. The task required the animals to fixate a central target light, to detect and remember the location of a transient spatial cue, and to respond when one of a series of stimuli appeared at the cued location. Neuronal responses evoked by the visual stimuli were recorded during each behavioral trial. 2. Thirty-eight percent of the neurons isolated and studied in these experiments responded to visual stimuli. The responses of 55% of the neurons tested were suppressed, and 5% enhanced for stimuli presented at the attended location. Responses in the remaining neurons (40%) were unaffected by shifts in attention. 3. Activity in 57% of the suppressed neurons was reduced to rates not significantly different from spontaneous activity. 4. The extent of suppression for individual neurons was often restricted to the attended portion of the receptive field. 5. These data suggest a potential role for these neurons in the redirection of visual attention.

scholarly journals Speed tuning in the macaque posterior parietal cortex

2017 ◽  
Author(s):  
Eric Avila ◽  
Kaushik J Lakshminarasimhan ◽  
Gregory C DeAngelis ◽  
Dora E Angelaki
Keyword(s):  
Parietal Cortex ◽  
Optic Flow ◽  
Posterior Parietal Cortex ◽  
Potential Role ◽  
Motion Platform ◽  
Neural Recordings ◽  
Motion Speed ◽  
Area 7A ◽  
Posterior Parietal ◽  
Self Motion

ABSTRACTNeurons in the macaque posterior parietal cortex are known to encode the direction of self-motion. But do they also encode one’s speed? To test this, we performed neural recordings from area 7a while monkeys were passively translated or rotated at various speeds. Visual stimuli were delivered as optic flow fields and vestibular stimuli were generated by a motion platform. Under both conditions, the responses of a fraction of neurons scaled linearly with self-motion speed, and speed-selective neurons were not localized to specific layers or columns. We analyzed ensembles of simultaneously recorded neurons and found that the precision of speed representation was sufficient to support path integration over modest distances. Our findings describe a multisensory neural code for linear and angular self-motion speed in the posterior parietal cortex of the macaque brain, and suggest a potential role for this representation.

The role of the posterior parietal cortex in coordinate transformations for visual–motor integration

1988 ◽  
Vol 66 (4) ◽  
pp. 488-501 ◽  
Author(s):  
Richard A. Andersen ◽  
David Zipser
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Visual Stimuli ◽  
Back Propagation ◽  
Spatial Location ◽  
Eye Position ◽  
Area 7A ◽  
Posterior Parietal ◽  
Visual Motor

Lesion to the posterior parietal cortex in monkeys and humans produces spatial deficits in movement and perception. In recording experiments from area 7a, a cortical subdivision in the posterior parietal cortex in monkeys, we have found neurons whose responses are a function of both the retinal location of visual stimuli and the position of the eyes in the orbits. By combining these signals area 7a neurons code the location of visual stimuli with respect to the head. However, these cells respond over only limited ranges of eye positions (eye-position-dependent coding). To code location in craniotopic space at all eye positions (eye-position-independent coding) an additional step in neural processing is required that uses information distributed across populations of area 7a neurons. We describe here a neural network model, based on back-propagation learning, that both demonstrates how spatial location could be derived from the population response of area 7a neurons and accurately accounts for the observed response properties of these neurons.

Electrical Microstimulation Distinguishes Distinct Saccade-Related Areas in the Posterior Parietal Cortex

1998 ◽  
Vol 80 (4) ◽  
pp. 1713-1735 ◽  
Author(s):  
Peter Thier ◽  
Richard A. Andersen
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Parietal Lobe ◽  
Current Strength ◽  
Lateral Intraparietal Area ◽  
Electrical Microstimulation ◽  
Different Types ◽  
Spatially Distributed ◽  
Area 7A ◽  
Posterior Parietal

Thier, Peter and Richard A. Andersen. Electrical microstimulation distinguishes distinct saccade-related areas in the posterior parietal cortex. J. Neurophysiol. 80: 1713–1735, 1998. Electrical microstimulation (0.1-ms bipolar pulses at 500 Hz, current strength usually between 100 and 200 μA) was used to delineate saccade-related areas in the posterior parietal cortex of monkeys. Stimulation-induced saccades were found to be restricted to the lateral intraparietal area (area LIP) in the intraparietal sulcus (IPS) and a region on the medial aspect of the parietal lobe (area MP, medial parietal area), close to the caudal end of the cingulate sulcus, whereas stimulation of area 7a did not evoke eye movements. Two different types of evoked saccades were observed. Modified vector saccades, whose amplitude was modified by the position of the eyes at stimulation onset were the hallmark of sites in area LIP and area MP. The same sites were characterized by a propensity of single units active in the memory and presaccadic response segments of the memory saccade paradigm. Goal-directed saccades driving the eyes toward a circumscribed region relative to the head were largely restricted to a small strip of cortex on the lateral bank and the floor of the IPS (the intercalated zone), separating the representation of upward and downward directed saccades in LIP. Unlike stimulation in LIP or MP, stimulation in the intercalated zone gave rise to head, pinnae, facial, and shoulder movements accompanying the evoked saccades. We propose that the amplitude modification of vector saccades characterizing LIP and MP may reflect a spatially distributed head-centered coding scheme for saccades. On the other hand, the goal-directed saccades found in the intercalated zone could indicate the use of a spatially much more localized representation of desired location in head-centered space.

Posterior parietal cortex mediates encoding processes in change blindness

2009 ◽  
Author(s):  
Philip Tseng ◽  
Cassidy Sterling ◽  
Adam Cooper ◽  
Bruce Bridgeman ◽  
Neil G. Muggleton ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Change Blindness ◽  
Posterior Parietal

The Grasp Cell Hypothesis: Near-miss effect points to common neurological machinery in posterior parietal cortex for controllable objects and concepts

2018 ◽  
Author(s):  
Imogen M Kruse
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Near Miss ◽  
Illusion Of Control ◽  
Gambling Behaviour ◽  
Drug Seeking ◽  
Spatial Influence ◽  
Reward Probability ◽  
Posterior Parietal ◽  
Action Value

The near-miss effect in gambling behaviour occurs when an outcome which is close to a win outcome invigorates gambling behaviour notwithstanding lack of associated reward. In this paper I postulate that the processing of concepts which are deemed controllable is rooted in neurological machinery located in the posterior parietal cortex specialised for the processing of objects which are immediately actionable or controllable because they are within reach. I theorise that the use of a common machinery facilitates spatial influence on the perception of concepts such that the win outcome which is 'almost complete' is perceived as being 'almost within reach'. The perceived realisability of the win increases subjective reward probability and the associated expected action value which impacts decision-making and behaviour. This novel hypothesis is the first to offer a neurological model which can comprehensively explain many empirical findings associated with the near-miss effect as well as other gambling phenomena such as the ‘illusion of control’. Furthermore, when extended to other compulsive behaviours such as drug addiction, the model can offer an explanation for continued drug-seeking following devaluation and for the increase in cravings in response to perceived opportunity to self-administer, neither of which can be explained by simple reinforcement models alone. This paper therefore provides an innovative and unifying perspective for the study and treatment of behavioural and substance addictions.

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