@article {5511, title = {Dissociable neuronal substrates of visual feature attention and working memory}, journal = {Neuron}, volume = {112}, year = {2024}, month = {01/2024}, pages = {850 - 863.e6}, abstract = {

Attention and working memory (WM) are distinct cognitive functions, yet given their close interactions, it is often assumed that they share the same neuronal mechanisms. We show that in macaques performing a WM-guided feature attention task, the activity of most neurons in areas middle temporal (MT), medial superior temporal (MST), lateral intraparietal (LIP), and posterior lateral prefrontal cortex (LPFC-p) displays attentional modulation or WM coding and not both. One area thought to play a role in both functions is LPFC-p. To test this, we optogenetically inactivated LPFC-p bilaterally during different task periods. Attention period inactivation reduced attentional modulation in LPFC-p, MST, and LIP neurons and impaired task performance. In contrast, WM period inactivation did not affect attentional modulation or performance and minimally affected WM coding. Our results suggest that feature attention and WM have dissociable neuronal substrates and that LPFC-p plays a critical role in feature attention, but not in WM.

}, issn = {08966273}, doi = {10.1016/j.neuron.2023.12.007}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0896627323009352}, author = {Diego Mendoza-Halliday and Xu, Haoran and Azevedo, Frederico A.C. and Desimone, Robert} } @article {5512, title = {A ubiquitous spectrolaminar motif of local field potential power across the primate cortexAbstract}, journal = {Nature Neuroscience}, volume = {27}, year = {2024}, month = {01/2024}, pages = {547 - 560}, abstract = {

The mammalian cerebral cortex is anatomically organized into a six-layer
motif. It is currently unknown whether a corresponding laminar motif of
neuronal activity patterns exists across the cortex. Here we report such a
motif in the power of local field potentials (LFPs). Using laminar probes,
we recorded LFPs from 14 cortical areas across the cortical hierarchy in five
macaque monkeys. The laminar locations of recordings were histologically
identified by electrolytic lesions. Across all areas, we found a ubiquitous
spectrolaminar pattern characterized by an increasing deep-to-superficial
layer gradient of high-frequency power peaking in layers 2/3 and an
increasing superficial-to-deep gradient of alpha-beta power peaking in
layers 5/6. Laminar recordings from additional species showed that the
spectrolaminar pattern is highly preserved among primates{\textemdash}macaque,
marmoset and human{\textemdash}but more dissimilar in mouse. Our results suggest
the existence of a canonical layer-based and frequency-based mechanism
for cortical computation.

}, issn = {1097-6256}, doi = {10.1038/s41593-023-01554-7}, url = {https://www.nature.com/articles/s41593-023-01554-7}, author = {Diego Mendoza-Halliday and Major, Alex James and Lee, Noah and Lichtenfeld, Maxwell J. and Carlson, Brock and Mitchell, Blake and Meng, Patrick D. and Xiong, Yihan and Westerberg, Jacob A. and Jia, Xiaoxuan and Johnston, Kevin D. and Selvanayagam, Janahan and Everling, Stefan and Maier, Alexander and Desimone, Robert and Miller, Earl K. and Bastos, Andr{\'e} M.} } @article {4066, title = {Neuronal population coding of perceived and memorized visual features in the lateral prefrontal cortex}, journal = {Nature Communications}, volume = {8}, year = {2017}, month = {June 2017}, type = {Article No. 15471}, abstract = {

The primate lateral prefrontal cortex (LPFC) encodes visual stimulus features while they are perceived and while they are maintained in working memory. However, it remains unclear whether perceived and memorized features are encoded by the same or different neurons and population activity patterns. Here we record LPFC neuronal activity while monkeys perceive the motion direction of a stimulus that remains visually available, or memorize the direction if the stimulus disappears. We find neurons with a wide variety of combinations of coding strength for perceived and memorized directions: some neurons encode both to similar degrees while others preferentially or exclusively encode either one. Reading out the combined activity of all neurons, a machine-learning algorithm reliably decode the motion direction and determine whether it is perceived or memorized. Our results indicate that a functionally diverse population of LPFC neurons provides a substrate for discriminating between perceptual and mnemonic representations of visual features.

}, url = {https://doi.org/10.1038/ncomms15471}, author = {Diego Mendoza-Halliday and Julio Martinez-Trujillo} } @article {4067, title = {Sustained Activity Encoding Working Memories: Not Fully Distributed}, journal = {Trends in Neurosciences }, volume = {40 }, year = {2017}, month = {June 2017}, pages = {328-346}, abstract = {

Working memory (WM) is the ability to remember and manipulate information for short time intervals. Recent studies have proposed that sustained firing encoding the contents of WM is ubiquitous across cortical neurons. We review here the collective evidence supporting this claim. A variety of studies report that neurons in prefrontal, parietal, and inferotemporal association cortices show robust sustained activity encoding the location and features of memoranda during WM tasks. However, reports of WM-related sustained activity in early sensory areas are rare, and typically lack stimulus specificity. We propose that robust sustained activity that can support WM coding arises as a property of association cortices downstream from the early stages of sensory processing.

}, keywords = {working memory sustained activity neurophysiology fMRI primate review}, doi = {https://doi.org/10.1016/j.tins.2017.04.004}, url = {https://www.sciencedirect.com/science/article/pii/S0166223617300711}, author = {Leavitt, M.L. and Diego Mendoza-Halliday and Martinez-Trujillo J.C.} } @inbook {4069, title = {Working Memory Representations of Visual Motion along the Primate Dorsal Visual Pathway}, booktitle = {Mechanisms of Sensory Working Memory: Attention and Performance XXV.}, year = {2015}, publisher = {Elsevier Inc. }, organization = {Elsevier Inc. }, abstract = {

Mechanisms of Sensory Working Memory: Attention and Performance XXV provides an update on the research surrounding the memory processes that are crucial for many facets of cognitive processing and experience, with new coverage of emerging areas of study, including a new understanding of working memory for features of stimuli devoid of verbal, phonological, or long-term memory content, such as memory for simple visual features (e.g., texture or color), simple auditory features (e.g., pitch), or simple tactile features (e.g., vibration frequency), now called sensory memory to distinguish from verbal memory.

This contemporary focus on sensory memory is just beginning, and this collection of original contributions provides a foundational reference for the study mechanisms of sensory memory.

}, issn = {978-0-12-801371-7}, url = {https://www.sciencedirect.com/book/9780128013717/mechanisms-of-sensory-working-memory}, author = {Diego Mendoza-Halliday and Torres, S. and Julio Martinez-Trujillo} } @article {1910, title = {Sharp emergence of feature-selective sustained activity along the dorsal visual pathway}, journal = {Nature Neuroscience}, volume = {7}, year = {2014}, month = {09/2014}, chapter = {1255}, abstract = {

Sustained activity encoding visual working memory representations has been observed in several cortical areas of primates. Where along the visual pathways this activity emerges remains unknown. Here we show in macaques that sustained spiking activity encoding memorized visual motion directions is absent in direction-selective neurons in early visual area middle temporal (MT). However, it is robustly present immediately downstream, in multimodal association area medial superior temporal (MST), as well as and in the lateral prefrontal cortex (LPFC). This sharp emergence of sustained activity along the dorsal visual pathway suggests a functional boundary between early visual areas, which encode sensory inputs, and downstream association areas, which additionally encode mnemonic representations. Moreover, local field potential oscillations in MT encoded the memorized directions and, in the low frequencies, were phase-coherent with LPFC spikes. This suggests that LPFC sustained activity modulates synaptic activity in MT, a putative top-down mechanism by which memory signals influence stimulus processing in early visual cortex.

}, doi = {doi:10.1038/nn.3785}, url = {http://www.nature.com/neuro/journal/v17/n9/abs/nn.3785.html}, author = {Diego Mendoza-Halliday and Santiago Torres and Julio Martinez-Trujillo} } @article {2637, title = {Combined effects of feature-based working memory and feature-based attention on the perception of visual motion direction}, journal = {Journal of Vision}, volume = {11}, year = {2011}, chapter = {11}, author = {Diego Mendoza-Halliday and Megan Schneiderman and Christian Kaul and Julio Martinez-Trujillo} } @article {4065, title = {Combined effects of feature-based working memory and feature-based attention on the perception of visual motion direction}, journal = {Journal of Vision}, volume = {11}, year = {2011}, abstract = {

We investigated whether human subjects{\textquoteright}ability to identify the direction of a brief pulse of coherent motion in a random-dotpattern (RDP) was influenced by: (a) maintaining in working memory the direction of motion of an RDP previously presentedfar from the pulse (feature-based working memory or FBWM,Experiment 1), (b) attending to the direction of an RDPco-occurring with but far from the pulse (feature-based attention or FBA,Experiment 2), and (c) both FBWM and FBA actingsimultaneously (Experiment 3). In thefirst two experiments, pulse direction identification performance was higher when theremembered direction (FBWM) or the direction of the concurrently attended RDP (FBA) matched the pulse direction thanwhen it was opposite. InExperiment 3, performance was highest when both the remembered and the attended directionsmatched the pulse direction (combined effects of FBWM and FBA), it was intermediate when only one of them matched thepulse direction, and it was lowest when neither matched the pulse direction. Our results demonstrate that both feature-based working memory and feature-based attention can individually modulate the perception of motion direction and thatwhen acting together they produce an even larger modulation.

}, keywords = {feature-based attention, motion direction, motion perception, Psychophysics, working memory}, doi = {doi:10.1167/11.1.11}, url = {http://www.journalofvision.org/content/11/1/11}, author = {Diego Mendoza-Halliday and Schneiderman, M. and Kaul, C. and Julio Martinez-Trujillo} }