Tim Gastrell
@tgastrell.bsky.social
Kiwi in QLD 🥝 Science nerd 🔭 Computer enjoyer 💻
PhD researcher in Cognitive/Computational Neuroscience 🧠 Studying how the brain leverages experience to support sensory processing and decision-making under uncertainty.
Distractions encouraged.
PhD researcher in Cognitive/Computational Neuroscience 🧠 Studying how the brain leverages experience to support sensory processing and decision-making under uncertainty.
Distractions encouraged.
Reposted by Tim Gastrell
New paper in Imaging Neuroscience by Margaret Jane Moore, Amanda K. Robinson, and Jason B. Mattingley:
Expectation dynamically modulates the representational time course of objects and locations
doi.org/10.1162/IMAG...
Expectation dynamically modulates the representational time course of objects and locations
doi.org/10.1162/IMAG...
November 13, 2025 at 8:51 AM
New paper in Imaging Neuroscience by Margaret Jane Moore, Amanda K. Robinson, and Jason B. Mattingley:
Expectation dynamically modulates the representational time course of objects and locations
doi.org/10.1162/IMAG...
Expectation dynamically modulates the representational time course of objects and locations
doi.org/10.1162/IMAG...
Reposted by Tim Gastrell
The final bit of work from my PhD just got published at JOV! We looked at similarity judgements made for naturalistic image patches, and whether these are predicted by simple image statistics… (spoiler: yep!)
Link to paper: doi.org/10.1167/jov....
1/11
Link to paper: doi.org/10.1167/jov....
1/11
Low-level features predict perceived similarity for naturalistic images | JOV | ARVO Journals
doi.org
October 8, 2025 at 7:13 AM
The final bit of work from my PhD just got published at JOV! We looked at similarity judgements made for naturalistic image patches, and whether these are predicted by simple image statistics… (spoiler: yep!)
Link to paper: doi.org/10.1167/jov....
1/11
Link to paper: doi.org/10.1167/jov....
1/11
Reposted by Tim Gastrell
Just published some work at Scientific Reports! We investigated visual adaptation following free viewing of a film (Casablanca) that had its oriented contrast altered. To our surprise, we found adaptation effects to be pretty negligible…
www.nature.com/articles/s41...
1/10
www.nature.com/articles/s41...
1/10
Investigating orientation adaptation following naturalistic film viewing - Scientific Reports
Scientific Reports - Investigating orientation adaptation following naturalistic film viewing
www.nature.com
September 29, 2025 at 8:27 AM
Just published some work at Scientific Reports! We investigated visual adaptation following free viewing of a film (Casablanca) that had its oriented contrast altered. To our surprise, we found adaptation effects to be pretty negligible…
www.nature.com/articles/s41...
1/10
www.nature.com/articles/s41...
1/10
Reposted by Tim Gastrell
🚨Pre-print of some cool data from my PhD days!
doi.org/10.1101/2025...
☝️Did you know that visual surprise is (probably) a domain-general signal and/or operates at the object-level?
✌️Did you also know that the timing of this response depends on the specific attribute that violates an expectation?
doi.org/10.1101/2025...
☝️Did you know that visual surprise is (probably) a domain-general signal and/or operates at the object-level?
✌️Did you also know that the timing of this response depends on the specific attribute that violates an expectation?
The Latency of a Domain-General Visual Surprise Signal is Attribute Dependent
Predictions concerning upcoming visual input play a key role in resolving percepts. Sometimes input is surprising, under which circumstances the brain must calibrate erroneous predictions so that perc...
doi.org
August 19, 2025 at 12:30 AM
🚨Pre-print of some cool data from my PhD days!
doi.org/10.1101/2025...
☝️Did you know that visual surprise is (probably) a domain-general signal and/or operates at the object-level?
✌️Did you also know that the timing of this response depends on the specific attribute that violates an expectation?
doi.org/10.1101/2025...
☝️Did you know that visual surprise is (probably) a domain-general signal and/or operates at the object-level?
✌️Did you also know that the timing of this response depends on the specific attribute that violates an expectation?
Reposted by Tim Gastrell
My final Registered Report from my PhD is now out in Cortex!
We investigated the role of dopamine & HD-tDCS in mind wandering & sustained attention. While stimulation had no effect, increasing dopamine reduced spontaneous thought and may protect against performance deficits. doi.org/10.1016/j.co...
We investigated the role of dopamine & HD-tDCS in mind wandering & sustained attention. While stimulation had no effect, increasing dopamine reduced spontaneous thought and may protect against performance deficits. doi.org/10.1016/j.co...
On the neural substrates of mind wandering and dynamic thought: A drug and brain stimulation study
The impact of mind wandering on our daily lives ranges from diminishing productivity, to facilitating creativity and problem solving. There is evidenc…
www.sciencedirect.com
July 19, 2025 at 3:16 AM
My final Registered Report from my PhD is now out in Cortex!
We investigated the role of dopamine & HD-tDCS in mind wandering & sustained attention. While stimulation had no effect, increasing dopamine reduced spontaneous thought and may protect against performance deficits. doi.org/10.1016/j.co...
We investigated the role of dopamine & HD-tDCS in mind wandering & sustained attention. While stimulation had no effect, increasing dopamine reduced spontaneous thought and may protect against performance deficits. doi.org/10.1016/j.co...
Reposted by Tim Gastrell
I really like this paper. I fear that people think the authors are claiming that the brain isn’t predictive though, which this study cannot (and does not) address. As the title says, the data purely show that evoked responses are not necessarily prediction errors, which makes sense!
1/3) This may be a very important paper, it suggests that there are no prediction error encoding neurons in sensory areas of cortex:
www.biorxiv.org/content/10.1...
I personally am a big fan of the idea that cortical regions (allo and neo) are doing sequence prediction.
But...
🧠📈 🧪
www.biorxiv.org/content/10.1...
I personally am a big fan of the idea that cortical regions (allo and neo) are doing sequence prediction.
But...
🧠📈 🧪
Sensory responses of visual cortical neurons are not prediction errors
Predictive coding is theorized to be a ubiquitous cortical process to explain sensory responses. It asserts that the brain continuously predicts sensory information and imposes those predictions on lo...
www.biorxiv.org
July 15, 2025 at 11:43 AM
I really like this paper. I fear that people think the authors are claiming that the brain isn’t predictive though, which this study cannot (and does not) address. As the title says, the data purely show that evoked responses are not necessarily prediction errors, which makes sense!
Excited to be presenting behavioral and modeling work looking at perceptual decision making under uncertainty with recently learned priors at the EPC/APCV joint meeting today at UNSW, Sydney!
Catch me at 2:45pm in Gallery 1!
@expsyanz.bsky.social
#epc2025
Catch me at 2:45pm in Gallery 1!
@expsyanz.bsky.social
#epc2025
June 20, 2025 at 2:28 AM
Excited to be presenting behavioral and modeling work looking at perceptual decision making under uncertainty with recently learned priors at the EPC/APCV joint meeting today at UNSW, Sydney!
Catch me at 2:45pm in Gallery 1!
@expsyanz.bsky.social
#epc2025
Catch me at 2:45pm in Gallery 1!
@expsyanz.bsky.social
#epc2025
New paper @ JOV!
With Matt Oxner, Frank Schumann and David Carmel.
🧠 Perception of ambiguous motion is shaped by recent visual experience - but does this differ across the visual field?
Yes!
Full open access paper here (Gastrell et al., 2025, Journal of Vision): 🔗 doi.org/10.1167/jov....
🧵
With Matt Oxner, Frank Schumann and David Carmel.
🧠 Perception of ambiguous motion is shaped by recent visual experience - but does this differ across the visual field?
Yes!
Full open access paper here (Gastrell et al., 2025, Journal of Vision): 🔗 doi.org/10.1167/jov....
🧵
June 4, 2025 at 4:51 AM
New paper @ JOV!
With Matt Oxner, Frank Schumann and David Carmel.
🧠 Perception of ambiguous motion is shaped by recent visual experience - but does this differ across the visual field?
Yes!
Full open access paper here (Gastrell et al., 2025, Journal of Vision): 🔗 doi.org/10.1167/jov....
🧵
With Matt Oxner, Frank Schumann and David Carmel.
🧠 Perception of ambiguous motion is shaped by recent visual experience - but does this differ across the visual field?
Yes!
Full open access paper here (Gastrell et al., 2025, Journal of Vision): 🔗 doi.org/10.1167/jov....
🧵
Reposted by Tim Gastrell
*Please repost* @sjgreenwood.bsky.social and I just launched a new personalized feed (*please pin*) that we hope will become a "must use" for #academicsky. The feed shows posts about papers filtered by *your* follower network. It's become my default Bluesky experience bsky.app/profile/pape...
March 10, 2025 at 6:14 PM
*Please repost* @sjgreenwood.bsky.social and I just launched a new personalized feed (*please pin*) that we hope will become a "must use" for #academicsky. The feed shows posts about papers filtered by *your* follower network. It's become my default Bluesky experience bsky.app/profile/pape...
Reposted by Tim Gastrell
William James's take on psychophysics is *incredible*. Worth reading the whole quote. #psychSciSky #philsky #VisionScience
"But psychology is passing into a less simple phase. Within a few years what one may call a microscopic psychology has arisen in Germany, carried on by experimental methods,
"But psychology is passing into a less simple phase. Within a few years what one may call a microscopic psychology has arisen in Germany, carried on by experimental methods,
March 17, 2025 at 6:19 PM
William James's take on psychophysics is *incredible*. Worth reading the whole quote. #psychSciSky #philsky #VisionScience
"But psychology is passing into a less simple phase. Within a few years what one may call a microscopic psychology has arisen in Germany, carried on by experimental methods,
"But psychology is passing into a less simple phase. Within a few years what one may call a microscopic psychology has arisen in Germany, carried on by experimental methods,
Reposted by Tim Gastrell
Out now in AP&P!
Effects of perceptual and decisional uncertainty on serial dependence in orientation perception
link.springer.com/article/10.3...
link.springer.com/article/10.3...
Effects of perceptual and decisional uncertainty on serial dependence in orientation perception - Attention, Perception, & Psychophysics
Where assimilative serial dependence occurs in perception, responses to visual attributes such as orientation are typically biased towards the attributes of visual stimuli seen in the recent past. Ser...
link.springer.com
March 8, 2025 at 2:20 AM
Out now in AP&P!
Reposted by Tim Gastrell
Cognitive psych is often traced back to the 1950s.
Psychology is often traced to Wundt's lab in 1879.
Textbooks speak of "proto-psychologists" like Fechner & Helmholtz in the 1800s... Westerners all.
Have you heard about Ibn al-Haytham, whose work predated them by 100s of years?
1/4
Psychology is often traced to Wundt's lab in 1879.
Textbooks speak of "proto-psychologists" like Fechner & Helmholtz in the 1800s... Westerners all.
Have you heard about Ibn al-Haytham, whose work predated them by 100s of years?
1/4
January 31, 2025 at 9:55 AM
Cognitive psych is often traced back to the 1950s.
Psychology is often traced to Wundt's lab in 1879.
Textbooks speak of "proto-psychologists" like Fechner & Helmholtz in the 1800s... Westerners all.
Have you heard about Ibn al-Haytham, whose work predated them by 100s of years?
1/4
Psychology is often traced to Wundt's lab in 1879.
Textbooks speak of "proto-psychologists" like Fechner & Helmholtz in the 1800s... Westerners all.
Have you heard about Ibn al-Haytham, whose work predated them by 100s of years?
1/4
Reposted by Tim Gastrell
Excited to share my first paper: a novel visual illusion discovered by my co-authors Will Turner and Hinze Hogendoorn which we call the "Split-Stimulus Effect", in which a single flashed stimulus is perceived to be in two different locations simultaneously jov.arvojournals.org/article.aspx... [1/5]
Concurrent perception of competing predictions: A “split-stimulus effect” | JOV | ARVO Journals
jov.arvojournals.org
November 16, 2024 at 2:14 AM
Excited to share my first paper: a novel visual illusion discovered by my co-authors Will Turner and Hinze Hogendoorn which we call the "Split-Stimulus Effect", in which a single flashed stimulus is perceived to be in two different locations simultaneously jov.arvojournals.org/article.aspx... [1/5]
Reposted by Tim Gastrell
New from my lab: "Priors for natural image statistics inform confidence in perceptual decisions"
We used a natural image statistics approach to investigate the computations underlying perceptual confidence. 🧵
Article: www.sciencedirect.com/science/arti...
We used a natural image statistics approach to investigate the computations underlying perceptual confidence. 🧵
Article: www.sciencedirect.com/science/arti...
January 29, 2025 at 2:57 AM
New from my lab: "Priors for natural image statistics inform confidence in perceptual decisions"
We used a natural image statistics approach to investigate the computations underlying perceptual confidence. 🧵
Article: www.sciencedirect.com/science/arti...
We used a natural image statistics approach to investigate the computations underlying perceptual confidence. 🧵
Article: www.sciencedirect.com/science/arti...
Reposted by Tim Gastrell
“The PhD stipend is $33,511 … well below minimum wage of $47,627”
“Universities can raise the stipend to a maximum of $52,352, but a ACGR survey found none have done so. The highest stipend is just over $40,000 … with the average at $34,244.”
#RaiseTheStipend
“Universities can raise the stipend to a maximum of $52,352, but a ACGR survey found none have done so. The highest stipend is just over $40,000 … with the average at $34,244.”
#RaiseTheStipend
PhD student Jesse Gardner-Russell earns $20 an hour. Experts say low pay is turning Australia’s best and brightest away
The University of Melbourne student whose work could contribute to curing blindness says ‘people are shocked to find out how unlivable it is’
www.theguardian.com
January 16, 2025 at 11:37 PM
“The PhD stipend is $33,511 … well below minimum wage of $47,627”
“Universities can raise the stipend to a maximum of $52,352, but a ACGR survey found none have done so. The highest stipend is just over $40,000 … with the average at $34,244.”
#RaiseTheStipend
“Universities can raise the stipend to a maximum of $52,352, but a ACGR survey found none have done so. The highest stipend is just over $40,000 … with the average at $34,244.”
#RaiseTheStipend
Reposted by Tim Gastrell
🖨️ Fresh off the press! www.sciencedirect.com/science/arti...
We have shown that the brain processes visual input differently as a function of display density, violating predictions of dominant cognitive control theories.
We have shown that the brain processes visual input differently as a function of display density, violating predictions of dominant cognitive control theories.
Prefrontal dimension change-related activation differs for visual search in sparse and dense displays
Changes of the target-defining feature dimension have previously been shown to elicit anterior prefrontal activation increases. In the majority of stu…
www.sciencedirect.com
January 6, 2025 at 10:59 PM
🖨️ Fresh off the press! www.sciencedirect.com/science/arti...
We have shown that the brain processes visual input differently as a function of display density, violating predictions of dominant cognitive control theories.
We have shown that the brain processes visual input differently as a function of display density, violating predictions of dominant cognitive control theories.
Reposted by Tim Gastrell
New results for a new year! “Linking neural population formatting to function” describes our modern take on an old question: how can we understand the contribution of a brain area to behavior?
www.biorxiv.org/content/10.1...
🧠👩🏻🔬🧪🧵
#neuroskyence
1/
www.biorxiv.org/content/10.1...
🧠👩🏻🔬🧪🧵
#neuroskyence
1/
Linking neural population formatting to function
Animals capable of complex behaviors tend to have more distinct brain areas than simpler organisms, and artificial networks that perform many tasks tend to self-organize into modules (1-3). This sugge...
www.biorxiv.org
January 4, 2025 at 4:25 PM
New results for a new year! “Linking neural population formatting to function” describes our modern take on an old question: how can we understand the contribution of a brain area to behavior?
www.biorxiv.org/content/10.1...
🧠👩🏻🔬🧪🧵
#neuroskyence
1/
www.biorxiv.org/content/10.1...
🧠👩🏻🔬🧪🧵
#neuroskyence
1/
Reposted by Tim Gastrell
Conscious awareness, sensory integration, and evidence accumulation in bodily self-perception: http://osf.io/e6tdy/
January 1, 2025 at 1:10 AM
Conscious awareness, sensory integration, and evidence accumulation in bodily self-perception: http://osf.io/e6tdy/
Reposted by Tim Gastrell
"The Illusion-Illusion: Vision Language Models See
Illusions Where There are None"
osf.io/preprints/ps...
(this is a more systematic examination of the thing I was looking at a few days ago)
Illusions Where There are None"
osf.io/preprints/ps...
(this is a more systematic examination of the thing I was looking at a few days ago)
December 19, 2024 at 1:40 PM
"The Illusion-Illusion: Vision Language Models See
Illusions Where There are None"
osf.io/preprints/ps...
(this is a more systematic examination of the thing I was looking at a few days ago)
Illusions Where There are None"
osf.io/preprints/ps...
(this is a more systematic examination of the thing I was looking at a few days ago)
Reposted by Tim Gastrell
Reposted by Tim Gastrell
OK If we are moving to Bluesky I am rescuing my favourite ever twitter thread (Jan 2019).
The renamed:
Bluesky-sized history of neuroscience (biased by my interests)
The renamed:
Bluesky-sized history of neuroscience (biased by my interests)
December 1, 2024 at 8:29 PM
OK If we are moving to Bluesky I am rescuing my favourite ever twitter thread (Jan 2019).
The renamed:
Bluesky-sized history of neuroscience (biased by my interests)
The renamed:
Bluesky-sized history of neuroscience (biased by my interests)
An absolute pleasure to present some new data at ACNS 2024 in (mostly) sunny Newcastle. Here we showed that human observers judgements of simple motion stimuli broadly follow precision-weighted inference principles. @acnsau.bsky.social
November 30, 2024 at 6:42 AM
An absolute pleasure to present some new data at ACNS 2024 in (mostly) sunny Newcastle. Here we showed that human observers judgements of simple motion stimuli broadly follow precision-weighted inference principles. @acnsau.bsky.social