Create accountLogin

Recent searches

No recent searches

Search options

Only available when logged in.
mas.to is one of the many independent Mastodon servers you can use to participate in the fediverse.
Hello! mas.to is a fast, up-to-date and fun Mastodon server.

Administered by:

Server stats:

13K
active users

mas.to: AboutStatusProfiles directoryPrivacy policy

Mastodon: AboutGet the appKeyboard shortcutsView source codev4.3.7

Public
Meredith Schmehl, PhD

New preprint with @jmgrohneuro and more! Neurons in several visual areas show fluctuating responses in the presence of multiple objects. An important general finding with potential connections to object formation!

doi.org/10.1101/2023.07.19.549

Thread: 🧵 👇

1/10

#Neuroscience#NeuroMastodon#NeuroMigration
Public
Meredith Schmehl, PhD

In a previous eLife paper (doi.org/10.7554/eLife.76452), we showed that neurons in V1 and V4 fluctuate (across trials) between responding to each of two gratings when both were presented adjacently. But when two gratings overlapped to form a plaid, neurons in V1 did not fluctuate.

2/10

Screenshot of scientific figures showing a statistical method that separates neural responses into four categories, one of which is called mixture and indicates fluctuating activity when two stimuli are presented simultaneously. Results are shown for situations in which stimuli are presented adjacent to one another or overlapping in space, showing a high proportion of mixture or fluctuating responses in the adjacent case but not in the overlapping case.
Public
Meredith Schmehl, PhD

Here (doi.org/10.1101/2023.07.19.549) we expand to new brain areas and stimulus types. We wondered:

1. Are fluctuations widespread in the visual pathway?
2. Do they occur only when two stimuli are distinct?
3. Do they depend on the type of stimulus a brain area is specialized for?

3/10

Public *
Meredith Schmehl, PhD

We explored these questions in several datasets recorded by the labs of Marlene Cohen, Winrich Freiwald, and Stefan Treue, using a custom analysis method we previously published (doi.org/10.1038/s41467-018-051).

4/10

Public
Meredith Schmehl, PhD

We studied the relationship between the responses to two stimuli together (AB) vs. the two stimuli individually (A or B), looking for AB responses that fluctuated between A and B ("mixtures").

5/10

Screenshot of scientific figures showing a statistical method that separates neural responses into four categories, one of which is called mixture and indicates fluctuating activity when two stimuli are presented simultaneously.
Meredith Schmehl, PhD

First, we found evidence for fluctuating activity in visual area MT. Like in V1, neurons in MT only fluctuate when stimuli form distinct objects (two gratings) and not when they fuse into one object (gratings overlaid to form a plaid).

6/10

Screenshot of scientific figures. On the left are the responses of one example neuron in visual area MT, showing that when two stimuli are presented simultaneously, the neuron fluctuates between responses that match either of the two individual stimuli. On the right is a population summary showing that these fluctuating patterns are far more likely to occur when two stimuli are perceptually distinct than when they fuse to form a single object.
Jul 24, 2023, 05:30 PM·Public
0boosts·0favorites
Public
Meredith Schmehl, PhD

Second, we expanded our study to the face patch system to determine whether these fluctuations depend on the type of stimulus a brain area is specialized for. We found that both face-face and face-object pairs elicited fluctuating activity in face patches MF and AL.

7/10

Screenshot of scientific figures. Four subpanels show the responses of example neurons in visual areas MF and AL for pairs of two faces or pairs of one face and one non-face object, showing that in all combinations the neurons fluctuate between responses that match either of the two individual stimuli.
Public
Meredith Schmehl, PhD

However, fluctuations were more prevalent in AL, which is thought to be "later" in the face patch hierarchy than MF - lending support to the idea that fluctuations may vary by stage of visual processing.

8/10

Screenshot of a scientific figure showing population results of the proportion of fluctuating responses across both brain areas MF and AL, and both face-face and face-object stimulus pairs. The proportion of fluctuating responses is larger for all combinations in AL than in MF, and is larger for MF face-face pairs than for MF face-object pairs.
Public
Meredith Schmehl, PhD

Overall, our work expands the range of brain areas and stimulus conditions in which we have observed fluctuating activity, identifying a potential neural correlate of information preservation and object formation.

9/10

Public
Meredith Schmehl, PhD

Thanks to all the coauthors for their collaboration on this work! It's been fun to work on this important finding alongside my work on these fluctuations in audiovisual contexts!

doi.org/10.1101/2023.07.19.549

10/10

ExploreLive feeds
About