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spring 2018 Colloquia

Tuesdays – 11:30 am – Elliott N639

Next Up ...

Abril 17

Kendrick Kay (Kay Lab)

"The HCP 7T Retinotopy Dataset"
One of the datasets collected by the Human Connectome Project (HCP) involved ultra-high-field (7 Tesla) fMRI retinotopic mapping in 181 healthy adults (1.6-mm resolution). This is the largest freely available collection of retinotopy data. In this talk, I will describe the experimental paradigm that we designed and the results of model-based analysis of the fMRI data. Both the group-average and individual-subject results reveal robust signals across much of the brain, including occipital, temporal, parietal, and frontal cortex as well as subcortical areas. The data and model solutions that we provide allow studying fine-scale individual variability in cortical and subcortical organization, and can be combined with other HCP measures acquired in these same participants.

 

Previously ...

 

 

January 23

Yingchen He (Legge Lab)

"Electrically-elicited brain responses in visual prosthesis users."

 

 

 

Sheng He

 

 

January 30

Sheng He

 

 

 

February 6

Dustin Alfonso Chacón, Linguistics

"Agreeing to Disagree: Encoding and Memory Retrieval in Language Perception"

Abstract:
One of the major issues in sentence processing is the nature of "grammatical illusions", i.e., sentences that are perceived as acceptable at first blush, but later perceived as unacceptable. For instance, the agreement error in (1) is immediately noticeable, as measured in judgment studies and reading-time studies, but the same agreement error in (2) often goes unnoticed. This phenomenon is known as "agreement attraction", because the distractor plural noun (cabinets) appears to erroneously license the plural verb (are), even though it is not the main subject noun.

(1) the key to the cabinet are rusty from years of disuse

(2) the key to the cabinets are rusty from years of disuse

Some theories hold that agreement attraction illusions arise because the cognitive systems used to encode grammatical representations are lossy (e.g., Solomon & Pearlmutter 2004; Eberhard, Cutting, & Bock 2005), whereas other theories attribute the effect to a misretrieval of the distractor noun (cabinets) at the offending verb (are) (Wagers, Lau, & Phillips 2009; Dillon, Mishler, Sloggett, Phillips 2013). In three experiments, I investigate the processing of agreement errors with sentences with subject clauses (e.g., [That the doctors studied long and hard] are a relief to the nervous patients) in comparison with sentences with noun subjects (e.g., [The fact that the doctors studied long and hard] are a relief to the nervous patients). This comparison is theoretically interesting, because the agreement relation is claimed to only be represented in with noun phrase subjects in syntactic theory (McCloskey 1991). I found that the distractor plural noun (doctors) facilitates reading times at the offending verb (are) regardless of whether the subject is a clause or a noun phrase. However, improved ratings are only observed for sentences with noun phrase subjects, i.e., sentences with "real" agreement (McCloskey 1991). To explain this contrast, I argue that initially, participants misretrieve the distractor plural noun regardless of the sentence type, easing processing. However, this misretrieval only translates into a perception of acceptability when an agreement relation was anticipated. I also argue that these results are less compatible with noisy encoding theories.

 

 

February 13

Tatyana Matveeva, Psychology

"Transmembrane protein 35 (TMEM35) modulates pain and drug-seeking behavior"

Abstract:
Previously we have shown that TMEM35 (NACHO) KO mice exhibit heightened pain sensitivity. Given the comorbidity of pain and drug-seeking behavior, the present study investigated whether TMEM35 KO mice also show increased risk for drug seeking behavior. To test this, we examined conditioned place preference (CPP) for morphine and nicotine in separate experiments. TMEM35 KO mice exhibited significantly stronger CPP for both morphine and nicotine than WT controls. For morphine, there was a main effect of genotype and conditioning context, and a significant genotype X context interaction, revealing that the effect of morphine on CPP was greater in the KO animals.

Similarly, TMEM35 KO mice showed a significant increase in preference for the nicotine-paired context compared to pre-test, while WT animals showed no change in preference for the drug-paired side. Additionally, antagonists specific to distinct subunits of the nicotinic cholinergic receptor administered prior to nicotine injections rescued the observed phenotype. Together, these results provide strong evidence implicating TMEM35 in drug-seeking behavior. Given a recent finding implicating TMEM35 in the expression of functional nicotinic acetylcholine receptors (nAchRs), these behavioral effects in TMEM35KO mice may be associated with the reduced expression of nAchRs. Contrary to a previous report showing a complete loss of a7 expression in TMEM35 KO mice, we report residual a7 expression in KO mouse brain, suggesting alternative mechanisms underpinning these drug-seeking behaviors. Additional preliminary data will also be discussed.

 

February 20

Douglas Addleman and Alexander Bratch, Kersten Lab, Psychology

"Perception of Human Bodies in Natural Images"

Abstract:
Detecting, identifying, and interpreting features of human bodies are basic visual functions that occur under a wide range of variability in appearances, in particular those resulting from pose variability, blur, and occlusion. We will provide an overview of several ongoing projects in our lab investigating the limits and abilities of human visual perception of human bodies. Data from psychophysics using low-resolution natural images, computational models for body pose representations, and fMRI of body part perception will be discussed.

 

February 27 - Yijun Ge (He Lab)

"From the Flash-Grab Illusion to the Tilt Aftereffect: Adaptation to Feedback Signals in the Brain"

Abstract:
Neurons adapt, adjusting their sensitivity, based on the ambient stimulus level. Given the abundance of feedback signals in the brain, we ask whether neurons also adjust their sensitivity based on feedback signals. The Tilt Aftereffect (TAE) results from adaptation of orientation-selective neurons. We used an illusion - The Flash-Grab Effect (FGE) to disassociate the physical and perceived orientation of adaptor, to investigate whether feedback signals contribute to the tilt aftereffect, and their interaction with feed forward signals. Psychophysical results showed that a physically vertical but perceptually tilted bar generated a significant TAE on a vertical test bar; In contrast, when the perceived orientation of the adapting bar was adjusted to be vertical but physically tilted, no TAE was observed on a vertical test bar. Thus TAE is mainly dependent on the perceived rather than the physical orientation of the adapting bar. We further investigated the neural representation of FGE using fMRI and EEG and demonstrated that the perceived orientation of the flashed bar in FGE was mainly supported by feedback signals in the cortex. Together these findings show that top-down modulation is critical in orientation selective adaptation. Therefore, neurons do adapt to feedback signals in the brain."

 

March 6

Dr. Peggy Nelson, Speech, Language and Hearing Sciences

"Evaluation of self-fitted hearing technology"

Abstract
Assistive technology for persons with hearing loss has made good strides in recent years, but adoption and satisfaction with technology is less than ideal. In this study we evaluate a method of user self-adjustment of hearing aids, and discuss methods for evaluating its possible success. Outcomes from the current study indicate that users choose amplification parameters that are quite different from those selected by conventional audiological methods. Behavioral and functional outcome measures of hearing technology will be discussed, including social engagement and quality of life.

 

 

Spring Break

March 13 - Spring Break (No colloquium)

 

 

 

Caitlin Sisk

 

March 20

Caitlin Sisk, Jiang Lab

"Unimpaired habit-guided spatial attention in patients with Parkinson's Disease"

Abstract:
Cognitive deficits in Parkinson's Disease (PD) are commonly explained in terms of a selective deficit in habit learning. Contrary to this view, here we show that Parkinson's patients are unimpaired in habit-guided spatial attention. Parkinson's patients and age-matched controls completed a difficult visual search task in two sessions. In Session 1, unbeknownst to the participants, the target appeared most often in one quadrant in an early, training phase of the experiment and was randomly located in a later, testing phase. Both healthy controls and Parkinson's patients acquired an attentional preference toward the high probability quadrant during training that persisted in the testing phase. In Session 2, administered several days later, the target's high-probability quadrant changed. Both groups acquired a new preference for Session 2's high-probability quadrant, demonstrating reversal learning. These findings contrast with previously observed deficits in PD in acquiring probabilistic learning and contextual cueing. This suggests that not all habit learning depends on the basal ganglia and the dopaminergic system. Instead, preservation of habit-guided spatial attention may compensate for other types of attentional deficits in PD. This study elucidates the need for a better taxonomy of habit learning.

 

Juergen KonczakMarch 27

Jürgen Konczak

"Proprioception - the silent sense: What happens, if it is no longer there?"

Abstract: Proprioception refers to one’s sense of the position and motion of body parts relative to each other and to the force or effort related to produce a movement or to hold a specific posture. Sherrington coined this term in 1906 to refer to information derived from mechanoreceptors embedded in tendons, muscles and articular tissue. Proprioceptive afferents together with vestibular inputs give rise to our perception of our body and limbs in space. Conversely, partial or complete loss of proprioceptive information has grave consequences for the control of muscle tone, posture and movement. I will illustrate what happens if someone experiences complete or partial loss of proprioception by referring to classic clinical studies and by showing data from our own work in patients with dystonia, Parkinson’s disease and cortical stroke.

 

April 3

Nori Jacoby, Columbia University (hosted by Oxenham Lab)

"Cross-cultural similarities and differences in musical pitch representations"

Abstract
The use of pitch in Western music is marked by three defining characteristics. First, pitch intervals expressed on a logarithmic scale are heard as equivalent irrespective of the register. Second, individual pitches separated by octaves are heard as musically equivalent. Third, music is composed of pitches from a finite range, beyond which pitch abilities deteriorate. Because pitch representations have not been studied in nonwestern cultures, it has remained unclear whether these aspects of pitch perception inevitably result from nonmusical constraints (e.g. acoustics and the biology of the auditory system), and/or whether they depend on experience with Western music. We tested members of a small-scale society from the Bolivian Amazon (the Tsimane’), who live in relative isolation from Western culture and music (McDermott et al. 2016). We developed a new paradigm to probe pitch representations that can be efficiently used across cultures: participants were asked to sing back a melody comprised of two pure tones. We manipulated the pitch register of the tones and the interval between them, and measured the reproduced interval. Reproduced intervals of both Amazonian and US participants approximately replicated the heard intervals in semitones, even for tones well beyond the singing range. Moreover, Amazonian reproductions showed the same dependence on frequency evident in US listeners, breaking down in accuracy for very high frequency tones. However, whereas US participants sung back pitches that reproduced the chroma of the heard tones, Amazonians did not, ignoring the chroma class of the tones. The findings are consistent with the cross-cultural presence of a logarithmic scale for pitch, and with biological constraints on the upper limit of pitch, but suggest that octave equivalence is culturally contingent, potentially resulting from experience with musical harmony.

 

April 10

Geoffrey Ghose